Rural Melanoma Patients Have Less Surgery and Higher Melanoma-Specific Mortality

BACKGROUND

Melanoma causes most skin cancer-related deaths, and disparities in mortality persist. Rural communities, compared to urban, face higher levels of poverty and more barriers to care, leading to higher stage at presentation and shorter survival in melanoma. To further evaluate these disparities, we sought to assess the association between rurality and melanoma cause-specific mortality and receipt of recommended surgery in a national cohort.

METHODS

Patients with primary non-ocular, cutaneous melanoma from the SEER database, 2000-2017, were included. Outcomes included melanoma-specific survival and receipt of recommended surgery. Rurality was based on Rural-Urban Continuum Codes. Variables included age, sex, race, ethnicity, income, and stage. Multivariate regression models assessed the effect of rurality on survival and receipt of recommended surgery.

RESULTS

103,606 patients diagnosed with non-ocular cutaneous primary melanoma met criteria during this period. 93.3% (n = 96620) were in urban areas and 6.7% (n = 6986) were in rural areas. On multivariate regression controlling for age, sex, race, ethnicity, and stage patients living in a rural area were less likely to receive recommended surgery (aOR .52, 95% CI: .29-.90, P = .02) and had increased hazard of melanoma-specific mortality (aHR 1.19, 95% CI: 1.02-1.40, P = .03) even after additionally controlling for surgery receipt.

CONCLUSION

Using a large national cohort, our study found that rural patients were less likely to receive recommended surgery and had shorter melanoma cause-specific survival. Our findings highlight the importance of access to cancer care in rural areas and how this ultimately effects survival for these patients.

Everything old is new again. revisiting hypophysectomy for the treatment of refractory cancer-related pain: a systematic review

Cancer-related pain is a common and debilitating condition that can significantly affect the quality of life of patients. Opioids, NSAIDs, and antidepressants are among the first-line therapies, but their efficacy is limited or their use can be restricted due to serious side effects. Neuromodulation and lesioning techniques have also proven to be a valuable instrument for managing refractory pain. For patients who have exhausted all standard treatment options, hypophysectomy may be an effective alternative treatment. We conducted a comprehensive systematic review of the available literature on PubMed and Scielo databases on using hypophysectomy to treat refractory cancer-related pain. Data extraction from included studies included study design, treatment model, number of treated patients, sex, age, Karnofsky Performance Status (KPS) score, primary cancer site, lead time from diagnosis to treatment, alcohol injection volume, treatment data, and clinical outcomes. Statistical analysis was reported using counts (N, %) and means (range). The study included data from 735 patients from 24 papers treated with hypophysectomy for refractory cancer-related pain. 329 cancer-related pain patients were treated with NALP, 216 with TSS, 66 with RF, 55 with Y90 brachytherapy, 51 with Gamma Knife radiosurgery (GK), and 18 with cryoablation. The median age was 58.5 years. The average follow-up time was 8.97 months. Good pain relief was observed in 557 out of 735 patients, with complete pain relief in 108 out of 268 patients. Pain improvement onset was observed 24 h after TSS, a few days after NALP or cryoablation, and a few days to 4 weeks after GK. Complications varied among treatment modalities, with diabetes insipidus (DI) being the most common complication. Although mostly forgotten in modern neurosurgical practice, hypophysectomy is an attractive option for treating refractory cancer-related pain after failure of traditional therapies. Radiosurgery is a promising treatment modality due to its high success rate and reduced risk of complications.

Racial and ethnic minorities in lower income brackets are associated with late-stage diagnosis of non-ocular melanoma

INTRODUCTION

Despite advances in oncologic care, racial and socio-economic outcome disparities persist in non-ocular melanoma patients. However, the unmet need is understanding the population at risk for late tumor stage at diagnosis. We sought to analyze the groups with an increased risk of unfavorable tumor stage at diagnosis.

