INCREASED ANTIOXIDANT ENZYME-ACTIVITIES IN THE COLORECTAL ADENOMA ANDCARCINOMA

Most colon carcinomas are preceded by an adenomatous polyp - adenoma-c arcinoma sequence. Active oxygen species (AOS) can play a role in the pathogenesis of this process. Antioxidant enzymes (AE) are the primary defense against the deleterious effect of AOS. Activities of AE in 56 individuals with colorectal adenoma (CA), 29 individuals with colorec tal carcinoma (CC) and in 24 control subjects were examined. Biopsy sp ecimens from the non-neoplastic colonic mucosa and from the CA and CC were taken during colonoscopy for histological and enzymological analy sis. Activities of following AE were estimated: CuZn-superoxide dismut ase (CuZn-SOD), catalase (CAT) and glutathione peroxidase (GPx). It wa s found that individuals with CA and CC were characterized by: (1) inc reased activities of CAT and GPx in non-neoplastic mucosa, that persis ted in some of the patients even after removal of tumors; (2) increase d activities of CuZn-SOD, CAT and PGx in CA and CC tissues. It can be inferred that the accumulation of peroxides in the non-neoplastic colo nic mucosa induced higher activities of CAT and GPx. The reasons of hi gh activities of all AE in the tissues of CA and CC and their relation to carcinogenesis are not clear and require further studies.