BRCA1 and breast cancer: Approximately 5% to 10% of breast cancer cases and 11% to 18% of ovarian cancer cases are a result of a mutation in the BRCA1 and BRCA2 genes, otherwise known as hereditary breast and ovarian cancer (HBOC; American Cancer Society [ACS], 2014; Campeau, Foulkes, & Tischkowitz, 2008; National Cancer Institute [NCI], n.d; Pal et al., 2005, Venkitaraman, 2002; Walsh et al., 2011).