ESR1 and triple-negative breast carcinoma: Among BC subtypes, triple-negative breast cancer (TNBC), characterized by the absence or low expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) [3, 4], poses the greatest challenge due to its aggressive nature, high metastatic potential, and poor prognosis [5, 6].