Characterizing the Genomic Landscape of the Micropapillary Subtype of Urothelial Carcinoma of the Bladder Harboring Activating Extracellular Mutations of ERBB2

The micropapillary subtype of urothelial carcinoma (MPUC) of the bladder is a very aggressive histological variant of urothelial bladder cancer (UBC). A high frequency of MPUC contains activating mutations in the extracellular domain (ECD) of ERBB2. We sought to further characterize ERBB2 ECD-mutated MPUC to identify additional genomic alterations that have been associated with tumor progression and therapeutic response. In total, 5,485 cases of archived formalin-fixed, paraffin-embedded UBC underwent comprehensive genomic profiling to identify ERBB2 ECD-mutated MPUC and evaluate the frequencies of genomic co-alterations. We identified 219 cases of UBC with ERBB2 ECD mutations (74% S310F and 26% S310Y), of which 63 (28.8%) were MPUC. Genomic analysis revealed that TERT, TP53, and ARID1A were the most common co-altered genes in ERBB2-mutant MPUC (82.5%, 58.7%, and 39.7%, respectively) and did not differ from ERBB2-mutant non-MPUC (86.5%, 51.9%, and 35.3%). The main differences between ERBB2 ECD-mutated MPUC compared with non-MPUC were KMT2D, RB1, and MTAP alterations. KMT2D and RB1 are tumor-suppressor genes. KMT2D frequency was significantly decreased in ERBB2 ECD-mutated MPUC (6.3%) in contrast to non-MPUC (27.6%; P < .001). RB1 mutations were more frequent in ERBB2 ECD-mutated MPUC (33.3%) than in non-MPUC (17.3%; P = .012). Finally, MTAP loss, an emerging biomarker for new synthetic lethality-based anticancer drugs, was less frequent in ERBB2 ECD-mutated MPUC (11.1%) than in non-MPUC (26.9%; P = .018). Characterizing the genomic landscape of MPUC may not only improve our fundamental knowledge about this aggressive morphological variant of UBC but also has the potential to identify possible prognostic and predictive biomarkers that may drive tumor progression and dictate treatment response to therapeutic approaches.

First analysis of the safety and efficacy of UGN-101 in the treatment of ureteral tumors

OBJECTIVE

UGN-101 has been approved for the chemoablation of low-grade upper tract urothelial cancer (UTUC) involving the renal pelvis and calyces. Herein is the first reported cohort of patients with ureteral tumors treated with UGN-101.

PATIENTS AND METHODS

We performed a retrospective review of patients treated with UGN-101 for UTUC at 15 high-volume academic and community centers focusing on outcomes of patients treated for ureteral disease. Patients received UGN-101 with either adjuvant or chemo-ablative intent. Response rates are reported for patients receiving chemo-ablative intent. Adverse outcomes were characterized with a focus on the rate of ureteral stenosis.

RESULTS

In a cohort of 132 patients and 136 renal units, 47 cases had tumor involvement of the ureter, with 12 cases of ureteral tumor only (8.8%) and 35 cases of ureteral plus renal pelvic tumors (25.7%). Of the 23 patients with ureteral involvement who received UGN-101 induction with chemo-ablative intent, the complete response was 47.8%, which did not differ significantly from outcomes in patients without ureteral involvement. Fourteen patients (37.8%) with ureteral tumors had significant ureteral stenosis at first post-treatment evaluation, however, when excluding those with pre-existing hydronephrosis or ureteral stenosis, only 5.4% of patients developed new clinically significant stenosis.

CONCLUSIONS

UGN-101 appears to be safe and may have similar efficacy in treating low-grade urothelial carcinoma of the ureter as compared to renal pelvic tumors.

Genomic Profiles and Clinical Outcomes of Penile Squamous Cell Carcinoma With Elevated Tumor Mutational Burden

Importance

Tumor mutational burden (TMB) is a putative biomarker of efficacy for immune checkpoint inhibitor (ICI) therapies of solid tumors, but not specifically for penile squamous cell carcinoma (PSCC).

Objective

To characterize biomarker features and ICI therapy outcomes associated with high TMB in PSCC in the routine clinical practice setting.

Design, Setting, and Participants

In this cohort study, 397 PSCC cases were analyzed to identify genomic alterations in more than 300 cancer-associated genes and genomic signatures, including TMB, using a hybrid capture-based comprehensive genomic profiling assay. Tumor mutational burden was categorized as low (<10 mutations per megabase [mut/Mb]), high (10-19 mut/Mb), or very high (≥20 mut/Mb). Germline status of genetic alterations was predicted using a validated somatic-germline computational method. Clinical outcomes of patients with metastatic PSCC receiving first-line ICI were abstracted using the deidentified nationwide Clinico-Genomic Database (CGDB) from January 1, 2011, through December 31, 2022.

Exposure

Comprehensive genomic profiling was performed using FoundationOne and FoundationOne CDx assays from Foundation Medicine Inc.

Main outcomes and measures

The spectrum of genetic alterations by TMB level in PSCC, the percentage of germline genetic alterations, and the outcome (overall survival with routine clinical treatment) by TMB of chemotherapy-naive patients with PSCC who received ICI treatment up front were assessed in this descriptive study.

Results

Among 397 patients (median [IQR] age, 65 [54-73] years; 266 [67.0%] of European, 83 [20.9%] of admixed American, and 34 [8.5%] of African or other genomic ancestry), the median (IQR) age (eg, 65 [53-73] years for low TMB vs 68 [61-78] years for TMB ≥10 mut/Mb) and genomic ancestry distribution (eg, European 228 of 339 [67.3%] for low TMB vs 38 of 58 [65.5%] for TMB ≥10 mut/Mb) were similar between TMB subgroups. There were 339 PSCC cases (85.4%) with low TMB, 40 cases (10.1%) with high TMB, and 18 cases (4.5%) with very high TMB. Comparisons of TMB of 10 mut/Mb or higher vs low TMB showed an enrichment of genetic alterations in PIK3CA (48.3% vs 18.3%; P < .001) and KMT2D (29.3% vs 7.7%; P < .001) and less frequent genetic alterations in CDKN2A (25.9% vs 45.7%; P = .05). Most genetic alterations did not co-occur. Human papillomavirus identification was more frequent as TMB increased: 28.3% for low TMB, 50.0% for high, and 72.2% for very high. In total, 95 of 1377 genetic alterations (6.9%) were germline. Of 10 patients identified from the CGDB receiving frontline ICIs, median (IQR) follow-up was 9.9 months. Four patients had overall survival with clinical treatment of more than 12 months, including 2 of 3 patients with TMB of 10 mut/Mb or higher.

Conclusions and Relevance

In this cohort study of advanced metastatic PSCC based on TMB levels, significant differences were observed for biomarkers in nearly 15% of patients with a TMB of 10 mut/Mb or higher. Germline testing and ICI-based therapy should be integrated into the management of selected PSCC cases.

Disparities Associated with Shared Decision-making in Prostate Cancer Screening

BACKGROUND

Prostate cancer screening guidelines recommend shared decision-making (SDM) regarding prostate-specific antigen (PSA) testing. However, it is unclear who undergoes SDM and whether any disparities exist.

OBJECTIVE

To examine sociodemographic differences in participation of SDM and its association with PSA testing in prostate cancer screening.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cross-sectional study was conducted among men aged 45-75 yr undergoing PSA screening, using the 2018 National Health Interview Survey database. The evaluated sociodemographic features included age, race, marital status, sexual orientation, smoking status, working status, financial difficulty, US geographic regions, and cancer history. Questions regarding self-reported PSA testing and whether respondents discussed its advantages and disadvantages with their healthcare provider were analyzed.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Our primary outcome was to evaluate the possible associations between various sociodemographic factors and undergoing PSA screening and SDM. We used multivariable logistic regression analyses to detect potential associations.

RESULTS AND LIMITATIONS

A total of 59596 men were identified, of whom 5605 answered the question regarding PSA testing, with 2288 (40.6%) undergoing PSA testing. Of these men, 39.5% (n = 2226) discussed the advantages and 25.6% (n = 1434) discussed the disadvantages of PSA testing. On a multivariable analysis, older (odds ratio [OR] 1.092; 95% confidence interval [CI] 1.081-1.103, p < 0.001) and married (OR 1.488; 95% CI 1.287-1.720, p < 0.001) men were more likely to undergo PSA testing. Although Black men were more likely to discuss PSA advantages (OR 1.421; 95% CI 1.150-1.756, p = 0.001) and disadvantages (OR 1.554; 95% CI 1.240-1.947, p < 0.001) than White men, this did not correlate with higher rates of PSA screening (OR 1.086; 95% CI 0.865-1.364, p = 0.477). The lack of important clinical data remains a limitation.

CONCLUSIONS

Overall, SDM rates were low. Older and married men had an increased likelihood of SDM and PSA testing. Despite higher rates of SDM, Black men had similar rates of PSA testing to White men.

PATIENT SUMMARY

We evaluated sociodemographic differences in shared decision-making (SDM) in prostate cancer screening using a large national database. We found that SDM had varying results in different sociodemographic groups.

Comparative Genomic Landscape of Urothelial Carcinoma of the Bladder Among Patients of East and South Asian Genomic Ancestry

BACKGROUND

Despite the low rate of urothelial carcinoma of the bladder (UCB) in patients of South Asian (SAS) and East Asian (EAS) descent, they make up a significant portion of the cases worldwide. Nevertheless, these patients are largely under-represented in clinical trials. We queried whether UCB arising in patients with SAS and EAS ancestry would have unique genomic features compared to the global cohort.

METHODS

Formalin-fixed, paraffin-embedded tissue was obtained for 8728 patients with advanced UCB. DNA was extracted and comprehensive genomic profiling was performed. Ancestry was classified using a proprietary calculation algorithm. Genomic alterations (GAs) were determined using a 324-gene hybrid-capture-based method which also calculates tumor mutational burden (TMB) and determines microsatellite status (MSI).

RESULTS

Of the cohort, 7447 (85.3%) were EUR, 541 (6.2%) were AFR, 461 (5.3%) were of AMR, 74 (0.85%) were SAS, and 205 (2.3%) were EAS. When compared with EUR, TERT GAs were less frequent in SAS (58.1% vs. 73.6%; P = .06). When compared with non-SAS, SAS had less frequent GAs in FGFR3 (9.5% vs. 18.5%, P = .25). TERT promoter mutations were significantly less frequent in EAS compared to non-EAS (54.1% vs. 72.9%; P < .001). When compared with the non-EAS, PIK3CA alterations were significantly less common in EAS (12.7% vs. 22.1%, P = .005). The mean TMB was significantly lower in EAS vs. non-EAS (8.53 vs. 10.02; P = .05).

CONCLUSIONS

The results from this comprehensive genomic analysis of UCB provide important insight into the possible differences in the genomic landscape in a population level. These hypothesis-generating findings require external validation and should support the inclusion of more diverse patient populations in clinical trials.

Extracellular domain ERBB2 (ERBB2 ECD+) mutations in urothelial bladder cancer (UBC)

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Background: Given the recent approval in lung cancer for the first anti-HER2 targeted therapy directed against activating kinase domain exon 20 ERBB2 insertion mutations, considerable interest has arisen in targeting additional locations in the ERBB2 gene in other tumor types. Methods: 5,485 UBC samples were sequenced using a hybrid capture-based comprehensive genomic profiling (CGP) assay to assess all classes of genomic alterations (GA), tumor mutational burden (TMB), microsatellite instability (MSI), genomic loss of heterozygosity (gLOH), trinucleotide signatures and predominant genetic ancestry. Statistical comparisons utilized the Bonferroni correction. Results: 548 (10.0%) of UBC featured ERBB2 gene amplification (amp) and 219 (4.0%) featured an ERBB2 ECD+ sequence mutation (74% S310F and 26% S310Y). ERBB2 ECD+ mutations and ERBB2 amplification were mutually exclusive. 16.4% of ERBB2 ECD+ UBC had more than one E RBB2 sequence mutation. Central pathology review of the 219 ERBB2 ECD+ UBC revealed that 63 (28.8%) featured a micropapillary histologic appearance (MPUC). ERBB2 ECD+ UBC featured more patients with European ancestry than both ERBB2 WT (90.9% vs 84.2%; p=.03) and ERBB2 amp (90.9% vs 83.2%; p=.04). ECD mut+ UBC also featured lower association with African ancestry than ERBB2 amp (2.7% vs 7.8%; p=.04) and lower frequency of gLOH > 16% (9.3% vs 19.1%; p=.04). MSI-High status was similar and rare in all 3 groups (range 0 to 0.9%). ERBB2 ECD+ UBC had a higher frequency of APOBEC signature than ERBB2 amp (82.9% vs 72.4%; p=.03). TMB > 10 mut/mb was higher in ERBB2 amp (49.2% vs 31.4%; p<.0001) and ERBB2 ECD+ (59.8% vs 31.4%; p<.0001) compared to ERBB2 WT as was the mean TMB (11.8 and 17.4 mut/Mb respectively vs 8.9 mut/Mb, p<0.001 for both). Among important UBC individual genes, FGFR3 GA were significantly higher in ERBB2 WT than both ERBB2 amp (19.9% vs 6.2%; p<.0001) and ERBB2 ECD+ (19.9% vs 10.5%; p=.0002). CDKN2A GA were significantly higher in ERBB2 amp (39.1% vs 27.9% ERBB2 WT; p<.0001) only. The higher frequency of KMT2D GA in MPUC+ ECD+ and MPUC- ECD+ UBC (63.4% vs 27.6%; p=.02) was the only genomic difference between these cohorts. Conclusions: ERBB2 ECD mutation driven UBC is a unique form of UBC featuring enrichment of MPUC histology and a unique clinical and genomic landscape including genomic signatures and ancestry.

