Molecular Characterization of TFE3-Rearranged Renal Cell Carcinoma: A Comparative Study With Papillary and Clear Cell Renal Cell Carcinomas

TFE3-rearranged renal cell carcinoma (rRCC) is a rare subtype of renal cell carcinomas belonging to the MiT family translocation RCC. To further elucidate the co-alterations that occur along with TFE3 fusions in rRCC, we characterized the genomic, transcriptional, and immune landscapes in comparison to clear cell (ccRCC) and papillary renal cell carcinoma (pRCC). Next-generation sequencing of RNA (whole transcriptome) and DNA (592-gene panel or whole exome) for rRCC (N = 20), pRCC (N = 20), and ccRCC samples (N = 392) was performed. Patients with rRCC were significantly younger and more frequently female (median 44.5 years, 75.0% female) as compared with patients with pRCC (68.5 years, 25.0% female; P < .05) and ccRCC (62.0 years, 27.8% female; P < .05). A total of 8 unique fusion partners were observed, including a novel fusion with SRRM2::TFE3 in 2 patients. ccRCC exhibited significantly higher mutation rates of VHL (0% rRCC, 0% pRCC, 78.7% ccRCC; P < .05) and PBMR1 (0% rRCC, 5.0% pRCC, 49.4% ccRCC; P < .05). The genomic landscapes of rRCC were sparse with no mutations occurring with a prevalence higher than 10% other than pTERT (18.2% rRCC, 0% pRCC, 9.2% ccRCC). rRCC were associated with significantly less M1 macrophages (0.8%) as compared with pRCC (1.4%) and ccRCC (2.7%) (P < .05), suggesting a cold tumor-immune microenvironment. However, rRCC were more commonly PD-L1+ (rRCC 50%, pRCC 19.0%, ccRCC 12.2%; P < .05). Gene set enrichment analysis showed that rRCC are enriched in genes related to oxidative phosphorylation when compared with both ccRCC and pRCC. Despite having a colder tumor-immune microenvironment than pRCC and ccRCC, increased PDL1+ rates in rRCC suggest a potential benefit from immune checkpoint inhibitor therapy.

A Phase 2 Study of Sitravatinib in Combination with Nivolumab in Patients with Advanced or Metastatic Urothelial Carcinoma

BACKGROUND AND OBJECTIVE

Checkpoint inhibitor therapy (CPI) has demonstrated survival benefits in urothelial carcinoma (UC); however, not all patients benefit from CPI due to resistance. Combining sitravatinib, a multitargeted receptor tyrosine kinase inhibitor of TYRO3, AXL, and MERTK (TAM) receptors and VEGFR2, with CPI may improve antitumor responses. Our objective was to assess the efficacy and safety of sitravatinib plus nivolumab in patients with advanced/metastatic UC.

METHODS

The 516-003 trial (NCT03606174) is an open-label, multicohort phase 2 study evaluating sitravatinib plus nivolumab in patients with advanced/metastatic UC enrolled in eight cohorts depending on prior treatment with CPI, platinum-based chemotherapy (PBC), or antibody-drug conjugate (ADC). Overall, 244 patients were enrolled and treated with sitravatinib plus nivolumab (median follow-up 14.1-38.2 mo). Sitravatinib (free-base capsules 120 mg once daily [QD] or malate capsule 100 mg QD) plus nivolumab (240 mg every 2 wk/480 mg every 4 wk intravenously).

KEY FINDINGS AND LIMITATIONS

The primary endpoint was objective response rate (ORR; RECIST v1.1). The secondary endpoints included progression-free survival (PFS) and safety. The Predictive probability design and confidence interval methods were used. Among patients previously treated with PBC, ORR, and median PFS were 32.1% and 3.9 mo in CPI-naïve patients (n = 53), 14.9% and 3.9 mo in CPI-refractory patients (n = 67), and 5.4% and 3.7 mo in CPI- and ADC-refractory patients (n = 56), respectively. Across all cohorts, grade 3 treatment-related adverse events (TRAEs) occurred in 51.2% patients and grade 4 in 3.3%, with one treatment-related death (cardiac failure). Immune-related adverse events occurred in 50.4% patients. TRAEs led to sitravatinib/nivolumab discontinuation in 6.1% patients.

CONCLUSIONS AND CLINICAL IMPLICATIONS

Sitravatinib plus nivolumab demonstrated a manageable safety profile but did not result in clinically meaningful ORRs in patients with advanced/metastatic UC in the eight cohorts studied.

PATIENT SUMMARY

In this study, the combination of two anticancer drugs, sitravatinib and nivolumab, resulted in manageable side effects but no meaningful responses in patients with bladder cancer.

Contaminants of emerging concern: Silylation procedures, evaluation of the stability of silyl derivatives and associated measurement uncertainty

Analyte range of gas chromatography-mass spectrometry (GC-MS), widely used in environmental analysis, can be significantly broadened by derivatization. Silyl derivatives have improved volatility and thermal stability, chromatographic and mass spectrometric behaviors, and thus detection, structural elucidation and quantification. However, silylation use is often hindered by the stability of generated derivatives and the need to optimize silylation conditions. In this study, we optimized the derivatization conditions for 70 selected contaminants of emerging concern (CEC) using chemometrics approaches. N-methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA), N, O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) and BSTFA + 1 % trimethylchlorosilane (TMCS) were investigated, among which the latter gave the best yield. CEC were grouped in three derivatization protocols: 60 °C/45 min, 70 °C/90 min, and 70 °C/45 min. The short- and long-term stability of the CEC-trimethylsilyl (TMS) derivatives, i.e. for 28 days and up to 20 weeks were examined in a solvent and artificial wastewater (AWW) extract at 25 °C, 4 °C and - 18 °C, and during repeated five freeze-thaw (F/T) cycles, at two concentration levels: 100 μg/L and 1000 μg/L. Except for TMS derivatives of shikimic acid (SHA), quinic acid (QA) and sulfanilamide (SFA), the remaining derivatized compounds were stable in solvent (EtAc) for 28 days. In AWW extract, TMS derivatives of citric acid (CA), 17β-estradiol (E2), estriol (E3) and 17α-ethinyl estradiol (EE2) were unstable at 25 °C and 4 °C. Within up to 20 weeks, only the TMS derivatives of CA, meso-erythritol (ERY) and bisphenol BP (BPBP) were unstable. The most significant hydrolytic breakdown was observed during repeated F/T cycles. After three cycles, ≤ 20 % of the initial concentration of six and nine CEC-TMS derivatives had degraded in solvent and AWW extracts, respectively. According to the deep statistical comparison (DSC) approach, the most prominent degradation was observed for TMS derivatives of E2, CA, 9-hydroxyfluorene (9-HF), estrone (E1) and trans-3'-hydroxycotinine (T3HC) in solvent; E2, CA, 9-HF, E3 and E1 in AWW extracts and ERY, E2, CA, 9-HF and E1 in both matrices. Finally, the sample concentration of CEC accounted for most of the measurement uncertainty (MU). Based on our findings, we recommend the derivatized samples to be stored at -18 °C for up to 20 weeks to ensure the stability of their TMS derivatives. Sample freezing and thawing of not more than twice is allowed to maintain ≥80 % of the initial CEC-TMS concentration.

Quality of life in the year after new diagnosis with advanced prostate cancer for Black and White individuals living in the US

PURPOSE

To assess differences in baseline and longitudinal quality of life among Black and White individuals in the US with advanced prostate cancer.

METHODS

Secondary analysis of data from the International Registry for Men with Advanced Prostate Cancer (IRONMAN) including US participants newly diagnosed with advanced prostate cancer and identifying their race as Black or White from 2017 to 2023. Participants completed the EORTC QLQ-C30 Quality of Life (QoL) Survey at study enrollment and every 3 months thereafter for up to 1 year of follow-up reporting 15 scale scores ranging from 0 to 100 (higher functioning and lower symptom scores represent better quality of life). Linear mixed effects models with race and month of questionnaire completion were fit for each scale, and model coefficients were used to assess differences in baseline and longitudinal QoL by race.

RESULTS

Eight hundred and seventy-nine participants were included (20% identifying as Black) at 38 US sites. Compared to White participants at baseline, Black participants had worse constipation (mean 6.3 percentage points higher; 95% CI 2.9-9.8), financial insecurity (5.7 (1.4-10.0)), and pain (5.1 (0.9-9.3)). QoL decreased over time similarly by race; most notably, role functioning decreased by 0.7 percentage points (95% CI -0.8, -0.5) per month.

CONCLUSION

There are notable differences in quality of life at new diagnosis of advanced prostate cancer for Black and White individuals, and quality of life declines similarly in the first year for both groups. Interventions that address specific aspects of quality of life in these patients could meaningfully improve the overall survivorship experience.

Experience with the US health care system for Black and White patients with advanced prostate cancer

OBJECTIVE

The purpose of this study was to assess differences in reported information about treatment, integration into care, and respect by self-identified Black and White individuals with advanced prostate cancer in the United States.

