Zhong, Jun

Abstract Background: Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer-related deaths in the U.S. mainly because of late-stage diagnosis. Heritable genetic information can improve risk stratification for individuals with moderate to high-risk of PDAC for targeted screening and early detection. We aimed to develop an enhanced polygenic risk score (PRS) for PDAC using a Bayesian approach, LDpred2, that reweights risk estimates attributed to millions of polymorphisms (SNPs) estimated from genome-wide association studies (GWASs). We then compared the performance of LDpred2 with the commonly used genetic risk score (GRS) approach that is based only on genome-wide significant SNPs. Methods: GWAS summary statistics were obtained from the Pancreatic Cancer Cohort Consortium and the Pancreatic Cancer Case Control Consortium for 9040 cases and 12496 controls and were used to compute weights for a GRS (17 SNPs) using a p-value threshold of 5e-8 and weights for an enhanced PRS (1.3 million SNPs) using LDpred2. These weights were then used to compute risk scores in an independent validation sample of 2616 cases and 45407 controls from the Mayo Clinic. We used logistic regression to test for associations of the GRS and PRS with PDAC risk, adjusting for age, sex, and the first 10 principal components of ancestry. Results: The validation sample was of mostly European ancestries (>95%). Cases were slightly older than controls (median age: 66 yrs. vs. 63 yrs.) and had a higher frequency of men than controls (57% vs. 42%). Comparisons between the GRS and the PRS are shown in Table 1. DeLong’s test comparing the AUCs between the two genetic scores showed the PRS significantly outperformed the GRS (AUC = 0.68 vs. 0.67; p = 7.6e-7). Conclusions: The LDpred2 PRS model that used a larger set of SNPs significantly improved prediction of PDAC. Comparing the top percentile of the PRS versus the rest showed that the PRS is a clinically significant risk score (OR > 3) for PDAC and could inform clinical decision making and genetic counseling of individuals identified as having a high risk of PDAC. Citation Format: Samuel O. Antwi, Brandon J. Coombes, Nicholas B. Larson, Erin E. Carlson, Kari G. Rabe, Hunter J. Atkinson, Shounak Majumder, Jun Zhong, David McKean, Pancreatic Cancer Cohort & Case Control Consortia (PanScan and PanC4), Brian M. Wolpin, Rachael Z. Stolzenberg-Solomon, Alison P. Klein, Laufey T. Amundadottir, Ann L. Oberg. Enhanced polygenic risk score for pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_2):Abstract nr LB331.

Abstract Background: Genome-wide association studies (GWAS) have linked single nucleotide polymorphisms (SNPs) to pancreatic ductal adenocarcinoma (PDAC) risk at over 20 genomic loci. The Pancreatic Cancer Cohort Consortium and Pancreatic Cancer Case-Control Consortium are currently expanding on previous GWAS studies for PDAC from ∼9,000 cases and ∼12,000 controls to ∼36,000 cases and ∼800,000 controls in individuals of European and Asian ancestry. This ongoing GWAS phase is estimated to detect up to 50 new risk signals. Post-GWAS studies aim to fine-map and functionally assess risk variants in disease-relevant cell types and contexts to identify target genes and underlying mechanisms of risk. Massively parallel reporter assays (MPRAs) are a powerful method of assessing allele-specific gene regulatory effects. Integrating sequences into the genome using lentiviruses (Lenti-MPRA) enables the capture of variant function in the context of the native cellular chromatin. An added benefit is that Lenti-MPRAs can be used for difficult to transfect cells such as primary cells, that often reflect the disease relevant cell types. Methods: We have used a lentiviral MPRA to test 228 fine-mapped SNPs at the chr5p15.33 multi-cancer risk locus in PDAC cell lines (MIA PaCa-2, PANC-1) and the normal-derived ductal pancreas (HPDE) cell line. Additionally, we have optimized the transduction of large MPRA libraries into primary pancreas cells. Tunicamycin was used to induce ER stress in cell lines and primary cells, assessing downstream gene expression using RT-qPCR. Results: Our pilot MPRA demonstrated high reproducibility in PDAC cell lines (r2=0.93-0.97, MIA PaCa-2, PANC-1 cells) and normal-derived pancreatic ductal cells (r2=0.68-0.86, HPDE cells). We identified 33 SNPs out of 228 with significant allele-specific transcriptional activity in PDAC cell lines and 5 in HPDE cells (FDR ≤0.05). An additional 6-15% of variants exhibited significant allele-specific transcriptional activity when in the frames of the SNP-centered tested oligos were shifted left or right. We demonstrate the inducibility of ER-stress with tunicamycin treatment over 24 hours in cells lines and primary pancreatic cells. Additionally, we observed increased expression of CLPTM1IL at the chr5p15.33 locus after tunicamycin treatment over 24 hours in cell lines and primary pancreatic cells, suggesting ER-stress and inflammation may influence gene expression at this locus. Conclusions: Lentiviral MPRA assays in commonly used PDAC cell lines have demonstrated good reproducibility. The optimization studies and preliminary work in primary pancreatic cells provide a solid foundation for the next steps of assessing all GWAS loci in ER stress, an important disease relevant condition. Citation Format: Minal B Patel, Aidan O'Brien, Jun Zhong, Irene Collins, Jason W Hoskins, Stephen J Chanock, Samuel O Antwi, Rachel Z Stolzenberg-Solomon, Alison P Klein, Brian M Wolpin, Sara Lindström, H. Efsun Arda, Kevin M Brown, Katelyn E Connelly, Laufey T Amundadottir, Meagan Jezek. The functional characterization of pancreatic ductal adenocarcinoma GWAS risk variants in primary pancreatic cells – A pilot study [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A018.

