Publications by authors named "Gloria M Petersen"

230 Publications

Novel Models of Genetic Education and Testing for Pancreatic Cancer Interception: Preliminary Results from the GENERATE Study.

Cancer Prev Res (Phila) 2021 Oct 8. Epub 2021 Oct 8.

Dana-Farber Cancer Institute, Boston, Massachusetts.

Up to 10% of patients with pancreatic ductal adenocarcinoma (PDAC) carry underlying germline pathogenic variants in cancer susceptibility genes. The GENetic Education Risk Assessment and TEsting (GENERATE) study aimed to evaluate novel methods of genetic education and testing in relatives of patients with PDAC. Eligible individuals had a family history of PDAC and a relative with a germline pathogenic variant in , or genes. Participants were recruited at six academic cancer centers and through social media campaigns and patient advocacy efforts. Enrollment occurred via the study website (https://GENERATEstudy.org) and all participation, including collecting a saliva sample for genetic testing, could be done from home. Participants were randomized to one of two remote methods that delivered genetic education about the risks of inherited PDAC and strategies for surveillance. The primary outcome of the study was uptake of genetic testing. From 5/8/2019 to 5/6/2020, 49 participants were randomized to each of the intervention arms. Overall, 90 of 98 (92%) of randomized participants completed genetic testing. The most frequently detected pathogenic variants included those in ( = 15, 17%), ( = 11, 12%), and ( = 4, 4%). Participation in the study remained steady throughout the onset of the Coronavirus disease (COVID-19) pandemic. Preliminary data from the GENERATE study indicate success of remote alternatives to traditional cascade testing, with genetic testing rates over 90% and a high rate of identification of germline pathogenic variant carriers who would be ideal candidates for PDAC interception approaches. PREVENTION RELEVANCE: Preliminary data from the GENERATE study indicate success of remote alternatives for pancreatic cancer genetic testing and education, with genetic testing uptake rates over 90% and a high rate of identification of germline pathogenic variant carriers who would be ideal candidates for pancreatic cancer interception.
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http://dx.doi.org/10.1158/1940-6207.CAPR-20-0642DOI Listing
October 2021

A 584 bp deletion in CTRB2 inhibits chymotrypsin B2 activity and secretion and confers risk of pancreatic cancer.

Am J Hum Genet 2021 Oct 23;108(10):1852-1865. Epub 2021 Sep 23.

Laboratory of Translational Genomics, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Bethesda, MD 20892, USA. Electronic address:

Genome-wide association studies (GWASs) have discovered 20 risk loci in the human genome where germline variants associate with risk of pancreatic ductal adenocarcinoma (PDAC) in populations of European ancestry. Here, we fine-mapped one such locus on chr16q23.1 (rs72802365, p = 2.51 × 10, OR = 1.36, 95% CI = 1.31-1.40) and identified colocalization (PP = 0.87) with aberrant exon 5-7 CTRB2 splicing in pancreatic tissues (p = 1.40 × 10, β = 1.99; p = 1.02 × 10, β = 1.99). Imputation of a 584 bp structural variant overlapping exon 6 of CTRB2 into the GWAS datasets resulted in a highly significant association with pancreatic cancer risk (p = 2.83 × 10, 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 chymotrypsinogen B2 protein that lacks chymotrypsin activity, is poorly secreted, and accumulates intracellularly in the endoplasmic reticulum (ER). We propose that intracellular accumulation of a nonfunctional chymotrypsinogen B2 protein leads to ER stress and pancreatic inflammation, which may explain the increased pancreatic cancer risk in carriers of CTRB2 exon 6 deletion alleles.
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http://dx.doi.org/10.1016/j.ajhg.2021.09.002DOI Listing
October 2021

Risk of Pancreatic Cancer Among Individuals With Pathogenic Variants in the ATM Gene.

JAMA Oncol 2021 Sep 16. Epub 2021 Sep 16.

Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, Maryland.

Importance: Pathogenic germline variants in the ATM gene have been associated with pancreatic cancer risk. Although genetic testing identifies these variants in approximately 1% to 3% of unselected patients with pancreatic cancer, the lifetime risk of pancreatic cancer among individuals with pathogenic ATM variants has not been well estimated.

Objective: To estimate age-specific penetrance of pancreatic cancer in individuals with a pathogenic variant in the ATM gene.

Design, Setting, And Participants: This was a multicenter cohort study of pancreatic cancer family registries in the US and Canada using pedigree data from 130 pancreatic cancer kindreds with a pathogenic germline ATM variant. Data analyses were performed from January 2020 to February 2021.

Main Outcomes And Measures: Observational age-specific risk of pancreatic cancer. Penetrance was estimated using modified segregation analysis.

Results: The study population of 130 families (123 [95%] White families) comprised 2227 family members (mean age [SD], 58 [22] years; 1096 [49%] women) with complete records (ie, including familial relationships, pancreatic cancer diagnosis, ATM status, proband status, and age), of which 155 individuals had positive results for an ATM pathogenic variant, 16 had a negative result, and the remainder did not have a test result. In these 130 families, 217 individuals had pancreatic cancer: 78 families had 1 such member; 34 families had 2 such members; and 18 families had 3 or more members with pancreatic cancer. The average (range) age at diagnosis was 64 (31-98) years. The cumulative risk of pancreatic cancer among individuals with a germline pathogenic ATM variant was estimated to be 1.1% (95% CI, 0.8%-1.3%) by age 50 years; 6.3% (95% CI, 3.9%-8.7%) by age 70 years; and 9.5% (95% CI, 5.0%-14.0%) by age 80 years. Overall, the relative risk of pancreatic cancer was 6.5 (95% CI, 4.5-9.5) in ATM variant carriers compared with noncarriers.

Conclusions And Relevance: This multicenter cohort study found that individuals with a germline pathogenic ATM variant were at an increased lifetime risk of pancreatic cancer. These risk estimates can help guide decision-making when evaluating the risks and benefits of enhanced early detection surveillance.
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http://dx.doi.org/10.1001/jamaoncol.2021.3701DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8446906PMC
September 2021

Hepcidin-regulating iron metabolism genes and pancreatic ductal adenocarcinoma: a pathway analysis of genome-wide association studies.

Am J Clin Nutr 2021 10;114(4):1408-1417

Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD, USA.

Background: Epidemiological studies have suggested positive associations for iron and red meat intake with risk of pancreatic ductal adenocarcinoma (PDAC). Inherited pathogenic variants in genes involved in the hepcidin-regulating iron metabolism pathway are known to cause iron overload and hemochromatosis.

Objectives: The objective of this study was to determine whether common genetic variation in the hepcidin-regulating iron metabolism pathway is associated with PDAC.

Methods: We conducted a pathway analysis of the hepcidin-regulating genes using single nucleotide polymorphism (SNP) summary statistics generated from 4 genome-wide association studies in 2 large consortium studies using the summary data-based adaptive rank truncated product method. Our population consisted of 9253 PDAC cases and 12,525 controls of European descent. Our analysis included 11 hepcidin-regulating genes [bone morphogenetic protein 2 (BMP2), bone morphogenetic protein 6 (BMP6), ferritin heavy chain 1 (FTH1), ferritin light chain (FTL), hepcidin (HAMP), homeostatic iron regulator (HFE), hemojuvelin (HJV), nuclear factor erythroid 2-related factor 2 (NRF2), ferroportin 1 (SLC40A1), transferrin receptor 1 (TFR1), and transferrin receptor 2 (TFR2)] and their surrounding genomic regions (±20 kb) for a total of 412 SNPs.