PATIENTS AND METHODS

This is a prospective cohort study of 701 participants (20% identifying as Black) enrolled in the International Registry for Men with Advanced Prostate Cancer at 37 US sites from 2017 to 2022. Participants were asked six questions from the Cancer Australia National Cancer Control Indicators about their experience with care at study enrollment. Prevalence differences by self-reported race were estimated using marginal standardization of logistic-normal mixed effects models (adjusted for age at enrollment and disease state at enrollment), and 95% CIs were estimated using parametric bootstrapping.

RESULTS

Most participants reported a high quality of care for each question. Black participants generally reported higher care quality compared with White participants. Black participants reported more frequently that they were offered a written assessment and care plan (71%) compared with White participants (58%; adjusted difference, 13 percentage points; 95% CI, 4-23). Black participants also reported more frequently being given the name of nonphysician personnel who would support them (64%) than White participants (52%; adjusted difference, 10; 95% CI, 1-20). Prevalence differences did not differ by disease state at enrollment.

CONCLUSIONS

Black participants generally reported a higher quality of care compared with White participants. This study calls attention to the need to study potential mediating factors and interpersonal aspects of care in this population to improve survivorship.

Abstract 1895: Molecular characterization of prostate cancer between Hispanic American and Non-Hispanic Whites: Implications for cancer ethnic health disparities

Background: Although there is increased awareness leading to early detection and prevention, Hispanic American (HA) men with prostate cancer (PC) continue to have greater mortality rates compared to their Non-Hispanic White (NHW) counterparts. Moreover, HA men with PC are more likely to have more advanced disease compared to NHW men. Here, we characterized the molecular and immune differences in HA and NHW tumors and their association with PC ethnic disparity.

Methods: 88 PC samples (HA=34, NHW=54) obtained from treatment-naive metastatic hormone-sensitive PC (mHSPC) were analyzed by next-generation sequencing (592, NextSeq; WES, NovaSeq), Whole Transcriptome Sequencing (WTS; NovaSeq) (Caris Life Sciences, Phoenix, AZ). AR signature and NEPC score were calculated based on the expression level of previously defined genes (Hieronymus et al. 2006, Beltran et al. 2016). Medical record was reviewed in a deidentified fashion for clinal features. Statistical significance was determined using chi-square and Mann-Whitney U (p&lt;0.05).

Results: HA patients with PC had higher level of PSA (111.5 vs 52.6 ng/ml, p=0.12) and stage (T4: 41% vs 14% p=0.01, M1c: 41% vs 16% p=0.04) but no significant difference in frequency of Gleason score &gt; 4 (79% vs 73%, p=0.61) or stage N1 (69% vs 61%, p=0.85) compared to NHW. HA PC had a significantly higher frequency of TMPRSS2-fusion (46.4% vs 20.0%, p=0.04) compared to NHW PC. By Gene Set Enrichment Analysis, HA PC had enrichment of KRAS signaling (NES: 1.44, FDR=0.02), Hedgehog signaling (NES: 1.45, FDR=0.04), NOTCH signaling (NES: 1.41, FDR=0.07), Hypoxia (NES: 1.38, FDR=0.10) and IL2-STAT5 signaling (NES: 1.35, FDR=0.10) pathways compared to NHW tumors. There was no difference in median Androgen Receptor signature (p=0.78) or Neuroendocrine Prostate Cancer (NEPC) score (p=0.79). Also, no significant difference in AR positivity by IHC (100% vs 95.7%) between HA and NHW PC tumors (p=0.51). HA PC had significantly higher expression of stem cell markers ALDH1A1 (2.1-fold), ALDH1A2 (3-fold), and PROM1 (1.6-fold) and immunoinhibitory genes PDCD1LG2 (1.68-fold) and FOXP3 (1.45-fold) compared to NHW tumors (all p&lt;0.05). Additionally, HA tumors had increased infiltration of M1 Macrophages (0.72% vs 0%) and NK cells (4.84% vs 3.55%, all p&lt;0.05), and increased T-cell inflamed score (44.0 vs -49.0, p=0.14) compared to NHW.

Conclusion: Our data suggest that HA mHSPC is associated with higher levels of PSA, stage, TMPRSS2-fusions, stemness marker expression, immunoinhibitory gene expression, and increased M1 Macrophage and NK cell infiltration. Together, these findings suggest a crucial role of differential molecular and tumor immune microenvironment in PC ethnic disparity. A better understanding of these differences with additional research may help in designing the approaches for reducing the ethnic disparities gaps in PC patients.

Citation Format: Alejandro Recio-Boiles, Sachin Kumar Deshmukh, Juan Chipollini, Ken Batai, Sharon Wu, Joanne Xiu, Alex Farrell, Milan Radovich, Elisabeth Heath, Rana McKay, Chadi Nabhan. Molecular characterization of prostate cancer between Hispanic American and Non-Hispanic Whites: Implications for cancer ethnic health disparities [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1895.

Pembrolizumab versus placebo as post-nephrectomy adjuvant therapy for clear cell renal cell carcinoma (KEYNOTE-564): 30-month follow-up analysis of a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

The first interim analysis of the KEYNOTE-564 study showed improved disease-free survival with adjuvant pembrolizumab compared with placebo after surgery in patients with clear cell renal cell carcinoma at an increased risk of recurrence. The analysis reported here, with an additional 6 months of follow-up, was designed to assess longer-term efficacy and safety of pembrolizumab versus placebo, as well as additional secondary and exploratory endpoints.

METHODS

In the multicentre, randomised, double-blind, placebo-controlled, phase 3 KEYNOTE-564 trial, adults aged 18 years or older with clear cell renal cell carcinoma with an increased risk of recurrence were enrolled at 213 hospitals and cancer centres in North America, South America, Europe, Asia, and Australia. Eligible participants had an Eastern Cooperative Oncology Group performance status of 0 or 1, had undergone nephrectomy 12 weeks or less before randomisation, and had not received previous systemic therapy for advanced renal cell carcinoma. Participants were randomly assigned (1:1) via central permuted block randomisation (block size of four) to receive pembrolizumab 200 mg or placebo intravenously every 3 weeks for up to 17 cycles. Randomisation was stratified by metastatic disease status (M0 vs M1), and the M0 group was further stratified by ECOG performance status and geographical region. All participants and investigators involved in study treatment administration were masked to the treatment group assignment. The primary endpoint was disease-free survival by investigator assessment in the intention-to-treat population (all participants randomly assigned to a treatment). Safety was assessed in the safety population, comprising all participants who received at least one dose of pembrolizumab or placebo. As the primary endpoint was met at the first interim analysis, updated data are reported without p values. This study is ongoing, but no longer recruiting, and is registered with ClinicalTrials.gov, NCT03142334.

FINDINGS

Between June 30, 2017, and Sept 20, 2019, 994 participants were assigned to receive pembrolizumab (n=496) or placebo (n=498). Median follow-up, defined as the time from randomisation to data cutoff (June 14, 2021), was 30·1 months (IQR 25·7-36·7). Disease-free survival was better with pembrolizumab compared with placebo (HR 0·63 [95% CI 0·50-0·80]). Median disease-free survival was not reached in either group. The most common all-cause grade 3-4 adverse events were hypertension (in 14 [3%] of 496 participants) and increased alanine aminotransferase (in 11 [2%]) in the pembrolizumab group, and hypertension (in 13 [3%] of 498 participants) in the placebo group. Serious adverse events attributed to study treatment occurred in 59 (12%) participants in the pembrolizumab group and one (<1%) participant in the placebo group. No deaths were attributed to pembrolizumab.

INTERPRETATION

Updated results from KEYNOTE-564 support the use of adjuvant pembrolizumab monotherapy as a standard of care for participants with renal cell carcinoma with an increased risk of recurrence after nephrectomy.

FUNDING

Merck Sharp & Dohme LLC, a subsidiary of Merck & Co, Inc, Rahway, NJ, USA.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Development and pilot test of a physician-focused cancer clinical trials communication training intervention

Objective

We describe the development and pilot test of a physician-focused, web-based training module designed to improve physician communication related to clinical trials in a diverse cancer patient population.

Methods

Researchers and stakeholders developed the training module, which included a video explaining patient-centered communication strategies for discussing trials, and re-enactments of actual clinical interactions. For the pilot test, the module was provided to physician participants in the Partnering Around Cancer Clinical Trials (PACCT) trial at two major urban cancer centers. Questionnaires assessed change in beliefs, behavioral attitudes, knowledge and comfort; and perceptions of the module.

Results

Nineteen physicians participated in the pilot test. Most were experienced in discussing trials. Assessments of change were mixed regarding beliefs; they showed marginal improvement in attitudes, and significant improvement in knowledge, but no change in comfort. Feedback on the module was favorable.

Conclusions

This stakeholder-developed physician communication training module was acceptable and effective, albeit in this small and highly-experienced physician sample. Future research should determine its effectiveness on communication in clinical settings.

