Triple-negative breast cancer (TNBC), with no estrogen receptor (ER), progesterone receptor (PR), or human epidermal growth factor receptor 2 (HER2) expression, has the highest rate of metastasis, relapse, and death among all breast cancer subtypes, accounting for 15-20% of all patients with breast cancer 1. The gene discussed is PGR; the disease is triple-negative breast carcinoma.