Results: The hepcidin-regulating gene pathway was significantly associated with PDAC (P = 0.002), with the HJV, TFR2, TFR1, BMP6, and HAMP genes contributing the most to the association.

Conclusions: Our results support that genetic susceptibility related to the hepcidin-regulating gene pathway is associated with PDAC risk and suggest a potential role of iron metabolism in pancreatic carcinogenesis. Further studies are needed to evaluate effect modification by intake of iron-rich foods on this association.
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http://dx.doi.org/10.1093/ajcn/nqab217DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8488877PMC
October 2021

A rare germline CDKN2A variant (47T>G; p16-L16R) predisposes carriers to pancreatic cancer by reducing cell cycle inhibition.

J Biol Chem 2021 Jan-Jun;296:100634. Epub 2021 Apr 3.

Division of Oncology Research, Schulze Center for Novel Therapeutics, Mayo Clinic, Rochester, Minnesota, USA. Electronic address:

Germline mutations in CDKN2A, encoding the tumor suppressor p16, are responsible for a large proportion of familial melanoma cases and also increase risk of pancreatic cancer. We identified four families through pancreatic cancer probands that were affected by both cancers. These families bore a germline missense variant of CDKN2A (47T>G), encoding a p16-L16R mutant protein associated with high cancer occurrence. Here, we investigated the biological significance of this variant. When transfected into p16-null pancreatic cancer cells, p16-L16R was expressed at lower levels than wild-type (WT) p16. In addition, p16-L16R was unable to bind CDK4 or CDK6 compared with WT p16, as shown by coimmunoprecipitation assays and also was impaired in its ability to inhibit the cell cycle, as demonstrated by flow cytometry analyses. In silico molecular modeling predicted that the L16R mutation prevents normal protein folding, consistent with the observed reduction in expression/stability and diminished function of this mutant protein. We isolated normal dermal fibroblasts from members of the families expressing WT or L16R proteins to investigate the impact of endogenous p16-L16R mutant protein on cell growth. In culture, p16-L16R fibroblasts grew at a faster rate, and most survived until later passages than p16-WT fibroblasts. Further, western blotting demonstrated that p16 protein was detected at lower levels in p16-L16R than in p16-WT fibroblasts. Together, these results suggest that the presence of a CDKN2A (47T>G) mutant allele contributes to an increased risk of pancreatic cancer as a result of reduced p16 protein levels and diminished p16 tumor suppressor function.
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http://dx.doi.org/10.1016/j.jbc.2021.100634DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8121974PMC
August 2021

High Detection Rates of Pancreatic Cancer Across Stages by Plasma Assay of Novel Methylated DNA Markers and CA19-9.

Clin Cancer Res 2021 May 16;27(9):2523-2532. Epub 2021 Feb 16.

Division of Gastroenterology & Hepatology, Mayo Clinic, Rochester, Minnesota.

Purpose: We have previously identified tissue methylated DNA markers (MDMs) associated with pancreatic ductal adenocarcinoma (PDAC). In this case-control study, we aimed to assess the diagnostic performance of plasma MDMs for PDAC.

Experimental Design: Thirteen MDMs (, and ) were identified on the basis of selection criteria applied to results of prior tissue experiments and assays were optimized in plasma. Next, 340 plasma samples (170 PDAC cases and 170 controls) were assayed using target enrichment long-probe quantitative amplified signal method. Initially, 120 advanced-stage PDAC cases and 120 healthy controls were used to train a prediction algorithm at 97.5% specificity using random forest modeling. Subsequently, the locked algorithm derived from the training set was applied to an independent blinded test set of 50 early-stage PDAC cases and 50 controls. Finally, data from all 340 patients were combined, and cross-validated.

Results: The cross-validated area under the receiver operating characteristic curve (AUC) for the training set was 0.93 (0.89-0.96) for the MDM panel alone, 0.91 (95% confidence interval, 0.87-0.96) for carbohydrate antigen 19-9 (CA19-9) alone, and 0.99 (0.98-1) for the combined MDM-CA19-9 panel. In the test set of early-stage PDAC, the AUC for MDMs alone was 0.84 (0.76-0.92), CA19-9 alone was 0.87 (0.79-0.94), and combined MDM-CA19-9 panel was 0.90 (0.84-0.97) significantly better compared with either MDMs alone or CA19-9 alone ( = 0.0382 and 0.0490, respectively). At a preset specificity of 97.5%, the sensitivity for the combined panel in the test set was 80% (28%-99%) for stage I disease and 82% (68%-92%) for stage II disease. Using the combined datasets, the cross-validated AUC was 0.9 (0.86-0.94) for the MDM panel alone and 0.89 for CA19-9 alone (0.84-0.93) versus 0.97 (0.94-0.99) for the combined MDM-CA19-9 panel ( ≤ 0.0001). Overall, cross-validated sensitivity of MDM-CA19-9 panel was 92% (83%-98%), with an observed specificity of 92% at the preset specificity of 97.5%.

Conclusions: Plasma MDMs in combination with CA19-9 detect PDAC with significantly higher accuracy compared with either biomarker individually.
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http://dx.doi.org/10.1158/1078-0432.CCR-20-0235DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8102343PMC
May 2021

Smoking Modifies Pancreatic Cancer Risk Loci on 2q21.3.

Cancer Res 2021 06 11;81(11):3134-3143. Epub 2021 Feb 11.

Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, Maryland.

Germline variation and smoking are independently associated with pancreatic ductal adenocarcinoma (PDAC). We conducted genome-wide smoking interaction analysis of PDAC using genotype data from four previous genome-wide association studies in individuals of European ancestry (7,937 cases and 11,774 controls). Examination of expression quantitative trait loci data from the Genotype-Tissue Expression Project followed by colocalization analysis was conducted to determine whether there was support for common SNP(s) underlying the observed associations. Statistical tests were two sided and < 5 × 10 was considered statistically significant. Genome-wide significant evidence of qualitative interaction was identified on chr2q21.3 in intron 5 of the transmembrane protein 163 (TMEM163) and upstream of the cyclin T2 (CCNT2). The most significant SNP using the Empirical Bayes method, in this region that included 45 significantly associated SNPs, was rs1818613 [per allele OR in never smokers 0.87, 95% confidence interval (CI), 0.82-0.93; former smokers 1.00, 95% CI, 0.91-1.07; current smokers 1.25, 95% CI 1.12-1.40, = 3.08 × 10). Examination of the Genotype-Tissue Expression Project data demonstrated an expression quantitative trait locus in this region for TMEM163 and CCNT2 in several tissue types. Colocalization analysis supported a shared SNP, rs842357, in high linkage disequilibrium with rs1818613 ( = 0. 94) driving both the observed interaction and the expression quantitative trait loci signals. Future studies are needed to confirm and understand the differential biologic mechanisms by smoking status that contribute to our PDAC findings. SIGNIFICANCE: This large genome-wide interaction study identifies a susceptibility locus on 2q21.3 that significantly modified PDAC risk by smoking status, providing insight into smoking-associated PDAC, with implications for prevention.
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http://dx.doi.org/10.1158/0008-5472.CAN-20-3267DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8178175PMC
June 2021

A multilayered post-GWAS assessment on genetic susceptibility to pancreatic cancer.