Innovation

This is the first physician training module to focus on communicating about clinical trials in a diverse patient population. It offers a web-based format and re-enactments of naturally-occurring clinical interactions.

Trial Registration Number: NCT02906241

Performance of the HOOS-12 and KOOS-12 instruments for evaluating outcomes from joint replacement surgery

OBJECTIVE

To evaluate the psychometric properties of the 12-item Hip disability and Osteoarthritis Outcome Score (HOOS-12) and Knee injury and Osteoarthritis Outcome Score (KOOS-12) for use in evaluating outcomes after joint replacement for osteoarthritis.

DESIGN

Patient-reported outcomes data collected by the Australian Orthopaedic Association National Joint Replacement Registry were used for this analysis. HOOS-12 and KOOS-12 domain (pain, function, quality of life) and summary impact data were available. The Oxford Hip Score (OHS), Oxford Knee Score (OKS) and EQ-5D-5L were used as comparators. Instruments were administered pre-operatively and at 6 months post-operatively. Internal consistency reliability, floor and ceiling effects, convergent validity, known groups validity, and responsiveness were evaluated using standard psychometric techniques.

RESULTS

Baseline HOOS-12 and KOOS-12 data were available for 3,023 patients undergoing primary total hip replacement and 4,010 patients undergoing primary total knee replacement. At baseline, high internal consistency was demonstrated for all domains and summary scores (Cronbach's alpha: HOOS-12 = 0.81-0.93; KOOS-12 = 0.82-0.92). Post-operative ceiling effects (>15% of patients scoring the best possible score) were identified for the HOOS-12 pain (46%), function (39%) and quality of life domains (26%) and summary score (17%), and for the KOOS-12 pain (21%) and function domains (18%). The HOOS-12 and KOOS-12 could differentiate between two known groups (lowest/highest OHS or OKS quartiles post-operatively; p < 0.001) and were highly responsive to change (effect sizes for HOOS-12: 2.20-2.83; KOOS-12: 1.82-2.35).

CONCLUSION

The HOOS-12 and KOOS-12 have good psychometric properties for capturing joint replacement outcomes including excellent responsiveness, although ceiling effects may limit monitoring of post-operative improvement.

Discovery of primary prostate cancer biomarkers using cross cancer learning

Prostate cancer (PCa), the second leading cause of cancer death in American men, is a relatively slow-growing malignancy with multiple early treatment options. Yet, a significant number of low-risk PCa patients are over-diagnosed and over-treated with significant and long-term quality of life effects. Further, there is ever increasing evidence of metastasis and higher mortality when hormone-sensitive or castration-resistant PCa tumors are treated indistinctively. Hence, the critical need is to discover clinically-relevant and actionable PCa biomarkers by better understanding the biology of PCa. In this paper, we have discovered novel biomarkers of PCa tumors through cross-cancer learning by leveraging the pathological and molecular similarities in the DNA repair pathways of ovarian, prostate, and breast cancer tumors. Cross-cancer disease learning enriches the study population and identifies genetic/phenotypic commonalities that are important across diseases with pathological and molecular similarities. Our results show that ADIRF, SLC2A5, C3orf86, HSPA1B are among the most significant PCa biomarkers, while MTRNR2L1, EEPD1, TEPP and VN1R2 are jointly important biomarkers across prostate, breast and ovarian cancers. Our validation results have further shown that the discovered biomarkers can predict the disease state better than any randomly selected subset of differentially expressed prostate cancer genes.

Tackling Diversity in Prostate Cancer Clinical Trials: A Report From the Diversity Working Group of the IRONMAN Registry

Prostate cancer disproportionately affects racial and ethnic minority populations. Reasons for disparate outcomes among minority patients are multifaceted and complex, involving factors at the patient, provider, and system levels. Although advancements in our understanding of disease biology have led to novel therapeutics for men with advanced prostate cancer, including the introduction of biomarker-driven therapeutics, pivotal translational studies and clinical trials are underrepresented by minority populations. Despite attempts to bridge the disparities gap, there remains an unmet need to expand minority engagement and participation in clinical trials to better define the impact of therapy on efficacy outcomes, quality of life, and role of biomarkers in diverse patient populations. The IRONMAN registry (ClinicalTrials.gov identifier: NCT03151629), a global, prospective, population-based study, was borne from this unmet medical need to address persistent gaps in our knowledge of advanced prostate cancer. Through integrated collection of clinical outcomes, patient-reported outcomes, epidemiologic data, and biospecimens, IRONMAN has the goal of expanding our understanding of how and why prostate cancer outcomes differ by race and ethnicity. To this end, the Diversity Working Group of the IRONMAN registry has developed informed strategies for site selection, recruitment, engagement and retention, and trial design and eligibility criteria to ensure broad inclusion and needs awareness of minority participants. In concert with systematic strategies to tackle the complex levels of disparate care, our ultimate goal is to expand minority engagement in clinical research and bridge the disparities gap in prostate cancer care.

Machine learning analysis using 77,044 genomic and transcriptomic profiles to accurately predict tumor type

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CUP occurs in as many as 3–5% of patients when standard diagnostic tests are not able to determine the origin of cancer.

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MI GPSai (Genomic Prevalence Score) is an AI that uses genomic and transcriptomic data to elucidate tumor origin.

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The algorithm was trained on molecular data from 57,489 cases and validated on 19,555 cases.

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MI GPSai predicted the tumor type out of 21 options in the labeled data set with an accuracy of over 94% on 93% of cases.

•

When also considering the second highest prediction, the accuracy increases to 97%.

Cancer of Unknown Primary (CUP) occurs in 3–5% of patients when standard histological diagnostic tests are unable to determine the origin of metastatic cancer. Typically, a CUP diagnosis is treated empirically and has very poor outcomes, with median overall survival less than one year. Gene expression profiling alone has been used to identify the tissue of origin but struggles with low neoplastic percentage in metastatic sites which is where identification is often most needed. MI GPSai, a Genomic Prevalence Score, uses DNA sequencing and whole transcriptome data coupled with machine learning to aid in the diagnosis of cancer. The algorithm trained on genomic data from 34,352 cases and genomic and transcriptomic data from 23,137 cases and was validated on 19,555 cases. MI GPSai predicted the tumor type in the labeled data set with an accuracy of over 94% on 93% of cases while deliberating amongst 21 possible categories of cancer. When also considering the second highest prediction, the accuracy increases to 97%. Additionally, MI GPSai rendered a prediction for 71.7% of CUP cases. Pathologist evaluation of discrepancies between submitted diagnosis and MI GPSai predictions resulted in change of diagnosis in 41.3% of the time. MI GPSai provides clinically meaningful information in a large proportion of CUP cases and inclusion of MI GPSai in clinical routine could improve diagnostic fidelity. Moreover, all genomic markers essential for therapy selection are assessed in this assay, maximizing the clinical utility for patients within a single test.

Practical Considerations and Challenges for Germline Genetic Testing in Patients With Prostate Cancer: Recommendations From the Germline Genetics Working Group of the PCCTC

Germline genetic testing is now routinely recommended for patients with prostate cancer (PCa) because of expanded guidelines and options for targeted treatments. However, integrating genetic testing into oncology and urology clinical workflows remains a challenge because of the increased number of patients with PCa requiring testing and the limited access to genetics providers. This suggests a critical unmet need for genetic services outside of historical models. This review addresses current guidelines, considerations, and challenges for PCa genetic testing and offers a practical guide for genetic counseling and testing delivery, with solutions to help address potential barriers and challenges for both providers and patients. As genetic and genomic testing become integral to PCa care, developing standardized systems for implementation in the clinic is essential for delivering precision oncology to patients with PCa and realizing the full scope and impact of genetic testing.

Abstract 3639: Fusion-associated neoantigen burden and predicted immunogenicity of CDK12 biallelic loss-of-function tumors vary substantially across cancer types

Background: Biallelic inactivation of CDK12 is associated with a distinct genomic signature of focal tandem duplications (FTDs). Gene fusions resulting from CDK12-associated FTDs increase neoantigen load, raising interest in CDK12 as a biomarker of response to immune checkpoint inhibitors (ICIs). Although FTDs have been detected at higher rates in CDK12-altered tumors compared to CDK12 WT tumors for multiple cancer types, fusion-associated neoantigen burden has only been evaluated in metastatic castration-resistant prostate cancer.

Methods: By retrospective review of molecular profiles, we identified tumors with CDK12 biallelic loss-of-function (LOF) in a primary cohort of over 9000 patient tumors, representing 39 cancer types, and assessed fusions detected by whole transcriptome sequencing for immune epitopes. Biomarker and fusion results for a second cohort of over 13,000 patient tumors were reviewed for validation of the initial findings.

