We found that DHCR7 knockdown suppressed cell proliferation and induced apoptosis and decreased the cell cycle and apoptosis related gene expression involved in tumor carcinogenesis and proliferation, especially the CDK6, caspase9, and Bcl2 in MDA-MB-231 cells, which suggests that DHCR7 is a key oncogene in BC proliferation. This evidence concerns the gene BCL2 and breast cancer.