ESR1 and triple-negative breast carcinoma: Triple-negative breast cancer (TNBC), which lacks expression of the estrogen receptor (ER), progesterone receptor (PgR), and human epidermal receptor 2 (HER2), is associated with a dismal prognosis despite its good response to anthracycline and taxane-based neoadjuvant chemotherapy (NAC), which yield a higher rate of pathologic complete response (pCR) [1, 3].