Activities of erythrocyte antioxidant enzymes in cancer patients.

We measured the activities of erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GPX) before therapy in 97 patients with cancer in various sites (gastrointestinal tract (GIT) (n=40), breast (n=30), and others (n=27)), and in 60 matched controls to assess antioxidant enzyme protection. Hemolysate hemoglobin (Hb) was measured spectrophotometrically. The activity of SOD (U/g Hb) was significantly lower in all sites (when all the cancer sites were considered as a group), GIT, breast, and other sites compared to the controls (P<0.