PGR and breast carcinoma: Breast cancer, the most common cause of cancer death in women, is a kind of complex and heterogeneous neoplasm.1 Approximately 15% of breast carcinomas are triple-negative breast cancers (TNBCs), which have high rates of recurrences and mortality.2 TNBCs are defined by the lack of expression of estrogen receptor, progesterone receptor and human epidermal growth factor receptor type 2 (HER2).