The breast and ovarian cancer susceptibility gene 1 (BRCA1) on chromosome 17q21 was identified and cloned in 1994 by Miki et al. (1994), 1 year before the reported cloning of a second breast cancer susceptibility gene (BRCA2) on chromosome 13q12-13 by Wooster et al. (1995). The gene discussed is BRCA1; the disease is breast cancer.