In all, 114 patients (57 women, 57 men) were studied; 46 had R‐CRC (f‐Hb = 113 μg Hb/g) and 68 had L‐CRC (f‐Hb = 342 μg Hb/g) (P = 0.07). Here, GSTM1 is linked to colorectal carcinoma.