CASP3 and neoplasm: It was found that the activity of cells overexpressing ABTB2 was significantly increased after given epirubicin (Figures 3A–D), and the activity of caspase-3 in this group of cell lines was significantly inhibited (Figures 3E,F), disclosing that ABTB2 reduces the sensitivity of ER-positive breast cancer cell lines to epirubicin by inhibiting tumor cell apoptosis.