ESR1 and triple-negative breast carcinoma: The observed associations were mainly confined to women with triple negative breast cancer (TNBC, ER–/PR–/HER2–, Ptrend ≤0.02) or luminal A-like subtype (ER+ or PR+ plus HER2–) who were former users of menopausal hormone therapy at baseline (Ptrend = 0.02, Phomogeneity of trends ≤0.03).