Cell proliferation and cell death (apoptosis) in epithelial tumors of the stomach--analysis of tumor tissues by the endoscopic mucosal resection

Abstract

To answer the question why some gastric cancers make elevation while others make depression in their early stage, and why polypoid cancers grow larger than their benign counterpart adenomas, the distribution of proliferating cells and apoptotic cells was compared between these lesions. Proliferating cells and apoptotic cells were detected with anti Ki-67 antibody (MIB-1) and with the in situ nick end labeling (ISNEL), respectively. A total of 62 gastric tumors, taken by the endoscopic mucosal resection method, was assessed. They consisted of 14 adenomas and 48 mucosal carcinomas (27 polypoid and 21 depressed type). Overall positive rates of Ki-67 were 27.5 +/- 9.0% in adenoma, 40.1 +/- 11.1% in polypoid cancer and 47.5 +/- 9.7% in depressed cancer. Proliferating cells were preferentially found in the cripts of metaplastic mucosa, in the middle to upper layer of adenomas, and in the whole layer including their surface of adenocarcinomas. Within cancers the polypoid type had more positive cells in the upper layer, so did the depressed type in the lower layer. ISNEL positive nuclei showed sphere, fragmented, ringed forms, or the same form as neighboring tumor nuclei. Apoptotic cells lay scattered throughout tumor glands. Apoptotic cell counts per 1000 tumor cells were 26.0 +/- 9.7 in adenoma, 36.3 +/- 32.1 in polypoid cancer, and 52.5 +/- 19.3 in depressed cancer. Depressed type cancers and a few polypoid cancers rich in non-tumor tissues showed higher numbers of apoptotic cells than adenomas and usual polypoid cancers. (ABSTRACT TRUNCATED AT 250 WORDS)