TOPOISOMERASE II-ALPHA EXPRESSION IN NORMAL, INFLAMMATORY, AND NEOPLASTIC CONDITIONS OF THE GASTRIC AND COLONIC MUCOSA

Topoisomerase II alpha (TP) excises and reconnects double-stranded sup er-coiled DNA during the replicative cell cycle, We studied the locali zation of TP and Ki-67 in inflammatory and neoplastic mucosal lesions of the stomach and of TP in similar conditions of the colon, TP expres sion was correlated with tumor stage, grade, and survival time in the colonic tumors to evaluate its potential utility as a predictive marke r for clinical outcome, Forty-three sections of chronic gastritis, les ions indefinite for dysplasia, low- and high-grade dysplasia, and gast ric adenocarcinomas were immunostained with antibody against TP and Ki -67, For the colon, 71 sections of normal mucosa, chronic colitis, hyp erplastic polyps, adenomas, and carcinomas were examined; fresh tissue was analyzed by now cytometry, Expression of TP in non-neoplastic gas tric mucosa was maximal in neck/foveolar cells and focal in surface an d deep gland cells, Increased surface and deep gland positivity was fo und in low-grade dysplasia and a diffuse distribution of positive cell s in high-grade dysplasia and carcinoma. The Ki-67 staining pattern wa s similar, TP in non-neoplastic colon was restricted to the lower cryp t zone; it was greatly expanded in the surface/upper crypt region in a denomas and was diffuse in carcinomas. Flow cytometric analysis reveal ed TP expression mainly in the S and G2/M phase, with higher labeling index in tumors, There was no correlation of TP with stage, grade, or survival times in the colonic tumors, Staining for TP and Ki-67 might help in the distinction of inflammatory and neoplastic lesions of the stomach and colon.