Prevalence of pathogenic mutations in cancer predisposition genes among pancreatic cancer patients

The prevalence of germline pathogenic mutations in a comprehensive panel of cancer predisposition genes is not well-defined for patients with pancreatic ductal adenocarcinoma (PDAC). To estimate the frequency of mutations in a panel of 22 cancer predisposition genes, 96 patients unselected for a family history of cancer who were recruited to the Mayo Clinic Pancreatic Cancer patient registry over a 12-month period were screened by next-generation sequencing. Fourteen pathogenic mutations in 13 patients (13.5%) were identified in eight genes: four in ATM, two in BRCA2, CHEK2, and MSH6, and one in BARD1, BRCA1, FANCM, and NBN. These included nine mutations (9.4%) in established pancreatic cancer genes. Three mutations were found in patients with a first-degree relative with PDAC, and 10 mutations were found in patients with first- or second-degree relatives with breast, pancreas, colorectal, ovarian, or endometrial cancers. These results suggest that a substantial proportion of patients with PDAC carry germline mutations in predisposition genes associated with other cancers and that a better understanding of pancreatic cancer risk will depend on evaluation of families with broad constellations of tumors. These findings highlight the need for recommendations governing germline gene-panel testing of patients with pancreatic cancer.