EPITHELIAL PROLIFERATION AND DIFFERENTIATION IN FLAT DUODENAL MUCOSA OF PATIENTS WITH FAMILIAL ADENOMATOUS POLYPOSIS

The colonic mucosa in patients with familial adenomatous polyposis (FA P) exhibits altered epithelial cell proliferation, differentiation, an d mucin histochemical properties compared with unaffected controls. Ho wever, Little is known regarding Obese parameters in FAP-associated du odenal mucosa, an area in which adenomas also develop at a high rate. The purpose of this study is to evaluate the morphologic, mucin histoc hemical, and proliferative characteristics of the epithelium in the fl at duodenal mucosa from 32 patients with FAP (18 with and 14 without a denomas), and compare the results with those observed in 18 non-FAP ag e-matched controls. The proliferative properties of the epithelium wer e analyzed immunohistochemically with the MIB-1 antibody, which recogn izes the Ki-67 proliferation-associated nuclear antigen in formalin-fi xed tissue. No significant differences were detected with regard to th e mucin histochemical properties (sialomucins, sulfomucins, and o-acyl ated sialomucins) or the proliferative characteristics of the duodenal epithelium in FAP versus non-FAP controls. However, FAP-associated du odenal epithelium showed a significant increase in the number of Panet h cells (P = 0.04) and endocrine cells (P = 0.01) per crypt in compari son with controls. This specialized cell hyperplasia occurred in the f lat mucosa of FAP patients regardless of the presence or absence of ad enomas and may represent a primary defect in the regulation of stem ce ll differentiation in the duodenum in FAP.