METHODS

Patients with non-ocular melanoma were reviewed using the 2000-2019 SEER Research Data (SEER*Stat) and grouped into early tumor stage at diagnosis (stage I-IIC) and late (stage III-IVC). Multivariable logistic and Cox regression examined the association of demographic, socioeconomic, and clinical factors with late-stage diagnosis and overall survival, respectively. Kaplan-Meier estimates were calculated with racial and county-level household income stratification to evaluate overall survival differences.

RESULTS

Of 147,606 patients diagnosed with non-ocular melanoma, 38,695 cases were identified based on inclusion and exclusion criteria and separated into those with early-stage diagnosis (median 63 years) and those with late-stage (median 62 years). Male gender, Black race, Asian or Pacific Islander race, and Hispanic ethnicity were significantly associated with late-stage tumor diagnosis (p < 0.001). Receipt of surgery and a median county-level household income >$75,000 were protective for late-stage tumor diagnosis (p < 0.001). Additionally, male gender, Black, Asian or Pacific Islander, American Indian/Alaskan Native races, metastasis, and late-stage diagnosis were associated with factors significantly associated with decreased overall survival (p-value <0.001). Receipt of surgery and a median household income of $50,000-$74,999 and >$75,000 were factors associated with increased overall survival (p < 0.001). The median overall survival was 89 months, but Black patients (58 months) and <$50,000 income households (75 months) had significantly worse survival (p < 0.001).

CONCLUSIONS

Hispanic ethnicity, Black and Asian or Pacific Islander race, and low-income households were associated with late-stage non-ocular melanoma at diagnosis. Black, Asian or Pacific Islander and American Indian/Alaskan Native races and lower-income households were associated with worse overall survival. Identifying addressable causal factors that link this at-risk population to poor cancer prognosis is warranted.

Multiomic Characterization Reveals a Distinct Molecular Landscape in Young-Onset Pancreatic Cancer

PURPOSE

Using a real-world database with matched genomic-transcriptomic molecular data, we sought to characterize the distinct molecular correlates underlying clinical differences between patients with young-onset pancreatic cancer (YOPC; younger than 50 years) and patients with average-onset pancreatic cancer (AOPC; 70 years and older).

METHODS

We analyzed matched whole-transcriptome and DNA sequencing data from 2,430 patient samples (YOPC, n = 292; AOPC, n = 2,138) from the Caris Life Sciences database (Phoenix, AZ). Immune deconvolution was performed using the quanTIseq pipeline. Overall survival (OS) data were obtained from insurance claims (n = 4,928); Kaplan-Meier estimates were calculated for age- and molecularly defined cohorts. Significance was determined as FDR-corrected P values (Q) < .05.

RESULTS

Patients with YOPC had higher proportions of mismatch repair-deficient/microsatellite instability-high, BRCA2-mutant, and PALB2-mutant tumors compared with patients with AOPC, but fewer SMAD4-, RNF43-, CDKN2A-, and SF3B1-mutant tumors. Notably, patients with YOPC demonstrated significantly lower incidence of KRAS mutations compared with patients with AOPC (81.3% v 90.9%; Q = .004). In the KRAS wild-type subset (n = 227), YOPC tumors demonstrated fewer TP53 mutations and were more likely driven by NRG1 and MET fusions, whereas BRAF fusions were exclusively observed in patients with AOPC. Immune deconvolution revealed significant enrichment of natural killer cells, CD8+ T cells, monocytes, and M2 macrophages in patients with YOPC relative to patients with AOPC, which corresponded with lower rates of HLA-DPA1 homozygosity. There was an association with improved OS in patients with YOPC compared with patients with AOPC with KRAS wild-type tumors (median, 16.2 [YOPC-KRASWT] v 10.6 [AOPC-KRASWT] months; P = .008) but not KRAS-mutant tumors (P = .084).

CONCLUSION

In this large, real-world multiomic characterization of age-stratified molecular differences in pancreatic ductal adenocarcinoma, YOPC is associated with a distinct molecular landscape that has prognostic and therapeutic implications.