Genome Med 2021 02 1;13(1):15. Epub 2021 Feb 1.

CIBERONC, Madrid, Spain.

Background: Pancreatic cancer (PC) is a complex disease in which both non-genetic and genetic factors interplay. To date, 40 GWAS hits have been associated with PC risk in individuals of European descent, explaining 4.1% of the phenotypic variance.

Methods: We complemented a new conventional PC GWAS (1D) with genome spatial autocorrelation analysis (2D) permitting to prioritize low frequency variants not detected by GWAS. These were further expanded via Hi-C map (3D) interactions to gain additional insight into the inherited basis of PC. In silico functional analysis of public genomic information allowed prioritization of potentially relevant candidate variants.

Results: We identified several new variants located in genes for which there is experimental evidence of their implication in the biology and function of pancreatic acinar cells. Among them is a novel independent variant in NR5A2 (rs3790840) with a meta-analysis p value = 5.91E-06 in 1D approach and a Local Moran's Index (LMI) = 7.76 in 2D approach. We also identified a multi-hit region in CASC8-a lncRNA associated with pancreatic carcinogenesis-with a lowest p value = 6.91E-05. Importantly, two new PC loci were identified both by 2D and 3D approaches: SIAH3 (LMI = 18.24), CTRB2/BCAR1 (LMI = 6.03), in addition to a chromatin interacting region in XBP1-a major regulator of the ER stress and unfolded protein responses in acinar cells-identified by 3D; all of them with a strong in silico functional support.

Conclusions: This multi-step strategy, combined with an in-depth in silico functional analysis, offers a comprehensive approach to advance the study of PC genetic susceptibility and could be applied to other diseases.
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http://dx.doi.org/10.1186/s13073-020-00816-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7849104PMC
February 2021

Accuracy of Smoking Status Reporting: Proxy Information in a Rapidly Fatal Cancer Setting.

Mayo Clin Proc Innov Qual Outcomes 2020 Dec 10;4(6):801-809. Epub 2020 Dec 10.

Department of Health Sciences Research, Mayo Clinic, Rochester, MN.

Objective: To assess whether patients and relatives can serve as reliable proxy reporters of other family members' cigarette-smoking history.

Patients And Methods: Two samples (325 patients, 707 relatives) were identified from the Mayo Clinic Biospecimen Resource for Pancreas Research, enrolled from November, 6, 2000, to March 15, 2018. Smoking-history data, including categorical (ever/never) and quantitative (packs per day and years smoked) smoking measures, were obtained from self-completed questionnaires by patients and relatives. Relative reports were compared with patient reports on self; patient reports were compared with relative reports on self.

Results: Overall, spouses and first-degree relatives (FDRs) were accurate (94.5%) when reporting patient ever smoking; spouse reports were 98.6% sensitive and 97.7% accurate. Accuracy of patient reports was 97.8% for spouse smoking and 85.5% for FDR smoking; accuracy varied by relationship of FDR. When not concordant, patients generally over-reported daily packs smoked by relatives and under-reported years smoked. Within a 25% agreement range, spouse reports about patients' daily packs smoked was 46.7%, and years smoked was 69.6%, whereas FDRs were 50% and 64.6%, respectively. When not concordant, relatives generally over-reported daily packs smoked by patients, but no consistent pattern was observed of over- or under-reporting years smoked by patients.

Conclusions: Patients and relatives can be reliable proxies for smoking history (ever/never) in their family members, especially spouses. An accurate reporting of smoking status will help physicians to better gauge performance status and family smoking exposures to inform disease management.
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http://dx.doi.org/10.1016/j.mayocpiqo.2020.07.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7749254PMC
December 2020

Shorter Treatment-Naïve Leukocyte Telomere Length is Associated with Poorer Overall Survival of Patients with Pancreatic Ductal Adenocarcinoma.

Cancer Epidemiol Biomarkers Prev 2021 01 13;30(1):210-216. Epub 2020 Nov 13.

Division of Epidemiology, Mayo Clinic, Rochester, Minnesota.

Background: Critically shortened telomeres contribute to chromosomal instability and neoplastic transformation and are associated with early death of patients with certain cancer types. Shorter leukocyte telomere length (LTL) has been associated with higher risk for pancreatic ductal adenocarcinoma (PDAC) and might be associated also with survival of patients with PDAC. We investigated the association between treatment-naïve LTL and overall survival of patients with incident PDAC.

Methods: The study included 642 consecutively enrolled PDAC patients in the Mayo Clinic Biospecimen Resource for Pancreas Research. Blood samples were obtained at the time of diagnosis, before the start of cancer treatment, from which LTL was assayed by qRT-PCR. LTL was first modeled as a continuous variable (per-interquartile range decrease in LTL) and then as a categorized variable (short, medium, long). Multivariable-adjusted HRs and 95% confidence intervals (CI) were calculated for overall mortality using Cox proportional hazard models.

Results: Shorter treatment-naïve LTL was associated with higher mortality among patients with PDAC (HR = 1.13, 95% CI: 1.01-1.28, = 0.03; HR = 1.29, 95% CI: 1.05-1.59, = 0.01). There was a difference in the association between LTL and overall mortality by tumor stage at diagnosis; resectable tumors (HR = 0.91; 95% CI: 0.73-1.12), locally advanced tumors (HR = 1.29; 95% CI: 1.07-1.56), and metastatic tumors (HR = 1.17; 95% CI: 0.96-1.42), = 0.04.

Conclusion: Shorter treatment-naïve LTL is associated with poorer overall survival of patients with incident PDAC.

Impact: Peripheral blood LTL might be a prognostic marker for PDAC.
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http://dx.doi.org/10.1158/1055-9965.EPI-20-1279DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7855627PMC
January 2021

THBS2/CA19-9 Detecting Pancreatic Ductal Adenocarcinoma at Diagnosis Underperforms in Prediagnostic Detection: Implications for Biomarker Advancement.

Cancer Prev Res (Phila) 2021 02 16;14(2):223-232. Epub 2020 Oct 16.

Institute for Regenerative Medicine, Department of Cell and Developmental Biology, Abramson Cancer Center (Tumor Biology Program), Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.

