HIGH-LEVELS OF DNA-ADDUCTS IN HUMAN COLON ARE ASSOCIATED WITH COLORECTAL-CANCER

Colon cancer is one of the most frequent causes of cancer death in wes tern countries. Epidemiological studies suggest that colorectal cancer can be attributed, at least in part, to carcinogens and mutagens pres ent in the diet and/or the environment. The covalent binding of these xenobiotics or their reactive metabolites to DNA is believed to initia te this chemical carcinogenesis. In the present study, using a P-32-po stlabeling method, we investigated DNA adduct levels in control colons from patients without colorectal adenocarcinorna and in nontumoral an d tumoral tissues from patients with colorectal adenocarcinoma. Our re sults show that the DNA adduct level is significantly higher (P < 0.00 1) in nontumoral than in control or tumoral colon samples. For the fir st time, we demonstrate in humans that the presence of nnmerous adduct s in colonic mucosa is associated with colorectal cancer, a finding in agreement with the importance of chemical factors in causing this dis ease; therefore, after confirmation of the link between DNA adducts an d colorectal cancer, the measurement of DNA adduct levels in colon sam ples could constitute a useful approach to the early detection of colo rectal cancer.