Single and multi-hit PIK3CA short variant (SV) genomic alterations (GA) in clinically advanced prostate cancer (CAPC): A genomic landscape study

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Background: Tumors harboring 2 or more PIK3CA Short variants (SV) (“Multi-hit”) have been described in breast cancer as linked to enhanced clinical outcome from anti-PIK3CA targeted therapies including alpelisib and investigational agents in clinical trials. The landscape and clinical implications of multi-hit PIK3CA alterations in other tumors, including in CAPC, are underexplored. Methods: 19,978 CAPC samples underwent hybrid capture based comprehensive genomic profiling (CGP) to evaluate all classes of GA and determine tumor mutational burden (TMB), microsatellite instability (MSI), genomic ancestry, signature and loss of heterozygosity (gLOH). Tumor cell PD-L1 expression was determined by IHC (Dako 22C3). Results: 18,741 (93.8%) CAPC were PIK3CA wild type (WT), 1,155 (5.8%) featured a single PIK3CA SV and 82 (0.4%) featured multi-hit PIK3CA SVs. The median ages of CAPC patients with single hit (69.1 yrs) or multi-hit (68.7 yrs) PIK3CA SV were older than the PIK3CA WT (67.6 yrs) CAPC (p<.0001 for both). At 14.0%, African ancestry was more frequent in PIK3CA WT CAPC than in single-hit (10.4%; p=.001) and multi-hit (10.2%; not significant). Single-hit (81.4%; p<.0001) and multi-hit (85.2% p=.05) PIK3CA SV CAPC featured significantly more MMR trinucleotide genomic signatures than PIK3CA WT (64.8%). Single-hit (2.7%; p=.02) and multi-hit (5.8% p=.05) PIK3CA SV CAPC featured significantly more POLE trinucleotide genomic signatures than PIK3CA WT (0.4%). MSI high status was significantly more common in both PIK3CA single-hit (12.4% vs 2.5%; p<.0001) and multi-hit (35.4% vs 2.5%; p<.0001). Mean TMB was also significantly higher in single-hit PIK3CA (11.1 vs 3.5 mut/Mb; p<.0001) and multi-hit (42.9 vs 3.5 mut/Mb; p<.0001). Noteworthy differences in GA of potential importance for CAPC pts included significantly higher frequencies of GA in BRCA2 in multi-hit vs WT (18.3% vs 8.5%; p=.019), ATM in multi-hit vs WT (13.4% vs 5.6%; p=.02) and PTEN in single-hit vs WT (40.2% vs 30.1%; p<.0001) and lower frequencies of GA in CDK12 (3.6% vs 5.6%; p=.009) and SPOP (7.4% vs 9.8%; p=.012) in single-hit vs WT. There were no differences in gLOH or PD-L1 expression among the 3 groups. Conclusions: Although uncommon, the identification of multi-hit PIK3CA GA in CAPC highlights a potentially unique subtype of this disease that may be associated with enhanced responsiveness to anti-PIK3CA targeted therapy strategies.

CDH1-mutated clinically advanced urothelial bladder cancer (UBC): A genomic landscape and real-world clinical outcome study (RWCOS)

564

Background: CDH1 mutated UBCs are characterized by plasmacytoid histology and are associated with an aggressive clinical course at the time of diagnosis. Methods: Cohort 1: 6,676 clinically advanced UBC patients (pts) underwent comprehensive genomic profiling (CGP) to evaluate all classes of genomic alterations (GA), microsatellite instability (MSI), tumor mutational burden (TMB), and genomic loss of heterozygosity (gLOH, high ≥16%). Predominant genetic ancestry was determined using a SNP-based approach and classified as one of the 5 categories: African (AFR), European (EUR), Central and South American (AMR), South Asian (SAS), or East Asian (EAS). Cohort 2: 586 UBC pts underwent a RWCOS using the nationwide (US-based) de-identified Flatiron Health-Foundation Medicine urothelial clinico-genomic database (FH-FMI CGDB). The de-identified data originated from approximately 280 US cancer clinics (~800 sites of care) Jan 2011-Apr 2022. Differences in real-world progression-free survival (rwPFS) and overall survival (rwOS) were evaluated by Cox proportional hazard models. Results: Cohort 1: 217 (3.3%) of UBC had a CDH1 short variant (SV) mutation with 65.2% featuring plasmacytoid histology. When compared with CDH1 wild-type (WT) UBC, the CDH1-mutated UBC had similar age, gender, and genetic ancestry. The CDH1-mutated UBC featured a higher frequency of MSI (2.7% vs 0.8%; p=.002), mean TMB (14.8 vs 9.9 mut/Mb p<.0001), RB1 GA (52.5% vs 20.3%; p<.0001), PTEN GA (9.2% vs 4.3%; p=.006) and PIK3CA GA (29.5% vs 21.8%; p=.02), but less gLOH high (6.8% vs 15.9%; p=.009), CDKN2A loss (12.4% vs 38.3%; p<.0001), MTAP loss (10.1% vs 25.1%; p<.0001) and FGFR3 GA (9.7% vs 18.1%; p=.002). TP53 GA were similar (62.3% vs 60.3%). Cohort 2: 22 (3.7%) featured CDH1 mutations. Compared with the CDH1 WT pts, the age, gender, ethnicity and ECOG status were similar. Evaluation of the RWCOS showed that CDH1 mutation was associated with less favorable outcomes for 270 UBC pts treated with immune checkpoint inhibitors (ICPI) including rwPFS (2.8 vs 3.5 months; p=.096) and rwOS (3.3 vs 9.5 months; p=.03). Similar comparisons for 316 UBC pts treated with chemotherapy showed no significant adverse impact of CDH1 mutation status on either rwPFS (7.9 vs 6.2 months) and rwOS (13.4 vs 13.4 months). Conclusions: In addition to its classic association with plasmacytoid histology, CDH1-mutated UBC features a unique CGP pattern including higher MSI and TMB status and activating GA in the MTOR pathway while harboring a lower FGFR3 GA frequency. RWCOS further supports that CDH1 mutation predicts resistance to ICPI-based treatments but does not impact responsiveness to chemotherapy. These results further support that CGP has the potential to customize the treatment and improve outcomes for UBC patients based on the determination of their genomic signatures.

Landscape of genomic alterations (GA) in urothelial bladder carcinoma (UBC) in patients of East Asian and South Asian ancestry

567

Background: UBC is the 10th most common cancer worldwide, with more than 550,00 new cases annually (WHO, International Agency for Research on Cancer, 2020). Rates vary by regions of the world, explained in part by the fact that different genetic ancestries demonstrate varying germline genetics, environmental exposures, and social risk factors. Methods: 8,728 UBC samples underwent hybrid capture-based comprehensive genomic profiling (CGP) to determine all classes of genomic alterations (GA), microsatellite instability (MSI) status, tumor mutational burden (TMB), and genomic trinucleotide signature. Predominant genetic ancestry was determined using a SNP-based approach using an algorithm trained on the 1000 Genomes data (Connelly et al. AACR 2018). Ancestry was classified as one of the five following categories: African (AFR), European (EUR), Central and South American (AMR), South Asian (SAS), or East Asian (EAS). Results: Of the cohort, 7,447 (85.3%) were EUR, 541 (6.2%) were AFR, 461 (5.3%) were of AMR, 74 (0.85%) were SAS, and 205 (2.3%) were EAS. Age, gender, genomic signature distributions, and MSI status (range 0.9%-1.5%) were similar in all cohorts. The frequency of TMB >10 mutations/Megabase was similar in all cohorts (range 30.7%-39.1%) as was the median TMB (6.3 mutations/Megabase for all). At 67.6%, TP53 was the most frequent GA in SAS cohort. When compared with the non-SAS cohort, TERT GA were lower in the SAS cohort (58.1% vs 72.6%; p=0.06) as were GA in FGFR3 (9.5% vs 18.5%, p=0.25). In the EAS cohort, at 59.0%, GA in TP53 were the most common. TERT mutations were significantly lower in EAS compared to the non-EAS cohort (54.1% vs 72.9%; p <0.001). When compared with the non-EAS cohort, PIK3CA alterations were significantly less common in the EAS cohort (12.7% vs 22.1%, p =0.005). GA in FGFR3 were similar in the EAS and non-EAS cohorts (16.6% vs 18.4%). There were no significant differences in genomic landscapes identified between the EAS and SAS cohorts when directly compared to one another. Conclusions: The results from this comprehensive genomic analysis of UBC in East Asian and South Asian patients provides important insight into the unique differences in the genomic landscapes that exist on a population level. These findings should motivate future investigators to include more diverse patient populations in clinical trials of targeted agents and immunotherapy strategies.

Penile squamous cell carcinoma (PSCC) with elevated tumor mutational burden (TMB): A genomic landscape study

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Background: TMB has emerged as a major biomarker of efficacy in immune checkpoint inhibitor (ICPI) therapies in the neoadjuvant, adjuvant and metastatic disease setting in a wide variety of malignancies, but not in PSCC. Methods: 397 clinically advanced (local major recurrence and/or metastatic disease) PSCC underwent hybrid capture-based comprehensive genomic profiling (CGP) to evaluate all classes of genomic alterations (GA). Tumor mutational burden (TMB) was determined on up to 1.1 Mb of sequenced DNA and microsatellite instability (MSI) was determined on up to 114 loci. Trinucleotide mutation signatures were evaluated (Alexandrov, et al. 2013). Genome-wide loss of heterozygosity (gLOH) was determined using validated pipelines and excluding whole-arm and whole-chromosome events. TMB was categorized into three cohorts: <10 mutations/Megabase [muts/Mb] (low), 10-19 muts/Mb (high), and >20 muts/Mb (very high). Tumor cell PD-L1 expression was determined by IHC (Dako 22C3) and defined as tumor proportion score (TPS) >1. The presence of HPV16/18 was determined by next generation sequencing (NGS). Statistical comparisons were corrected for multiple comparisons using the Bonferonni method. Results: There were 339 (85.4%) TMB low, 40 (10.1%) TMB 10-19 and 18 (4.5%) TMB very high PSCC cases in this study. The mean age of PSCC with very high TMB at 70.1 yrs was older than for TMB low at 63.4 yrs (p=.08). There were no significant differences in genomic ancestry among the 3 groups. The TMB 10-19 and TMB very high tended to feature an APOBEC genomic mutational signature more than the TMB low PSCC cases (74 and 76% vs 44%). MSI high status was absent in the TMB low PSCC, but was present in 7.5% of the TMB 10-19 and 11.8% of the TMB very high cases. gLOH levels above 16% were similar in all 3 groups and ranged from 6.2 to 9.4%. GA associated with differences in TMB status in the PSCC cases included higher PIK3CA GA in TMB 10-19 (40.0%) vs TMB low (18.3%; p=.035) and TMB very high (66.7%) vs TMB low (p=.0002). CDKN2A GA were higher in TMB low (45.7%) than in the combined TMB 10-19 + very high (25.9%; p=.049). GA in KMT2D were higher in the combined TMB 10-19 + very high (29.3%) than the TMB low PSCC (7.7%; p=0002). FGFR3 GA were similar in all 3 groups. PD-L1 expression was not significantly different among the 3 groups with TMB low (78.3%), TMB 10-19 (64.2%) and TMB very high (54.5%). HPV identification was more frequent as TMB increased: 28.3% for the TMB low, 50.0% for the TMB high and 58.8% for the TMB very high groups. Conclusions: The evaluation of PSCC by CGP based on TMB levels revels significant differences in biomarkers for the near 15% of cases that have TMB >10 muts/Mb. Further study of TMB as a biomarker in ICPI-based clinical trials for advanced PSCC appear warranted.

Novel synthetic lethality drug target in urothelial bladder cancer based on MTAP genomic loss

BACKGROUND

When urothelial carcinoma of the bladder (UCB) presents or progresses to chemo-refractory metastatic disease, the search for new therapeutic targets is paramount. Targeting protein arginine methyltransferase 5 accumulation in tumors with methylthioadenosine phosphorylase (MTAP) genomic loss has been proposed as a new anti-tumor strategy. We evaluated the incidence of patients with MTAP loss and correlate to treatment-guiding targets and biomarkers.

METHODS

Two thousand six hundred eighty-three cases of advanced UCB underwent hybrid-capture based comprehensive genomic profiling using the FDA-approved F1CDx assay to evaluate all classes of genomic alterations (GA) among 324 genes. Tumor mutational burden was determined on at least 0.8 Mbp of sequenced DNA and microsatellite instability was determined on at least 95 loci.

RESULTS

650 (24%) of UCB featured MTAP loss mutations (MTAP-). The gene and age distributions were similar in MTAP intact (MTAP+) and MTAP- UCB. MTAP- UCB contained higher GA/tumor frequency than MTAP+ UCB likely reflecting the frequent co-deletions of cyclin-dependent kinase inhibitor 2A/B. Of potential therapeutic targets, fibroblast growth factor receptor 3, and phosphatase and tensin homolog GA were more frequent in MTAP- UCB. In contrast, biomarkers of immunotherapy response, including higher frequencies of high tumor mutational burden and high programmed death-ligand 1 IHC staining, were observed in the MTAP+ UCB.

CONCLUSIONS

When compared with MTAP+ UCB, MTAP- UCB differs in genomic signatures including an increase in potentially targetable alterations but a lower frequency of immunotherapy drug biomarkers. Thus, the genomic landscape in MTAP- UCB may play a role in the design of clinical trials incorporating combination treatment strategies when targeting protein arginine methyltransferase 5 in MTAP- tumors.

Establishment and Characterization of Advanced Penile Cancer Patient-derived Tumor Xenografts: Paving the Way for Personalized Treatments

BACKGROUND

Systemic treatments for penile squamous cell carcinoma (pSCC) are toxic and inefficient. Patient-based preclinical models are essential to study novel treatments.