Pancreatic ductal adenocarcinoma (PDAC) is often diagnosed too late for effective therapy. The classic strategy for early detection biomarker advancement consists of initial retrospective phases of discovery and validation with tissue samples taken from individuals diagnosed with disease, compared with controls. Using this approach, we previously reported the discovery of a blood biomarker panel consisting of thrombospondin-2 (THBS2) and CA19-9 that together could discriminate resectable stage I and IIa PDAC as well as stages III and IV PDAC, with c-statistic values in the range of 0.96 to 0.97 in two phase II studies. We now report that in two studies of blood samples prospectively collected from 1 to 15 years prior to a PDAC diagnosis (Mayo Clinic and PLCO cohorts), THBS2 and/or CA19-9 failed to discriminate cases from healthy controls at the AUC = 0.8 needed. We conclude that PDAC progression may be heterogeneous and for some individuals can be more rapid than generally appreciated. It is important that PDAC early-detection studies incorporate high-risk, prospective prediagnostic cohorts into discovery and validation studies. A blood biomarker panel of THBS2 and CA19-9 detects early stages of pancreatic ductal adenocarcinoma at diagnosis, but not when tested across a population up to 1 year earlier. Our findings suggest serial sampling over time, using prospectively collected samples for biomarker discovery, and more frequent screening of high-risk individuals.
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http://dx.doi.org/10.1158/1940-6207.CAPR-20-0403DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8050137PMC
February 2021

Targeting DNA Damage Response and Replication Stress in Pancreatic Cancer.

Gastroenterology 2021 01 9;160(1):362-377.e13. Epub 2020 Oct 9.

Barts Cancer Institute, Queen Mary University of London, London, United Kingdom.

Background & Aims: Continuing recalcitrance to therapy cements pancreatic cancer (PC) as the most lethal malignancy, which is set to become the second leading cause of cancer death in our society. The study aim was to investigate the association between DNA damage response (DDR), replication stress, and novel therapeutic response in PC to develop a biomarker-driven therapeutic strategy targeting DDR and replication stress in PC.

Methods: We interrogated the transcriptome, genome, proteome, and functional characteristics of 61 novel PC patient-derived cell lines to define novel therapeutic strategies targeting DDR and replication stress. Validation was done in patient-derived xenografts and human PC organoids.

Results: Patient-derived cell lines faithfully recapitulate the epithelial component of pancreatic tumors, including previously described molecular subtypes. Biomarkers of DDR deficiency, including a novel signature of homologous recombination deficiency, cosegregates with response to platinum (P < .001) and PARP inhibitor therapy (P < .001) in vitro and in vivo. We generated a novel signature of replication stress that predicts response to ATR (P < .018) and WEE1 inhibitor (P < .029) treatment in both cell lines and human PC organoids. Replication stress was enriched in the squamous subtype of PC (P < .001) but was not associated with DDR deficiency.

Conclusions: Replication stress and DDR deficiency are independent of each other, creating opportunities for therapy in DDR-proficient PC and after platinum therapy.
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http://dx.doi.org/10.1053/j.gastro.2020.09.043DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8167930PMC
January 2021

Effect of Germline Mutations in Homologous Recombination Repair Genes on Overall Survival of Patients with Pancreatic Adenocarcinoma.

Clin Cancer Res 2020 12 7;26(24):6505-6512. Epub 2020 Oct 7.

Department of Oncology, Mayo Clinic, Rochester, Minnesota.

Purpose: To compare the clinical characteristics and overall survival (OS) of germline mutation carriers in homologous recombination repair (HRR) genes and noncarriers with pancreatic ductal adenocarcinoma (PDAC).

Experimental Design: Germline DNA from 3,078 patients with PDAC enrolled in a prospective registry at Mayo Clinic between 2000 and 2017 was analyzed for mutations in 37 cancer predisposition genes. Characteristics and OS of patients with mutations in eight genes and involved in HRR were compared with patients testing negative for mutations in all 37 genes.

Results: The 175 HRR mutation carriers and 2,730 noncarriers in the study had a median duration of follow-up of 9.9 years. HRR mutation carriers were younger (median age at diagnosis: 63 vs. 66 years, < 0.001) and more likely to have metastatic disease at diagnosis (46% vs. 36%, = 0.004). In a multivariable model adjusting for sex, age at diagnosis, and tumor staging, patients with germline HRR mutations had a significantly longer OS compared with noncarriers [HR, 0.83; 95% confidence interval (CI), 0.70-0.97; = 0.02]. Further gene-level analysis demonstrated that germline mutation carriers had longer OS compared with patients without germline mutations in any of the 37 genes (HR, 0.72; 95% CI, 0.55-0.94; = 0.01).

Conclusions: This study demonstrates that germline mutation carrier status in PDAC is associated with longer OS compared with noncarriers. Further research into tumor biology and response to platinum-based chemotherapy in germline mutation carriers with PDAC are needed to better understand the association with longer OS.
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http://dx.doi.org/10.1158/1078-0432.CCR-20-1788DOI Listing
December 2020

Mendelian Randomization Analysis of n-6 Polyunsaturated Fatty Acid Levels and Pancreatic Cancer Risk.

Cancer Epidemiol Biomarkers Prev 2020 12 23;29(12):2735-2739. Epub 2020 Sep 23.

Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts.

Background: Whether circulating polyunsaturated fatty acid (PUFA) levels are associated with pancreatic cancer risk is uncertain. Mendelian randomization (MR) represents a study design using genetic instruments to better characterize the relationship between exposure and outcome.

Methods: We utilized data from genome-wide association studies within the Pancreatic Cancer Cohort Consortium and Pancreatic Cancer Case-Control Consortium, involving approximately 9,269 cases and 12,530 controls of European descent, to evaluate associations between pancreatic cancer risk and genetically predicted plasma n-6 PUFA levels. Conventional MR analyses were performed using individual-level and summary-level data.

Results: Using genetic instruments, we did not find evidence of associations between genetically predicted plasma n-6 PUFA levels and pancreatic cancer risk [estimates per one SD increase in each PUFA-specific weighted genetic score using summary statistics: linoleic acid odds ratio (OR) = 1.00, 95% confidence interval (CI) = 0.98-1.02; arachidonic acid OR = 1.00, 95% CI = 0.99-1.01; and dihomo-gamma-linolenic acid OR = 0.95, 95% CI = 0.87-1.02]. The OR estimates remained virtually unchanged after adjustment for covariates, using individual-level data or summary statistics, or stratification by age and sex.

Conclusions: Our results suggest that variations of genetically determined plasma n-6 PUFA levels are not associated with pancreatic cancer risk.

Impact: These results suggest that modifying n-6 PUFA levels through food sources or supplementation may not influence risk of pancreatic cancer.
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http://dx.doi.org/10.1158/1055-9965.EPI-20-0651DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7710600PMC
December 2020

Gallbladder disease, cholecystectomy, and pancreatic cancer risk in the International Pancreatic Cancer Case-Control Consortium (PanC4).

Eur J Cancer Prev 2020 09;29(5):408-415

Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy.

Background: The association among gallbladder disease, cholecystectomy, and pancreatic cancer is unclear. Moreover, time interval between gallbladder disease or cholecystectomy and pancreatic cancer diagnosis is not considered in most previous studies.

Aim: To quantify the association among gallbladder disease, cholecystectomy, and pancreatic cancer, considering time since first diagnosis of gallbladder disease or cholecystectomy.

Methods: We used data from nine case-control studies within the Pancreatic Cancer Case-Control Consortium, including 5760 cases of adenocarcinoma of the exocrine pancreas and 8437 controls. We estimated pooled odds ratios and the corresponding 95% confidence intervals by estimating study-specific odds ratios through multivariable unconditional logistic regression models, and then pooling the obtained estimates using fixed-effects models.

