CYP26A1 and breast cancer: The top three enriched KEGG terms shared between T2DM and BC DE mRNAs were “drug metabolism-cytochrome P450,” “metabolism of xenobiotics by cytochrome P450,” and “chemical carcinogenesis.” In addition, CYP4B1, CYP7B1, and CYP26B1 are upregulated in BC, and CYP4X1 and CYP26A1 are upregulated in both BC and T2DM.