XDH and colorectal carcinoma: This confirms the previous hypothesis of an antioxidant adaptive response to ROS overproduction in CRC patients, as also evidenced by the positive correlation between NOX and CAT (p < 0.005, R = 0.509), NOX and TAC (p < 0.005, R = 0.504) and XO and GR (p < 0.0001, R = 0.745).