ESR1 and triple-negative breast carcinoma: Indications of increased risks of hormone receptor-negative [22] and triple-negative breast cancer (ER-/PR-/HER2-; TNBC) [21] associated with MHT have also been reported, although findings regarding MHT use and hormone receptor-negative subtypes, including TNBC and HER2-enriched (ER-/PR-/HER2 +), are inconsistent.