Germline cancer susceptibility gene variants, somatic second hits, and survival outcomes in patients with resected pancreatic cancer.
PURPOSE
Germline variants in double-strand DNA damage repair (dsDDR) genes (e.g., BRCA1/2) predispose to pancreatic adenocarcinoma (PDAC) and may predict sensitivity to platinum-based chemotherapy and poly(ADP) ribose polymerase (PARP) inhibitors. We sought to determine the prevalence and significance of germline cancer susceptibility gene variants in PDAC with paired somatic and survival analyses.


METHODS
Using a customized next-generation sequencing panel, germline/somatic DNA was analyzed from 289 patients with resected PDAC ascertained without preselection for high-risk features (e.g., young age, personal/family history). All identified variants were assessed for pathogenicity. Outcomes were analyzed using multivariable-adjusted Cox proportional hazards regression.


RESULTS
We found that 28/289 (9.7%; 95% confidence interval [CI] 6.5-13.7%) patients carried pathogenic/likely pathogenic germline variants, including 21 (7.3%) dsDDR gene variants (3 BRCA1, 4 BRCA2, 14 other dsDDR genes [ATM, BRIP1, CHEK2, NBN, PALB2, RAD50, RAD51C]), 3 Lynch syndrome, and 4 other genes (APC p.I1307K, CDKN2A, TP53). Somatic sequencing and immunohistochemistry identified second hits in the tumor in 12/27 (44.4%) patients with germline variants (1 failed sequencing). Compared with noncarriers, patients with germline dsDDR gene variants had superior overall survival (hazard ratio [HR] 0.54; 95% CI 0.30-0.99; P = 0.05).


CONCLUSION
Nearly 10% of PDAC patients harbor germline variants, although the majority lack somatic second hits, the therapeutic significance of which warrants further study.
['Yurgelun|Matthew B|MB|', 'Chittenden|Anu B|AB|', 'Morales-Oyarvide|Vicente|V|', 'Rubinson|Douglas A|DA|', 'Dunne|Richard F|RF|', 'Kozak|Margaret M|MM|', 'Qian|Zhi Rong|ZR|', 'Welch|Marisa W|MW|', 'Brais|Lauren K|LK|', 'Da Silva|Annacarolina|A|', 'Bui|Justin L|JL|', 'Yuan|Chen|C|', 'Li|Tingting|T|', 'Li|Wanwan|W|', 'Masuda|Atsuhiro|A|', 'Gu|Mancang|M|', 'Bullock|Andrea J|AJ|', 'Chang|Daniel T|DT|', 'Clancy|Thomas E|TE|', 'Linehan|David C|DC|', 'Findeis-Hosey|Jennifer J|JJ|', 'Doyle|Leona A|LA|', 'Thorner|Aaron R|AR|', 'Ducar|Matthew D|MD|', 'Wollison|Bruce M|BM|', 'Khalaf|Natalia|N|', 'Perez|Kimberly|K|', 'Syngal|Sapna|S|', 'Aguirre|Andrew J|AJ|', 'Hahn|William C|WC|', 'Meyerson|Matthew L|ML|', 'Fuchs|Charles S|CS|', 'Ogino|Shuji|S|', 'Hornick|Jason L|JL|', 'Hezel|Aram F|AF|', 'Koong|Albert C|AC|', 'Nowak|Jonathan A|JA|', 'Wolpin|Brian M|BM|']
D000230:Adenocarcinoma D000328:Adult D000368:Aged D053903:DNA Breaks, Double-Stranded D018572:Disease-Free Survival D005006:Ethnicity D005260:Female D020022:Genetic Predisposition to Disease D018095:Germ-Line Mutation D059014:High-Throughput Nucleotide Sequencing D006801:Humans D008297:Male D008875:Middle Aged D009363:Neoplasm Proteins D010190:Pancreatic Neoplasms
Lynch syndrome Familial pancreatic cancer Hereditary breast and ovarian cancer PARP inhibitors