Abstract 2879: Cell-autonomous Cxcl1 sustains tolerogenic circuitries and stromal inflammation via neutrophil-derived TNF in pancreatic cancer

Objective: We have shown that KRAS-TP53 genomic co-alteration is associated with immune-excluded microenvironments, chemoresistance, and poor survival in pancreatic ductal adenocarcinoma (PDAC) patients. By treating KRAS-TP53 cooperativity as a model for high-risk biology, we sought to define how cancer cell-autonomous transcriptional programs orchestrate tolerogenic circuitries and stromal inflammation to mediate chemoresistance.

Methods: Spatial neighborhood analysis via Imaging Mass Cytometry (IMC) was performed in human PDAC sections. Immune profiling and RNA-seq in whole tumors, bulk-RNA-seq in intratumoral neutrophilic(PMN)-MDSCs in orthotopic KPC tumors with/without CRISPR/Cas9 editing of Cxcl1 was performed. Effect of TNFR2 inhibition via etanercept on ex vivo co-cultures of intratumoral PMN-MDSC with KPC tumor cells/CAFs and T-cells, as well as in orthotopic KPC models in vivo with/without gemcitabine+paclitaxel was examined.

Results: Interrogation of cancer cell transcriptomes and IMC architecture in human tumors reveals enrichment of Cxcl1 in KRAS-TP53 co-altered PDAC. IMC-enabled spatial neighborhood analysis in KRAS-TP53 co-altered human tumors demonstrate spatial contiguity between PanCK+CXCL1+ tumor islands and cognate CD15+CXCR2+ PMN-MDSCs, with exclusion of CD8+ T-cells from tumor cell:MDSC communities. In murine orthotopic models, silencing of cancer cell-intrinsic Cxcl1 reprograms trafficking and functional dynamics of CXCR2+ PMN-MDSCs to overcomes T-cell exclusion, and controls tumor growth in a CD8+ T-cell dependent manner. Transcriptomes from KPC-Cxcl1KO tumors reveal enrichment in pathways encoding for T-cell effector activity, and attenuation in pathways related to innate immunoregulatory function. Mechanistically, neutrophil-derived TNF emerges as a central regulator of this immunologic rewiring, with transcriptomes from intratumoral KPC-Cxcl1KO PMN-MDSCs revealing a novel MAPK-reliant Cxcr2-Ikk-Map3k8-Tnf axis. Neutrophil-derived TNF instigates feed-forward Cxcl1 overproduction from tumor cells and CAFs, T-cell dysfunction, and inflammatory CAF polarization via transmembraneTNF-TNFR2 interactions. Systemic TNFR2 inhibition via etanercept augments T-cell activation, and mitigates tumor-wide Cxcl1 production, stromal inflammation, and CAF:tumor cell IL6-STAT3 signaling to improve sensitivity to chemotherapy in vivo.

Conclusion: By decoding the link between high-risk cancer cell genotypes, cell-autonomous inflammatory programs, and myeloid-enriched and T-cell-excluded contexts, we identify a previously unrecognized role of neutrophil-derived TNF in sustaining tolerogenic circuitries and stromal inflammation in the PDAC TME. Our data suggest that targeting context-dependent TNF signaling may overcome hallmarks of therapeutic resistance in PDAC.

Citation Format: Anna Bianchi, Iago De Castro Silva, Nilesh Deshpande, Samara Singh, Siddharth Mehra, Vanessa Garrido, Ifeanyichukwu Ogobuiro, Haleh Amirian, Christine Rafie, Zhiqun Zhou, Nagaraj Nagathihalli, Alejandro Villarino, Nipun Merchant, Jashodeep Datta. Cell-autonomous Cxcl1 sustains tolerogenic circuitries and stromal inflammation via neutrophil-derived TNF in pancreatic cancer [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 2879.

Multi-omic characterization reveals a distinct molecular landscape in young-onset pancreatic cancer

Purpose

Using a real-world database with matched genomic-transcriptomic molecular data, we sought to characterize the distinct molecular correlates underlying clinical differences between young-onset pancreatic cancer (YOPC; <50-yrs.) and average-onset pancreatic cancer (AOPC; ≥70-yrs.) patients.