OBJECTIVE

To establish a library of patient-derived tumor xenograft (PDX) models of human papillomavirus-positive (HPV⁺) and -negative (HPV^-) pSCC and characterize these at the genomic and histological levels.

DESIGN, SETTING, AND PARTICIPANTS

Eighteen tumor samples from 14 patients with recurrent or metastatic pSCC were implanted in nude mice. A biobank of PDX tumors was established after passaging of patient samples (F0) for three generations (F1, F2, F3) and was characterized using histopathology and targeted next-generation sequencing (tNGS). Single-nucleotide polymorphism fingerprinting was used to confirm PDX genealogy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The engraftment rate, overall growth rate, and pSCC histomorphology were checked for each PDX generation. Staining for p40 (a pSCC marker) and p16 (a surrogate for HPV infection) was performed for F0 samples. The mutational profile according to a validated panel of 96 cancer genes was determined for F0 and F3 samples and compared to a larger tNGS database.

RESULTS AND LIMITATIONS

Including a previously established pilot model, 11 out of 18 tumor samples (61%) successfully engrafted in F1. The mean time from implantation in F1 to completion of F3 was 36 wk (standard deviation 18). Histological fidelity was demonstrated across generations. The patient mutational profiles were preserved in F3 and were representative of 277 pSCC samples in the Foundation Medicine database. The rapid progression of pSCC in patients from our selected high-risk cohort impeded the use of PDXs as avatars.

CONCLUSIONS

We successfully established the first library of 11 PDX models of HPV^- and HPV⁺ pSCC. Our PDX models showed high engraftment rates and histological and genomic fidelity to the tumor tissue of origin. These models may help in paving the way towards the development of novel treatments.

PATIENT SUMMARY

We established 11 animal models based on tumor tissue from patients with penile cancer. These models could play a vital role in selection of novel treatments according to genetic mutations. In the future, therapies with confirmed preclinical effects may have a profound impact on the development of personalized treatments in penile cancer.

The association of sexual orientation with prostate, breast, and cervical cancer screening and diagnosis

PURPOSE

Data on heterogeneity in cancer screening and diagnosis rates among lesbians/gays and bisexuals (LGBs) is lacking. Recent studies showed that LGBs have decreased healthcare utilization compared to heterosexual counterparts. Few studies have examined how sexual orientation impacts cancer screening and prevalence. We, therefore, investigated the association between sexual orientation and prevalent sex-specific cancer including prostate (PCa), breast (BC), and cervical (CC) cancer.

METHODS

This was a cross-sectional survey-based US study, including men and women aged 18 + from the Health Information National Trends Survey (HINTS) database between 2017 and 2019. The primary endpoint was individual-reported prostate, breast, and cervical cancer screening and prevalence rates among heterosexual and LGB men and women. Multivariable logistic regression analyses assessed association of various covariates with undergoing screening and diagnosis of these cancers.

RESULTS

Overall, 4,441 and 6,333 heterosexual men and women, respectively, were compared to 225 and 213 LGB men and women, respectively. LGBs were younger and less likely to be screened for PCa, BC, and CC than heterosexuals. A higher proportion of heterosexual women than lesbian and bisexual women were screened for CC with pap smears (95.36% vs. 90.48% and 86.11%, p ≤ 0.001) and BC with mammograms (80.74% vs. 63.81% and 45.37%, p ≤ 0.001). Similarly, a higher proportion of heterosexual men than gay and bisexual men were screened for PCa with PSA blood tests (41.27% vs. 30.53% and 27.58%, p ≤ 0.001).

CONCLUSION

There were more heterosexuals than LGBs screened for CC, BC, and PCa. However, no association between sexual orientation and cancer diagnosis was found. Healthcare professionals should be encouraged to improve cancer screening among LGBs.

Financial Toxicity and Its Association With Prostate and Colon Cancer Screening

BACKGROUND

The term "financial toxicity" or "hardship" is a patient-reported outcome that results from the material costs of cancer care, the psychological impacts of these costs, and the coping strategies that patients use to deal with the strain that includes delaying or forgoing care. However, little is known about the impact of financial toxicity on cancer screening. We examined the effects of financial toxicity on the use of screening tests for prostate and colon cancer. We hypothesized that greater financial hardship would show an association with decreased prevalence of cancer screening.

METHODS

This cross-sectional survey-based US study included men and women aged ≥50 years from the National Health Interview Survey database from January through December 2018. A financial hardship score (FHS) between 0 and 10 was formulated by summarizing the responses from 10 financial toxicity dichotomic questions (yes or no), with a higher score associated with greater financial hardship. Primary outcomes were self-reported occurrence of prostate-specific antigen (PSA) blood testing and colonoscopy for prostate and colon cancer screening, respectively.

RESULTS

Overall, 13,439 individual responses were collected. A total of 9,277 (69.03%) people had undergone colonoscopies, and 3,455 (70.94%) men had a PSA test. White, married, working men were more likely to undergo PSA testing and colonoscopy. Individuals who had not had a PSA test or colonoscopy had higher mean FHSs than those who underwent these tests (0.70 and 0.79 vs 0.47 and 0.61, respectively; P≤.001 for both). Multivariable logistic regression models demonstrated that a higher FHS was associated with a decreased odds ratio for having a PSA test (0.916; 95% CI, 0.867-0.967; P=.002) and colonoscopy (0.969; 95% CI, 0.941-0.998; P=.039).

CONCLUSIONS

Greater financial hardship is suggested to be associated with a decreased probability of having prostate and colon cancer screening. Healthcare professionals should be aware that financial toxicity can impact not only cancer treatment but also cancer screening.

Comprehensive genomic profiling (CGP) of chromophobe renal cell carcinoma (chrRCC) compared with non-chromophobe RCC (nonchrRCC): Impact of FLCN genomic alteration (GA) status

4550

Background: FLCN is a tumor suppressor gene associated with cutaneous hair follicle development. FLCN germline mutations are linked to inherited chrRCC in the Birt-Hogg-Dube (BHD) syndrome. We queried whether clinically sporadic chrRCC featured FLCN mutations by comparing the genomic profiles of chrRCC with nonchrRCC. Methods: 109 chrRCC and 5,862 nonchrRCC underwent hybrid-capture based comprehensive genomic profiling (CGP) to evaluate all classes of genomic alterations (GA). Tumor mutational burden (TMB) was determined on up to 1.1 Mb of sequenced DNA and microsatellite instability (MSI) was determined on 114 loci. PD-L1 expression was determined by IHC (Dako 22C3). Results: Patients (pts) with chrRCC were more frequently female (37 [34%] vs. 1,817 [31%]) and younger than pts with nonchrRCC (median age 58 vs 62 years, p <.0001). None of the submitted clinical records in the chrRCC cases listed signs of BHD syndrome. FLCN GA were identified in the nonchrRCC cases only at 2.3% with 37% of the GA being germline. 1/109 (0.9%) of chrRCC featured a germline FLCN GA. GA/tumor were slightly higher in nonchrRCC vs chrRCC (3.6 vs 2.4; NS). There were no significant differences in gLOH, genomic signatures or ancestry between the groups. GA more frequent in chrRCC included TP53, RB1, PTEN. GA more frequent in the nonchrRCC included VHL, BAP1, PBRM1, SETD2, CDKN2A/B, ARID1A, NF2, PIK3CA and TERT. Biomarkers of immune checkpoint inhibitor (ICPI) drug response revealed higher mean TMB, TMB ≥10 mutations/Mb and PBRM1 inactivating mutation frequencies in the nonchrRCC than the chrRCC indicating possible differences in IO drug response. Conclusions: FLCN mutations that are associated with familial incidence of chrRCC are rarely associated with sporadic chrRCC. Sporadic chrRCC has a substantially different genomic profile from nonchrRCC and appears to harbor fewer opportunities for both targeted and immunotherapies. [Table: see text]

Association of RB1 mutational status with overall genomic landscape in neuroendocrine prostate cancer (NEPC)

5063

Background: NEPC is a high-grade aggressive form of prostate cancer. We queried whether RB1 mutation status would impact the genomic features of NEPC in RB1 mutated vs non-mutated cases. Methods: From a series of 13,496 cases of clinically advanced PC, we identified 415 cases (3.1%) with a diagnosis of small cell PC or NEPC as determined by the submitting physician. They were sequenced using a hybrid capture-based FDA-approved clinical genomic profiling (CGP) assay to detect all classes of genomic alterations (GA). Tumor mutational burden (TMB) was determined on 0.8 Mbp of sequenced DNA and microsatellite instability (MSI) was determined on 95 loci. PD-L1 expression was determined by IHC (Dako 22C3) with low tumor cell positive staining 1-49% and high staining ≥50% expression. Results: 253 (61%) of NEPC feature GA in RB1 (RB1 mut+). This contrasts with a 5.8% frequency of RB1 GA in the non-NEPC (P <.0001). The RB1 mut+ NEPC featured a slightly greater number of pathogenic GA/tumor than the RB1 mut- NEPC (5.1 vs 4.2). Age and TMPRSS2-ERG fusion frequency were similar between the groups. RB1 Mut- NEPC was associated with significantly higher amplifications (amp) and total GA in AR compared to RB1 mut+ NEPC. RB1 mut+ NEPC featured significantly greater frequency of PTEN GA. GA frequencies in targetable kinases and DNA repair GA including BRCA1/2 and ATM linked to PARP inhibitor (PARPi) response were similar in both groups. For potential immune-oncology (IO) biomarkers, RB1 Mut+ NEPC featured significantly greater frequency of positive PD-L1 expression and lower frequencies of MDM2 and CDK12 GA. CD274 ( PD-L1) amplification, MSI-high status and cases with TMB ≥10 mut/Mb were uncommon in both groups. gLOH was higher in RB1 mut+ than RB1 mut- (P =.005). There were more cases of non-European ancestry in the RB1 mut- group. APC I1307K mut were found in 3/162 (1.9%) RB1 mut- NEPC only. Conclusions: In NEPC, the presence of RB1 mutation is associated with various GA that may have clinical relevance. Further study of RB1 status as a guide in trial designs on therapy selection for men with NEPC appears warranted. [Table: see text]

Landscape of fibroblast growth factor receptor (FGFR) genomic alterations (GA) in urothelial bladder cancer (UBC)

4568

Background: Urothelial bladder carcinomas (UBC) with genomic alterations (GA) in the Fibroblast Growth Factor Receptor ( FGFR) genes have been postulated to be less responsive to immune checkpoint inhibitors (ICI). Immune microenvironment of these tumors could be altered due to suppression of interferon signaling pathways. Here, we present comprehensive genomic profiling (CGP) of FGFR altered UBC to study the underlying immunogenomic mechanisms of response and resistance. Methods: 4,035 UBC underwent hybrid capture based CGP. Tumor mutational burden (TMB) was determined on up to 1.1 Mbp of sequenced DNA and microsatellite instability (MSI) was determined using 114 loci. Programmed death ligand (PD-L1) expression in tumor cells was assessed by IHC (Dako 22C3). Results: 894 (22%) of UBC featured FGFR GA ( FGFR1 3.7%; FGFR2 1.1%; FGFR3 17.4%). Gender and age distribution was similar in all groups. FGFR3 cases had lower GA/tumor and 14.7% GA were fusions. ERBB2 amplification was significantly higher in FGFR1/2 altered UBC compared with FGFR3 altered UBC. MTOR pathway GA were highest in FGFR3 altered UBC. FGFR3 altered UBC featured significantly higher frequencies of biomarkers predicting resistance to ICI including lower TMB, lower PD-L1 expression and higher frequencies of GA in MDM2. FGFR3 driven UBC also features significantly higher frequencies of CDKN2A/B loss and MTAP loss which have also recently been linked to IO drug resistance. Conclusions: UBC harboring FGFR GA have increased frequency of alterations that have been linked to ICI resistance. Further evaluation of FGFR-based biomarkers in UBC clinical trials focused on the assessment of the patient response to ICI appears warranted. [Table: see text]

Impact of PD-L1 expression on conventional urothelial bladder carcinoma (UCB) genomic alteration (GA) profile

e16535

Background: Immunohistochemistry (IHC) to determine PD-L1 expression level has been used as a biomarker to predict immune checkpoint inhibitors response in UCB. We hypothesized that the GA profiles would differ between UCB featuring high vs negative PD-L1 expression. Methods: 102 cases of advanced UCB with known PD-L1 tumor cell expression underwent hybrid-capture based comprehensive genomic profiling to evaluate all classes of genomic alteration (GA). Tumor mutational burden (TMB) was determined on up to 1.1 Mbp of sequenced DNA and microsatellite instability (MSI) was determined on 114 loci. Tumor cell (TC) PD-L1 expression was determined by IHC (Dako 22C3). Only PD-L1 high (H) (≥50% TC expression) and negative (N) (0% TC expression) cases were included in this study. Results: Overall, only 2 (8.3%) of the 24 PD-L1H UCB featured CD274 ( PD-L1) amplification (mean 19 copies) and none of 78 PD-L1N had CD274 amplification (P = .05). The gender, age and GA per tumor frequencies were similar in the groups. When compared with the PD-L1H UBC cases, FGFR3 GA were significantly more frequent in the UBC PD-L1N cases (p = .02). Currently “untargetable” GA that were more frequent in the PD-L1H UBC, but did not reach significance, included TP53, TERT and RB1. MTAP loss, a potential target for PRMT5 and MTA2 inhibitors, were 3X more frequent in the PD-L1N UBC. ERBB2 amplification and ERBB3 and PIK3CA short variant (SV) GA were more frequent in the PD-L1N UBC with differences not reaching significance. The mean gLOH scores were similar in both groups. Other ICPI-associated potential biomarkers, including MSI status, TMB level and GA in PBRM1, STK11 and MDM2 were not significantly different in the groups. For UCB cases where a mutational signature could be determined, 15/33 (45%) of PD-L1H and 34/112 (30%, p = 0.14) of PD-L1N UCB featured an APOBEC gene signature; 79% of PD-L1H and 83% of PD-L1N featured European ancestry (p = 0.61). Conclusions: PD-L1H and PD-L1N subtypes of UCB differ in their genomic profiles. PD-L1N UCB features greater frequencies of potentially “targetable” GA, including FGFR3, ERBB2, ERBB3 and PIK3CA. PD-L1 IHC may thus not only play a role in the selection of ICPI for advanced UCB but also in designing trials that may combine ICPI with targeted therapies.[Table: see text]

