The expression and clinical significance of connexin 32 in colorectal adenoma and colorectal carcinoma

Abstract

Objective To explore the expression of connexin 32 in normal colorectal mucosa, colorectal adenomas and colorectal carcinoma, and to analyze its relationships with different histological types of colorectal adenomas and colorectal carcinoma. Methods Immunohistochemistry was used to exzamine the location and expression of connnexin 32 in the colorectal tissues, colorectal carcinoma tissues and colorectal carcinoma tissues. Real-time fluorescent quantitative polymerase chain reaction (FQ-PCR) was used to detect connexin 32 mRNA expression. Results There was a significant correlation between up-regulated expression of connexin 32 and unfavorable variables, including nodal metastasis, Dukes stage and differentiation degree (P=0.032). There was no obvious difference in age and sex (P=0.061). The positive expression rate of connexin 32 protein in normal colorectal mucosa, colorectal adenoma and colorectal carcinoma tissues was 66.7%, 36.2% and 5.0% respectively, with significant differences among them (P=0.000). The positive expression rate of connexin 32 protein in tubular adenoma, mixed pattern of adenoma and villous adenoma was 47.5%, 35.0% and 15.0% respectively, with significant differences among them (P=0.047). FQ-PCR showed that the expression of connexin 32 gradually decreased in normal colorectal mucosa, tubular adenoma, mixed pattern of adenoma, villous adenoma and colorectal carcinoma (P=0.006). Conclusion Connexin 32 is correlated with canceration of colorectal adenoma and the development of colorectal carcinoma. Detecting the expression of connexin 32 can evaluate the progression of colorectal adenoma and the development of colorectal carcinoma. Key words: Colorectal adenoma; Real-time fluorescent quantitative polymerase chain reaction; Connexin 32