No abstract

In the colon of ulcerative colitis (UC) patients, apoptotic bodies have been recognized in routine histopathological preparations. To investigate the extent of the apoptosis, colonic biopsies were examined from involved and uninvolved areas of untreated active UC and from normal areas in patients with colonic polyps, utilizing various markers of apoptosis. The markers included DNA breaks detected by TUNEL, Fas (CD95/APO‐1) and Fas ligand (Fas‐L) localized by immunohistochemistry, electron microscopic features of apoptosis, and laddering of extracted DNA. Apoptosis marker positive cells were found mainly on the luminal epithelium of the normal colon and were present in active UC in crypts of involved and uninvolved areas of the colon, in addition to the luminal epithelium. The DNA extracted from active UC colon electrophoresed as a ladder. These findings suggest that the loss of epithelial cells in active UC occurs mainly by apoptosis in crypts of involved and adjacent uninvolved areas and that the Fas/Fas‐L interaction is a mediator of the apoptosis.

One-hundred twelve hyperplastic polyps were analyzed. The aim was to study their malignant transformation. Among them, four hyperplastic polyps harbored adenocarcinoma; two were from our own institution (1.8%). The majority were pedunculated and located in the antrum with an average of 14.5 mm in diameter. The four polyps bore well-differentiated adenocarcinoma. Dysplasia and intestinal metaplasia were detected in two and three polyps, respectively. The cancer and dysplastic foci shared the same type of neutral and acid mucosubstances. p53 oncoprotein was positive in three cancer foci and in the dysplastic areas, and nucleolar organizer region counts were higher in the cancer foci. In conclusion, hyperplastic polyps have malignant potential. Such possibility increases in polyps larger than 14.5 mm. In our cases, the carcinoma foci may have arisen from dysplastic areas. Once the neoplastic changes occur, the cancer cells proliferate and behave as other adenocarcinomas of the stomach.