CASP3 and breast cancer: To assess whether the increased susceptibility of BC cells with high expression of PIP to drug-induced cytotoxicity is the result of higher sensitivity to drug-induced apoptosis, they were grown in the presence of DOX, 4-HC and PAX for 48 h and the percentage of apoptotic cells was determined using the CaspGLOW fluorescein active caspase 3/7 staining kit.