BRCA2 and breast cancer: Women who carry BRCA1 mutations have a probability of about 80% for developing breast cancer, and 40 to 60% for developing ovarian cancer during their lifetime.5 Moreover, these women have a 65% probability for developing a second breast carcinoma if they reach the age of 70.6-8 Women who carry BRCA2 mutations have a likelihood of developing breast cancer of about 85%.6,8,9