The Effect Of HMSH2,MGMT And XRCC2 Expressions In Colorectal Carcinoma

Objective: colorectal carcinoma is a common digestive malignant tumor. In recent years, the incidence of colorectal carcinoma is increasing in China. Operation is the main therapeutic method to colorectal carcinoma now, but the mechanism of colorectal tumorigenesis is not clarified, and then effective pathway for predication is deficient, the most colorectal carcinoma patients were diagnosed at advanced stage, and the best opportunity for operation has gone. The cure rate will be increased if the pathogenesy is illuminated. It's usually considered that abnormal accumulation of gene mutation result in tumorigenesis, and the abnormal accumulation is the result of DNA repair system's functional defect, DNA can't be repaired exactly and promptly. There is a complete DNA repair system in normal cells including five repair methods. Colorectal mucosa are usually influenced by varied noxious substance, DNA are easy to be injured in different modes, different repair methods are required. In this study, we detected the protein expressions of mismatch repair gene hMSH2,damage reverse repair gene MGMT and homologous recombination repair gene XRCC2 in colorectal carcinoma and adjacent mucosa to carcinoma to analyze the role of their abnormal expressions in colorectal tumorigenesis.Method:colorectal carcinoma with clear pathological diagnosis from 200 patients were collected. Immunohistochemistry was used to detect the protein expressions of hMSH2,MGMT and XRCC2 in carcinoma group of all the patients and in adjacent mucosa group of 49 patients. SPSS13.0 statistic software was used to analyze the correlation of their abnormal expressions to colorectal carcinoma.Results:In carcinoma group and adjacent mucosa group, the positive rate of hMSH2 expressions were 87.00%(174/200) and 75.51%(37/49), there was significant difference between the two groups(P<0.05). In carcinoma, the positive rate of hMSH2expressions in well-moderate differentiation and poor differentiation were 89.20%(157/176) and 70.83%(17/24), there was significant difference between the two groups(P<0.05); the expressions of hMSH2 had no relationship with sex,age,location,infiltrate depth and lymph node metastasis(P>0.05).In carcinoma group and adjacent mucosa group, the positive rate of MGMT expressions were 74.50%(149/200) and 59.18%(29/49), there was significant difference between the two groups(P<0.05). In carcinoma, the positive rate of MGMT expressions in well-moderate differentiation and poor differentiation were 78.14%(138/176) and 45.82%(11/24), there was significant difference between the two groups(P<0.05); the expressions of MGMT had no relationship with sex,age,location,infiltrate depth and lymph node metastasis(P>0.05).In carcinoma group and adjacent mucosa group, the positive rate of XRCC2 expressions were 80.00%(160/200) and 91.84%(45/49), there was no significant difference between the two groups. In carcinoma, the expressions of XRCC2 had no relationship with sex,age,location,differentiation,infiltrate depth and lymph node metastasis(P>0.05).Conclusions:1. The expressions of hMSH2 and MGMT proteins were up-regulated in colorectal carcinoma.2. The expression of hMSH2 protein has direct correlation to the differentiation.3. The expression of MGMT protein has direct correlation to the differentiation.4. Colorectal tumorigenesis is closely related to base mismatch in replication and injury of aldyl agent.5. It may be helpful to detect the protein expressions of both hMSH2 and MGMT for the predication of colorectal carcinoma.