The association of COVID-19 testing with cancer care disruption

e18558

Background: Research has shown that the COVID-19 pandemic has reduced access to cancer treatment and care for patients, especially for COVID-19 patients. Methods: We investigated the impact of COVID-19 testing on access to cancer care. A US based cross sectional study was conducted on 2,393 cancer patients using data from the 2020 National Health Interview Survey. Multivariable logistic regression was used to assess associations between COVID-19 testing and likelihood of receiving cancer treatment or other cancer care during the pandemic. Results: Patients who reported ever being tested for COVID were on average younger (66.9 vs 69.3, p<0.001). Patients with professional school education reported higher rates of being tested than lower education levels (40.0%, p=0.032). Tested patients reported higher rates of not receiving medical care due to COVID-19 (23.3% vs. 19.1%, p=0.026). On multivariable analysis, patients who reported ever being tested for COVID-19 were less likely to receive cancer treatment (OR 0.639, 95% CI 0.489-0.834, p=0.001) or receive any other cancer medical care (OR 0.657, 95% CI 0.523-0.825, p<0.001) (Table). Conclusions: These data suggest COVID testing itself is associated with increased likelihood of cancer care disruption. As the pandemic persists, awareness of cancer care disruption, even by testing alone, should be raised.[Table: see text]

What is the impact of ischemic heart disease on PSA testing?

e17014

Background: Prostate Specific Antigen (PSA) testing can improve early prostate cancer detection. However, numerous factors can influence patients’ willingness and ability to undergo PSA testing. Methods: We performed a cross-sectional study investigating the impact of various degrees of ischemic heart disease (IHD) on PSA testing. We assessed 3,822 male respondents aged 55-75 from the 2018 year of the National Health Interview Survey (NHIS). Men were stratified according to the degree of IHD (none, history of angina pectoris (AP), history of myocardial infarction (MI), or history of neither, but with a diagnosis of IHD). Multivariable logistic regression analysis was used to assess the relationship between IHD and being tested for PSA, adjusting for known cofounders. Results: Multivariable logistic regression demonstrated that males with a history of IHD (no MI or AP) were more likely to have ever been PSA tested than males without IHD (p = 0.012, OR = 1.630, 95% CI 1.115-2.383), as seen in Table. Additionally, older age (p < 0.001), having a partner (vs. no partner p < 0.001), homosexual sexual orientation (vs. heterosexual orientation p = 0.007), and a history of cancer (vs. no history p < 0.001) all increased likelihood of being PSA tested. In contrast, Asian race (vs. White, p = 0.001), and being a current smoker (vs. no smoking history, p < 0.001) decreased the likelihood. Interestingly, males with a history of a symptomatic IHD (MI or AP) were not shown to be more likely to undergo PSA testing. Conclusions: Our results suggest that males with non-symptomatic IHD are more likely to be PSA tested. Males with symptomatic IHD do not seem to undergo more PSA screening, perhaps due to lower suggested life expectancy. Awareness of discrepancies in PSA testing in men with IHD should be raised. Table - Multivariable logistic regression analyses demonstrating relationships with likelihood of being PSA tested.[Table: see text]

Impact of PD-L1 expression on conventional urothelial bladder carcinoma (UBC) genomic alteration (GA) profile

563

Background: Immunohistochemistry (IHC) to determine PD-L1 expression level has been proposed a companion assay related to the approval of immune checkpoint inhibitors in UBC. We hypothesized that the GA profiles would differ between UBC featuring high vs negative PD-L1 expression. Methods: 102 cases of advanced UBC with known PD-L1 expression underwent hybrid-capture based comprehensive genomic profiling to evaluate all classes of GA. Tumor mutational burden (TMB) was determined on up to 1.1 Mbp of sequenced DNA and microsatellite instability (MSI) was determined on 114 loci. Tumor cell (TC) PD-L1 expression was determined by IHC (Dako 22C3). Only PD-L1 high (H) (≥50% TC expression) and negative (N) (0% TC expression) cases were included with PD-L1 Low (1-49% TC expression) cases excluded from this study. Results: Overall, only 2 (8.3%) of the 24 PD-L1H UBC featured CD274 ( PD-L1) amplification (mean 19 copies) and none of 78 PD-L1N had CD274 amp (P =.05). The gender, age was similar in the groups. When compared with the PD-L1H UBC cases, FGFR3 GA were significantly more frequent in the UBC PD-L1N cases (p =.02). Currently “untargetable” GA that were more frequent in the PD-L1H UBC, but did not reach statistical significance, included TP53, TERT and RB1. MTAP loss, a potential target for PRMT5 and MTA2 inhibitors, were 3X more frequent in the PD-L1N UBC. ERBB2 amplification and ERBB3 and PIK3CA short variant (SV) GA were more frequent in the PD-L1N UBC with differences not reaching significance. Other ICPI-associated potential biomarkers, including MSI status, TMB level and GA in PBRM1, STK11 and MDM2 were not significantly different in the groups. For UBC cases where a mutational signature could be determined, 10/12 (83%) of PD-L1H and 21/29 (72%) of PD-L1N UBC featured APOBEC signature; 2 PD-L1N featured MMR signature and 6 PD-L1N UBC featured no dominant signature. Conclusions: PD-L1H and PD-L1N subtypes of UBC differ in their genomic profiles:PD-L1N UBC features greater frequencies of potentially “targetable” GA, including FGFR3, ERBB2, ERBB3 and PIK3CA. PD-L1 IHC may thus not only play a role in the selection of ICPI for advanced UBC but also in designing trials that may combine ICPI with targeted therapies. Limitations include small sample size, possible selection bias and lack of clinical annotation.[Table: see text]

The association of the use of anxiety and depression medications with PSA testing

56

Background: Mental illness is a growing issue in the USA. More individuals continue to be diagnosed with illnesses such as depression and anxiety and placed on necessary medications. Studies have shown that the psychological makeup of an individual greatly impacts their health behavior and usage of preventative measures. However, there is limited research on the effect of anxiety and depression on PSA testing. This study explores the associations between the use of anxiety and depression medications and PSA testing. Methods: We used data from the National Health Interview Survey during the year 2018, and assessed responses to the question “Have you ever had a PSA test?” and “What is the number of PSA tests you had in the last 5 years?”. Responses were stratified by whether men were taking medications for anxiety, depression, both or none. We performed multivariable logistic regression analysis to define adjusted odds ratios of undergoing PSA testing adjusting for relevant socio-economic and demographic parameters. Results: Among the 5,035 male participants, 89.4% did not take any medication, 2.9% reported they took anxiety medication, 2.1% took depression medication and 5.5% took both medications. There was a significantly higher rate of PSA testing in men who took medications for both anxiety and depression compared to men taking no medications (p=0.002). Furthermore, the average number of PSA tests in the last 5 years was highest in the group of men taking both medications ( p < 0.0001). Multivariable analysis showed that men who took medications for both depression and anxiety were more likely to undergo PSA testing in comparison to men, not on any of these medications (OR=1.755, p=0.001). The multivariable analysis also showed that age, living with a spouse, and prior cancer history were associated with an increased likelihood of PSA testing while being a minority, living in the south of the USA, and being a current smoker was associated with a lower likelihood of undergoing PSA testing. Conclusions: Taking both anxiety and depression medications in men may be associated with a higher likelihood of undergoing PSA testing. Despite obvious limitations of this analysis including its retrospective nature and recall bias, this association needs to be further explored, especially due to rising use of these medication in the current era of the COVID-19 pandemic.[Table: see text]

Financial toxicity and its effect on screening for prostate and colon cancer

21

Background: The term ‘financial toxicity’ or ‘hardship’ is used to describe the financial problems patients experience due to high out-of-pocket costs for their healthcare. Financial toxicity in the context of cancer treatment is an area of recent study due to the significant costs associated with these treatments, but little is known about the effect of financial toxicity on cancer prevention. We examined the effects of financial toxicity on the utilization of screening tests for prevalent cancers, including prostate and colon cancer, using a US nationally representative survey-based data source. We hypothesized that patients with more financial hardship would show an association with decreased prevalence of prostate and colon cancer screening. Methods: This cross-sectional survey-based US study included men and women aged 18+ from the National Health Interview Survey (NHIS) database from January – December 2018. A financial hardship score between 0 and 1 was formulated by summarizing the responses from ten financial toxicity questions including if in the past 12 months one was unable to afford prescription medication or healthcare; or if one had to skip or take less medicine to save money. A higher score was associated with a worse financial hardship score. The primary outcomes of the study were self-reported occurrence of PSA blood testing for prostate cancer screening, and occurrence of colonoscopy for colon cancer screening. Results: As shown in table, a higher financial hardship score was associated with a decreased odds ratio for having a PSA test of 0.916 (95% CI 0.867-0.967, p=0.002) and colonoscopy of 0.969 (95% CI 0.941-0.998, p=0.039). Conclusions: Worse financial hardship is associated with a decreased probability of having PSA or colonoscopy screening tests. Awareness of this specific toxicity needs to be raised, examining the association of financial toxicity and screening of prostate, colon, and other additional cancers. [Table: see text]

Genomic classification of clinically advanced major genito-urinary cancers (GUca) based on methylthioadenosine phosphorylase (MTAP) genomic loss

164

Background: Novel treatments for clinically advanced GUca including castrate resistant prostate ca (PC), bladder urothelial ca (BUC) and clear cell renal ca (ccRCC) are widely needed. Recently, the targeting of cancer cells with arginine accumulation caused by MTAP loss has emerged as a new synthetic lethality-based anti-cancer program. Methods: 8,436 mCRPC, 2,683 BUC and 841 ccRCC underwent hybrid-capture based comprehensive genomic profiling (CGP) to evaluate all classes of genomic alterations (GA). Tumor mutational burden (TMB) was determined on up to 1.1 Mbp of sequenced DNA and microsatellite instability (MSI) was determined on up to 114 loci. PD-L1 tumor cell expression was determined by IHC (Dako 22C3). Results: 1.3% of PC, 24.2% of BUC and 5.5% of ccRCC featured MTAP loss. There were no significant age or gender differences associated with MTAP loss. CDKN2A/B loss ranged from 94% in ccRCC to > 99% in PC and BUC. The GA/tumor frequencies were similar when CDKN2A/B GA are excluded. In PC, GA in TP53, PTEN and BRCA1 were more frequent, while GA in AR, CDK12, RB1 and BRCA2 were less frequent in cases with MTAP loss. In BUC, GA in TSC1 and FGFR3 were more frequent and GA in RB1and TP53 were less frequent in cases with MTAP loss. In ccRCC, GA in NF2 were more frequent in cases with MTAP loss, while GA in VHL and PBRM1 were less frequent in cases with MTAP loss. “Targetable” kinase GA were rare in all groups, except for FGFR3 GA in MTAP loss BUC. Immunotherapy (IO) putative biomarkers varied among tumors, with MSI-high status less frequent and TMB ≥ 10 mut/Mb more frequent in BUC MTAP-intact than BUC with MTAP loss. PD-L1 expression was similar except for high PD-L1 expression more frequent in MTAP-intact BUC. Conclusions: When compared with PC and ccRCC, the clinical development of novel drugs, such as PRMT5 and MTA2 inhibitors in GUca will likely be focused on BUC given the 24% frequency of MTAP loss in that tumor type. CGP of PC, BUC and ccRCC reveal significant differences in GA in MTAP-intact and tumors with MTAP loss, which may impact future combinatorial clinical trial designs.[Table: see text]

Expanding the use of targeted therapy for urothelial bladder cancer (UBC): Non-FGFR3 receptor tyrosine kinase (RTK) gene rearrangements (ReAr) and fusions (fus)

550

Background: After the regulatory approval of erdafitinib targeting FGFR genomic alterations (GA), molecular profiling and targeted therapy indications may further expand in UBC. We queried a large database of advanced UBC to study the landscape of RTK ReAr and Fus to categorize additional targets beyond FGFR1-3 that have potential to further personalize treatment of this disease. Methods: We analyzed data from 8,233 UBC cases, which underwent hybrid capture-based comprehensive genomic profiling (CGP). Tumor mutational burden (TMB) was determined on up to 1.1 Mbp of sequenced DNA and microsatellite instability (MSI) was determined on 114 loci. PD-L1 expression in tumor cells was assessed by IHC (Dako 22C3). Results: A total of 1,210 (14.7%) UBC featured known and likely large-scale (LS) internal ReAr with 414 (5%) ReAr in RTK genes. The ReAr/fus were distributed among ABL1 (3), ALK (3), BRAF (29), CDK12 (44), CDK8 (1), EGFR (10 ), ERBB2 (3), FGFR1 (2), FGFR2 (16 ), FGFR3 (231), FLT3 (1), MAO2K4 (4), NTRK1 (7 ), NTRK2 (5), NTRK3 (7), RAF1 (31 ), RET (8) and ROS1 (9). LS ReAr were divided into LS ReAr-associated gene deletions (1%), truncations (1%), rearrangements (61%) and fusions (37%). FGFR3 fus accounted for 81% of RTK fus with BRAF and RAF1 both at 2%. The greatest frequencies of kinase ReAr were in CDK12 (29%), FGFR3 (16%), RAF1 (13%) and BRAF (12%). Additional noteworthy ‘targetable’ RTK ReAR and fus included NTRK1-3 (19 cases), ROS1 (9 cases), RET (8 cases) and ALK (1 case). 407 (98.4%) of the RTK ReAr/fus-positive UBC had only 1 RTK ReAr/fus GA and 7 (1.6%) had 2 ReAr ReAr/fus, 6 (85.7%) of which involved FGFR3. Compared with LS ReAR negative UBC, the LS ReAR UBC cases revealed similar gender and age characteristics, MSI status, similar frequencies of TMB ≥ 10 mut/Mb and PD-L1 expression in tumor cells ≥1% and ≥50%. Conclusions: At a 5% frequency, potentially ‘targetable’ RTK gene rearrangements and fusions are a rare but important opportunity to further personalize treatment selection of UBC, including RTK inhibitors, PARP inhibitors ( CDK12) and immunotherapy. This potential for clinical trials supports broader CGP, compared to targeted FGFR sequencing, in order to uncover additional opportunities for precision therapies that have the potential to improve patient outcomes.[Table: see text]

