[Inflammatory bowel disease and colorectal cancer].

Inflammatory bowel disease (IBD), ulcerative colitis (UC) and Crohn's disease (CD), have been considered as a risk of colorectal cancer (CRC). CRC associated with chronic intestinal inflammation has been known as "colitic cancer". Molecular mechanisms for developing of colitic cancer are different from those of sporadic CRC known as adenomacarcinoma sequence. Colitic cancer often involves dysplasia as precancerous lesions. Mutation of p53 gene is often observed not only in colitic cancer but also in dysplasia. Theory of "field cancerization" applies in colitic cancer resulting in several difficulties in clinical management of it such as multifocality and heterochrony.