MUCOSAL CELL-PROLIFERATION IN PATIENTS WITH HYPERPLASTIC COLORECTAL POLYPS

Background: Morphologic, histochemical, and cytoproliferative characte ristics differentiate hyperplastic polyps from adenomas. Even so, thes e polyps are indicators of populations with a high colorectal cancer r isk. Since changes in mucosal cell proliferation am highly predictive biomarkers of the adenomacarcinoma sequence, this study examined the c ytoproliferative profiles of mucosa bearing hyperplastic polyps, in a search for the significance of such lesions in bowel carcinogenesis. M ethods: Proliferative activity demonstrated by immunohistochemical det ection of the in vitro uptake of bromodeoxyuridine was evaluated in th e rectal mucosa of 26 patients with hyperplastic polyps, 35 with adeno mas <1 cm? 60 with adenomas >1 cm, 10 with adenomas + synchronous hype rplastic polyps, and 400 controls. Results: An upward shift of the maj or DNA synthesis zone to the intermediate and surface crypt compartmen ts was found in all four patient groups. Significant hyperproliferatio n, on the other hand, was only observed in patients with large adenoma s or hyperplastic polyps, or small adenomas and synchronous hyperplast ic polyps. Conclusions: These findings suggest that hyperplastic polyp s are morphologic indicators of tumor initiation in the rectal mucosa and its ensuing hyperproliferation. Abnormalities in the distribution of proliferation in the mucosa do not appear to be specifically associ ated with the morphogenesis of hyperplastic polyps.