Results: Tumors with CDK12 biallelic LOF (bLOF) (n=29) had significantly higher mean fusion rates (11.7 fusions/tumor) than CDK12 monoallelic LOF (mLOF) and WT tumors (4.1 and 2.6, respectively). Analysis of fusion topologies and breakpoints indicated a predominance of duplication events for CDK12 bLOF tumors and a bimodal distribution of breakpoint distances (modes at ~250-500 kb and ~1.0-2.5 Mb), consistent with prior reports. Fusion rates correlated with the rate of predicted neoantigens with high, intermediate, and low affinity for MHC class I. Fusion-associated neoantigen burden was significantly higher in CDK12 bLOF tumors (145.0 high affinity peptides/tumor) than mLOF (49.7) and WT (26.6) tumors. Among CDK12-altered tumors, fusion rates were significantly higher in prostate (16.4 fusions/tumor, n=11) and ovarian (19.7, n=6) than other cancer types (3.4 overall, n=12), potentially reflecting cancer type-specific roles for CDK12. Co-occurrence of mismatch repair deficiency (dMMR)/high microsatellite instability (MSI-High) with CDK12 bLOF (n=5), most often in colorectal tumors (n=4), correlated with a lower fusion rate (0.2 fusions/tumor); recurrent CDK12 frameshift mutations in these cases (G1461fs, T1463fs, and Q1291fs) coincide with poly-nucleotide tracts, suggesting CDK12 mutations are a secondary effect. In a separate cohort of over 13,000 patient tumors, additional CDK12 bLOF tumors (n=47) were identified, showing a similar distribution and association with high fusion rate (11.0 fusions/tumor).

Conclusion: Fusion rates and predicted neoantigen load varied significantly between CDK12 biallelic tumors across cancer types, highlighting the value of biomarkers with a quantitative immunogenic/phenotypic readout. We propose that fusion rates are linked to CDK12 alterations and may serve as useful biomarker to enhance our ability to identify responders of ICI therapy.

Citation Format: Andrew Elliott, Phillip Stafford, Jian Zhang, Qing Zhang, Jeff Swensen, Daniel Martin, Joanne Xiu, Zoran Gatalica, Daniel Vaena, Elisabeth Heath, W. Michael Korn. Fusion-associated neoantigen burden and predicted immunogenicity of CDK12 biallelic loss-of-function tumors vary substantially across cancer types [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3639.

Diversity of Enrollment in Prostate Cancer Clinical Trials: Current Status and Future Directions

BACKGROUND

Although there are considerable racial and ethnic disparities in prostate cancer incidence and mortality in the United States and globally, clinical trials often do not reflect disease incidence across racial and ethnic subgroups. This study aims to comprehensively review the reporting of race and ethnicity data and the representation of race and ethnicity across prostate cancer treatment-, prevention-, and screening-based clinical trials.

METHODS

Seventy-two global phase III and IV prevention, screening, and treatment prostate cancer clinical trials with enrollment start dates between 1987 and 2016 were analyzed in this study, representing a total of 893,378 individual trial participants. Availability and representation of race and ethnicity data by trial funding type, temporal changes in the racial/ethnic diversity of participants, and geographic representation of countries were assessed.

RESULTS

Of the 72 trials analyzed, 59 (81.9%) had available race data, and 11 (15.3%) of these trials additionally reported ethnicity. Of the trials reporting data, participants were overwhelmingly white men (with the highest proportion in U.S. nonpublicly funded trials), comprising over 96% of the study population. The proportion of white participants in prostate cancer clinical trials has remained at over 80% since 1990. Geographically, Africa and the Caribbean were particularly underrepresented with only 3% of countries included.

CONCLUSIONS

Trial participants continue to be majority white despite the known racial disparities in prostate cancer clinical outcomes.

IMPACT

Current and future trials must use novel recruitment strategies to ensure enrollment of underrepresented men. Targeting the inclusion of African and Caribbean medical centers is crucial to achieve equity in representation.

Abstract B022: Diversity of enrollment in prostate cancer clinical trials: Current status and future directions

Background: Prostate cancer incidence and mortality rates differ substantially by race and ethnicity globally and within the United States. Despite these disparities, many cancer clinical trials have a lack of representation of U.S. minority groups, and race is often overlooked when reporting trial results. The purpose of this study is to assess diversity of participants in prostate cancer clinical trials.

Methods: Available trials were identified through a systematic review of clinical trials using the U.S. National Library of Medicine's Clinical Trials Database and PubMed. Completed global phase III and phase IV clinical trials evaluating treatment, primary prevention, or screening of prostate cancer with published results were included in the analysis. Trials were analyzed for availability of race and ethnicity data and categories represented. Temporal and geographic trends were analyzed.

Results: Of the 61 treatment-based clinical trials analyzed, 39 (63.9%) reported race data. Twenty-one race categories were represented across the trials, with the largest categories being White (83.2% of participants), Black or African American (7.5%), other/not reported (4.4%), and Asian (2.7%). All other race categories represented less than 2% of participants each. Six trials (9.8%) additionally reported ethnicity data: 81.1% of participants with data were not Hispanic or Latino, 7.6% of participants were Hispanic or Latino, and 11.3% of participants did not indicate their ethnicity. Of four prevention-based trials, all had data available on race, but only one additionally reported ethnicity. The majority of participants in prevention trials were White (84.6%), with similar representation across race and ethnicity categories compared to the treatment clinical trials. Only one of the five screening trials had available race data, again showing majority White participants (85.0%). Categories unique to prevention and screening trials include Hispanic (non-African American), Hispanic (African American), non-Hispanic White, and non-Hispanic Black. The Swedish branch of the European Randomized Study for Screening for Prostate Cancer (ERSPC) reported country of origin rather than race data: 15% of participants were non-European. Additionally, diversity of participants has not changed over time, and representation of countries in trials is unequal.

Conclusions: More than one-third of prostate cancer clinical trials do not report race/ethnicity data. Moreover, there is significant variability in the race categories reported in trials, with 26 categories represented across the analyzed trials. Of the trials reporting race data, over 80% of participants were White. Current initiatives, such as the International Registry of Men with Advanced Prostate Cancer (IRONMAN), are aiming to recruit representative populations to decrease racial and ethnic disparities and ensure that men at risk for or diagnosed with prostate cancer are better represented in research and receive the best possible care.

Citation Format: Emily Rencsok, Latifa Bazzi, Rana McKay, Franklin Huang, Adam Friedant, Jake Vinson, Jelani Zarif, Stacey Simmons, Paul Villanti, Philip Kantoff, Elisabeth Heath, Daniel George, Lorelei Mucci. Diversity of enrollment in prostate cancer clinical trials: Current status and future directions [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr B022.

Evaluation of an x-ray CT polymer gel dosimetry system in the measurement of deformed dose

This study is an evaluation of the use of a N-isopropylacrylamide (NIPAM)-based x-ray CT polymer gel dosimetry (PGD) system in the measurement of deformed dose. This work also compares dose that is measured by the gel dosimetry system to dose calculated by a novel deformable dose accumulation algorithm, defDOSXYZnrc, that uses direct voxel tracking. Deformable gels were first irradiated using a single 3.5 × 5 cm² open field and the static dose was compared to defDOSXYZnrc as a control measurement. Gel measurement was found to be in excellent agreement with defDOSXYZnrc in the static case with gamma passing rates of 94.5% using a 3%/3 mm criterion and 93.3% using a 3%/2 mm criterion. Following the static measurements, a deformable gel was irradiated with the same single field under an external compression of 25 mm and then released from this compression for dosimetric read out. The measured deformed dose was then compared to deformed dose calculated by defDOSXYZnrc based on deformation vectors produced by the Velocity AI deformable image registration (DIR) algorithm. In the deformed dose distribution there were differences in the measured and calculated field position of up to 0.8 mm and differences in the measured in calculated field size of up to 11.9 mm. Gamma pass rates were 60.0% using a 3%/3 mm criterion and 56.8% using a 3%/2 mm criterion for the deforming measurements representing a decrease in agreement compared to the control measurements. Further analysis showed that passing rates increased to 86.5% using a 3%/3 mm criterion and 70.5% using a 3%/2 mm criterion in voxels within 5 mm of fiducial markers used to guide the deformable image registration. This work represents the first measurement of deformed dose using x-ray CT polymer gel dosimetry. Overall these results highlight some of the challenges in the calculation and measurement of deforming dose and provide insight into possible strategies for improvement.

eHealth Activity among African American and White Cancer Survivors: A New Application of Theory

eHealth is a promising resource for cancer survivors and may contribute to reducing racial disparities in cancer survivorship. This research applies the Unified Theory of Acceptance and Use of Technology (UTAUT) to examine eHealth activity among African American (AfAm) and White cancer survivors. In a population-based sample of AfAm and White survivors (n = 300), a Poisson regression tested whether UTAUT constructs (facilitating conditions, social influence, perceived ease of use, perceived usefulness) and beliefs about security/trustworthiness of eHealth were associated with the number of eHealth activities respondents had used. To test whether the effects varied across racial groups, interactions between each of these five facets and survivor race were included in the model. The model adjusted for demographic characteristics, cancer history, and internet access and use. Across racial groups, facilitating conditions (IRR = 1.44, 95%CI [1.17, 1.77]) and perceived usefulness (IRR = 1.16, 95%CI [1.08, 1.24]) were associated with increased eHealth activity. A marginally significant interaction between race and perceived ease of use (IRR = 1.17, 95%CI [0.99, 1.39]) indicated this perception was associated with decreased eHealth activity for White but not AfAm survivors. A significant interaction between race and perceived security/trustworthiness (IRR = 1.16, 95%CI [1.02, 1.32]) indicated this perception was associated with increased eHealth activity for AfAm but not White survivors. Social influence was not associated with eHealth use for either group (IRR = 1.07, 95%CI [0.98, 1.16]). Interventions targeting attitudes about eHealth may encourage its adoption and use. Furthermore, eHealth tools intended for use among AfAm cancer survivors should ensure they are secure and emphasize trustworthiness to intended users.