Results: Compared with patients with no history of gallbladder disease, the pooled odds ratio of pancreatic cancer was 1.69 (95% confidence interval, 1.51-1.88) for patients reporting a history of gallbladder disease. The odds ratio was 4.90 (95% confidence interval, 3.45-6.97) for gallbladder disease diagnosed <2 years before pancreatic cancer diagnosis and 1.11 (95% confidence interval, 0.96-1.29) when ≥2 years elapsed. The pooled odds ratio was 1.64 (95% confidence interval, 1.43-1.89) for patients who underwent cholecystectomy, as compared to those without cholecystectomy. The odds ratio was 7.00 (95% confidence interval, 4.13-11.86) for a surgery <2 years before pancreatic cancer diagnosis and 1.28 (95% confidence interval, 1.08-1.53) for a surgery ≥2 years before.

Conclusions: There appears to be no long-term effect of gallbladder disease on pancreatic cancer risk, and at most a modest one for cholecystectomy. The strong short-term association can be explained by diagnostic bias and reverse causation.
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http://dx.doi.org/10.1097/CEJ.0000000000000572DOI Listing
September 2020

Role of Surgery and Perioperative Therapy in Older Patients with Resectable Pancreatic Ductal Adenocarcinoma.

Oncologist 2020 11 4;25(11):e1681-e1690. Epub 2020 Aug 4.

Divisions of Medical Oncology, Mayo Clinic, Rochester, Minnesota, USA.

Background: It is unclear whether results from recent trials of resectable pancreatic ductal adenocarcinoma (PDAC) are generalizable to older patients, who are underrepresented. We aimed to evaluate outcomes of surgery and of neoadjuvant and adjuvant therapy in older patients with resectable PDAC.

Patients And Methods: We included patients aged ≥65 years with upfront resectable PDAC from a prospectively maintained pancreatic cancer registry from 2007 to 2016. Patients were stratified into ages 65-75 and 75+ years. Overall survival (OS) was assessed in treatment comparisons: (A) surgery (n = 636) versus nonsurgical (n = 178), (B) neoadjuvant therapy (n = 139) versus upfront surgery (n = 497), and (C) adjuvant therapy (n = 379) versus surgery alone (n = 118). We compared neoadjuvant (n = 139) versus adjuvant therapy (n = 379) in an exploratory analysis.

Results: Nine hundred and three patients had a median age of 73.7 (range, 65-96.6) years. Median OS was 26.6 versus 11.9 months (adjusted hazard ratio [HR ], 0.4; 95% confidence interval [CI], 0.31-0.52; p < .001) in Comparison A groups, 30.7 versus 25.8 months (HR , 0.69; 95% CI, 0.49-0.96; p = .03) in Comparison B groups, and 26.9 versus 17.4 months (HR , 0.62; 95% CI, 0.44-0.88; p = .008) in Comparison C groups, respectively. OS benefit in these treatment comparisons was present in age group 75+ with HR 0.24 (95% CI, 0.16-0.36; p < .001) in Comparison A and HR 0.52 (95% CI, 0.27-1; p = .049) in Comparison B, but not in Comparison C with HR 0.68 (95% CI, 0.43-1.08; p = .1). Statistically comparable median OS of patients who received neoadjuvant or adjuvant therapy stratified by age groups was observed.

Conclusion: Older patients with resectable PDAC who received surgery, neoadjuvant therapy, or adjuvant therapy appeared to have improved survival outcomes compared with those who did not receive such treatment.

Implications For Practice: Older patients with resectable pancreatic ductal adenocarcinoma (PDAC) in general are underrepresented in large clinical trials and less well studied in terms of the role of surgery, neoadjuvant therapy, and adjuvant therapy. This study collected data on older patients with resectable PDAC from a prospectively maintained single-institutional pancreatic cancer registry of a tertiary referral center from 2007 to 2016. It was found that, with multidisciplinary evaluation, older patients with resectable PDAC who received surgery, neoadjuvant therapy, or adjuvant therapy appeared to have improved survival outcomes compared with those who did not receive such treatment. These results are of substantial importance to practitioners who treat older patients, who are traditionally underrepresented in most clinical trials.
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http://dx.doi.org/10.1634/theoncologist.2020-0086DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7648330PMC
November 2020

Genome-Wide Association Study Data Reveal Genetic Susceptibility to Chronic Inflammatory Intestinal Diseases and Pancreatic Ductal Adenocarcinoma Risk.

Cancer Res 2020 09 8;80(18):4004-4013. Epub 2020 Jul 8.

Division of Cancer Epidemiology and Genetics, NCI, NIH, Bethesda, Maryland.

Registry-based epidemiologic studies suggest associations between chronic inflammatory intestinal diseases and pancreatic ductal adenocarcinoma (PDAC). As genetic susceptibility contributes to a large proportion of chronic inflammatory intestinal diseases, we hypothesize that the genomic regions surrounding established genome-wide associated variants for these chronic inflammatory diseases are associated with PDAC. We examined the association between PDAC and genomic regions (±500 kb) surrounding established common susceptibility variants for ulcerative colitis, Crohn's disease, inflammatory bowel disease, celiac disease, chronic pancreatitis, and primary sclerosing cholangitis. We analyzed summary statistics from genome-wide association studies data for 8,384 cases and 11,955 controls of European descent from two large consortium studies using the summary data-based adaptive rank truncated product method to examine the overall association of combined genomic regions for each inflammatory disease group. Combined genomic susceptibility regions for ulcerative colitis, Crohn disease, inflammatory bowel disease, and chronic pancreatitis were associated with PDAC at values < 0.05 (0.0040, 0.0057, 0.011, and 3.4 × 10, respectively). After excluding the 20 PDAC susceptibility regions (±500 kb) previously identified by GWAS, the genomic regions for ulcerative colitis, Crohn disease, and inflammatory bowel disease remained associated with PDAC ( = 0.0029, 0.0057, and 0.0098, respectively). Genomic regions for celiac disease ( = 0.22) and primary sclerosing cholangitis ( = 0.078) were not associated with PDAC. Our results support the hypothesis that genomic regions surrounding variants associated with inflammatory intestinal diseases, particularly, ulcerative colitis, Crohn disease, inflammatory bowel disease, and chronic pancreatitis are associated with PDAC. SIGNIFICANCE: The joint effects of common variants in genomic regions containing susceptibility loci for inflammatory bowel disease and chronic pancreatitis are associated with PDAC and may provide insights to understanding pancreatic cancer etiology.
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http://dx.doi.org/10.1158/0008-5472.CAN-20-0447DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7861352PMC
September 2020

Assessment of polygenic architecture and risk prediction based on common variants across fourteen cancers.

Nat Commun 2020 07 3;11(1):3353. Epub 2020 Jul 3.

Section of Epidemiology and Biostatistics, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK.