Methods

We analyzed matched whole-transcriptome and DNA sequencing data from 2430 patient samples (YOPC, n=292; AOPC, n=2138) from the Caris Life Sciences database (Phoenix, AZ). Immune deconvolution was performed using the quanTIseq pipeline. Overall survival (OS) data was obtained from insurance claims (n=4928); Kaplan-Meier estimates were calculated for age-and molecularly-defined cohorts. Significance was determined as FDR-corrected P -values ( Q )<0.05.

Results

YOPC patients had higher proportions of mismatch repair-deficient (dMMR)/microsatellite instability-high (MSI-H), BRCA2 -mutant, and PALB2 -mutant tumors compared with AOPC patients, but fewer SMAD4-, RNF43-, CDKN2A- , and SF3B1- mutant tumors. Notably, YOPC patients demonstrated significantly lower incidence of KRAS mutations compared with AOPC patients (81.3% vs. 90.9%; Q =0.004). In the KRAS- wildtype subset (n=227), YOPC tumors demonstrated fewer TP53 mutations and were more likely driven by NRG1 and MET fusions, while BRAF fusions were exclusively observed in AOPC patients. Immune deconvolution revealed significant enrichment of natural killer (NK) cells, CD8 + T cells, monocytes, and M2 macrophages in YOPC patients relative to AOPC patients, which corresponded with lower rates of HLA-DPA1 homozygosity. There was an association with improved OS in YOPC patients compared with AOPC patients with KRAS -wildtype tumors (median 16.2 [YOPC- KRAS WT ] vs. 10.6 [AOPC- KRAS WT ] months; P =0.008) but not KRAS -mutant tumors ( P =0.084).

Conclusion

In this large, real-world multi-omic characterization of age-stratified molecular differences in PDAC, YOPC is associated with a distinct molecular landscape that has prognostic and therapeutic implications.

Racial Disparity in Pathologic Response following Neoadjuvant Chemotherapy in Resected Pancreatic Cancer: A Multi-Institutional Analysis from the Central Pancreatic Consortium

BACKGROUND

Major pathologic response (MPR) following neoadjuvant therapy (NAT) in pancreatic ductal adenocarcinoma (PDAC) patients undergoing resection is associated with improved survival. We sought to determine whether racial disparities exist in MPR rates following NAT in patients with PDAC undergoing resection.

METHODS

Patients with potentially operable PDAC receiving at least 2 cycles of neoadjuvant FOLFIRINOX or gemcitabine/nab-paclitaxel ± radiation followed by pancreatectomy (2010-2019) at 7 high-volume centers were reviewed. Self-reported race was dichotomized as Black and non-Black, and multivariable models evaluated the association between race and MPR (i.e., pathologic complete response [pCR] or near-pCR). Cox regression evaluated the association between race and disease-free (DFS) and overall survival (OS).

RESULTS

Results of 486 patients who underwent resection following NAT (mFOLFIRINOX 56%, gemcitabine/nab-paclitaxel 25%, radiation 29%), 67 (13.8%) patients were Black. Black patients had lower CA19-9 at diagnosis (median 67 vs. 204 U/mL; P = 0.003) and were more likely to undergo mild/moderate chemotherapy dose modification (40 vs. 20%; P = 0.005) versus non-Black patients. Black patients had significantly lower rates of MPR compared with non-Black patients (13.4 vs. 25.8%; P = 0.039). Black race was independently associated with worse MPR (OR 0.26, 95% confidence interval [CI] 0.10-0.69) while controlling for NAT duration, CA19-9 dynamics, and chemotherapy modifications. There was no significant difference in DFS or OS between Black and non-Black cohorts.

CONCLUSIONS

Black patients undergoing pancreatectomy appear less likely to experience MPR following NAT. The contribution of biologic and nonbiologic factors to reduced chemosensitivity in Black patients warrants further investigation.

Distinct Profiles of DNA Repair Activity Define Favorable-risk Prostate Cancer Subtypes With Divergent Outcome

INTRODUCTION

Understanding if divergent molecular profiles of DNA damage and repair (DDR) pathway activity, a biomarker of disease progression, exist in prostate tumors with favorable-risk features is an unmet need, which this study aim to unearth.

