RESUMO
BACKGROUND/AIMS: The gastrointestinal tract is particularly susceptible to reactive oxygen species attack which lead to carcinogenesis. An important role in defense strategy against reactive oxygen species is played by antioxidants. The present study aims at examining antioxidant parameters and malondialdehyde--the product of lipid peroxidation as well as the marker of cancer progression--and cancer procoagulant in esophageal, gastric and colorectal cancer patients. METHODOLOGY: The activity of superoxide dismutase, catalase, glutathione peroxidase and reductase and the level of glutathione, vitamin C, malondialdehyde and cancer procoagulant were determined in tumors and normal mucous from 18 patients with esophageal cancer, 18 patients with stomach tumor and 62 patients with colorectal cancer. RESULTS: In esophageal tumor the activity of all enzymes has been increased compared with normal mucous. Stomach tumor has been also characterized by an increase in antioxidant enzymes activity except glutathione peroxidase and reductase whose activities have been decreased. However in colorectal tumor the activity of enzymes has been increased apart from catalase. In all cases the glutathione level has been increased while the vitamin C content has been significantly decreased. Tumor malondialdehyde level was significantly increased, too. The level of cancer procoagulant also increased in cancer tissues as well as in the serum. CONCLUSIONS: Antioxidant potential in all cases of gastrointestinal tract cancer has been unbalanced which has lead to increase in reactive oxygen species action and enhancement of lipid peroxidation and cancer procoagulant generation.