Abstract Background: Pancreatic cancer is a leading cause of cancer-related death globally. Risk factors for pancreatic cancer include common genetic variants and potentially heavy alcohol consumption. We assessed if genetic variants modify the association between heavy alcohol consumption and pancreatic cancer risk. Methods: We conducted a genome-wide interaction analysis of single-nucleotide polymorphisms (SNP) by heavy alcohol consumption (more than three drinks per day) for pancreatic cancer in European ancestry populations from genome-wide association studies. Our analysis included 3,707 cases and 4,167 controls from case–control studies and 1,098 cases and 1,162 controls from cohort studies. Fixed-effect meta-analyses were conducted. Results: A potential novel region of association on 10p11.22, lead SNP rs7898449 (interaction P value (Pinteraction) = 5.1 × 10−8 in the meta-analysis; Pinteraction = 2.1 × 10−9 in the case–control studies; Pinteraction = 0.91 in the cohort studies), was identified. An SNP correlated with this lead SNP is an expression quantitative trait locus for the neuropilin 1 gene. Of the 17 genomic regions with genome-wide significant evidence of association with pancreatic cancer in prior studies, we observed suggestive evidence that heavy alcohol consumption modified the association for one SNP near LINC00673, rs11655237 on 17q25.1 (Pinteraction = 0.004). Conclusions: We identified a novel genomic region that may be associated with pancreatic cancer risk in conjunction with heavy alcohol consumption located near an expression quantitative trait locus for neuropilin 1, a protein that plays an important role in the development and progression of pancreatic cancer. Impact: This work can provide insights into the etiology of pancreatic cancer, particularly in heavy drinkers.

Abstract Background: There are conflicting data on whether nonalcoholic fatty liver disease (NAFLD) is associated with susceptibility to pancreatic cancer. Using Mendelian randomization (MR), we investigated the relationship between genetic predisposition to NAFLD and risk for pancreatic cancer. Methods: Data from genome-wide association studies (GWAS) within the Pancreatic Cancer Cohort Consortium (PanScan; cases n = 5,090, controls n = 8,733) and the Pancreatic Cancer Case Control Consortium (PanC4; cases n = 4,163, controls n = 3,792) were analyzed. We used data on 68 genetic variants with four different MR methods [inverse variance weighting (IVW), MR-Egger, simple median, and penalized weighted median] separately to predict genetic heritability of NAFLD. We then assessed the relationship between each of the four MR methods and pancreatic cancer risk, using logistic regression to calculate ORs and 95% confidence intervals (CI), adjusting for PC risk factors, including obesity and diabetes. Results: No association was found between genetically predicted NAFLD and pancreatic cancer risk in the PanScan or PanC4 samples [e.g., PanScan, IVW OR, 1.04; 95% confidence interval (CI), 0.88–1.22; MR-Egger OR, 0.89; 95% CI, 0.65–1.21; PanC4, IVW OR, 1.07; 95% CI, 0.90–1.27; MR-Egger OR, 0.93; 95% CI, 0.67–1.28]. None of the four MR methods indicated an association between genetically predicted NAFLD and pancreatic cancer risk in either sample. Conclusions: Genetic predisposition to NAFLD is not associated with pancreatic cancer risk. Impact: Given the close relationship between NAFLD and metabolic conditions, it is plausible that any association between NAFLD and pancreatic cancer might reflect host metabolic perturbations (e.g., obesity, diabetes, or metabolic syndrome) and does not necessarily reflect a causal relationship between NAFLD and pancreatic cancer.

