Triple-negative breast cancer (TNBC) accounts for 15%–25% of all breast cancers as it lacks oestrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression, and exhibits high genomic instability with a high mutation burden (Harbeck et al., 2019). The gene discussed is PGR; the disease is triple-negative breast carcinoma.