Breast cancer is the leading cause of death in women worldwide.1 Around 12–17% of breast cancer patients have triple negative breast cancer (TNBC),2 an aggressive, heterogeneous subtype characterized by the lack of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor Type 2 (HER2) expression. Here, PGR is linked to triple-negative breast carcinoma.