Comprehensive genomic profiling (CGP) of chromophobe renal cell carcinoma (chrRCC) compared with clear cell RCC (ccRCC): Impact of FLCN genomic alteration (GA) status

292

Background: FLCN is a tumor suppressor gene associated with cutaneous hair follicle development. FLCN germline mutations are linked to inherited chrRCC in the Birt-Hogg-Dube (BHD) syndrome. We queried whether clinically sporadic chrRCC featured FLCN mutations by comparing the genomic profiles of chrRCC with ccRCC. Methods: 108 chrRCC and 2110 ccRCC underwent hybrid-capture based comprehensive genomic profiling (CGP) to evaluate all classes of genomic alterations (GA). Tumor mutational burden (TMB) was determined on up to 1.1 Mbp of sequenced DNA and microsatellite instability (MSI) was determined on 114 loci. PD-L1 expression was determined by IHC (Dako 22C3). Results: Patients (pts) with chrRCC were more frequently female and younger than pts with ccRCC p <.0001). None of the submitted clinical records in the chrRCC cases listed signs of BHD syndrome. FLCN GA were identified in only 2.3% of the ccRCC cases with 37% of the GA predicted to be germline. chrRCC did not reveal somatic or germline FLCN GA. GA/tumor were slightly higher in ccRCC vs chrRCC (3.6 vs 2.4; NS). GA more frequent in chrRCC included TP53, RB1 and PTEN. GA more frequent in the ccRCC included VHL, BAP1, PBRM1, SETD2, CDKN2A/B, ARID1A, NF2, PIK3CA and TERT. Putative biomarkers of immune checkpoint inhibitor (ICPI) response were infrequent in both groups with only a slightly higher, but still low, mean TMB in ccRCC vs chrRCC cases. IHC revealed moderate PD-L1 expression at low and minimal PD-L1 expression at high staining level, which was slightly increased in the chrRCC group. Conclusions: FLCN mutations that are associated with the familial incidence of chrRCC were not associated with sporadic chrRCC. Sporadic chrRCC has substantially different genomic profile from ccRCC and may harbor a few ‘targetable’ GA. The prediction of response to ICPI in RCC remains challenging with chrRCC featuring slightly higher PD-L1 expression and ccRCC featuring higher PBRM1 GA and higher TMB.[Table: see text]

E-cigarette use and the risk of bladder and lung cancer

443

Background: Electronic cigarette smoking and similar novel smoking modalities have raised questions about their impact on various cancers compared with traditional forms of tobacco smoking. Tobacco smoking has been concretely proven to increase the risk of many cancers, including lung (LCa) and bladder (BCa) cancer. To date, there is little data on how e-cigarette smoking impacts the incidence of these cancers. We investigated whether any disparities exist in the prevalence of LCa and BCa between various smoking histories using a US nationally representative data source. Methods: This cross-sectional survey-based US study included men and women aged 18+ from the National Health Interview Survey (NHIS) database between 2016-2018. Primary endpoint was self-reported occurrence of LCa and BCa diagnosis. Multivariable logistic regression analyses assessed possible association of various covariates with diagnosis of these cancers. Results: Prevalence of BCa and LCa was higher in all smoking histories compared to never smokers. Patients with a history of e-cigarette smoking vs. no history of e-cigarette smoking were significantly younger at BCa diagnosis (56.87 [±9.86] vs. 65.00 [±12.60] years, p=0.001). Multivariable logistic regression models showed that a history of cigarette smoking and e-cigarette smoking individually was associated with increased ORs of 2.476 (p≤0.001) and 1.577 (p≤0.001) for BCa diagnosis, respectively, and 4.589 (p≤0.001) and 1.614 (p=0.007) for LCa diagnosis, respectively. Conclusions: Compared to never smokers, history of e-cigarette smoking was associated with increased risk of LCa and BCa development and earlier BCa diagnosis. Additional studies are needed to better define the public health effects of these novel and unregulated products.

Association of RB1 mutational status with overall genomic landscape in neuroendocrine prostate cancer (NEPC)

156

Background: NEPC is a high-grade aggressive form of prostate cancer. We queried whether RB1 mutation status would impact the genomic features of NEPC. We hypothesized that there would be differences in GA frequencies in RB1 mutated vs non mutated cases. Methods: From a series of 13,496 cases of clinically advanced PC, 415 (3.1%) histologically defined NEPC were sequenced using a hybrid capture-based FDA-approved clinical genomic profiling (CGP) assay to detect all classes of genomic alterations (GA). Tumor mutational burden (TMB) was determined on 0.8 Mbp of sequenced DNA and microsatellite instability (MSI) was determined on 95 loci. PD-L1 expression was determined by IHC (Dako 22C3) with low tumor cell positive staining 1-49% and high staining ≥50% expression. Results: 253 (61%) of NEPC feature GA in RB1 (RB1 mut+). This contrasts with a 5.8% frequency of RB1 GA in the non-NEPC (P <.0001). The RB1 mut+ NEPC featured a slightly greater number of driver GA/tumor than the RB1 mut- NEPC (5.1 vs 4.2). Age and TMPRSS2-ERG fusion frequency were similar between the groups. RB1 Mut- NEPC was associated with significantly higher amplifications (amp) and total GA in AR compared to RB1 mut+ NEPC. RB1 mut+ NEPC featured significantly greater frequency of PTEN GA. GA frequencies in targetable kinases and DNA repair GA including BRCA1/2 and ATM linked to PARP inhibitor (PARPi) response were similar in both groups. For potential immune-oncology (IO) biomarkers, RB1 Mut+ NEPC featured significantly greater frequency of low positive PD-L1 expression and lower frequencies of MDM2 and CDK12 GA. CD274 ( PD-L1) amplification, MSI-high status and cases with TMB ≥10 mut/Mb were very uncommon in both groups. Conclusions: In NEPC, the presence of RB1 mutation is associated with various GA that may have clinical relevance. Limitations include possible selection and confounding biases, and lack of clinical annotation. Further study of RB1 status as a guide of trial designs on therapy selection for men with NEPC is warranted.[Table: see text]

SunRISe-1: Phase 2b study of TAR-200 plus cetrelimab, TAR-200 alone, or cetrelimab alone in participants with high-risk nonmuscle-invasive bladder cancer unresponsive to Bacillus Calmette-Guérin who are ineligible for or decline radical cystectomy

TPS593

Background: Treatment options are limited for patients with high-risk non-muscle-invasive bladder cancer (HR-NMIBC) unresponsive to intravesical bacillus Calmette–Guérin (BCG). TAR-200 is an intravesical drug delivery system for local continuous release of gemcitabine within the bladder. The current study will assess the rate of complete response (CR) upon treatment with TAR-200 + systemic cetrelimab (CET [anti–PD-1 antibody]), TAR-200, and CET in BCG-unresponsive participants with HR-NMIBC who are ineligible for or decline radical cystectomy (RC). Methods: SunRISe-1 (NCT04640623) is an open-label, parallel-group, multicenter phase 2b study designed to assess the efficacy and safety of TAR-200 + CET, TAR-200 alone, and CET alone in participants with BCG-unresponsive HR-NMIBC. Eligible participants are aged ≥ 18 years with ECOG PS 0, 1, or 2 and recurrent or persistent histologically confirmed HR-NMIBC (carcinoma in situ) with or without papillary disease (T1, high-grade Ta), who have been diagnosed within 12 months of last BCG treatment and are ineligible for or declined RC. Participants (N≈200) are randomized 2:1:1 to receive TAR-200 + CET (Cohort 1, n≈100), TAR-200 (Cohort 2, n≈50), or CET (Cohort 3, n≈50). In Cohorts 1 and 2, participants receive intravesical TAR-200 every 3 weeks through Week 24, and every 12 weeks thereafter until Week 96. In Cohorts 1 and 3, participants receive CET until Week 78. Primary disease assessments (cystoscopy, urine cytology, transurethral resection of bladder tumor [TURBT], and magnetic resonance imaging/computed tomography) are made at baseline; subsequent cystoscopy and centrally read urine cytology are performed every 12 weeks through Year 2, every 24 weeks until end of Year 3, and in Year 4 and Year 5 in accordance with institutional standards of care. TURBT is conducted at 24 and 48 weeks. The primary end point for the 3 cohorts is overall CR rate at any time point. Secondary end points include duration of response (ie, from time of first CR achieved to first evidence of recurrence, progression, or death [whichever is earlier] for participants who achieve a CR), overall survival, PK immunogenicity of cetrelimab, safety and tolerability, and patient-reported outcomes. Exploratory end points include incidence and time to cystectomy (measured from randomization to date of cystectomy), biomarkers, and health care resource utilization. This study opened in January 2021 and is enrolling participants at ≈165 study sites worldwide. Currently, the study is active in 13 countries with 12 participants enrolled as of September 12, 2021. Clinical trial information: NCT04640623.

Comparison of prostate specific antigen testing in men aged 55 to 69 with and without a history of cancer

230

Background: Prostate specific antigen (PSA) screening remains a controversial issue. However, most urological guidelines recommend PSA testing through a shared decision-making process with the patient. The rate of PSA screening in men with a history of cancer compared to men with no cancer history is not well known. We aimed to compare PSA testing in men aged 55-69 years with and without a history of cancer (excluding prostate cancer patients). Methods: Utilizing the National Health Interview Survey (NHIS) a retrospective cross-sectional study between the years 2015 and 2018 was carried out to analyze and compare PSA testing rates in men aged 55-69 years. Multivariable logistic regression model was implemented do demonstrate potential associations with PSA testing. Results: A total of 13,850 men aged 55-69 years included in the NHIS Survey were analyzed. 1519 (10.9%) men had a history of cancer (non-prostate). On multivariable analysis, men who were previously diagnosed with cancer had a higher rate of PSA testing compared to men with no history of cancer (OR: 1.88, 95% CI 1.39-2.54, p < 0.001). Other factors associated with an increased likelihood of undergoing PSA testing included: age, homosexual orientation, and married men. In contrast, current smokers, American Indians and Alaskan Natives and Asians were less likely to undergo PSA testing. Conclusions: Our data suggest that men aged 55-69 with a history of cancer are more likely to undergo PSA testing than men with no cancer history.[Table: see text]

Association of Race With Cancer-Related Financial Toxicity

PURPOSE

We investigated the association between race and FT among previous patients with cancer. Studies show that patients with cancer experience financial toxicity (FT) because of their cancer treatment.

METHODS

Data on individuals with a cancer history were collected in this cross-sectional study during 2012, 2014, and 2017, from the US Health Information National Trends Survey. This survey is conducted by mail with monetary compensation as an incentive. We specifically assessed responses to two questions: Has cancer hurt you financially? Have you been denied health insurance because of cancer? Multivariable logistic regression analyses were used to assess the associations between these questions and race.

RESULTS

Of 10,592 individuals participating, 1,328 men and women (12.5%) with a cancer history were assessed. Compared with Blacks, Whites were found to have a higher rate of insurance (95.4% v 90.0%), were more likely to receive cancer treatment (93.9% v 85%), and had a higher rate of surgical treatment than Blacks (77% v 60%), Hispanics (55%), and others (77%, 60%, 55%, and 74.2%, respectively, P < .001). On multivariable analysis, Blacks were more than five times as likely to be denied insurance (odds ratio, 5.003; 95% CI, 2.451 to 10.213; P < .001) and more than twice as likely to report being hurt financially because of cancer (odds ratio, 2.448; 95% CI, 1.520 to 3.941; P < .001) than Whites. Of all cancer groups analyzed (genitourinary, gynecologic, gastrointestinal, and breast), genitourinary malignancies were the only group in which the rate of reporting being hurt financially varied in a statistically significant manner (Whites 36.7%, Hispanics 62.5%, and Blacks 59.3%, P = .004).

CONCLUSION

Our data suggest that race is significantly associated with FT because of cancer. Awareness of racial inequality with regards to FT should be raised among health care workers.