Abstract Genome wide association studies (GWAS) in 9,013 pancreatic cancer patients and 12,452 controls of European ancestry have discovered over 20 risk loci in the human genome. Here, we fine mapped one such locus on chromosome 16q23.1 in the vicinity of two Chymotrypsinogen precursor genes, CTRB1 and CTRB2. We fine-mapped this locus to rs72802365 (P=2.51x10-17, OR=1.36, 95% CI=1.31-1.40) and identified colocalization (PP=87%) with aberrant exon 5→7 CTRB2 splicing in pancreatic tissues. Imputation of a 584 bp insertion/deletion variant overlapping exon 6 of CTRB2 into the GWAS datasets resulted in a highly significant association with pancreatic cancer risk (P=2.83x10-16, OR=1.36, 95% CI=1.31-1.42), indicating that it may underlie this signal. Exon skipping attributable to the deletion (risk) allele introduces a premature stop codon in exon 7 of CTRB2, yielding a truncated chymotrypsin B2 protein that lacks chymotrypsin activity, is poorly secreted, and accumulates intracellularly in the endoplasmic reticulum (ER). The intracellular accumulation of a nonfunctional chymotrypsinogen B2 protein may lead to ER stress and pancreatic inflammation, which in turn, may explain the increased pancreatic cancer risk in carriers of CTRB2 exon 6 deletion alleles. Citation Format: Ashley Jermusyk, Jun Zhong, Naomi Gordon, Katelyn Connelly, Sumeth Perera, Ehssan Abdolalizadeh, Tongwu Zhang, Aidan O'Brien, Jason Hoskins, Irene Collins, Daina Eiser, Chen Yuan, Harvey Risch, Eric J. Jacobs, Donghui Li, Mengmeng Du, Rachael Stolzenberg-Solomon, Alison P. Klein, Jill P. Smith, Brian M. Wolpin, Stephen J. Chanock, Jianxin Shi, Gloria M. Petersen, Christopher Westlake, Laufey T. Amundadottir. An exception to the rule: A coding functional variant at a pancreatic cancer GWAS locus [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2020 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2020;80(22 Suppl):Abstract nr IA-11.

Abstract Background Although 20 pancreatic cancer susceptibility loci have been identified through genome-wide association studies in individuals of European ancestry, much of its heritability remains unexplained and the genes responsible largely unknown. Methods To discover novel pancreatic cancer risk loci and possible causal genes, we performed a pancreatic cancer transcriptome-wide association study in Europeans using three approaches: FUSION, MetaXcan, and Summary-MulTiXcan. We integrated genome-wide association studies summary statistics from 9040 pancreatic cancer cases and 12 496 controls, with gene expression prediction models built using transcriptome data from histologically normal pancreatic tissue samples (NCI Laboratory of Translational Genomics [n = 95] and Genotype-Tissue Expression v7 [n = 174] datasets) and data from 48 different tissues (Genotype-Tissue Expression v7, n = 74–421 samples). Results We identified 25 genes whose genetically predicted expression was statistically significantly associated with pancreatic cancer risk (false discovery rate < .05), including 14 candidate genes at 11 novel loci (1p36.12: CELA3B; 9q31.1: SMC2, SMC2-AS1; 10q23.31: RP11-80H5.9; 12q13.13: SMUG1; 14q32.33: BTBD6; 15q23: HEXA; 15q26.1: RCCD1; 17q12: PNMT, CDK12, PGAP3; 17q22: SUPT4H1; 18q11.22: RP11-888D10.3; and 19p13.11: PGPEP1) and 11 at six known risk loci (5p15.33: TERT, CLPTM1L, ZDHHC11B; 7p14.1: INHBA; 9q34.2: ABO; 13q12.2: PDX1; 13q22.1: KLF5; and 16q23.1: WDR59, CFDP1, BCAR1, TMEM170A). The association for 12 of these genes (CELA3B, SMC2, and PNMT at novel risk loci and TERT, CLPTM1L, INHBA, ABO, PDX1, KLF5, WDR59, CFDP1, and BCAR1 at known loci) remained statistically significant after Bonferroni correction. Conclusions By integrating gene expression and genotype data, we identified novel pancreatic cancer risk loci and candidate functional genes that warrant further investigation.

