PGR and breast cancer: Triple‐negative breast cancer (TNBC), defined by the lack of estrogen (ER) and progesterone receptors (PR), and the absence of human epidermal growth factor receptor 2 (HER2) overexpression, often leads to high‐grade invasive ductal carcinoma (IDC) in the patients accounting for one‐fourth of all breast cancer deaths.1, 2