In the intestinal mucosa, diamine oxidase probably is involved in a feedback regulation mechanism for the termination of proliferation. This was proven by a considerable promotion of large bowel tumors induced by diamine oxidase inhibition in a rat model. Carcinogenesis was accompanied by characteristic alterations in mucosal diamine oxidase activity. In large bowel cancer patients similar changes in intestinal diamine oxidase activity had been observed as in the animal model.
Conclusion: Events entailing a reduction of diamine oxidase activity are suspicious for large bowel cancer promotion under experimental and clinical conditions.