결직장선암종에서 connexin 26 발현의 의의

Abstract

Gap junctions are specialized cell membrane channels which composed of transmembrane proteins called connexin (Cx). A member of Cx family, Cx26, which is normally located in the cell membrane, is considered as a potential tumor suppressor in several cancers. The aim of the present study was to examine the significance between Cx26 expression and clinicopathologic parameters in colorectal adenocarcinoma, adenoma and normal epithelium by immunohistochemistry. The author also purpose to evaluate the relationship between expression of COX-2 and p53 protein in human colorectal adenocarcinoma and well-known clinicopathologic parameters. The expression of Cx26 was evaluated using immunohistochemistry in total 127 surgical resected colorectal adenocarcinomas, 12 adenomas, and 10 normal mucosae. There are statistical significance in difference of Cx26 expression rate among the normal epithelium, adenoma and adenocarcinoma (p<0.001). Of 127 cases of adenocarcinoma, 49% were positive for Cx26, and 51% were negative for that. Whereas in adenoma and normal epithelium, all cases showed positivity for Cx26, however, positive cell rates of Cx26 in adenoma were decreased rather than those in normal epithelium. Cytoplasmic staining was found in colorectal adenocarcinomas (22%), but not showing in adenoma and normal epithelium. Positive correlation between decrement of membrane expression of Cx26 and tumor invasion (pT) was statistically significant (p<0.05). The positivity for COX-2 and p53 were 47%, 49%, respectively. Extent of COX-2 expression was related to tumor progression (pT) and clinical stage. And, Multiplication of intensity score and extent score resulted in the COX-2 immunoreactivity score (IRS-COX2), which showed significant difference in clinical stage. And, p53 protein expression was increased in reverse proportion to Cx26 membrane staining. These results suggest that loss of intercellular Cx26 expression and cytoplasmic staining have a role in colorectal carcinogenesis, and tumor progression, especially, tumor invasion.