Oxidative stress could also be estimated through measuring the levels of erythrocyte MDA, erythrocyte activities of superoxide dismutase (CuZn-SOD), glutathione peroxidase (GPX), catalase (CAT), plasma nitrite/nitrate (NO(2)(−)/NO(3)(−)), cGMP and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in plasma of prostate cancer patients. This evidence concerns the gene CAT and prostate cancer.