Assessment of ornithine decarboxylase activity in rectal mucosa as a marker for colorectal adenomas and carcinomas

We have investigated the role of ornithine decarboxylase activity in rectal mucosa as a marker for colorectal neoplasia. Biopsies of normal rectal mucosa were taken from 18 patients with adenomas > 1 cm diameter, 11 with carcinomas and 16 controls. The mean ornithine decarboxylase activity in normal rectal mucosa of adenoma patients, 6·52 nmol CO2 released h−1 (mg cell protein)−1, was significantly lower than that in controls, 16·8, P = 0·006. The difference in rectal ornithine decarboxylase activities between cancer patients, 3·58, and controls was also significant, P = 0·001. These preliminary results suggest that ornithine decarboxylase may be a useful marker in screening for colorectal neoplasia.