The observation that BRCA1 mutation carriers tend to develop triple-negative breast cancers while BRCA2 mutation carriers show the same range of hormonal receptor subtypes as sporadic breast cancer, has previously been attributed to a role for BRCA1 in the maturation of ER-positive mammary epithelial progenitor cells25,26. The gene discussed is NR4A1; the disease is triple-negative breast carcinoma.