MATERIALS AND METHODS

This was a multicenter registry genome-wide expression profiling study of prospectively collected radical prostatectomy (RP) tumor samples from 2014 to 2016. DDR activity was calculated from average expression of 372 DDR genes. Consensus hierarchical clustering was used to arrive at a robust clustering solution based on DDR gene expression patterns. Genome-wide differential expression between clusters was performed, and outcomes were evaluated across expression patterns.

RESULTS

Of 5239 patients from the prospective registry, 376 had favorable-risk disease (Grade group [GG] 1 to 2, PSA prior to RP <10ng/ml, pT2 or less). DDR activity score was correlated with prognostic genomic signatures that predict for metastatic risk (r = 0.37, P < 2e^-16) and high grade groups (P < .001). High DDR activity (top-quartile) was observed in 28% of patients with favorable-risk disease. In favorable-risk disease, 3 distinct clusters with varied DDR activity emerged with consensus clustering. Cluster I (compared with cluster II-III and GG3-GG5 disease) had the highest expression of all DDR sub-pathways, MYC, PAPR1, AR, and AR activity (P < .001 for all). Furthermore, cluster I was associated with poorer metastasis-free survival (MFS) and Overall survival (OS) compared with other clusters (MFS; HR: 2.43, 95%CI, [1.22-4.83], P = .01; OS; HR: 2.77, 95%CI, [1.18-6.5], P = .01).

CONCLUSIONS

Cluster I is a novel subgroup of favorable-risk disease with high DDR activity, AR activity, PARP1 and chr8q/MYC expression, and poorer MFS and OS.

Abstract C031: Targeting granulocytic MDSC-derived inflammasome activation to overcome stromal inflammation in pancreatic cancer

Objective: The major drivers of therapeutic resistance in pancreatic ductal adenocarcinoma (PDAC) are myeloid cell-derived signaling that sustains immune tolerance/exclusion, and interleukin-1 (IL-1)-mediated inflammatory polarization of cancer-associated fibroblasts (iCAF) which promotes stromal inflammation by elaborating soluble factors (i.e., CXCL1, IL-6) that further accelerate myeloid chemotaxis. Moreover, we have recently shown that enrichment of pathways related to inflammasome activation-which involves recruitment of ASC complexes culminating in IL-1β generation—is a major contributor to chemoresistance in advanced PDAC patients. However, how these disparate pathways converge to mediate stromal inflammation in PDAC is incompletely understood. Methods: Single-cell RNA sequencing (scRNAseq) and caspase-1 luminescence assays in human and genetically engineered mouse (GEM) PDAC models were interrogated to identify cellular source of inflammasome-derived IL-1β. Gene set enrichment analysis in bulk RNA-sequencing data and signal transduction studies examined novel pathways associated with inflammasome activation in granulocytic myeloid-derived suppressor cells (gMDSC). scRNAseq and ASC-speck formation via confocal microscopy in intratumoral gMDSCs was performed in PKT mice treated with a novel anti-ASC antibody. Results: scRNAseq in human and GEM PDAC models revealed gMDSCs as the dominant source of inflammasome activation-derived IL1B expression. Functionally, caspase-1 activation and ASC-speck formation was strongest in intratumoral gMDSCs, compared with tumor-cell, CAF, macrophage, T-cell, and dendritic cell, compartments. Investigating developmental trajectories of single-cell transcriptomes in intratumoral gMDSCs from Panc02 tumors revealed an activated Cd14+ gMDSC state with strong co-expression of Cxcr2 and Il1b. As such, treatment of PKT GEM and orthotopically injected KPC tumor-bearing mice with CXCR2 inhibitor AZD5069 significantly abrogated inflammasome activation in intratumoral and splenic gMDSCs. In vitro signal transduction and RNA-seq studies revealed cooperativity between Tlr4-Myd88 and Cxcr2-Tpl2-p38 signaling in activating gMDSC-restricted inflammasome signaling. Co-culture of intratumoral gMDSCs and KPC CAFs ex vivo revealed strong induction of CAF-intrinsic Il6/Cxcl1 expression, which was dependent in part on CAF-Il1r1 expression and inflammasome activation in gMDSCs. We next used antibody to target ASC-a common downstream adaptor complex inducing inflammasomes-in vivo. Treatment of PKT mice with this anti-ASC antibody significantly attenuated ASC-speck formation in intratumoral gMDSCs as well as CAF-specific Il6/Cxcl1 expression via scRNAseq. Conclusions: These data uncover granulocytic MDSCs as the dominant source of inflammasome activation derived-IL1β in the PDAC TME, which promotes stromal inflammation via iCAF polarization. Therapeutic approaches-such as anti-ASC treatment-targeting gMDSC-intrinsic inflammasome activation may mitigate stromal inflammation and overcome therapeutic resistance in PDAC.