The association of sexual orientation with prostate, breast, and cervical cancer screening and diagnosis

129

Background: Data on heterogeneity in cancer screening and diagnosis rates among lesbians/gays and bisexuals is lacking. Recent studies showed that lesbians/gays and bisexuals have decreased healthcare utilization compared to heterosexual counterparts and continue to experience discrimination in healthcare. Few studies have examined how sexual orientation impacts cancer screening and prevalence. We, therefore, investigated the association between sexual orientation and prevalent sex-specific cancer including prostate, breast, and cervical cancer. Methods: This was a cross-sectional survey-based US study, including men and women aged 18+ from the Health Information National Trends Survey (HINTS) database between 2017-2019. The primary endpoint was individual-reported prostate, breast, and cervical cancer screening and prevalence rates among heterosexual and LGB men and women. Multivariable logistic regression analyses assessed association of various covariates with undergoing screening and diagnosis of these cancers. Results: Overall, 4,441 and 6,333 heterosexual men and women, respectively, were compared to 225 and 213 lesbian/gay and bisexual men and women, respectively. Lesbians/gays and bisexuals were younger and less likely to be screened for prostate, breast, and cervical cancer than heterosexuals. A higher proportion of heterosexual women than lesbian and bisexual women were screened for cervical cancer with pap smears (95.36% vs. 90.48% and 86.11%, p = < 0.001) and breast cancer with mammograms (80.74% vs. 63.81% and 45.37%, p = < 0.001). Similarly, a higher proportion of heterosexual men than gay and bisexual men were screened for prostate cancer with PSA blood tests (41.27% vs. 30.53% and 27.58%, p = < 0.001). Conclusions: Lesbians/gays and bisexuals in the US may be less likely to undergo screening of sex-specific prevalent malignancies, including prostate, breast, and cervical cancer. Healthcare professionals should be encouraged to improve cancer screening among lesbians/gays and bisexuals.

Multiresolution Application of Artificial Intelligence in Digital Pathology for Prediction of Positive Lymph Nodes From Primary Tumors in Bladder Cancer

PURPOSE

To develop an artificial intelligence (AI)-based model for identifying patients with lymph node (LN) metastasis based on digital evaluation of primary tumors and train the model using cystectomy specimens available from The Cancer Genome Atlas (TCGA) Project; patients from our institution were included for validation of the leave-out test cohort.

METHODS

In all, 307 patients were identified for inclusion in the study (TCGA, n = 294; in-house, n = 13). Deep learning models were trained from image patches at 2.5×, 5×, 10×, and 20× magnifications, and spatially resolved prediction maps were combined with microenvironment (lymphocyte infiltration) features to derive a final patient-level AI score (probability of LN metastasis). Training and validation included 219 patients (training, n = 146; validation, n = 73); 89 patients (TCGA, n = 75; in-house, n = 13) were reserved as an independent testing set. Multivariable logistic regression models for predicting LN status based on clinicopathologic features alone and a combined model with AI score were fit to training and validation sets.

RESULTS

Several patients were determined to have positive LN metastasis in TCGA (n = 105; 35.7%) and in-house (n = 3; 23.1%) cohorts. A clinicopathologic model that considered using factors such as age, T stage, and lymphovascular invasion demonstrated an area under the curve (AUC) of 0.755 (95% CI, 0.680 to 0.831) in the training and validation cohorts compared with the cross validation of the AI score (likelihood of positive LNs), which achieved an AUC of 0.866 (95% CI, 0.812 to 0.920; P = .021). Performance in the test cohort was similar, with a clinicopathologic model AUC of 0.678 (95% CI, 0.554 to 0.802) and an AI score of 0.784 (95% CI, 0.702 to 0.896; P = .21). In addition, the AI score remained significant after adjusting for clinicopathologic variables (P = 1.08 × 10^-9), and the combined model significantly outperformed clinicopathologic features alone in the test cohort with an AUC of 0.807 (95% CI, 0.702 to 0.912; P = .047).

CONCLUSION

Patients who are at higher risk of having positive LNs during cystectomy can be identified on primary tumor samples using novel AI-based methodologies applied to digital hematoxylin and eosin-stained slides.

The association of sexual orientation with cancer screening and diagnosis

6506

Background: Data on heterogeneity in cancer screening and diagnosis rates among sexual minorities (SMs) is lacking. Recent studies have shown SMs are more likely to engage in risky health behavior and have decreased healthcare utilization compared to heterosexual counterparts. However, few studies have examined how sexual orientation (SO) impacts cancer screening and prevalence. We therefore investigated whether SO affects prevalent gender-specific cancer screening and prevalence, including prostate (PCa), breast (BC), and cervical cancer (CC). Methods: This was a cross-sectional survey-based US study, including men and women aged 18+ from the Health Information National Trends Survey (HINTS) database (part of the National Cancer Institute’s division of cancer control and population sciences) between 2017-2019. The primary endpoint was individual-reported PCa, BC, and CC screening and prevalence rates among heterosexual and SM men and women. Multivariable logistic regression analyses assessed association of various covariates with undergoing screening and diagnosis of these cancers. Results: Overall, 4,441 (95.18%) men and 6,333 (96.75%) women reported a SO of heterosexual whereas 167 (3.6%) and 58 (1.2%) men and 105 (1.6%) and 108 (1.6%) women reported a SO of gay and bisexual, respectively. Mean age was higher in the heterosexual group compared to the gay and bisexual groups in both men (57.7 [±16.0] vs. 52.4 [±14.5] and 51.9 [±18.0] years, p = < 0.001) and women (56.2 [±16.7] vs. 49.0 [±17.1] and 40.0 [±14.8] years, p = < 0.001). Homosexuals and bisexuals were less likely to be screened for PCa (30.53% and 27.58% vs 41.27%, p = < 0.001), BC (63.81% and 45.37% vs 80.74%, p = < 0.001), and CC (90.48% and 86.11% vs 95.36%, p = < 0.001) than their heterosexual counterparts. While rates of PCa and BC diagnoses were similar across SO, more homosexual and bisexual women were diagnosed with CC compared to their heterosexual counterparts (4.76% and 3.70% vs 1.85%, p = 0.039). Multivariable logistic regression models showed that SMs were less likely to be screened for cancer with ORs of 0.61 (95% CI 0.39-0.95, p = 0.030) for PCa, 0.52 (95% CI 0.30-0.92, p = 0.025) for BC, and 0.21 (95% CI 0.09-0.46, p = < 0.001) for CC. Although multivariable models did not show that SMs were more likely to be diagnosed with PC, BC, or CC, SMs were more likely to be diagnosed with any cancer with ORs of 1.64 (95% CI 1.06-2.54, p = 0.026) in women only and 1.50 (95% CI 1.11-2.03, p = 0.009) in men and women combined. Conclusions: These data suggest that in addition to other established and known specific socio-economic risk factors, SMs may be less likely to undergo screening of prevalent malignancies such as PCa, BC, and CC. This provides more evidence of ongoing healthcare inequality, urging our healthcare system to invest more in cancer screening of this vulnerable population.

The influence of race on financial toxicity among cancer patients

1525

Background: Studies show that cancer patients and survivors are likely to endure financial toxicity long after being diagnosed. Methods: To examine the influence of race on financial toxicity among individuals with a history of cancer, a US based cross sectional study was conducted using data on 1,328 cancer patients collected from the Health Information National Trends Survey. Multivariable logistic regression analyses were used to analyze the relationship between race and financial toxicity, adjusting for known confounders. Results: Blacks, Hispanics and other races were shown to have a lower rate of insurance compared to Whites. Whites were also more likely to receive cancer treatment than other races (6.1% received no treatment vs 15.0% of Blacks, 17.8% of Hispanics, and 9.7% of other races, p<0.001). Considerably more Whites underwent surgical treatment of their cancer (77%) vs. 60% of Blacks, 55% of Hispanics and 74.2% of other races, p<0.001. Blacks were found to be over 5 times more likely to be denied insurance (OR 5.003, 95% CI 2.451-10.213, p<0.001) and more than twice as likely to be hurt financially than Whites (OR 2.448, 95% CI 1.520-3.941, p<0.001). Other racial minorities were also more than twice as likely to be hurt financially than Whites (OR 2.421, 95% CI 1.248-4.698, p=0.009) (Table). Conclusions: These data suggest that race is significantly associated with increased rates of being hurt financially and being denied insurance due to cancer. Awareness of race inequality should be raised so that equal cancer treatment can be provided, irrespective of race, gender or socioeconomic status.[Table: see text]

Genomic landscape of MSH6-mutated clinically advanced castrate-resistant prostate cancer (mCRPC)

5062

Background: Loss-of-function genomic alterations (GAs) in MSH6 have been associated with a unique subtype of hypermutated mCRPC that is often microsatellite stable (MSS) and may occur in either a sporadic or familial Lynch Syndrome-like clinical setting. Methods: 5,617 mCRPC cases were sequenced to evaluate all classes of GA using a hybrid capture-based FDA-approved comprehensive genomic profiling (CGP) assay. Tumor mutational burden (TMB) was determined on 0.8 Mb of sequenced DNA and microsatellite instability high (MSI-High) was determined on 95 loci. MSI-low status was not assessed. Results: 78 (1.4%) mCRPC were MSH6mut (Table). MSH6mut mCRPC included 73.1% short variant mutations, 23.1% biallelic deletions, 2.6% genomic rearrangements, and 1.3% multiple GAs/sample. Co-mutation of MSH2 was found in 28% of MSH6mut cases vs. 2% in MSH6wt cases (P <.0001) and was most frequently caused by biallelic co-deletion of both genes (73% of co-mutated cases). MSI-High status was present in 46% of MSH6mut mCRPC, which was significantly greater than the 2% seen in MSH6wt cases (P <.0001). An MMR single nucleotide mutational signature was observed in 65% of MSH6mut cases, compared to 3% MSH6wt cases (P <.0001). Among MSH6mut cases with neither MSI-High nor MMR mutational signature, 87% did not have biallelic loss of MSH6 or any other MMR gene, confirming that monoallelic pathogenic mutations are insufficient to cause the MMR-D phenotype. For subjects whose variants could be classified, 45% (19/42) of pathogenic MSH6 alleles were germline; of these, 58% (11/19) had neither MSI-High nor an MMR single nucleotide signature. MSH6mut cases had fewer TMPRSS2: ERG fusions (P =.01), but harbored significantly higher frequencies of GAs in AR (P =.0002), ATM (P =.04), PIK3CA (P =.0003), APC (P =.005), ERBB2 (P =.001), and CDK6 (p =.046), likely at least partially attributable to the higher TMB in MSH6mutcases (P <.0001). Conclusions: MSH6mut mCRPC is a unique disease that often features a hypermutated genomic signature, although only 46% of cases exhibited MSI-high status. This complex phenotype highlights the potential utility of multiple rather than single biomarkers to understand tumor biology and determine patients who may benefit from immunotherapy.[Table: see text]

Clinically advanced pelvic squamous cell carcinomas (pSCC) in men and women: A comprehensive genomic profiling (CGP) study

3130

Background: Given that the clinical manifestations, disease course, and treatment options for pSCC differ between tumor types, we performed CGP to examine possible genomic differences. Methods: 1,741 clinically advanced pSCCs including 230 penile (penSCC), 17 male urethral (murthSCC), 125 male anal (manSCC), 7 female urethral (furthSCC), 263 vulvar (vulSCC), 822 cervical (crvSCC), and 277 female anal SCCs (fanSCC) underwent hybrid capture-based CGP to evaluate all classes of genomic alterations (GAs). Tumor mutational burden (TMB) was determined on up to 1.1 Mb of sequenced DNA and microsatellite instability (MSI) was determined on up to 114 loci. PD-L1 expression was determined by IHC (Dako 22C3). Results: HPV-16/18 detection was lowest in murthSCC and vulSCC and highest in manSCC, fanSCC, and crvSCC. TP53 GAs were inversely associated with HPV status. PIK3CA GA frequency varied (22-43%). DNA-damage response (DDR) GAs (e.g., BRCA1/2, ATM, others) were low ( < 1-3%) throughout. Cell-cycle GAs were most frequent in external cases (penSCC, furthSCC, vulSCC). MTOR pathway GAs ( PTEN, FBXW7) were the most frequently identified “actionable” GAs. FGFR3 GA were present in >5% of murthSCC, crvSCC, and fanSCC; other receptor-tyrosine kinase (RTK) targeted options were 1% in BRAF/ ERBB2. NOTCH1 GAs were present in > 15% of penSCC and vulvSCC. TMB ≥10 mut/Mb was >15% in manSCC, fanSCC, and crvSCC. PD-L1 low expression was > 25% in all pSCC except crvSCC and high expression was > 18% in all pSCC except urthSCC and manSCC. Conclusions: Despite similar histology, pSCC differ widely in GAs and HPV status. PIK3CA is the most frequent “targetable” GA followed by MTOR pathway and cell cycle; RTK targets are extremely rare. PARP inhibitor options appear low given the infrequent finding of DDR GAs. Anti-PD(L)1 could be considered in a number of cases based on TMB>10 mut/Mb and PD-L1 expression.[Table: see text]

Comprehensive genomic profiling of metastatic collecting duct carcinoma, renal medullary carcinoma, and clear cell renal cell carcinoma

INTRODUCTION AND OBJECTIVE

Unlike clear cell renal cell carcinoma (CCRCC), collecting duct carcinoma (CDC) and renal medullary carcinoma (RMC) are rare tumors that progress rapidly and appear resistant to current systemic therapies. We queried comprehensive genomic profiling to uncover opportunities for targeted therapy and immunotherapy.

MATERIAL AND METHODS

DNA was extracted from 40 microns of formalin-fixed, paraffin-embedded specimen from relapsed, mCDC (n = 46), mRMC (n = 24), and refractory and metastatic (m) mCCRCC (n = 626). Comprehensive genomic profiling was performed, and Tumor mutational burden (TMB) and microsatellite instability (MSI) were calculated. We analyzed all classes of genomic alterations.

