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Background: Pancreatic ductal adenocarcinoma (PDAC) surveillance is recommended for some individuals with a pathogenic or likely pathogenic variant (PV/LPV) in a PDAC susceptibility gene; the recommendation is often dependent on family history of PDAC. This study aimed to describe PDAC family history in individuals with PDAC who underwent genetic testing to determine the appropriateness of including a family history requirement in these recommendations., Methods: Individuals with PDAC with a germline heterozygous PV/LPV in ATM, BRCA1, BRCA2, EPCAM, MLH1, MSH2, MSH6, PALB2, or PMS2 (PV/LPV carriers) were assessed for family history of PDAC in first-degree relatives (FDRs) or second-degree relatives (SDRs) from nine institutions. A control group of individuals with PDAC without a germline PV/LPV was also assessed., Results: The study included 196 PV/LPV carriers and 1184 controls. In the PV/LPV carriers, 25.5% had an affected FDR and/or SDR compared to 16.9% in the control group (p = .004). PV/LPV carriers were more likely to have an affected FDR compared to the controls (p = .003) but there was no statistical difference when assessing only affected SDRs (p = .344)., Conclusions: Most PV/LPV carriers who developed PDAC did not have a close family history of PDAC and would not have met most current professional societies' recommendations for consideration of PDAC surveillance before diagnosis. However, PV/LPV carriers were significantly more likely to have a family history of PDAC, particularly an affected FDR. These findings support family history as a risk modifier in PV/LPV carriers, and highlight the need to identify other risk factors., (© 2024 The Author(s). Cancer published by Wiley Periodicals LLC on behalf of American Cancer Society.)

The hallmark of Lynch syndrome (LS)-associated neoplasia is DNA mismatch repair protein (MMR) deficiency. Recent studies have demonstrated that histologically normal colonic crypts in patients with LS can exhibit deficient MMR expression. The aim of this study was to determine the feasibility of detecting MMR deficient crypts in random colonoscopic biopsies of normal mucosa in patients with and without LS. Forty-nine patients, including 33 with LS, 12 without LS, and 4 with germline MMR gene variants of uncertain significance (VUS), were prospectively and blindly evaluated by immunohistochemistry for MMR deficient crypts within random normal-appearing mucosal biopsies obtained during surveillance colonoscopy. MMR deficient crypts were identified in 70% (23/33) of patients with LS and in no patients without LS (0/12) (p < 0.001). MMR deficient crypts were identified with nearly equal frequency in both LS patients with and without a cancer history and were associated with germline variants in all four MMR genes and EPCAM. MMR deficient crypts were also identified in LS patients with a history of non-colorectal cancer types, including patients with endometrial cancer, skin sebaceous neoplasms, and renal cancer. Two of the four patients with germline MMR gene VUS had MMR deficient crypts. In conclusion, MMR deficient crypts are a specific biomarker of LS and can be identified in random normal mucosal biopsies in LS patients. Evaluation for MMR deficient crypts in colonoscopic biopsies of normal mucosa can help identify LS patients.

Background: The objective of this study was to investigate the prevalence of pathogenic germline variants (PGVs) in 32 cancer susceptibility genes in individuals with newly diagnosed pancreatic ductal adenocarcinoma (PDAC). A key secondary objective was to evaluate how often PGVs would have been undetected with existing genetic testing criteria., Methods: From May 2016 through May 2017, this multicenter cohort study enrolled consecutive patients aged 18 to 89 years with histologically confirmed PDAC diagnosed within the previous 12 weeks. Demographics, medical histories, and 3-generation pedigrees were collected from participants who provided samples for germline DNA analysis., Results: Four hundred nineteen patients were deemed eligible, 302 were enrolled, and 298 were included in the final cohort. Clinically actionable variants were reported in 29 PDAC patients (9.7%), with 23 (7.7%) having a PGV associated with an increased risk for PDAC. Six of 23 individuals (26%) with PDAC-associated gene mutations did not meet currently established genetic testing criteria. According to guideline-based genetic testing, only 11 of the 23 PGVs (48%) in known PDAC genes would have been detected. Six additional patients (2%) had PGVs associated with an increased risk for other cancers., Conclusions: These findings support the significant prevalence of PGVs associated with PDAC and the limitations of current paradigms for selecting patients for genetic testing, and they thereby lend support for universal germline multigene genetic testing in this population., (© 2018 American Cancer Society.)

Background: Approximately 10% of pancreatic adenocarcinoma (PC) cases are attributed to hereditary causes. Individuals with PC and a personal history of another cancer associated with hereditary breast and ovarian cancer (HBOC) or Lynch syndrome (LS) may be more likely to carry germline mutations., Methods: Participants with PC and a history of cancer were selected from a pancreatic disease registry. Of 1296 individuals with PC, 149 had a relevant history of cancer. If banked DNA was available, a multigene panel was performed for individuals who had not 1) previously had a mutation identified through clinical testing or 2) undergone clinical multigene panel testing with no mutations detected., Results: Twenty-two of 124 individuals with PC and another HBOC- or LS-related cancer who underwent genetic testing had a mutation identified in a PC susceptibility gene (18%). If prostate cancer is excluded, the mutation prevalence increased to 23% (21/93). Mutation carriers were more likely to have more than 1 previous cancer diagnosis (P = .001), to have had clinical genetic testing (P = .001), and to meet National Comprehensive Cancer Network (NCCN) genetic testing criteria (P < .001). Approximately 23% of mutation carriers did not meet NCCN HBOC or LS testing guidelines based on their personal cancer history and reported cancer history in first-degree relatives., Conclusion: At least 18% of individuals with PC and a personal history of other HBOC- or LS-related cancers carry mutations in a PC susceptibility gene based on our data, suggesting that criteria for genetic testing in individuals with PC should include consideration of previous cancer history. Cancer 2018;124:1691-700. © 2018 American Cancer Society., (© 2018 American Cancer Society.)