CASP3 and breast cancer: The co-administration of the steroid hormone precursor 1,25(OH)2D3 and the phytoestrogen genistein exerted a synergistic effect on apoptosis of MCF-7 and MDA-MB-231 BC cells as evidenced by an increase in BAX and CASP3 gene expression and downregulation of the BCL-2 gene compared to the single treatment [187].