High breast cancer risk in BRCA-mutation carriers is particularly evident premenopausally (relative risk 32 and 10 for 40–49-year-old BRCA1/2-mutation carriers, respectively) (Robson and Offit, 2007), whilst removal of both ovaries in premenopausal BRCA1/2-mutation carriers markedly reduces breast cancer risk (Domchek et al., 2010). Here, BRCA1 is linked to breast cancer.