BRCA1 and Hereditary breast and ovarian cancer syndrome: Hereditary breast and ovarian cancer (HBOC) genetic variants, particularly in the BRCA1 (OMIM 113705) and BRCA2 (OMIM 600185) genes, confer increased lifetime risk of developing cancer in women.1 Knowledge of HBOC variants empowers women to choose more intensive precancer screening practices, including magnetic resonance imaging (MRI) to detect cancer sooner, and for some to undergo chemoprevention and/or prophylactic risk-reducing mastectomy (RRM) and/or risk-reducing salpingo-oophorectomy (RRSO), which lower cancer risk and mortality.2,3