While hormone therapy and HER2-targeting drugs have improved prognosis of patients with estrogen/progesterone receptor-(ER/PR) and HER2-positive BrCa, respectively, triple-negative breast cancers (TNBCs), including the majority of basal-like tumors, lack all three of these receptors and are poorly responsive to available targeted therapies. The gene discussed is PGR; the disease is invasive breast carcinoma.