Genome-wide association studies (GWAS) have led to the identification of hundreds of susceptibility loci across cancers, but the impact of further studies remains uncertain. Here we analyse summary-level data from GWAS of European ancestry across fourteen cancer sites to estimate the number of common susceptibility variants (polygenicity) and underlying effect-size distribution. All cancers show a high degree of polygenicity, involving at a minimum of thousands of loci. We project that sample sizes required to explain 80% of GWAS heritability vary from 60,000 cases for testicular to over 1,000,000 cases for lung cancer. The maximum relative risk achievable for subjects at the 99th risk percentile of underlying polygenic risk scores (PRS), compared to average risk, ranges from 12 for testicular to 2.5 for ovarian cancer. We show that PRS have potential for risk stratification for cancers of breast, colon and prostate, but less so for others because of modest heritability and lower incidence.
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http://dx.doi.org/10.1038/s41467-020-16483-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7335068PMC
July 2020

Genome-Wide Gene-Diabetes and Gene-Obesity Interaction Scan in 8,255 Cases and 11,900 Controls from PanScan and PanC4 Consortia.

Cancer Epidemiol Biomarkers Prev 2020 09 16;29(9):1784-1791. Epub 2020 Jun 16.

Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, Maryland.

Background: Obesity and diabetes are major modifiable risk factors for pancreatic cancer. Interactions between genetic variants and diabetes/obesity have not previously been comprehensively investigated in pancreatic cancer at the genome-wide level.

Methods: We conducted a gene-environment interaction (GxE) analysis including 8,255 cases and 11,900 controls from four pancreatic cancer genome-wide association study (GWAS) datasets (Pancreatic Cancer Cohort Consortium I-III and Pancreatic Cancer Case Control Consortium). Obesity (body mass index ≥30 kg/m) and diabetes (duration ≥3 years) were the environmental variables of interest. Approximately 870,000 SNPs (minor allele frequency ≥0.005, genotyped in at least one dataset) were analyzed. Case-control (CC), case-only (CO), and joint-effect test methods were used for SNP-level GxE analysis. As a complementary approach, gene-based GxE analysis was also performed. Age, sex, study site, and principal components accounting for population substructure were included as covariates. Meta-analysis was applied to combine individual GWAS summary statistics.

Results: No genome-wide significant interactions (departures from a log-additive odds model) with diabetes or obesity were detected at the SNP level by the CC or CO approaches. The joint-effect test detected numerous genome-wide significant GxE signals in the GWAS main effects top hit regions, but the significance diminished after adjusting for the GWAS top hits. In the gene-based analysis, a significant interaction of diabetes with variants in the (family with sequence similarity 63 member A) gene (significance threshold < 1.25 × 10) was observed in the meta-analysis ( = 1.2 ×10, = 4.2 ×10).

Conclusions: This analysis did not find significant GxE interactions at the SNP level but found one significant interaction with diabetes at the gene level. A larger sample size might unveil additional genetic factors via GxE scans.

Impact: This study may contribute to discovering the mechanism of diabetes-associated pancreatic cancer.
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http://dx.doi.org/10.1158/1055-9965.EPI-20-0275DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7483330PMC
September 2020

Systemic Proteome Alterations Linked to Early Stage Pancreatic Cancer in Diabetic Patients.

Cancers (Basel) 2020 Jun 11;12(6). Epub 2020 Jun 11.

Section of Gastroenterology and Hepatology, Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA.

Background: Diabetes is a risk factor associated with pancreatic ductal adenocarcinoma (PDAC), and new adult-onset diabetes can be an early sign of pancreatic malignancy. Development of blood-based biomarkers to identify diabetic patients who warrant imaging tests for cancer detection may represent a realistic approach to facilitate earlier diagnosis of PDAC in a risk population.

Methods: A spectral library-based proteomic platform was applied to interrogate biomarker candidates in plasma samples from clinically well-defined diabetic cohorts with and without PDAC. Random forest algorithm was used for prediction model building and receiver operating characteristic (ROC) curve analysis was applied to evaluate the prediction probability of potential biomarker panels.

Results: Several biomarker panels were cross-validated in the context of detection of PDAC within a diabetic background. In combination with carbohydrate antigen 19-9 (CA19-9), the panel, which consisted of apolipoprotein A-IV (APOA4), monocyte differentiation antigen CD14 (CD14), tetranectin (CLEC3B), gelsolin (GSN), histidine-rich glycoprotein (HRG), inter-alpha-trypsin inhibitor heavy chain H3 (ITIH3), plasma kallikrein (KLKB1), leucine-rich alpha-2-glycoprotein (LRG1), pigment epithelium-derived factor (SERPINF1), plasma protease C1 inhibitor (SERPING1), and metalloproteinase inhibitor 1 (TIMP1), demonstrated an area under curve (AUC) of 0.85 and a two-fold increase in detection accuracy compared to CA19-9 alone. The study further evaluated the correlations of protein candidates and their influences on the performance of biomarker panels.

Conclusions: Proteomics-based multiplex biomarker panels improved the detection accuracy for diagnosis of early stage PDAC in diabetic patients.
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http://dx.doi.org/10.3390/cancers12061534DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7352938PMC
June 2020

Associations between Genetically Predicted Blood Protein Biomarkers and Pancreatic Cancer Risk.

Cancer Epidemiol Biomarkers Prev 2020 07 21;29(7):1501-1508. Epub 2020 May 21.

Department of Health Sciences Research, Mayo Clinic College of Medicine, Rochester, Minnesota.

Background: Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies, with few known risk factors and biomarkers. Several blood protein biomarkers have been linked to PDAC in previous studies, but these studies have assessed only a limited number of biomarkers, usually in small samples. In this study, we evaluated associations of circulating protein levels and PDAC risk using genetic instruments.

Methods: To identify novel circulating protein biomarkers of PDAC, we studied 8,280 cases and 6,728 controls of European descent from the Pancreatic Cancer Cohort Consortium and the Pancreatic Cancer Case-Control Consortium, using genetic instruments of protein quantitative trait loci.

Results: We observed associations between predicted concentrations of 38 proteins and PDAC risk at an FDR of < 0.05, including 23 of those proteins that showed an association even after Bonferroni correction. These include the protein encoded by , which has been implicated as a potential target gene of PDAC risk variant. Eight of the identified proteins (LMA2L, TM11D, IP-10, ADH1B, STOM, TENC1, DOCK9, and CRBB2) were associated with PDAC risk after adjusting for previously reported PDAC risk variants (OR ranged from 0.79 to 1.52). Pathway enrichment analysis showed that the encoding genes for implicated proteins were significantly enriched in cancer-related pathways, such as STAT3 and IL15 production.

Conclusions: We identified 38 candidates of protein biomarkers for PDAC risk.

Impact: This study identifies novel protein biomarker candidates for PDAC, which if validated by additional studies, may contribute to the etiologic understanding of PDAC development.
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http://dx.doi.org/10.1158/1055-9965.EPI-20-0091DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7334065PMC
July 2020

HNF4A and GATA6 Loss Reveals Therapeutically Actionable Subtypes in Pancreatic Cancer.

Cell Rep 2020 05;31(6):107625

The Kinghorn Cancer Centre, 370 Victoria Street, Darlinghurst and Garvan Institute of Medical Research, Sydney, NSW 2010, Australia; St Vincent's Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia.

