BRCA2 and breast cancer: Women who are heterozygous for a BRCA1 or BRCA2 pathogenic variant have up to an 80% risk of developing breast cancer by age 90; and an ovarian cancer risk of about 55% with BRCA1 mutations and 25% with BRCA2 mutations (Malander et al, 2004; Majdak et al, 2005; Alsop et al, 2012; Dann et al, 2012).