Detecting TRA-1-60 in Cancer via a Novel Zr-89 Labeled ImmunoPET Imaging Agent

TRA-1-60 (TRA) is a cell-surface antigen implicated in drug resistance, relapse, and recurrence. Its expression has been reported in breast, prostate, pancreatic, ovarian tumors, and follicular lymphoma, which paved the development of the therapeutic antibody, Bstrongomab (Bsg), and its drug conjugates. Because patient selection is critical to achieve clinical benefit, a noninvasive imaging agent to select TRA+ lesions in patients is needed. Herein, we report the development of the immunopositron emission tomography (immunoPET) radiotracer ⁸⁹Zr-radiolabeled Bsg and its potential to delineate TRA+ tumors. Bsg was conjugated to the bifunctional chelator desferrioxamine (DFO) and radiolabeled with [⁸⁹Zr]Zr-oxalate. [⁸⁹Zr]Zr-DFO-Bsg was characterized in vitro and evaluated in vivo for uptake and specificity in high and low TRA-expressing BxPC-3 pancreatic and PC-3 prostate cancer models, respectively. Uptake was compared against [⁸⁹Zr]Zr-DFO-IgG, a nonspecific control radiotracer. Immunohistochemical (IHC) staining of patient cancer tissues using Bsg was performed to explore its clinical significance. A specific activity of 0.18 ± 0.01 GBq/mg (4.8 ± 0.3 mCi/mg) was obtained for [⁸⁹Zr]Zr-DFO-Bsg. BxPC-3 xenografts exhibited three-fold higher radiotracer uptake compared to [⁸⁹Zr]Zr-DFO-IgG. Competitive saturation studies using BxPC-3 xenografts further confirmed tracer specificity. The TRA-specific probe had lower accumulation in PC-3 xenografts. Ex vivo autoradiographs correlated with TRA expression from the histopathology of the resected tumor xenografts. Additionally, patient cancer tissues demonstrated positive staining with Bsg with metastatic lesions exhibiting the highest staining. This study demonstrates the potential of [⁸⁹Zr]Zr-DFO-Bsg as an imaging agent for noninvasive detection of TRA+ tumors.

Smartphone apps for cancer: A content analysis of the digital health marketplace

Objective

The purpose of this study was to examine the state of smartphone applications for cancer intended for the general public with a focus on interactive features, content sources, and application developer affiliations. The level of health provider involvement in screening or appraising application content was also assessed.

Methods

A total of 123 apps were identified for analysis from two major mobile application marketplaces (Apple iTunes = 40; Google Play = 83). Application characteristics were collected, analyzed, and reported. These included the mobile platform, cost, application developer affiliation, date of last update, purpose of application, content sources, and interactive features.

Results

In the study sample, 50% of the applications focused on general information for cancer (62/123). Next, this was followed by applications for breast cancer (15%, 19/123) and skin cancer (7%, 8/123). Only 10% of application descriptions (12/123) identified sources for application content. Interactive features included the ability to monitor symptoms, side effects, treatments, and chronic pain (20%, 25/123). Only 3% of the applications (4/123) stated content had been evaluated by health providers.

Conclusions

This study contributes an updated analysis of applications for cancer available in the digital health marketplace. The findings have implications for information quality and supportive resources for cancer care. More transparent information about content sources, organizational affiliations, and level of health provider oversight in screening application content is warranted. Recommendations for improving the quality of cancer applications are also offered.

Abstract CT095: A Phase Ib/IIa study of the BET bromodomain inhibitor ZEN-3694 in combination with enzalutamide in patients with metastatic castration-resistant prostate cancer (mCRPC)

Background: Abiraterone (ABI) and enzalutamide (ENZ) have significant activity in mCRPC yet demonstrate frequent cross-resistance limiting efficacy of sequential androgen receptor (AR) targeting. Bromodomain extra terminal (BET) inhibitors (BETi) down-regulate the expression of putative drivers of ABI/ENZ resistance. ZEN-3694 is an orally bioavailable, potent, and selective BETi with significant anti-tumor activity in ENZ-resistant pre-clinical models. The safety and efficacy of ZEN-3694 in combination with ENZ was evaluated in a phase 1b/2a study in mCRPC (NCT02711956).

Methods: Patients (pts) were required to have progressive mCRPC, prior resistance to ABI and/or ENZ, and no prior chemotherapy for mCRPC. A 3 plus 3 dose escalation schema was utilized, with a starting daily oral dose of ZEN-3694 36 mg plus ENZ 160 mg. Dose expansion was conducted in parallel cohorts at low and high-dose ZEN-3694 (48 and 96 mg daily, respectively). The primary objective was determination of maximally tolerated dose (MTD); key secondary endpoints included time to radiographic progression (TTP) and pharmacokinetic (PK) parameters. Pharmacodynamic (PD) markers included whole blood RNA expression of BETi targets including MYC, IL-8, CCR1, and IL1RN.

Results: 64 pts were enrolled. The median age and PSA at study entry was 70 (range 47 - 89) and 25.9 (range 0.1 - 1701.8), respectively. At study entry, 24 (37.5%) of pts were resistant to ABI, 29 (45.3%) were resistant to ENZ, and 11 (17.2%) to both. ZEN-3694 dose levels ranged from 36 mg to 144 mg daily without reaching a MTD. The most common treatment-related adverse events (AEs) (any grade) included transient photophobia (66%), nausea (40%), fatigue (31%), decreased appetite (22%), and dysgeusia (16%). Grade ≥ 3 related AEs (N = 8) and dose-limiting toxicities (N = 1 at 96 mg dose level) were uncommon. No Grade ≥ 3 thrombocytopenia was observed. Exposure to ZEN-3694 increased with dose without significant drug-drug interaction with ENZ. PD analyses demonstrated exposure-dependent, up to 4-fold decrease in expression of BETi targets. RNA-Seq of paired tumor biopsies demonstrated suppression of BET-dependent genes. The overall median TTP was 44.4 weeks, and was similar in subgroups with prior ABI vs. ENZ resistance. Durable responses were observed, including 3 pts with disease primarily refractory to ABI on study treatment for 21.3 +, 20.8 +, and 17.3 months, respectively, with &gt; 90% decline in serum PSA. Early transitory serum PSA increases were associated with longer TTP.

Conclusions: ZEN-3694 demonstrates an acceptable safety and PK profile, robust target modulation, and encouraging disease stabilization in combination with ENZ in ABI/ENZ-refractory mCRPC. Analysis of paired metastatic tumor biopsies, circulating tumor cells and ctDNA is ongoing. Further investigation of the combination is warranted.

Citation Format: Rahul Aggarwal, Wassim Abida, Michael Schweizer, Allan Pantuck, David Nanus, Elisabeth Heath, Sanjay Lakhotia, Henrik Hansen, Michael Silverman, Lisa Bauman, Margo Snyder, Eric Campeau, Karen Norek, Sarah Attwell, Marie O'Farrell, Steve Smith, Philip Wegge, Ravi Jahagirdar, Joshi Alumkal. A Phase Ib/IIa study of the BET bromodomain inhibitor ZEN-3694 in combination with enzalutamide in patients with metastatic castration-resistant prostate cancer (mCRPC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT095.

Phase II, Multicenter, Randomized Trial of Docetaxel plus Prednisone with or Without Cediranib in Men with Chemotherapy-Naive Metastatic Castrate-Resistant Prostate Cancer

Lessons Learned.

The negative results are consistent with the negative results of large phase III trials in which docetaxel plus antiangiogenic agents were used in patients with metastatic castrate‐resistant prostate cancer (mCRPC).

The negative data underscore that, despite a sound biological rationale and supportive early‐phase clinical results, adding antiangiogenic agents to docetaxel for mCRPC is a great challenge.

Background.

Inhibition of vascular endothelial growth factor (VEGF) signaling abrogates tumor‐induced angiogenesis to constrain tumor growth, and can be exploited therapeutically by using cediranib, an oral tyrosine kinase inhibitor of VEGF receptor signaling. Our preliminary phase I trial data showed that adding cediranib to docetaxel plus prednisone (DP) was safe and feasible, with early evidence for efficacy in patients with metastatic castrate‐resistant prostate cancer (mCRPC).

