The catalase marker of cancer patients with deficiency was also found to be lower than the catalase marker of non-cancer patients with insufficiency (210.28 U/mg Hb, p < 0.001), deficiency (207.68 U/mg Hb, p < 0.001), and non-cancer vitamin D sufficiency (218.72 U/mg Hb, p < 0.001). Here, GSTM1 is linked to cancer.