RESULTS

mCDC had 1.7 versus 2.7 genomic alterations/tumor in mCCRCC ( = 0.04). Mutations in VHL (P < 0.0001) and TSC1 (P = 0.04) were more frequent in mCCRCC. SMARCB1 (P < 0.0001), NF2 (P = 0.0007), RB1 (P = 0.02) and RET (P = 0.0003) alterations were more frequent in mCDC versus mCCRCC. No VHL alterations in mRMC and mCDC were identified. SMARCB1 genomic alterations were significantly more frequent in mRMC than mCDC (P = 0.0002), but were the most common alterations in both subtypes. Mutations to EGFR, RET, NF2, and TSC2 were more frequently identified in mCDC versus mRMC. The median TMB and MSI-High status was low with <1% of mCCRC, mCDC, and mRMC having ≥ 20 mut/Mb.

CONCLUSION

Genomic alteration patterns in mCDC and mRMC differ significantly from mCCRCC. Targeted therapies for mCDC and mRMC appear limited with rare opportunities to target alterations in receptor tyrosine kinase and MTOR pathways. Similarly, TMB and absence of MSI-High status in mCDC and mRMC suggest resistance to immunotherapies.

The association between sexual orientation and screening of prevalent gender-specific cancers

198

Background: Data on heterogeneity in cancer screening and diagnosis rates among sexual minorities (SMs) is lacking. Recent studies have shown SMs are more likely to engage in risky health behavior and have decreased healthcare utilization. However, few studies have examined how sexual orientation impacts cancer screening and prevalence. We therefore investigated whether sexual orientation affects prevalent gender-specific cancer including prostate (PCa), breast (BC), and cervical cancer (CC). Methods: This was a cross-sectional survey-based US study, including men and women aged 18+ from the Health Information National Trends Survey (HINTS) database (part of the National Cancer Institute’s division of cancer control and population sciences) between 2017-2019. The primary endpoint was individual-reported PCa, BC, and CC screening and prevalence rates among heterosexuals and homosexuals/bisexuals. Multivariable logistic regression analyses assessed association of various covariates with undergoing screening and diagnosis of these cancers. Results: Overall, 4,441 and 6,333 heterosexual men and women, respectively, were compared to 225 and 213 homosexual/bisexual men and women, respectively. Homosexuals/bisexuals were younger and less likely to be screened for PCa (34.7% vs 41.3%, p=0.013), BC (54.5% vs 80.7%, p=<0.001), and CC (88.3% vs 95.4%, p=<0.001). While rates of PCa and BC diagnosis were similar, more than twice as many homosexual/bisexual women were diagnosed with CC (4.2% vs 1.9%, p=0.023). Multivariable logistic regression models (Table) showed homosexuals/bisexuals were less likely to be screened for cancer with ORs of 0.61 (95% CI 0.39-0.95) for PCa, 0.52 (95% CI 0.30-0.92) for BC, and 0.21 (95% CI 0.09-0.46) for CC. Homosexuals/bisexuals were more likely to be diagnosed with any cancer with ORs of 1.64 (95% CI 1.06-2.54) in women only and 1.50 (95% CI 1.11-2.03) in men and women combined. Conclusions: Homosexuals/bisexuals in the US may be less likely to undergo screening of gender-specific prevalent malignancies, including PCa, BC, and CC. The implementation of cancer screening among SMs should be improved. [Table: see text]

Sarcomatoid (srcRCC) versus clear cell (ccRCC) renal cell carcinoma: A comparative comprehensive genomic profiling (CGP) study

349

Background: srcRCC is a well-described histologic entity often featuring rapid progression and aggressive clinical course when compared with classic ccRCC. We queried whether CGP would uncover opportunities for targeted and immunotherapy (IO) for srcRCC patients that could individualize their treatment and entry into clinical trials. Methods: Using a hybrid capture-based CGP assay to evaluate all classes of genomic alterations (GA), 160 cases of srcRCC and 1,664 cases of ccRCC were sequenced from FFPE tissue samples. Tumor mutational burden (TMB) was determined on up to 1.1 Mbp of sequenced DNA and microsatellite instability (MSI) was determined on up to 114 loci. PD-L1 expression was determined by IHC (Dako 22C3) with low tumor cell positive staining set at 1-49% and high staining >50% expression. Results: Gender and age distributions for both tumor types were similar. srcRCC featured significantly higher GA/tumor than ccRCC (P < .0001). CGP revealed major differences with ccRCC associated more frequently with tumor suppressor gene (TSG) losses in VHL, PBRM1, TSC2 and SETD2 (all P < .0001). In contrast, srcRCC is associated with cell proliferation with increased inactivation of cell cycle regulatory genes including TP53, CDKN2A/B, MDM2 and TERT (all P < .0001). RB1 GA in srcRCC may reflect neuroendocrine differentiation occasionally found in these tumors. NF2 GA were more frequent in srcRCC (P < .0001). Conclusions: CGP reveals striking differences between srcRCC and ccRCC which may in part explain the differing histologic appearances and typical clinical course of these 2 aggressive malignancies. ccRCC is driven more by TSG loss and srcRCC is driven more by cell cycle dysregulation. Targeted therapy opportunities were uncommon for both tumor types although each featured biomarkers potentially predictive of mTOR inhibitor responses ( TSC2 in ccRCC and NF2 in srcRCC). Although the higher PBRM1 GA frequency in ccRCC may explain the IO benefit well-known for this tumor type, the srcRCC group features significantly increased TMB, CD274 amplification and PD-L1 staining which may also create IO opportunities for srcRCC patients. [Table: see text]

Novel synthetic lethality (SL) anti-cancer drug target in urothelial bladder cancer (UCB) based on MTAP genomic loss: Incidence and correlations in standard of care (SOC)

485

Background: When UCB presents or progresses to chemorefractory metastatic disease, the search for new therapy targets is paramount. Targeting PRMT5 arginine methyltransferase accumulation in tumors with MTAP (methylthioadenosine Phosphorylase) genomic loss has been proposed as a new SL based anti-tumor strategy and under consideration for development for UCB. We sought to evaluate the incidence of patients with candidate SL and correlate to treatment-guiding biomarkers currently evaluated in SOC. Methods: 2,683 cases of clinically advanced UCB underwent hybrid-capture based comprehensive genomic profiling in a standard of care setting using the F1CDx FDA-approved assay to evaluate all classes of genomic alterations (GA) among 324 genes. Tumor mutational burden (TMB) was determined on 0.8 Mbp of sequenced DNA and microsatellite instability (MSI) was determined on 95 loci. PD-L1 expression was determined by IHC (Dako 22C3). Results: 650 (24%) of UCB feature MTAP loss (MTAP-) (Table). The gene and age distributions were similar MTAP intact (MTAP+) and MTAP- UCB. The GA/tumor was higher in MTAP- UCB likely reflecting the significant GA co-deletions of CDKN2A/ B at the 9p21 locus. Of potential therapeutic targets, FGFR3 and PTEN GA were more frequent in the MTAP- UCB. In contrast, biomarkers of immunotherapy (IO) response included higher frequencies of high TMB and high PD-L1 IHC staining in the MTAP+ UCB. Conclusions: When compared with MATP+ UCB, MTAP- UCB differs in genomic signatures including an increase in potential for targeted therapies but a lower potential for IO drug benefit. Thus, the genomic landscape in MTAP- UCB may play a significant role in the design of clinical trials incorporating SL strategies when targeting PRMT5 in MTAP deficient tumors. [Table: see text]

Clinically advanced penile (pSCC) and male urethral (uSCC) squamous cell carcinoma: A comparative genomic profiling (CGP) study

2

Background: Although SCC of the penile skin (pSCC) and the male urethral surface epithelium (uSCC) arise in nearby locations and can feature similar histology, their clinical manifestations, disease course, and surgical and medical treatment options are distinct. We performed CGP on pSCC and uSCC to examine genomic profiles differences. Methods: Tissues obtained from men with clinically advanced pSCC (n = 230) and uSCC (n = 17) underwent hybrid capture-based CGP to evaluate all classes of genomic alterations (GAs). Tumor mutational burden (TMB) was determined on up to 1.1 Mb of sequenced DNA and microsatellite instability (MSI) was determined on up to 114 loci. PD-L1 expression was determined by IHC (Dako 22C3). Results: The median ages were similar in both groups. pSCC exhibited a slightly higher frequency of HPV-16/18 infection (29% vs. 12%, P = .16), although the TP53 mutation frequencies were nearly identical (55% vs. 59%, NS). CDKN2A inactivation (P = .08), CCND1 amplification trending higher and TERT promoter mutations (P = .01) were more frequent in pSCC, potentially indicating prior HPV infection. GAs in NOTCH1 were exclusively identified in pSCC. Potentially actionable GAs identified in both groups included PIK3CA activating mutations (TKIs) as well as pathogenic alterations in FBXW7 and PTEN (MTOR inhibitors). Rare BRCA1 and BRCA2 inactivation (PARP inhibitors) was seen in pSCC only. High-positive PD-L1 staining was elevated in pSCC (34 vs. 14%, P = .06). Although average TMB was similar in both groups, pSCC exhibited an elevated frequency of cases with CD274 ( PD-L1) amplification as well as TMB >10 mut/Mb which are on label for immune checkpoint inhibitor (ICPI) treatment. Conclusions: CGP of pSCC and uSCC identifies opportunities for both targeted and ICPI therapies. Compared to uSCC, pSCC had genomic features more similar to head and neck SCC including slightly increased cell-cycle perturbation, HPV infection, and NOTCH pathway signaling alterations. Further use of CGP in the treatment planning for pSCC and uSCC may be warranted. [Table: see text]

HHV-8 positive clinically advanced castrate-resistant prostate cancer (mCRPC): A potentially distinct molecular subset

163

Background: Herpesvirus HHV-8 has been detected in normal prostate tissue and has been linked to the acquisition of androgen-independent growth of prostate cancer cells in vitro, early development of anti-androgen therapy resistance, and more aggressive disease in a subset of patients with mCRPC. We used comprehensive genomic profiling (CGP) to test the hypothesis that HHV-8 associated mCRPC is a distinct molecular subset of mCRPC featuring altered AR signaling compared to HHV-8 negative mCRPC. Methods: Using a hybrid capture-based FDA-approved CGP assay, a series of 4,918 mCRPC were sequenced to evaluate all classes of genomic alterations (GAs). Tumor mutational burden (TMB) was determined on up to 1.1 Mb of sequenced DNA and microsatellite instability (MSI) was determined on 114 loci. PD-L1 expression was determined by IHC (Dako 22C3). HHV-8 status was determined by CGP-based identification of unique viral reads. Results: Overall, 128 (2.6%) of the mCRPC cases harbored HHV-8 sequences (Table). The patient age distribution was similar in the HHV-8+ and HHV-8− groups. GAs in AR, predominantly amplifications, and RAD21 were slightly reduced in HHV-8+ mCRPC cases (P = .01 for both). The frequencies of GAs in genes associated with mCRPC including PTEN, BRCA2, ATM, CDK12, and the TMPRSS2: ERG fusion were similar in the two groups. HHV-8+ patients were less likely to be of European ancestry (P = 0.001). Putative biomarkers associated with immunotherapy response (MSI status, TMB, and PD-L1 expression) were also similar in the two groups. Conclusions: HHV-8+ mCRPC is a rare sub-type of mCRPC with lower frequency of AR GAs compared to HHV-8− mCRPC cases, suggesting a potential role of HHV-8 in inducing androgen-independent prostate cancer growth. Additional alterations associated with potentially enhanced PARP inhibitor response seen in HHV-8+ mCRPC (e.g., RAD21) suggest that early performance of CGP may inform precision treatment strategies to be tested in clinical trials. [Table: see text]

HPV-16 positive clinically advanced squamous cell carcinoma of the urinary bladder (mBSCC): A comprehensive genomic profiling (CGP) study

481

Background: mBSCC is an uncommon form of urinary bladder malignancy when compared with the much higher urothelial carcinoma incidence. We studied the genomic alteration (GA) landscape in a series of mBSCC based on the association with HPV-16 to determine if differences would be observed between the positive and negative groups. Methods: Using a hybrid capture-based FDA-approved CGP assay, a series of 171 mBSCC were sequenced to evaluate all classes of GA. Tumor mutational burden (TMB) was determined on up to 1.1 Mbp of sequenced DNA and microsatellite instability (MSI) was determined on 114 loci. PD-L1 expression was determined by IHC (Dako 22C3) with low tumor cell positive staining set at 1-49% and high staining at ≥50% expression. Results: Overall, 11 (6.4%) of the mBSCC were found to harbor HPV-16 sequences (Table). HPV-16+ status was identified slightly more often in women (NS) and in younger patients (P = .04); 2 female patients with mBSCC had prior history of SCC including 1 anal SCC and 1 vaginal SCC. HPV-16+ mBSCC had fewer GA/tumor (P < .0001), and fewer inactivating GA in CDKN2A (P < .0001), CDKN2B (P = .05), TERT promoter (P = .0004) and TP53 (P < .0001). GA in genes associated with urothelial carcinoma including FGFR2 and FGFR3 were similar in both HPV-16+ and HPV-16- mBSCC groups. MTOR and PIK3CA pathway GA were not significantly different in the 2 groups. MSI and TMB were also similar in the 2 groups. The 3 HPV-16+ mBSCC cases showed high positive PD-L1 IHC staining. Conclusions: HPV-16+ mBSCC tends to occur more often in women and younger patients. As reported in other HPV-associated squamous cell carcinomas, HPV-16+ mBSCC demonstrates significantly reduced frequencies of inactivating mutations in cell cycle regulatory genes with similar GA in MTOR and PIK3CA pathways. The implication of HPV in the pathogenesis of bladder cancer remains unknown but warrants further exploration and clinical validation. [Table: see text]

Comprehensive genomic profiling (CGP) in patients with relapsed/refractory germ cell tumors (GCT)