Methods.

This multicenter phase II trial assessed whether adding cediranib to DP improves efficacy of DP in patients with mCRPC. Chemotherapy‐naive patients with mCRPC were randomly assigned to receive either docetaxel (75 mg/m² intravenously every 3 weeks) with prednisone (5 mg twice daily) plus cediranib (30 mg once daily; the DP+C arm) or DP only (the DP arm). The primary endpoint was to compare 6‐month progression‐free survival (PFS) rate between the two arms. Secondary endpoints included 6‐month overall survival (OS), objective tumor and prostate‐specific antigen (PSA) response rates, biomarkers, and adverse events.

Results.

The 6‐month PFS rate in a total of 58 patients was only numerically higher in the DP+C arm (61%) compared with the DP arm (57%). Similarly, the 6‐month OS rate, objective tumor and PSA response rates, and biomarkers were not significantly different between the two arms. Increased baseline levels of interleukin 6 (IL‐6), however, were significantly associated with increased risk of progression. Neutropenia was the only grade 4 toxicity (38% in the DP+C arm vs. 18% in the DP arm).

Conclusion.

Combining cediranib with docetaxel + prednisone failed to demonstrate superior efficacy, compared with docetaxel + prednisone, and added toxicity. Our data do not support pursuing the combination further in patients with mCRPC.

Racial differences in patterns of treatment among men diagnosed with de novo advanced prostate cancer: A SEER-Medicare investigation

Purpose

Approximately 5% of men were initially diagnosed with (also referred to as de novo) advanced stage prostate cancer and experience far poorer survival compared to men diagnosed with local or regionally advanced disease. Given the number of new therapies targeting metastatic and castrate‐resistant disease, we sought to describe recent treatment patterns by race for de novo AJCC stage IV prostate cancer.

Methods

We used Surveillance, Epidemiology, and End Results (SEER) data linked to Medicare files to identify men aged 66 and older diagnosed in 2004‐2014 with advanced prostate cancer, and examined patterns of treatment among all patients and stratified by race/ethnicity.

Results

There were 8828 eligible patients identified, and non‐Hispanic black (NHB) patients were more likely to go without treatment (P < 0.001) compared to non‐Hispanic white (NHW) patients, even after accounting for early mortality and TNM stage. The frequency of nearly all forms of treatment was lower among NHB with the exception of orchiectomy, which was significantly higher (10.1% vs 6.1%, P < 0.001), and the use of the progesterone Megace among Medicare Part D enrollees (24.6% vs 15.0%, P < 0.001).

Conclusions

Results from this study of elderly Medicare patients presenting with advanced stage prostate cancer suggest that NHB men are less likely to pursue aggressive treatment options. With the reduction in screening for prostate cancer, presumably tied to USPSTF recommendations, and the increasing incidence of men diagnosed with de novo metastatic disease, understanding drivers of treatment‐related decisions are critical in reducing racial disparities in advanced prostate cancer outcomes.

Abstract LB-309: Evaluation of ERG as a biomarker of responsiveness in a randomized trial of enzalutamide in combination with androgen deprivation in metastatic hormone sensitive prostate cancer

Background: TMPRSS2-ERG fusions are highly prevalent in prostate cancer patients, where androgen responsive TMPRSS2 gene promoter fused with coding sequence of ERG transcription factor resulting in androgen mediated expression of ERG factor. Metastatic cancer patients harbor the TMPRSS2-ERG fusions and presence of fusions associate with poor overall survival. The association between ERG transcription factor and anti-androgen therapy (enzalutamide (arm A) vs. bicalutamide (arm B)) responsiveness was evaluated in a randomized trial in metastatic hormone sensitive prostate cancer (mHSPC).

Methods: 40 of 71 patients had evaluable tissue from metastatic biopsy. 18 patients were on enzalutamide arm (A) and 22 patients were on bicalutamide arm (B). PSA was monitored monthly for first 7 months and then every 3 months. Total RNA was isolated from biopsy specimens, QPCR analysis was performed for ERG gene. A standard curve was developed with ERG expressing plasmid in QPCR experiment and the copy number of ERG was determined in the metastatic biopsies. Seven month PSA Response (SMPR) rates were calculated for the high and low subset categories of median-dichotomized ERG copy number. The odds of SMPR was modeled as a function of continuous ungrouped correlative via univariable logistic regression.

Results: 15/40 patients had both pre and post treatment biopsies available. The mean ERG copy number was increased in post treatment biopsy in both arms (enzalutamide, n=10 and bicalutamide, n=5). The mean copy increased (pre= 8541 and post =9789) upon enzalutamide treatment and also increased (pre=17186 and post = 23368) upon bicalutamide treatment. SMPR rates show that low copy number patients responded better (19/20) compared to high copy number patients (14/20). In arm A response rate is 100% (18/18), whereas in arm B, low ERG copy number patients responded better (8/11) compared to high copy number patients (7/11). Finally, the SMPR odds ratio remained close to 1.000 even for large copy number increase. Selective ERG responsive gene expression levels were determined in metastatic biopsies and will be associated with clinical endpoints.

Conclusions: Enzalutamide improved the likelihood of PSA remission in mHSPC and follow up is ongoing. Metastatic biopsy specimen analysis show that higher ERG copy number had a lower likelihood of PSA response with ADT and may serve as a prognostic or predictive marker, but further analysis is warranted.

Citation Format: Sreenivasa R. Chinni, Ulka N. Vaishampayan, Lance K. Heilbrun, Louie Semaan, Daryn Smith, Dipenkumar Modi, Paul Monk, Shiela Tejwani, Guru Sonpavde, Kimberlee Dobson, Brenda Dickow, Elisabeth Heath, Joseph Fontana, Micheal L. Cher. Evaluation of ERG as a biomarker of responsiveness in a randomized trial of enzalutamide in combination with androgen deprivation in metastatic hormone sensitive prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-309.

Abstract B09: Partnering around cancer clinical trials: Preliminary report of an intervention to improve patient-physician communication and clinical trial enrollment of Black and White men with prostate cancer

Background: Few patients, especially racial/ethnic minorities, enroll in clinical trials (CTs) in the United States, in part due to factors related to patient-physician interactions. We describe a theory-based patient intervention to improve communication and enrollment of Black and White men in prostate cancer CTs. We also report on preliminary baseline data comparing Black and White participants' demographic and social characteristics and their willingness to discuss a CT with a physician.

Method: A team of communication scientists, psychologists, and clinicians collaborated to create a theory-based, patient-focused intervention. Theories included the common ingroup identity model, which suggests people from different social groups can better achieve goals when they see themselves as members of the same team, and patient-centered communication, which suggests that patient active participation improves clinical communication. The intervention is in the form of a booklet given to patients prior to meeting with their oncologist. The booklet includes a) encouragement to view the patient and physician as a team and participate actively in clinical interactions, and b) 33 questions about participating in a CT. Preliminary data from one data collection site (Detroit, Michigan) include 72 Black (n=40) and White (n=32) men with prostate cancer who completed baseline measures assessing age; education; income; breadwinner status; marital status; health literacy; perceived economic burden (e.g., how difficult is it for you to live on your total household income right now?); general trust in physicians; group-based medical mistrust (including three subscales--suspicion, perceived racial health care disparities, and perceived health care provider support); and willingness to discuss a CT with a physician. Chi-square and independent samples t-tests were conducted to determine racial differences.

Results: Black patients were younger (p=.04), had less education (p=.006) and lower annual incomes (p&lt;.001) than White patients, but were equally likely to be the breadwinner. Blacks were more likely to be single than Whites (p&lt;.001). Blacks reported significantly higher economic burden (p=.02), greater group-based medical mistrust (p=.001), greater suspicion of health care (p=.003), greater perceived racial disparities in health care (p=.001), and less perceived support from health care providers (p=.002). Blacks and Whites did not differ in health literacy or general trust in physicians. Regarding willingness to discuss CTs with their physician, high means for both Blacks and Whites (4.2 and 4.7, respectively, on a 5-point scale) indicated that both groups were very willing to discuss a CT with their physician, but Whites were significantly more willing (p=.03).

Discussion: Black and White patients differed in many demographic and social characteristics. Both groups indicated they were very willing to discuss a CT with their physician, although Whites were significantly more willing. This finding suggests the intervention may be especially beneficial for Black patients, who are disproportionately under-represented in CTs. Next steps involve analysis of the effect of the intervention and addition of a physician-focused intervention.

Citation Format: Lauren M. Hamel, Louis A. Penner, Elisabeth Heath, Dina Lansey, Michael Carducci, Terrance L. Albrecht, Ellen Barton, Mark Manning, Tanina Foster, Mark Wojda, Susan Eggly. Partnering around cancer clinical trials: Preliminary report of an intervention to improve patient-physician communication and clinical trial enrollment of Black and White men with prostate cancer [abstract]. In: Proceedings of the Tenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2017 Sep 25-28; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2018;27(7 Suppl):Abstract nr B09.

