Entinostat has demonstrated significant potential in treatment of BC, particularly against ER+ and HER2-enriched subtypes [296]; the drug upregulates miR-125a, miR-125b, and miR-205, all of which are involved in apoptosis induction of BC cells and able to downregulate HER2 and HER3 expression [297]. This evidence concerns the gene ESR1 and breast cancer.