The Expression Of MCM2, Connexin-32and Cap43in Colorectal Adenoma

Objective: In recent years, with the improvement of living standards andchanges in diet,the morbidity and mortality of colorectal carcinoma show arising trend,which seriously affect people’s health and life.The developmentprocess of colorectal carcinoma which is associated with the oncogeneactivation and anti-oncogene inactivation includes inflammatory hyperplasia,adenoma,canceration and metastasis. Minichromosome maintenance protein2(MCM2) is an essential element of the DNA replication complex ineukaryotic cell,only existing in the nucleus. MCM2overexpression is detectedin proliferating cells,and no or weak expression is detected in quiescent cellsand well-differentiated cells. As a specific agent of tumor cells,MCM2can beconsidered as a preneoplastic marker.Calcium channel activated protein43（Cap43）,callded N-myc downstream regulated gene1（NDRG1）,is a newgene which was extracted from the human bronchial alveolar epithelial cellA549by differential display technique when studying carcinogenesismechanism of nickel compounds.The activation and expression of Cap43protein was documented in the earlier period of colorectal cancer,prostatecancer and breast cancer,which suggested that Cap43gene was an earlypromoter on the developmengt of tumour.Connexin （CX）is a channel proteinin charge of the exchange of material and information between cells, which isessential for cell proliferation,differentiation and development oforganism.Previous studies have suggested that the function of Cx involved inmany physiological and pathological processes,and it was obviouslyassociated with inhibiting the development of tumour,called as "the secondtype of anti-oncogenes".The aim of this study is to detect the expression levels of MCM2,Cap43and Cx-32in normal colorectal mucosa,colorectal adenomas and colorectal carcinoma,and to analyze the relationships among different histological typesof colorectal adenomas and colorectal carcinoma.It will provide a newtherapeutic target for gene therapy of tumor.Methods:①materials: We collect60normal colorectal mucosa tissuesadjacent to carcinoma and60colorectal carcinoma tissues from thedepartment of general surgery and80specimens (including40tubularadenoma,20villous adenoma and20mixed adenoma) from endoscopy centerof252Hospital during January2011to December2011.All specimens wereroutinely examined and diagnosed in the pathology department.②O bserving parameter:HE staining was used to observe the pathologicalchanges of colorectal adenoma,colorectal carcinoma,normal colorectal mucosaand to distinguish the pathological types of colorectal carcinoma and thedegree of histological differentiation.Immunohistochemistry is used to detect the location and expression ofMCM2,Cap43,Connnexin-32in the tissues.③Data Statistics and Analysis: The results were analyzed by chi-squarecriterion analysis with SPSS17.0.All reported P values were2sided,and thetest was considered stastistically significant when P＜0.05.Results:①T he positiveexpression rate of MCM2protein in normalcolorectal mucosa,colorectal adenoma and colorectal carcinoma tissues were16.7%,55.0%,80.0%,respectively,with significant differences among them(P＜0.05).The positive expression rate of MCM2protein in tubularadenoma,mixed pattern of adenoma and villous adenoma were40.0%,65.0%,75.0%,espectively,with significant differences among them(P＜0.05).②The positive expression rate of Connexin-32conprotein in normalcolorectal mucosa,colorectal adenoma and colorectal carcinoma tissues were66.7%,36.2%,5.0%,respectively,with significant differences among them(P＜0.05).The positive expression rate of Connexin-32protein in tubularadenoma,mixed pattern of adenoma and villous adenoma were47.5%,35.00%,15.00%,respectively,with significant differences among them(P＜0.05).③The positive expression rate of Cap43protein in normal colorectalmucosa,colorectal adenoma and colorectal carcinoma tissues were31.7%,63.8%,91.7%,respectively,with significant differences among them(P＜0.05).The positive expression rate of Cap43protein in tubularadenoma,mixed pattern of adenoma and villous adenoma were52.5%,60.0%,90.0%,respectively,with significant differences among them(P＜0.05).Conclusion:MCM2,Connexin32and Cap43are correlated with canceration ofcolorectal adenoma and the development of colorectal carcinoma.Detectingthe protein of MCM2,Connexin32,Cap43can evaluate the progression ofcolorectal adenoma and the development of colorectal carcinoma.They may bethe molecular biological indicators for predicting canceration of colorectaladenoma.