The Clinical Effect Of DNA Repair System-XRCC1, XRCC2 And XRCC3 Expressions In Colorectal Carcinoma

Objective: colorectal carcinoma is a common digestive malignant tumor. In recent years, with the changes of the dietetic structure and life style, the incidence of colorectal cancer increases in China. Operation is the main therapeutic method to colorectal cancer now, but the mechanism of colorectal carcinoma's occurrence is not clarified, effective prediction is deficient, most colorectal carcinoma patients were diagnosed in advanced stage, and the best opportunity for operation has gone. The early diagnosis and cure rate will be increased if the pathogenesy is illuminated. It's usually considered that abnormal accumulation of gene mutation result in tumorous occurrence, 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 restoration system in normal cells including five repair modes. But colorectal mucosa is usually influenced by varied noxious substance, DNA are easy to be injured in different modes, varied restoration are required. In this study, we detected the protein expressions of base excision repair gene XRCC1,homologous recombinational repair gene XRCC2 and XRCC3 in colorectal cancer and adjacent colorectal mucosa to analyze the role of their abnormal expressions in colorectal cancer.Method:colorectal carcinoma with clear pathological diagnosis from 204 patients were collected. Immunohistochemistry was used to detect the protein expressions of XRCC1,XRCC2 and XRCC3 in carcinoma group of all the patients and in adjacent mucosa group of 46 patients, normal group of 36.SPSS13.0 statistic software was used to analyze the correlation of their abnormal expressions to colorectal cancer.Results : In carcinoma group and adjacent mucosa group, the expressions of XRCC1 were 94.61%(193/204)and 89.13%(41/46),there was no significant difference between the two groups. But there was significant difference between they with normal mucosa ,in the later the expressions of XRCC1 were 27.78%(10/36).In carcinomas, the expressions of well-moderate differentiation and poor differentiation were 94.29%(165/175) and 96.55%(28/29), there was no significant difference between the two groups(P>0.05); the expressions of XRCC1 had no relationship with sex,age and infiltrate depth( P>0.05) .In carcinoma group and adjacent mucosa gruop, the expressions of XRCC2 were 87.25%( 178/204) and 78.26%( 36/46) ,there was no significant difference between the two groups. In carcinomas, the expressions of well-moderate differentiation and poor differentiation were 88.57%(155/175)and 79.31%(23/29), there was no significant difference between the two groups; the expressions of XRCC2 had no relationship with sex,age and infiltrate depth( P>0.05) .In carcinoma group and adjacent mucosa group, the expressions of XRCC3 were 79.40%(158/199) and 83.67%(41/49),there was no signi- ficant difference between the two groups. In carcinomas, the expressions of XRCC2 had no relationship with sex,age,location,differentiated degree and infiltrate depth( P>0.05) .Conclusions:1. The expression level of XRCC1 protein was up-regulated in colorectal cancer.2. The expression level of XRCC1 protein was up-regulated in adjacent mucosa.3. The expression of XRCC1, XRCC2 and XRCC3 has no relationship .They have unattached function.4. XRCC1 to colorectal carcinoma contain predicting function .