Roberts, Nicholas J.

Significance Much of the inherited susceptibility to pancreatic cancer remains unexplained. Germline variants that cause protein misfolding and impaired secretion of pancreatic enzymes such as CPA1 (encoding carboxypeptidase A1) can cause pancreatic acinar cell endoplasmic reticulum (ER) stress. We investigated the hypothesis that pancreatic cancer could arise from germline variants in genes encoding pancreatic secretory enzymes that induce pancreatic acinar cell stress. We find ∼1% of 1,579 patients with pancreatic cancer vs. 1 of 2,012 controls have germline variants in the genes encoding CPA1 and CPB1 (carboxypeptidase B1) that impair secretion of its protein product and induce ER stress. These findings implicate pancreatic acinar cell stress as a mechanism of pancreatic cancer susceptibility.

Abstract Pancreatic cancer is projected to become the second leading cause of cancer-related death in the United States by 2020. A familial aggregation of pancreatic cancer has been established, but the cause of this aggregation in most families is unknown. To determine the genetic basis of susceptibility in these families, we sequenced the germline genomes of 638 patients with familial pancreatic cancer and the tumor exomes of 39 familial pancreatic adenocarcinomas. Our analyses support the role of previously identified familial pancreatic cancer susceptibility genes such as BRCA2, CDKN2A, and ATM, and identify novel candidate genes harboring rare, deleterious germline variants for further characterization. We also show how somatic point mutations that occur during hematopoiesis can affect the interpretation of genome-wide studies of hereditary traits. Our observations have important implications for the etiology of pancreatic cancer and for the identification of susceptibility genes in other common cancer types. Significance: The genetic basis of disease susceptibility in the majority of patients with familial pancreatic cancer is unknown. We whole genome sequenced 638 patients with familial pancreatic cancer and demonstrate that the genetic underpinning of inherited pancreatic cancer is highly heterogeneous. This has significant implications for the management of patients with familial pancreatic cancer. Cancer Discov; 6(2); 166–75. ©2015 AACR. This article is highlighted in the In This Issue feature, p. 109

Abstract Pancreatic ductal adenocarcinoma (PDA) affects over 44,000 people in the United States every year and carries a dismal prognosis, with a 5-year survival rate of just 5%. A subset of these patients (5-10%) report a familial history of the disease. The genetic etiology in these familial cases is poorly defined, with known susceptibility genes, such as: BRCA2, PALB2, CDKN2A, BRCA1, PRSS1 and STK11, accounting for only 10-15% of familial pancreatic cancer. In an effort to identify previously unappreciated pancreatic cancer susceptibility genes, we used next generation sequencing technology to evaluate the whole genome and whole exome sequences of 16 (6 families) and 22 individuals (10 families) respectively. All of these families enrolled into one of the familial pancreatic cancer registries participating in the Pancreatic Cancer Genetic Epidemiology (PacGene) Consortium, all had at least three members with PDA, and DNA was available from at least two affected members in each kindred. Using this approach, we identified heterozygous, inactivating, ATM mutations in two kindreds with familial pancreatic cancer (c.8266A>AT; p.K2756X and c.170G>GA; p.W57X). These mutations were previously reported as disease causing variants in patients with ataxia-telangiectasia, an autosomal recessive condition resulting from bi-allelic deleterious mutations of ATM. Interestingly, heterozygotes of deleterious ATM mutations have an increased risk of breast cancer. However, there have been no previous reports of deleterious ATM mutations in the germline of familial PDA patients. In our study, mutations segregated with disease in both kindreds and tumor analysis demonstrated Loss of heterozygosity (LOH) of the wild-type allele. Sequence analysis of the entire ATM gene in an additional 166 familial pancreatic cancer probands indentified four additional patients with deleterious mutations in the ATM gene (c.3214G>GT; p.E1072X, c.6095G>GA; p.R2032K, IVS41-1G>GT and c.3801delG), while no deleterious mutations were identified in 190 spouse controls (p=0.046). When considering only the mostly severely affected families, those with three or more pancreatic cancer cases, four deleterious mutations were found in 87 families (P=0.009). These results indicate that ATM mutations play an important role in familial pancreatic cancer predisposition and have significant implications in the management of affected individuals and the risk assessment of family members. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2628. doi:1538-7445.AM2012-2628

Abstract Pancreatic cancers are the fourth most-common cause of cancer-related deaths in the Western world, with >200,000 cases reported in 2010. Although up to 10% of these cases occur in familial patterns, the hereditary basis for predisposition in the vast majority of affected families is unknown. We used next-generation sequencing, including whole-genome and whole-exome analyses, and identified heterozygous, constitutional, ataxia telangiectasia mutated (ATM) gene mutations in 2 kindreds with familial pancreatic cancer. Mutations segregated with disease in both kindreds and tumor analysis demonstrated LOH of the wild-type allele. By using sequence analysis of an additional 166 familial pancreatic cancer probands, we identified 4 additional patients with deleterious mutations in the ATM gene, whereas we identified no deleterious mutations in 190 spouse controls (P = 0.046). When we considered only the mostly severely affected families with 3 or more pancreatic cancer cases, 4 deleterious mutations were found in 87 families (P = 0.009). Our results indicate that inherited ATM mutations play an important role in familial pancreatic cancer predisposition. Significance: The genes responsible for the majority of cases of familial pancreatic ductal adenocarcinoma are unknown. We here identify ATM as a predisposition gene for pancreatic ductal adenocarcinoma. Our results have important implications for the management of patients in affected families and illustrate the power of genome-wide sequencing to identify the basis of familial cancer syndromes. Cancer Discovery; 2(1): 41–6. ©2011 AACR. Read the Commentary on this article by Bakker and de Winter, p. 14 This article is highlighted in the In This Issue feature, p. 1