[Activity of antioxidant enzymes in cancer diseases].

In this work comprehensive data of antioxidant enzymes are reviewed and their role in carcinogenesis is discussed. When compared to their normal tissue counterparts, more of the tumor tissues were low in Cu, Zn-SOD and catalase activity and in some cases in Mn-SOD. It is probably characteristic for tumor tissues. Glutathione peroxidase, and glutathione reductase and glucose-6-phosphate dehydrogenase activities are highly variable. The reason why cancerous cells exhibit abnormal levels and activities of antioxidant enzymes is unknown. It was hypothesized, that during formation of the tumor, by certain obscure mechanism, cells with imbalance of antioxidant enzymes profile were selected over normal cells. It is not known whether the changes in antioxidant defence observed in cancerous tissues play a role in carcinogenesis, or are formed as a results of the disease.