Abstract 2492: Down-regulation of AR splice variants through XPO1 suppression contributes to the inhibition of prostate cancer progression

Increased XPO1 (a key nuclear exporter of many tumor suppressor proteins [TSPs]) expression in prostate cancer (PCa) has been found to be associated with a high Gleason score and bone metastasis. However, it is unknown whether aberrant XPO1 activity regulates AR and AR splice variants (Arv) signaling in PCa progression. In this study, using 22Rv1 and VCaP prostate cancer cells which harbor full length AR and ARv, we conduct in vitro cellular and molecular biological experiments and in vivo animal studies to elucidate the role XPO1 inhibition plays in PCa progression through regulation of XPO1/AR/ARv signaling. We found that high expression of AR splice variant 7 (AR-v7) was correlated with increased XPO1 expression. Silencing of XPO1 by RNAi or treatment with Selective Inhibitor of Nuclear Export (SINE) compounds (selinexor and KPT-8602/eltanexor) down-regulated the expression of AR, AR-v7 and ARv567es at the mRNA and protein levels. Mechanistic studies showed that XPO1 silencing also inhibited the expression of AR/ARv regulators including FOXA1, Src, Vav3, MED1 and Sam68, leading to the suppression of ARv and AR target genes, UBE2C and PSA. SINE compound treatment of cells retained the eIF4E protein (translation initiation factor and nuclear transporter of capped depended mRNAs) in nuclear compartment, leading to nuclear retention of AR-v7 and PSA mRNAs. The nuclear localization of AR-v7 mRNA resulted in the reduction in the ARv protein. Furthermore, SINE compound treatment retained TSPs including Rb, p21, p53, APC and SMAD4 in the nucleus leading to inhibition of cell proliferation and induction of apoptosis. Moreover, by targeting XPO1/ARv signaling, SINE compounds suppressed prostate cancer growth in vitro and in vivo and potentiated the anti-cancer activity of conventional chemotherapeutic agent docetaxel and anti-AR agents (enzalutamide and abiraterone) through the inhibition of AR, AR-v7, FOXA1, PSA and UBE2C. From these results, we conclude that there is a causal relationship between XPO1 and AR splice variants. High expression of both XPO1 and AR-v7 could lead to constitutively activated AR signaling, CRPC development and progression, and anti-AR drug resistance. By targeting XPO1/AR/ARv signaling and increasing anti-AR sensitivity, SINE compounds could be novel agents used in combination with conventional chemotherapeutics and AR-targeted therapy for the treatment of PCa, especially CRPC.

Citation Format: Irfana Muqbil, Yiwei Li, Erkan Baloglu, William Senapedis, Yosef Landesman, Christian Argueta, Michael Kauffman, Sharon Friedlander, Hua Chang, Sharon Shacham, Elisabeth Heath, Asfar S. Azmi. Down-regulation of AR splice variants through XPO1 suppression contributes to the inhibition of prostate cancer progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2492.

Introduction of a deformable x-ray CT polymer gel dosimetry system

This study introduces the first 3D deformable dosimetry system based on x-ray computed tomography (CT) polymer gel dosimetry and establishes the setup reproducibility, deformation characteristics and dose response of the system. A N-isopropylacrylamide (NIPAM)-based gel formulation optimized for x-ray CT gel dosimetry was used, with a latex balloon serving as the deformable container and low-density polyethylene and polyvinyl alcohol providing additional oxygen barrier. Deformable gels were irradiated with a 6 MV calibration pattern to determine dosimetric response and a dosimetrically uniform plan to determine the spatial uniformity of the response. Wax beads were added to each gel as fiducial markers to track the deformation and setup of the gel dosimeters. From positions of the beads on CT images the setup reproducibility and the limits and reproducibility of gel deformation were determined. Comparison of gel measurements with Monte Carlo dose calculations found excellent dosimetric accuracy, comparable to that of an established non-deformable dosimetry system, with a mean dose discrepancy of 1.5% in the low-dose gradient region and a gamma pass rate of 97.9% using a 3%/3 mm criterion. The deformable dosimeter also showed good overall spatial dose uniformity throughout the dosimeter with some discrepancies within 20 mm of the edge of the container. Tracking of the beads within the dosimeter found that sub-millimetre setup accuracy is achievable with this system. The dosimeter was able to deform and relax when externally compressed by up to 30 mm without sustaining any permanent damage. Internal deformations in 3D produced average marker movements of up to 12 mm along the direction of compression. These deformations were also shown to be reproducible over 100 consecutive deformations. This work has established several important characteristics of a new deformable dosimetry system which shows promise for future clinical applications, including the validation of deformable dose accumulation algorithms.

Partnering around cancer clinical trials (PACCT): study protocol for a randomized trial of a patient and physician communication intervention to increase minority accrual to prostate cancer clinical trials

Background

Cancer clinical trials are essential for testing new treatments and represent state-of-the-art cancer treatment, but only a small percentage of patients ever enroll in a trial. Under-enrollment is an even greater problem among minorities, particularly African Americans, representing a racial/ethnic disparity in cancer care. One understudied cause is patient-physician communication, which is often of poor quality during clinical interactions between African-American patients and non-African-American physicians. Partnering Around Cancer Clinical Trials (PACCT) involves a transdisciplinary theoretical model proposing that patient and physician individual attitudes and beliefs and their interpersonal communication during racially discordant clinical interactions influence outcomes related to patients’ decisions to participate in a trial. The overall goal of the study is to test a multilevel intervention designed to increase rates at which African-American and White men with prostate cancer make an informed decision to participate in a clinical trial.

Methods/design

Data collection will occur at two NCI-designated comprehensive cancer centers. Participants include physicians who treat men with prostate cancer and their African-American and White patients who are potentially eligible for a clinical trial. The study uses two distinct research designs to evaluate the effects of two behavioral interventions, one focused on patients and the other on physicians. The primary goal is to increase the number of patients who decide to enroll in a trial; secondary goals include increasing rates of physician trial offers, improving the quality of patient-physician communication during video recorded clinical interactions in which trials may be discussed, improving patients’ understanding of trials offered, and increasing the number of patients who actually enroll. Aims are to 1) determine the independent and combined effects of the two interventions on outcomes; 2) compare the effects of the interventions on African-American versus White men; and 3) examine the extent to which patient-physician communication mediates the effect of the interventions on the outcomes.

Discussion

PACCT has the potential to identify ways to increase clinical trial rates in a diverse patient population. The research can also improve access to high quality clinical care for African American men bearing the disproportionate burden of disparities in prostate and other cancers.

Trial registration

Clinical Trials.gov registration number: NCT02906241 (September 8, 2016).

Neutrophil lymphocyte ratio and duration of prior anti-angiogenic therapy as biomarkers in metastatic RCC receiving immune checkpoint inhibitor therapy

Background

There is an unmet need to determine factors predictive of clinical benefit, to guide therapeutic sequencing and selection in metastatic RCC (mRCC). We evaluated clinical factors such as the neutrophil lymphocyte ratio (NLR) and duration of prior anti-vascular endothelial growth factor (VEGF) inhibitors, as predictors of response rate, progression free survival (PFS) and overall survival (OS) in mRCC patients treated with immune checkpoint inhibitor (ICI).

Methods

Regulatory approval was obtained. A single center retrospective chart review of mRCC patients at Karmanos Cancer Institute, treated with ICI based therapy (PD-1/PD-L1 inhibitors) was conducted. Data were collected on demographics, smoking status, prognostic scoring (Memorial Sloan Kettering and Heng criteria), NLR pretherapy, post 1 and 4 doses of ICI, and duration of prior anti-VEGF therapy ≥6 months or <6.

Results

42 patients were evaluated with median age of 61 years (range, 24-85). Pretherapy NLR < 3 and ≥3 was seen in 19 (45%) and 23 (55%) patients, respectively. 24 (57%) and 18 (43%) patients had prior anti-VEGF inhibitors for a duration of ≥6 months and <6 months, respectively. 12 (29%), 22 (52%) and 8 (19%) patients had favorable, intermediate and poor risk disease based on Heng criteria, respectively. Multivariable analysis showed pretherapy NLR ≥3 was predictive of shorter PFS and OS when treated with ICI with median 3.08 months and 13.50 months, respectively, versus 15.57 months and not reached for NLR < 3 (adjusted p-values =0.003 and 0.025, respectively). Prior anti-VEGF therapy <6 months was predictive of increased likelihood of benefit from ICI therapies (adjusted p = 0.028). The median PFS was 3.72 months and 14.33 months, respectively, in cases with prior anti-VEGF therapy for ≥6 months and <6 months.

Conclusion

Pretherapy NLR <3 and duration of prior anti-VEGF therapy of <6 months, are independent statistically significant predictors of longer PFS and OS with ICI therapy in mRCC. Validation is required in a larger sample size with multi-institutional collaboration.