Citation Format: Nilesh Deshpande, Anna Bianchi, Iago De Castro Silva, Vanessa Garrido, Siddharth Mehra, Samara Singh, Ifeanyichukwu Ogobuiro, Nagaraj Nagathihalli, Nipun B. Merchant, Jashodeep Datta. Targeting granulocytic MDSC-derived inflammasome activation to overcome stromal inflammation in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr C031.

Abstract 1328: Deciphering the role of CREB1 in shaping the tumor immune landscape of pancreatic ductal adenocarcinoma

Background: Pancreatic ductal adenocarcinoma (PDAC) remains a major therapeutic challenge with hallmarks including oncogenic mutations, desmoplastic architecture, and an immunosuppressive tumor microenvironment (TME). Previously, we have identified Cyclic AMP Response Element Binding protein 1 (CREB) as an oncogenic transcriptional factor downstream of KRAS that promotes disease aggressiveness, poor survival, and immune exclusion. Based on these, we sought to determine the impact of tumor intrinsic CREB deletion in shaping the tumor immune microenvironment.

Methods: We have generated a novel genetically engineered mouse model (GEMM) of pancreas-specific CREB deletion (CREBfl/fl) in LSL-KrasG12D/+; Trp53 R172H/+; Pdx1Cre/+ (KPC) mice that phenocopy human PDAC disease. CRISPR/CAS9-based genomic editing was utilized to ablate CREB (CREBKO) in KPC tumor cells. RNA-sequencing analysis was performed in KPC CREB wild type (CREBEV) vs. CREBKO tumor cells to identify CREB-mediated transcriptomic changes. Syngeneic orthotopic tumor implantation of these cells was performed into the pancreata of mice. High dimensional immunophenotyping was accomplished to assess changes in the immune subsets with CREB deletion in murine tumors. Additionally, these tissues were processed for immunohistochemical and qPCR-based analysis to assess changes in fibroinflammatory and immune mediators.

Results: Pancreas-specific CREB deletion in the KPC GEMM led to a significant reduction in the primary tumor burden, liver metastases and improved overall survival compared to wild-type KPC. Additionally, CREB deletion significantly remodeled the tumor stroma, as evidenced by the reduction in the expression of fibroinflammatory and immunosuppressive markers. In assessing the immune repercussions of CREB deletion in pancreatic tumors, we observed a decreased infiltration of CD11b+ myeloid-derived suppressor cells (MDSCs) and granulocytic-PMN MDSCs (CD11b+ Ly6Ghigh Ly6Clow F4/80-), with a concomitant increase in the antigen-presenting M1-like macrophages (F4/80+ MHC-II high CD86 high). Also, CREB ablation in these tumors further facilitated increased infiltration of activated effector CD8+ T cells resulted in enhanced anti-tumor immune response within the PDAC TME. Mechanistically, RNA transcriptomic and secretome analysis in CREBKO Vs. the wild type KPC tumor cells identified several differentially expressed immunomodulatory soluble mediators responsible for shaping CREB dependent immunogenic landscape in PDAC.

