Cancer Sci. 2019 Aug 20.
BRCA1/2 genes are the most frequently germline mutated DNA-repair genes and the survival of BRCA1/2 carriers has been extensively explored in breast cancer. However, the prevalence of germline mutations in non-BRCA1/2 DNA-repair genes and the survival of carriers are largely unknown in a large cohort of unselected breast cancer patients. Germline mutations in 16 DNA-repair genes were determined using a multigene panel in 7657 BRCA1/2-negative breast cancer patients who were unselected for family history of cancer or age at diagnosis. Among the 7657 BRCA1/2-negative breast cancer patients, 257 (3.4%) carried at least one pathogenic germline mutation in the 16 DNA-repair genes. The prevalence of DNA-repair gene mutation was significant higher in familial breast cancers (5.2%, P=0.002) and early-onset breast cancers (diagnosed at and before age of 40) (4.5%, P=0.003) than that of sporadic breast cancers (2.9%) (diagnosed above age of 40), respectively. The DNA-repair gene mutation carriers were significantly more likely to have a larger tumor (P=0.04) and axillary lymph-node metastasis (P=0.03). Moreover, DNA-repair gene mutation was an independent unfavorable factor for recurrence-free survival [adjusted hazard ratio (HR) =1.38, 95% CI: 1.00-1.91, P=0.05] and disease-specific survival (adjusted HR=1.63, 95% CI: 1.04-2.57, P=0.03) in this cohort. Overall, 3.4% of BRCA1/2-negative breast cancer patients carried germline mutations in the 16 DNA-repair genes, and the DNA-repair gene mutation carriers exhibited an aggressive phenotype and had a poor survival compared with noncarriers. This article is protected by copyright. All rights reserved.
Keywords: Breast cancer; Cancer susceptibility genes; DNA-repair genes; Germline mutation; Survival