ESR1 and triple-negative breast carcinoma: Ye et al[8] reported that breast MEC often presents a triple-negative immunophenotype with the absence of ER, progesterone receptor, and human epidermal growth factor receptor 2.[21] However, according to the study of Pia-Foschini et al,[18] unlike other triple-negative breast cancers, these tumors show a better prognosis.