Germline BARD1 Mutation in High-Risk Chinese Breast and Ovarian Cancer Patients

Background: The prevalence of BARD1 mutations in breast and ovarian cancers varies across different ethnic groups. Evaluating the cancer risk and clinical significance of BARD1 mutations in the local Chinese patients with breast cancer, ovarian cancer, or both is clinically important for designing an appropriate surveillance scheme. Methods: This study used a 30 gene panel to identify BARD1 germline mutations in 2658 breast and ovarian cancer patients. Results: Among this cohort, the BARD1 mutation prevalence was 0.45% for breast cancer and 0.29% for ovarian cancer. In our 12 mutation carriers, we identified eight types of mutation variants, including three novel mutations. BARD1 mutation carriers were more likely to have a family history of liver, prostate, and cervical cancers (p-values = 0.004, 0.018, and 0.037, respectively) than patients who tested negative for mutations. Among the BARD1 mutants, the majority of the breast tumors were invasive ductal carcinoma (NOS type) (10/11, 90.9%) of high-grade disease (9/9, 100%) and half of them were triple-negative breast cancer (5/10, 50%). Conclusions: Although the prevalence of BARD1 mutations is low and the penetrance is incomplete, we recommend including BARD1 in the test panel for breast cancer patients. Our data suggest that more comprehensive surveillance management may be considered in mutation carriers due to the familial aggregation of a relatively wide spectrum of cancers.