388

Background: Understanding the genetic alterations in patients with relapsed/refractory GCT (rrGCT) could delineate the pathogenesis of cisplatin resistance. Our study uses CGP to characterize genomic alterations (GA) in refractory GCT and correlate with clinical outcomes. Methods: 432 patients with rrGCT were seen at Indiana University between Jan 2016 to Sep 2019 of whom 52 patients underwent CGP using a hybrid-capture based commercial assay to evaluate all classes of GA. Tumor mutational burden (TMB) was determined on 1.1 Mbp of sequenced DNA and reported as mutations/Mb and microsatellite instability (MSI) was determined on 114 loci. PDL1 expression was determined by IHC (DAKO 22C3 antibody). Results: All patients relapsed after first-line cisplatin-based combination chemotherapy. Median age at diagnosis was 33 (range 15-68). Primary site of GCT was testicular in 85% and mediastinum in 8%. 6 patients had pure seminoma and 46 had non-seminoma. Platinum refractory disease, defined as serologic or radiographic progression within 4 weeks of first-line chemotherapy comprised 23% of patients. The primary tumor was used for sequencing in 6 cases (12%) and non-primary tumor metastatic site (lymph node, lung, liver, brain, omentum) in 46 cases (88%). The most common GA in the entire cohort were FGF6 (27%), FGF23 (27%), KDM5A (27%), CCND2 (27%), KRAS (18%), TP53 (14%), KIT (8%), APC (8%), ZNF217 (6%), MUTYH (6%), AURKA (6%), NRAS (6%), EGFR (6%), CTNNB1 (6%), GNAS (6%). Most common alterations for testicular primary tumors were FGF6, FGF23, KDM5A, CCND2, KRAS, TP53, KIT. For non-testicular primary GCT, most common GA were APC, TP53, EGFR. Most common GA for non-seminoma were FGF6, FGF23, KDM5A, CCND2, KRAS, TP53, APC. Most common GA for pure seminoma was KIT. Potentially targetable genomic alterations were found in 17 patients (33%). 10 of 17 patients (59%) tested had PDL1 score ≥1% and 3 patients had PDL1 ≥50%. Median TMB was 3.5 mutations/MB. There were 4 patients (8%) with TMB ≥ 10 mutations/Mb and 2 patients (4%) with TMB ≥ 20 mutations/Mb. 1 of 48 patients (2%) evaluated for MSI had MSI-High status. Isochromosome 12p was detected in the majority of samples where it was tested. Outcomes with GA-directed therapy will be presented at the conference. Conclusions: CGP can reveal potential therapeutic targets in patients with rrGCT including EGFR, ERBB3, KIT, and MET. Consistent with reported clinical trials in rrGCT, biomarkers predicting response to immune checkpoint blockade are uncommon with most patients having low TMB, absence of MSI-H status, and low expression of PDL1.

Genomic landscape of CDK12 mutated metastatic castrate-resistant prostate cancer (mCRPC)

165

Background: Identifying prostate cancer patients likely to benefit from immune checkpoint inhibitors (ICPI) remains an unmet need. Specific loss-of-function genomic alterations (GA) in CDK12 are associated with focal tandem duplications linked to fusion-induced production of neoantigens and are a promising candidate biomarker for ICPI. Using comprehensive genomic profiling (CGP) we compared the GA landscape of CDK12 altered (CDK12mut+) and unaltered (CDK12mut-) tumors. Methods: 4,918 mCRPC tumors were sequenced using a hybrid capture-based FDA-approved CGP assay. Tumor mutational burden (TMB) was determined on 0.8 Mbp of sequenced DNA and microsatellite instability (MSI) was determined on 95 loci. PD-L1 expression was determined by IHC (Dako 22C3) with low tumor cell positive staining -49% and high staining ≥50% expression. Results: Overall, 315 (6.4%) of the mCRPC cases were CDK12mut+ (Table). CDKmut+ cases had significantly fewer GA in TMPRSS2: ERG (P < .0001), TP53 (P < .0001), PTEN (P < .0001), ATM (P = .001), PIK3CA (P = .003), RB1 (P = .02), BRCA2 (P < .0001) and APC (P = .002). CDK12mut+ cases featured higher frequencies only in CCND1 (P < .0001), BRAF (P = .007) and ERBB2 (P < .001) as well as in cell cycle regulatory genes including MDM2/4 (P < .0001), CDK4 (P < .0001) and CDK6 (P = .002). CDK12mut+ cases featured more frequent MSI-H status (P = .007), significantly higher median TMB (P < .001) and more frequent low positive (1-49% staining) PD-L1 expression (P = .02). High (≥50%) PD-L1 expression was rarely identified in either cohort. Conclusions: CDK12mut+ mCRPC demonstrates a unique genomic profile with significant differences compared with CDK12mut- mCRPC. Lower frequencies of GA associated with homologous recombination defect and mTOR pathway may impact the use of platinum agents, as well as PARPi and PIK3CA/Akt/mTOR inhibitors. Opportunities for targeted therapies for BRAF and ERBB2 driven mCRPC may be enriched in the CDK12mut+ tumors and raise the possibility of combination therapy strategies although the numbers of patients are small and validation is needed. The slightly higher MSI High status, median TMB and PD-L1 staining may be associated with additional benefit from ICPI and warrants further prospective investigation. [Table: see text]

Contrasting genomic profiles in post-systemic treatment metastatic sites (MET), pretreatment primary tumors (PT), and liquid biopsies (LB) of clinically advanced prostate cancer (PC)

5534

Background: Comprehensive genomic profiling (CGP) was done on pre-systemic treatment (pre) PT, post-treatment (post) MET sites and LB in PC to uncover differences in genomic alterations (GA) and potential impact on therapy selection. Methods: 1,294 PC tissues and 782 LB underwent hybrid-capture based CGP. PT biopsies and resections were compared with post-treatment MET biopsies from bone (BO), liver (LIV), lung (LU), brain (BN), lymph node (LN) and soft tissue (ST) sites and LB. TMB was determined on up to 1.1 Mbp of sequenced DNA for tumor samples. Tumor cell PD-L1 IHC was measured (Dako 22C3). Results: Differences in alteration frequencies between PT, MET and LB for selected genes are shown in the Table. TMPRSS2:ERG fusion frequencies were similar between PT and MET (35% vs 33%) but varied between MET sites (27% in BO and ST to 40% in LN). GA in AR were lowest in pre PT (2%) and highest in MET (24% in LU to 50% in LIV). BN had the highest GA/tumor (8) and the most PTEN GA. BRCA2 GA frequency varied from 0% in BN to 15% in LI. Potential predictors of IO response included CDK12 GA (16% in LU) and MSI high status (29% in BN). High PD-L1 expression was found in only two cases (LN) and low PD-L1 expression was relatively uncommon. ERBB2 amplifications were increased in MET compared with PT. RB1 GA were increased in LIV cases. LB GA had a similar increase in AR and TP53 GA to MET and appeared to be a blend of MET site biopsies across alteration frequencies. Conclusions: CGP of PT, MET and LB in PC demonstrates differences most likely associated with exposure to systemic therapies. Differences identified in the MET GA landscape suggest that liquid biopsies may capture a broader range of therapeutic opportunities for PC patients. [Table: see text]

Comprehensive genomic profiling (CGP) in patients with relapsed/refractory germ cell tumors (GCT)

e17053

Background: Understanding the genetic alterations in patients with relapsed/refractory GCT (rrGCT) could delineate the pathogenesis of cisplatin resistance. Our study uses CGP to characterize genomic alterations (GA) in refractory GCT and correlate with clinical outcomes. Methods: 432 patients with rrGCT were seen at Indiana University between Jan 2016 to Sep 2019 of whom 52 patients underwent CGP using a hybrid-capture based commercial assay to evaluate all classes of GA. Tumor mutational burden (TMB) was determined on 1.1 Mbp of sequenced DNA and reported as mutations/Mb and microsatellite instability (MSI) was determined on 114 loci. PDL1 expression was determined by IHC (DAKO 22C3 antibody). Results: All patients relapsed after first-line cisplatin-based combination chemotherapy. Median age at diagnosis was 33 (range 15-68). Primary site of GCT was testicular in 85% and mediastinum in 8%. 6 patients had pure seminoma and 46 had non-seminoma. Platinum refractory disease, defined as serologic or radiographic progression within 4 weeks of first-line chemotherapy comprised 23% of patients. The primary tumor was used for sequencing in 6 cases (12%) and non-primary tumor metastatic site (lymph node, lung, liver, brain, omentum) in 46 cases (88%). The most common GA in the entire cohort were FGF6 (27%), FGF23 (27%), KDM5A (27%), CCND2 (27%), KRAS (18%), TP53 (14%), KIT (8%), APC (8%), ZNF217 (6%), MUTYH (6%), AURKA (6%), NRAS (6%), EGFR (6%), CTNNB1 (6%), GNAS (6%). Most common alterations for testicular primary tumors were FGF6, FGF23, KDM5A, CCND2, KRAS, TP53, KIT. For non-testicular primary GCT, most common GA were APC, TP53, EGFR. Most common GA for non-seminoma were FGF6, FGF23, KDM5A, CCND2, KRAS, TP53, APC. Most common GA for pure seminoma was KIT. Potentially targetable genomic alterations were found in 17 patients (33%). 10 of 17 patients (59%) tested had PDL1 score ≥1% and 3 patients had PDL1 ≥50%. Median TMB was 3.5 mutations/MB. There were 4 patients (8%) with TMB ≥ 10 mutations/Mb and 2 patients (4%) with TMB ≥ 20 mutations/Mb. 1 of 48 patients (2%) evaluated for MSI had MSI-High status. Isochromosome 12p was detected in the majority of samples where it was tested. Outcomes with GA-directed therapy will be presented at the conference. Conclusions: CGP can reveal potential therapeutic targets in patients with rrGCT including EGFR, ERBB3, KIT, and MET. Consistent with reported clinical trials in rrGCT, biomarkers predicting response to immune checkpoint blockade are uncommon with most patients having low TMB, absence of MSI-H status, and low expression of PDL1.

Comprehensive genomic profiling (CGP) of histologic subtypes of urethral carcinomas (UrthCa)

5087

Background: UrthCa is an uncommon GU malignancy that can progress to advanced metastatic disease. Methods: 127 metastatic UrthCa underwent hybrid-capture based CGP to evaluate all classes of genomic alterations (GA). Tumor mutational burden (TMB) was determined on up to 1.1 Mbp of sequenced DNA and microsatellite instability (MSI) was determined on 114 loci. PD-L1 expression was determined by IHC (Dako 22C3). Results: 49 (39%) urothelial (UrthUC), 31 (24%) squamous (UrthSCC), 34 (19%) adenocarcinomas (UrthAC) and 13 (9%) clear cell (UrthCC) were evaluated along with a control cohort of 2,130 bladderUC cases. UrthUC and UrthSCC were more common in men; UrthAC and UrthCC more common in women. Age was similar in all 4 groups. GA in PIK3CA were the most frequent potentially targetable GA; MTOR pathway GA in PTEN also identified. GA in other potentially targetable genes were also identified including ERBB2(6% in UrthUC, 3% in UrthSCC and 12% in UrthAC), FGFR1-3 (3% in UrthSCC), BRAF (3% in UrthAC), PTCH1 (8% in UrthCC) and MET (8% in UrthCC). Higher TMB was seen in UrthUC and UrthCC compared to UrthAC and UrthSCC, possibly reflecting their higher GA/tumor status and suggesting potential for immunotherapy benefit. MSI high status was absent throughout. The bladderUC cases had similar genomic pattern as UrthUC with significantly lower frequency of HPV16/18 positive cases. Conclusions: CGP reveals GA that may be predictive of both targeted and immunotherapy benefit in patients with advanced UrthCa and that could potentially be used in future adjuvant, neoadjuvant and metastatic disease trials. [Table: see text]

Clinically advanced renal cell carcinoma (RCC) and renal sarcoma (RSC) in young patients: A comprehensive genomic profiling (CGP) study

5066

Background: We queried whether the landscape of genomic alterations (GA) would differ in patients with metastatic RCC under 40 years of age (under40) and patients 40 years of age or older (over40). Methods: FFPE tissues from 2,128 clinically advanced RCC and 25 RSC underwent hybrid-capture based CGP to evaluate all classes of GA. Samples were classified at time of sequencing as the following RCC subtypes: clear cell (ccRCC), papillary (papRCC), chromophobe (chrRCC), medullary (medRCC), collecting duct (cdRC), sarcomatoid (sarcRCC) and NOS (nosRCC). Tumor mutational burden (TMB) was determined on up to 1.1 Mbp of sequenced DNA. Tumor cell PD-L1 expression was determined by IHC (Dako 22C3). Results: The male preponderance increased in the over40 patients. The GA/tumor increased in the over40 cohorts except for medRCC. Similarly, TMB was consistently higher in over40 groups. MSI high status was virtually absent. PD-L1 expression, available only in small subsets, was generally absent although 44% high positive staining in sarcRCC was noteworthy. Differences in GA in under40 vs over40 RCC were seen and included increased PBRM1 and SETD2 GA in over40 vs under40 ccRCC; increased C DKN2A/B and TERT and decreased FH GA in over40 vs under40 papRCC; increased TP53 and decreased VHL, BAP1, SETD2 and PTEN in over40 vs under40 chrRCC; increased TP53, PTEN and TERT GA with decreased NF2 GA in over40 vs under 40 sarcRCC; and increased TP53, VHL and TERT in over40 vs under40 nosRCC. Changes in GA in under40 vs over40 medRCC, cdRCC and RSC were noted but insufficient cases prevented further evaluation. Conclusions: When separately evaluated by under/over 40 years of age, CGP of clinically advanced RCC demonstrates differences in genomic landscapes with over40 cases featuring increasing male preponderance, higher GA/tumor, higher TMB and increases in a variety of GA. These findings may play important roles in the planning of future clinical trials designed to personalize the treatment of metastatic RCC. [Table: see text]