ESR1 and triple-negative breast carcinoma: Triple-negative breast cancer (TNBC) represents a particularly aggressive subtype of BC that is characterized by high heterogeneity, aggressive nature, high metastatic potential, proneness to relapse, and poor prognosis due to a lack of estrogen receptor (ER), progesterone receptor (PR), or human epidermal growth factor receptor 2 (HER-2) [1].