Luminal breast cancers (65–75%) express estrogen and/or progesterone receptors and are typically treated with anti-estrogens, such as aromatase inhibitors (e.g., anastrozole), selective estrogen receptor modulators (e.g., tamoxifen) and selective estrogen receptor degraders (e.g., fulvestrant)5. The gene discussed is PGR; the disease is breast carcinoma.