BRCA1 and breast cancer: Germline mutations in high-risk susceptibility genes (e.g. BRCA1, BRCA2) account for 5-10% of breast cancers and up to 20% of ovarian cancers in white Europeans.9–12 Women with a germline BRCA1 mutation have a lifetime risk of ovarian cancer by age 70 years of up to 63% and of breast cancer by age 70 years of up to 85%.13 Risks of ovarian and breast cancers in women by age 70 years among BRCA2 carriers are reported to be up to 27% and 84%, respectively.