We investigated the association of CRC with vitamin D by analyzing the following markers: 25-OHD, serum VDBP, VDR, and GC (that encoded VDBP) polymorphisms and polymorphisms of vitamin D-metabolizing enzymes (CYP24A1, CYP27B1, and CYP2R1), and consumption of cholecalciferol-rich fatty fish. The gene discussed is CYP2R1; the disease is colorectal carcinoma.