Pancreatic ductal adenocarcinoma (PDAC) can be divided into transcriptomic subtypes with two broad lineages referred to as classical (pancreatic) and squamous. We find that these two subtypes are driven by distinct metabolic phenotypes. Loss of genes that drive endodermal lineage specification, HNF4A and GATA6, switch metabolic profiles from classical (pancreatic) to predominantly squamous, with glycogen synthase kinase 3 beta (GSK3β) a key regulator of glycolysis. Pharmacological inhibition of GSK3β results in selective sensitivity in the squamous subtype; however, a subset of these squamous patient-derived cell lines (PDCLs) acquires rapid drug tolerance. Using chromatin accessibility maps, we demonstrate that the squamous subtype can be further classified using chromatin accessibility to predict responsiveness and tolerance to GSK3β inhibitors. Our findings demonstrate that distinct patterns of chromatin accessibility can be used to identify patient subgroups that are indistinguishable by gene expression profiles, highlighting the utility of chromatin-based biomarkers for patient selection in the treatment of PDAC.
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http://dx.doi.org/10.1016/j.celrep.2020.107625DOI Listing
May 2020

Survival Benefit of Combination Chemotherapy in Elderly Patients With Metastatic Pancreatic Ductal Adenocarcinoma.

Am J Clin Oncol 2020 08;43(8):586-590

Division of Medical Oncology.

Objectives: Survival benefit of combination over single-agent chemotherapy for metastatic pancreatic ductal adenocarcinoma (PDAC) was demonstrated in younger patients in clinical trials. The authors aimed to evaluate whether this survival benefit of combination chemotherapy is present in elderly patients with metastatic PDAC.

Materials And Methods: The authors identified elderly patients (age 65 y or older) with stage IV PDAC and extracted available clinical information from a prospectively maintained institutional pancreatic cancer registry from 2007 to 2016. The primary endpoint was overall survival. Cox proportional hazards regression was used for multivariable survival analyses. Survival outcomes for the entire cohort and by age group I (elderly, 65 to 75 y) and age group II (very elderly, older than 75 y) were assessed.

Results: A total of 606 patients were included with a median age of 73.8 years. Among them, 239 patients (39%) received combination chemotherapy and 152 patients (25.1%) received single-agent chemotherapy as first-line treatment. Combination chemotherapy was associated with significantly longer median overall survival compared with single-agent chemotherapy (10.9 vs. 7.5 mo, P<0.001) with hazard ratio 0.62 (95% confidence interval, 0.47-0.81; P=0.001) after adjusting for age, sex, comorbidity, Eastern Cooperative Oncology Group (ECOG) performance status, and carbohydrate antigen 19-9 level. Analyses by age groups indicated that very elderly patients (age group II) benefited from combination chemotherapy compared with single-agent chemotherapy with hazard ratio 0.56 (95% confidence interval, 0.31-1; P=0.049), comparable with the age group I (Page-treatment interaction=0.81).

Conclusion: Elderly patients, even those older than 75 years, with metastatic PDAC benefited from combination chemotherapy.
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http://dx.doi.org/10.1097/COC.0000000000000708DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7395872PMC
August 2020

Leukocyte Telomere Length and Its Interaction with Germline Variation in Telomere-Related Genes in Relation to Pancreatic Adenocarcinoma Risk.

Cancer Epidemiol Biomarkers Prev 2020 07 20;29(7):1492-1500. Epub 2020 Apr 20.

Division of Epidemiology, Mayo Clinic, Rochester, Minnesota.

Background: Leukocyte telomere length (LTL) has been associated with risk of multiple cancers, but its association with pancreatic ductal adenocarcinoma (PDAC) is unclear. We therefore investigated the association between peripheral blood LTL and PDAC risk, and examined effect modification by candidate SNPs previously reported to be associated with variation in LTL.

Methods: A case-control study of 1,460 PDAC cases and 1,459 frequency-matched controls was performed using biospecimens and data from the Mayo Clinic Biospecimen Resource for Pancreas Research. Quantitative PCR was used to measure LTL and categorized into tertiles based on sex-specific control distribution. Eleven telomere-related SNPs also were genotyped. Logistic regression was used to calculate ORs and 95% confidence intervals (CI).

Results: Shorter peripheral blood LTL was associated with a higher risk of PDAC (OR = 1.26, 95% CI = 1.03-1.54, = 0.02; OR = 1.14, 95% CI = 1.02-1.28), but the association was restricted to cases with treatment-naïve blood samples (OR = 1.51, 95% CI = 1.16-1.96, = 0.002; OR = 1.25, 95% CI = 1.08-1.45) and not cases whose blood samples were collected after initiation of cancer therapy (OR = 1.10, 95% CI = 0.87-1.39, = 0.42; OR = 1.08, 95% CI = 0.94-1.23). Three SNPs (-rs10936599, rs11125529, and rs1317082) were each associated with interindividual variation in LTL among controls, but there was no evidence of effect modification by these SNPs.

Conclusions: Treatment-naïve short LTL is associated with a higher risk of PDAC, and the association does not differ by germline variation in the candidate telomere-related SNPs examined.

Impact: Peripheral blood LTL might serve as a molecular marker for risk modeling to identify persons at high risk of PDAC.
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http://dx.doi.org/10.1158/1055-9965.EPI-19-1597DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7334088PMC
July 2020

A Transcriptome-Wide Association Study Identifies Novel Candidate Susceptibility Genes for Pancreatic Cancer.

J Natl Cancer Inst 2020 10;112(10):1003-1012

Yale Cancer Center, New Haven, CT, USA.

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.
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http://dx.doi.org/10.1093/jnci/djz246DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7566474PMC
October 2020

Postdiagnosis Loss of Skeletal Muscle, but Not Adipose Tissue, Is Associated with Shorter Survival of Patients with Advanced Pancreatic Cancer.

Cancer Epidemiol Biomarkers Prev 2019 12 18;28(12):2062-2069. Epub 2019 Sep 18.

Dana-Farber Cancer Institute, Boston, Massachusetts.

Background: Pancreatic cancer is associated with development of cachexia, a wasting syndrome thought to limit survival. Few studies have longitudinally quantified peripheral tissues or identified biomarkers predictive of future tissue wasting.

Methods: Adipose and muscle tissue were measured by computed tomography (CT) at diagnosis and 50 to 120 days later in 164 patients with advanced pancreatic cancer. Tissue changes and survival were evaluated by Cox proportional hazards regression. Baseline levels of circulating markers were examined in relation to future tissue wasting.

Results: Compared with patients in the bottom quartile of muscle change per 30 days (average gain of 0.8 ± 2.0 cm), those in the top quartile (average loss of 12.9 ± 4.9 cm) had a hazard ratio (HR) for death of 2.01 [95% confidence interval (CI), 1.12-3.62]. Patients in the top quartile of muscle attenuation change (average decrease of 4.9 ± 2.4 Hounsfield units) had an HR of 2.19 (95% CI, 1.18-4.04) compared with those in the bottom quartile (average increase of 2.4 ± 1.6 Hounsfield units). Changes in adipose tissue were not associated with survival. Higher plasma branched chain amino acids (BCAA; = 0.004) and lower monocyte chemoattractant protein-1 (MCP-1; = 0.005) at diagnosis were associated with greater future muscle loss.

Conclusions: In patients with advanced pancreatic cancer, muscle loss and decrease in muscle density in 2 to 4 months after diagnosis were associated with reduced survival. BCAAs and MCP-1 levels at diagnosis were associated with subsequent muscle loss.

