Immunohistochemical analysis defined five major intrinsic or molecular subtypes of breast cancer based on the expression of estrogen and progesterone receptors (ER/PR) status [4], including the Luminal A (40%), Luminal B (20%), HER2-enriched (10–15%), Normal-like (2–8%) and Triple Negative (15–20%) [2, 5]. The gene discussed is PGR; the disease is breast cancer.