Conclusion: Overall, depleting CREB reshapes the tumor immune landscape to reduce innate immunosuppressive myeloid infiltration and reinvigorate the antitumor T cell immune responses to improve overall survival in PDAC.

Citation Format: Siddharth Mehra, Vanessa Garrido, Samara Singh, Iago D Silva, Luis Alberto Nivelo, Anna Bianchi, Shrey Modi, Zhiqun Zhou, Austin Dosch, Nilesh Deshpande, Supriya Srinivasan, Christine Rafie, Ifeanyichukwu Ogobuiro, Xi Chen, Alejandro Villarino, Jashodeep Datta, Nipun Merchant, Nagaraj Nagathihalli. Deciphering the role of CREB1 in shaping the tumor immune landscape of pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1328.

Multiomic characterization to reveal a distinct molecular landscape in young-onset pancreatic cancer

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Background: Young-onset pancreatic cancer (YOPC; < 50 years at diagnosis) has been associated with male preponderance, extensive smoking history, and a trend towards improved survival compared with average-onset pancreatic cancer (AOPC; ≥70 years). However, the genomic and transcriptomic correlates underlying these clinical differences are incompletely understood. Using a large matched genomic-transcriptomic next-generation sequencing (NGS) dataset, we sought to characterize the distinct molecular landscape associated with YOPC compared with AOPC. Methods: A total of 2430 pancreatic ductal adenocarcinoma NGS samples (YOPC n = 292; AOPC n = 2138) with matched whole-transcriptome (NovaSeq) and DNA (NextSeq, 592-gene or NovaSeq, whole-exome) sequencing data were analyzed (Caris Life Sciences, Phoenix, AZ). Immune deconvolution was performed using the QuantiSeq pipeline. Limited clinical data precluded stage- and treatment-stratified comparisons between cohorts. Overall survival (OS) was obtained from insurance claims, and Kaplan-Meier estimates were calculated for age- and molecularly-defined cohorts. Significance was determined as FDR-corrected P-values (Q) < 0.05. Results: Of 2430 PDAC patients undergoing NGS, YOPC patients (median age 46 years) were more likely to be male (65% vs. 52%; P < 0.001) and current smokers (32% vs. 11%; P = 0.02) compared with AOPC patients (median age 75 years). YOPC patients had higher proportions of mismatch repair-deficient (MMR)/MSI-H (2.8% vs. 0.8%, P = 0.001), BRCA2-mutant (4.7% vs 2.1%, P = 0.009), and PALB2-mutant (1.4% vs 0.5%, P = 0.04) tumors compared with AOPC patients, while tumors in AOPC patients had more frequent SMAD4 (20.1% vs. 14.7%, P = 0.03), RNF43 (6.3% vs. 2.5%, P = 0.012), CDKN2A (24.8% vs. 19.2%, P = 0.04), and SF3B1 (2.7% vs. 0.7%, P = 0.04) mutations. YOPC patients also demonstrated lower HLA-DPA1 homozygosity (55.2% vs. 64.1%, Q < 0.05) vs. AOPC patients. Notably, YOPC patients demonstrated significantly lower incidence of KRAS-mutant (81.3% vs. 90.9%, Q < 0.01) tumors compared with AOPC patients. In the KRAS-wildtype subset (n = 225), YOPC tumors were more likely to be driven by NRG1 and MET fusions, while BRAF fusions were exclusively observed in AOPC patients. Computationally inferred immune deconvolution revealed enrichment of NK cell (Q = 0.04) and M2 macrophages (Q = 0.01) populations in YOPC tumors. There was an association with improved OS in YOPC patients with KRAS-wildtype (median 22.4 [YOPC- KRASWT] vs. 15.1 [AOPC- KRASWT] months, P = 0.02) but not KRAS-mutant (P = 0.28), tumors compared with AOPC patients. Conclusions: In this large real-world multi-omic characterization of age-stratified molecular differences in PDAC, YOPC is associated with a distinct molecular landscape compared with AOPC. These data reveal molecular features of YOPC with prognostic and therapeutic implications.