Impact: BCAAs and MCP-1 levels at diagnosis could identify a high-risk group for future tissue wasting.
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http://dx.doi.org/10.1158/1055-9965.EPI-19-0370DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6891169PMC
December 2019

A region-based gene association study combined with a leave-one-out sensitivity analysis identifies SMG1 as a pancreatic cancer susceptibility gene.

PLoS Genet 2019 08 30;15(8):e1008344. Epub 2019 Aug 30.

The Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada.

Pancreatic adenocarcinoma (PC) is a lethal malignancy that is familial or associated with genetic syndromes in 10% of cases. Gene-based surveillance strategies for at-risk individuals may improve clinical outcomes. However, familial PC (FPC) is plagued by genetic heterogeneity and the genetic basis for the majority of FPC remains elusive, hampering the development of gene-based surveillance programs. The study was powered to identify genes with a cumulative pathogenic variant prevalence of at least 3%, which includes the most prevalent PC susceptibility gene, BRCA2. Since the majority of known PC susceptibility genes are involved in DNA repair, we focused on genes implicated in these pathways. We performed a region-based association study using the Mixed-Effects Score Test, followed by leave-one-out characterization of PC-associated gene regions and variants to identify the genes and variants driving risk associations. We evaluated 398 cases from two case series and 987 controls without a personal history of cancer. The first case series consisted of 109 patients with either FPC (n = 101) or PC at ≤50 years of age (n = 8). The second case series was composed of 289 unselected PC cases. We validated this discovery strategy by identifying known pathogenic BRCA2 variants, and also identified SMG1, encoding a serine/threonine protein kinase, to be significantly associated with PC following correction for multiple testing (p = 3.22x10-7). The SMG1 association was validated in a second independent series of 532 FPC cases and 753 controls (p<0.0062, OR = 1.88, 95%CI 1.17-3.03). We showed segregation of the c.4249A>G SMG1 variant in 3 affected relatives in a FPC kindred, and we found c.103G>A to be a recurrent SMG1 variant associating with PC in both the discovery and validation series. These results suggest that SMG1 is a novel PC susceptibility gene, and we identified specific SMG1 gene variants associated with PC risk.
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http://dx.doi.org/10.1371/journal.pgen.1008344DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6742418PMC
August 2019

Analysis of Heritability and Genetic Architecture of Pancreatic Cancer: A PanC4 Study.

Cancer Epidemiol Biomarkers Prev 2019 07 23;28(7):1238-1245. Epub 2019 Apr 23.

Department of Epidemiology, Johns Hopkins School of Public Health, Baltimore, Maryland.

Background: Pancreatic cancer is the fourth-leading cause of cancer death in both men and women in the United States. The currently identified common susceptibility loci account for a small fraction of estimated heritability. We sought to estimate overall heritability of pancreatic cancer and partition the heritability by variant frequencies and functional annotations.

Methods: Analysis using the genome-based restricted maximum likelihood method (GREML) was conducted on Pancreatic Cancer Case-Control Consortium (PanC4) genome-wide association study (GWAS) data from 3,568 pancreatic cancer cases and 3,363 controls of European Ancestry.

Results: Applying linkage disequilibrium- and minor allele frequency-stratified GREML (GREML-LDMS) method to imputed GWAS data, we estimated the overall heritability of pancreatic cancer to be 21.2% (SE = 4.8%). Across the functional groups (intronic, intergenic, coding, and regulatory variants), intronic variants account for most of the estimated heritability (12.4%). Previously identified GWAS loci explained 4.1% of the total phenotypic variation of pancreatic cancer. Mutations in hereditary pancreatic cancer susceptibility genes are present in 4% to 10% of patients with pancreatic cancer, yet our GREML-LDMS results suggested these regions explain only 0.4% of total phenotypic variance for pancreatic cancer.

Conclusions: Although higher than previous studies, our estimated 21.2% overall heritability may still be downwardly biased due to the inherent limitation that the contribution of rare variants in genes with a substantive overall impact on disease are not captured when applying these commonly used methods to imputed GWAS data.

Impact: Our work demonstrated the importance of rare and common variants in pancreatic cancer risk.
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http://dx.doi.org/10.1158/1055-9965.EPI-18-1235DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6606380PMC
July 2019

Psychological Impact of Learning CDKN2A Variant Status as a Genetic Research Result.

Public Health Genomics 2018 18;21(3-4):154-163. Epub 2019 Apr 18.

Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, USA,

Objectives: Little is known about genetic research participants' responses to receiving individual research results (IRR) from cancer genetic research. We examined the immediate and delayed psychological impact of returning a CDKN2A variant result that is associated with increased risk of pancreatic cancer and melanoma.

Methods: One hundred and thirty-three pancreas research registry enrollees whose samples were tested in a research laboratory for the CDKN2A variant were invited by mail to learn the result by telephone and participate in a study about the disclosure process. Self-rated health, quality of life, and emotional responses were surveyed before and 6 months after disclosure. Genetic testing-specific distress, uncertainty, and positive experiences were assessed 6 months after disclosure.

Results: Eighty individuals agreed to participate; 63 completed the study. Both carriers and noncarriers showed no change over time in self-rated health, quality of life, or anxiety levels. Carriers reported more sadness than noncarriers before and 6 months after disclosure. Both carriers and noncarriers showed more hopefulness 6 months after than before disclosure. Carriers experienced greater test-specific distress and uncertainty than noncarriers, but levels were low. -Conclusions: Return of IRR in conjunction with cancer prevention counseling led to low levels of test-specific distress and uncertainty among carriers. No other adverse psychological outcomes were observed.
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http://dx.doi.org/10.1159/000496556DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6760672PMC
September 2019

Pancreatic cancer and melanoma related perceptions and behaviors following disclosure of CDKN2A variant status as a research result.

Genet Med 2019 11 17;21(11):2468-2477. Epub 2019 Apr 17.

Department of Health Sciences Research, Mayo Clinic College of Medicine and Science, Mayo Clinic, Rochester, MN, USA.

Purpose: This study examined whether participants who learned research results related to a germline CDKN2A variant known to be associated with increased risk of pancreatic cancer and malignant melanoma would pursue confirmatory testing and cancer screening, share the genetic information with health care providers and family, and change risk perceptions.

Methods: Participants were pancreas research registry enrollees whose biological sample was tested in a research laboratory for the variant. In total, 133 individuals were invited to learn a genetic research result and participate in a study about the disclosure process. Perceived cancer risk, screening intentions, and behaviors were assessed predisclosure, immediately postdisclosure, and six months postdisclosure.

Results: Eighty individuals agreed to participate and 63 completed the study. Immediately postdisclosure, carriers reported greater intentions to undergo pancreatic cancer and melanoma screening (p values ≤0.024). Seventy-three percent of carriers (47.5% noncarriers) intended to seek confirmatory testing within six months and 20% (2.5% noncarriers) followed through. All participants shared results with ≥1 family member. More carriers shared results with their health care provider than noncarriers (p = 0.028).

Conclusion: Recipients of cancer genetic research results may not follow through with recommended behaviors (confirmatory testing, screening), despite stated intentions. The research result disclosure motivated follow-up behaviors among carriers more than noncarriers.
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http://dx.doi.org/10.1038/s41436-019-0517-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6800778PMC
November 2019
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