When combined in vitro, calcitriol augmented MCF7 breast cancer cell line cytotoxicity via reduction in super oxide dismutase mRNA levels and suppression of Bcl2 protein levels rendering the cells more susceptible to doxorubicin 16 and paclitaxel 19, respectively, compared to either chemotherapeutic alone 16,17,19,40. This evidence concerns the gene BCL2 and breast carcinoma.