BRCA1 and breast cancer: Particularly, in about 65–85% of hereditary ovarian tumors, the genetic abnormality is a germline mutation in BRCA genes that causes DNA repair defects. BRCA1 and BRCA2 mutation carriers have an increased lifetime risk of developing breast and ovarian cancer (up to 85% for breast cancer and up to 54% for ovarian cancer), as well as pancreatic and prostate cancer [4–8].