Abstract Pancreatic Ductal Adenocarcinoma (PDAC) is the third leading cause of cancer-related deaths in United States with a 5-year survival rate of only 8%. Inherited predisposition plays an important role in PDAC risk. Rare, moderately to highly penetrant mutations in hereditary cancer and pancreatitis genes, identified in families with a high incidence of disease, account for a small fraction of cases. At the other end of the spectrum, common risk variants of low penetrance have been discovered through genome-wide association studies (GWAS). Currently, over 20 common PDAC risk signals have been identified through GWAS in populations of European ancestry. However, these loci explain only a small fraction of genetic heritability for PDAC, and the causal genes for the large majority of these are unknown. Most susceptibility alleles discovered through GWAS are located in noncoding regions of the genome and are likely to function through allele specific regulation of gene expression. Transcriptome-wide association studies integrate expression quantitative trait loci (eQTL) with GWAS data to discover genes whose cis-regulated expression is associated with complex traits. To identify novel susceptibility loci and likely causal genes, we applied this approach to PDAC. Firstly, we used two reference datasets generated from histologically normal pancreatic tissue samples from individuals of European ancestry, the DCEG/LTG (n=95) and Genotype-Tissue Expression (GTEx v7, n=174), to build robust predictors for gene expression (n=2,872-5,906; r2>0.01), using 5 different models (Top1, Lasso, Enet, Blup and Bslmm) in FUSION and PrediXcan. Gene expression predictors (n=2,043-21,422) were also generated by Enet in 48 different tissues (n=74-421 samples) from 608 individuals of European ancestry (GTEx). We then applied these predictor models to PDAC GWAS summary statistics from 9,040 PC cases and 12,496 controls. We discovered 24 genes whose genetically predicted expression is significantly associated with PDAC risk (FDR < 0.05), including 13 candidate genes at 10 novel loci (CELA3B, SMC2, SMC2-AS1, RP11-80H5.9, SMUG1, BTBD6, RCCD1, PNMT, CDK12, PGAP3, SUPT4H1, RP11-888D10.3 and PGPEP1) and 11 at 5 known risk loci (TERT, CLPTM1L, ZDHHC11B, INHBA, ABO, PDX1, KLF5, WDR59, CFDP1, BCAR1 and TMEM170A). Pathway enrichment analysis for genes differentially expressed in the top vs. bottom quartile of CELA3B expression highlighted higher expression of inflammatory and immune response genes in both the DCEG/LTG and GTEx pancreatic transcriptome datasets, indicating that low expression of this gene may be associated with an inflammatory state in the pancreas. Our findings showcase the utility of integrating multiple datasets to generate hypotheses and provide novel clues for the genetic mechanisms underlying pancreatic cancer risk. Citation Format: Jun Zhong, Ashley Jermusyk, Lang Wu, Jason W. Hoskins, Irene Collins, Mingfeng Zhang, Song Lei, Charles C. Chung, Tongwu Zhang, Wenming Xiao, Rachael Stolzenberg-Solomon, Alison P. Klein, Brian M. Wolpin, Xiao-Ou Shu, Stephen J. Chanock, Sara Olson, Nilanjan Chatterjee, Jill Smith, Jianxin Shi, Peter Kraft, Gloria M. Petersen, Wei Zheng, Laufey T. Amundadottir. Large-scale transcriptome-wide association study (TWAS) identifies novel candidate susceptibility genes for pancreatic cancer [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 1591.