Electronic supplementary material

The online version of this article (10.1186/s40425-017-0287-5) contains supplementary material, which is available to authorized users.

The influence of PSA autoantibodies in prostate cancer patients: a prospective clinical study-II

The U.S. Preventive Services Task Force (USPSTF) has recommended against PSA-based screening for prostate cancer due to potential possibilities of false-results. Since no alternative test is available to replace it, we have initiated a trial with the purpose of establishing whether Galectin-3 (Gal-3) serum level and/or the patients immune response to PSA and Gal-3 antigens could complement the PSA test as diagnostic tools for prostate cancer patients. A blind, prospective, single institution, pilot study was conducted. A total of 95 men were recruited and classified into 5 different groups: healthy controls (Group1), newly diagnosed patients (Group2), no recurrence after local therapy (Group3), rising PSA after local therapy (Group4), and metastatic patients (Group5). The primary endpoints were the levels of serum PSA, PSA autoantibodies (AAPSA), Gal-3, and Gal-3 autoantibodies (AAGal-3). Data were analyzed by Spearmans rank correlation (rho) and least squares linear regression modeling. The expression levels of PSA, AAPSA, Gal-3, and AAGal-3 were determined in both healthy controls and prostate cancer patients. Negative correlations were observed between PSA and AAPSA levels among all 95 men combined (rho = −0.321, P = 0.0021; fitted slope −0.288, P = 0.0048), and in metastatic patients (rho = −0.472, P = 0.0413; fitted slope −1.145, P = 0.0061). We suggest an association between PSA and AAPSA, whereby the AAPSA may alter PSA levels. It provides a novel outlook for prostate cancer diagnosis, and should serve as a basis for an all-inclusive diagnostic trial centering on patients with metastasis.

Percutaneous Cryoablation of Renal Tumors: Is It Time for a New Paradigm Shift?

PURPOSE

To retrospectively assess long-term outcomes of percutaneous renal cryoablation, including factors affecting complications and local recurrence rates.

MATERIALS AND METHODS

A total of 357 computed tomographic (CT) fluoroscopy-guided percutaneous cryoablation procedures were performed for 382 masses in 302 outpatients; 347 were biopsy-proven renal-cell carcinoma (RCC) or Bosniak category > III masses (n = 28). Benign pathologic conditions (n = 18) or metastatic non-RCC disease (n = 17) were included to analyze procedural complication rate, but recurrence rates, tumor staging, and nephrometry score were limited to RCCs. The average tumor diameter was 2.9 cm (range, 1-10.3 cm), and median nephrometry score for RCC was 8 (mean, 7.4). Protection of adjacent vital structures was performed in 34% of procedures (n = 121), and ureteral stent placement was performed for 9.2% (n = 33). All major complications were graded per surgical Clavien-Dindo criteria.

RESULTS

The average CT-visible cryoablation zone diameter was 5 cm (range, 2.5-10.5 cm). Grade ≥ 3 complications occurred in 2.8% of procedures (n = 10), and appeared related to only high nephrometry scores (P = .0086) and larger tumors (P = .0034). No significant changes in renal function before and after the procedure were noted (P = .18). At a mean follow-up of 31.8 months, the local tumor recurrence rate was 3.2% (11 of 347) for RCC, and no significant difference was noted between tumors larger or smaller than 3 cm (P = .15). The difference reached significance only among the small number of stage ≥ T2 RCC tumors (P = .0039).

CONCLUSIONS

Long-term follow-up of percutaneous renal cryoablation demonstrates low recurrence rates with preserved renal function, even for patients with high nephrometry scores and body mass index, assuming thorough cytotoxic technique and protection measures.

Brachytherapy for Patients With Prostate Cancer: American Society of Clinical Oncology/Cancer Care Ontario Joint Guideline Update

Purpose

To jointly update the Cancer Care Ontario guideline on brachytherapy for patients with prostate cancer to account for new evidence.

Methods

An Update Panel conducted a targeted systematic literature review and identified more recent randomized controlled trials comparing dose-escalated external beam radiation therapy (EBRT) with brachytherapy in men with prostate cancer.

Results

Five randomized controlled trials provided the evidence for this update.

Recommendations

For patients with low-risk prostate cancer who require or choose active treatment, low–dose rate brachytherapy (LDR) alone, EBRT alone, and/or radical prostatectomy (RP) should be offered to eligible patients. For patients with intermediate-risk prostate cancer choosing EBRT with or without androgen-deprivation therapy, brachytherapy boost (LDR or high–dose rate [HDR]) should be offered to eligible patients. For low-intermediate risk prostate cancer (Gleason 7, prostate-specific antigen < 10 ng/mL or Gleason 6, prostate-specific antigen, 10 to 20 ng/mL), LDR brachytherapy alone may be offered as monotherapy. For patients with high-risk prostate cancer receiving EBRT and androgen-deprivation therapy, brachytherapy boost (LDR or HDR) should be offered to eligible patients. Iodine-125 and palladium-103 are each reasonable isotope options for patients receiving LDR brachytherapy; no recommendation can be made for or against using cesium-131 or HDR monotherapy. Patients should be encouraged to participate in clinical trials to test novel or targeted approaches to this disease. Additional information is available at www.asco.org/Brachytherapy-guideline and www.asco.org/guidelineswiki .

Galectin-3 in bone tumor microenvironment: a beacon for individual skeletal metastasis management

The skeleton is frequently a secondary growth site of disseminated cancers, often leading to painful and devastating clinical outcomes. Metastatic cancer distorts bone marrow homeostasis through tumor-derived factors, which shapes different bone tumor microenvironments depending on the tumor cells' origin. Here, we propose a novel insight on tumor-secreted Galectin-3 (Gal-3) that controls the induction of an inflammatory cascade, differentiation of osteoblasts, osteoclasts, and bone marrow cells, resulting in bone destruction and therapeutic failure. In the approaching era of personalized medicine, the current treatment modalities targeting bone metastatic environments are provided to the patient with limited consideration of the cancer cells' origin. Our new outlook suggests delivering individual tumor microenvironment treatments based on the expression level/activity/functionality of tumor-derived factors, rather than utilizing a commonly shared therapeutic umbrella. The notion of "Gal-3-associated bone remodeling" could be the first step toward a specific personalized therapy for each cancer type generating a different bone niche in patients afflicted with non-curable bone metastasis.

Barriers to Clinical Trial Enrollment in Racial and Ethnic Minority Patients With Cancer

BACKGROUND

Clinical trials that study cancer are essential for testing the safety and effectiveness of promising treatments, but most people with cancer never enroll in a clinical trial - a challenge exemplified in racial and ethnic minorities. Underenrollment of racial and ethnic minorities reduces the generalizability of research findings and represents a disparity in access to high-quality health care.

METHODS

Using a multilevel model as a framework, potential barriers to trial enrollment of racial and ethnic minorities were identified at system, individual, and interpersonal levels. Exactly how each level directly or indirectly contributes to doctor-patient communication was also reviewed. Selected examples of implemented interventions are included to help address these barriers. We then propose our own evidence-based intervention addressing barriers at the individual and interpersonal levels.

RESULTS

Barriers to enrolling a diverse population of patients in clinical trials are complex and multilevel. Interventions focused at each level have been relatively successful, but multilevel interventions have the greatest potential for success.

CONCLUSION

To increase the enrollment of racial and ethnic minorities in clinical trials, future interventions should address barriers at multiple levels.

Global peak alignment for comprehensive two-dimensional gas chromatography mass spectrometry using point matching algorithms

Comprehensive two-dimensional gas chromatography coupled with mass spectrometry (GC[Formula: see text][Formula: see text][Formula: see text]GC-MS) has been used to analyze multiple samples in a metabolomics study. However, due to some uncontrollable experimental conditions, such as the differences in temperature or pressure, matrix effects on samples and stationary phase degradation, there is always a shift of retention times in the two GC columns between samples. In order to correct the retention time shifts in GC[Formula: see text][Formula: see text][Formula: see text]GC-MS, the peak alignment is a crucial data analysis step to recognize the peaks generated by the same metabolite in different samples. Two approaches have been developed for GC[Formula: see text][Formula: see text][Formula: see text]GC-MS data alignment: profile alignment and peak matching alignment. However, these existing alignment methods are all based on a local alignment, resulting that a peak may not be correctly aligned in a dense chromatographic region where many peaks are present in a small region. False alignment will result in false discovery in the downstream statistical analysis. We, therefore, develop a global comparison-based peak alignment method using point matching algorithm (PMA-PA) for both homogeneous and heterogeneous data. The developed algorithm PMA-PA first extracts feature points (peaks) in the chromatography and then searches globally the matching peaks in the consecutive chromatography by adopting the projection of rigid and nonrigid transformation. PMA-PA is further applied to two real experimental data sets, showing that PMA-PA is a promising peak alignment algorithm for both homogenous and heterogeneous data in terms of [Formula: see text]1 score, although it uses only peak location information.