Study Of HMSH2 Gene Mutation In Guangxi Spordic Colorectal Cancer

Background and Objective:Colorectal cancer is one of the most common malignant tumors in most regions of the world.A great of studys indicated that Cancer originated in gene mutations, gene mutations originated from carcinogenic agents and bases mispairing in metabolic process of the deoxyribonucleic acid. To ensure Integrity and stabilization of hereditary material, There are mang systems to prevent the cell from gene mutation,it includes excision repair, direct repair, recombination repair and mismatch repair(MMR), MMR system was not only to rectify base mispairing in DNA recombination and replication for remaining genomic stability, but also to induce apoptosis of DNA damaging cell. for eliminating canceration of the mutant cell. Human mismatch repair genes include hMSH2,hMLH1,hMSH3,hPMH1,hPMH2 etc, in which hMSH2 and hMLH1 genes play a major role.The technique of Polymerase Chain Reaction-Single Strand Conformation Polymorphism (PCR-SSCP) analysis is a new technology for mutation screening,which was created by Orita in 1989. The technique has been widely used in the research of the tumor of related genes mutation because it is a method of a relatively simple, rapid and economic means of the point mutation screening.The objective of this research was used to detect mismatch repair gene mutation in the hMSH2 of sporadic colorectal cancer in Guangxi Province through the use of PCR-SSCP combined with DNA sequencing, and to explore the role of mismatch repair gene hMSH2 in the carcinogenesis of sporadic colorectal carcinoma in Guangxi.Methods:DNA was extracted by phenol-chloroform method from tumor and its corresponding near or distal normal mucosal tissues of 44 cases of Guangxi sporadic colorectal cancer. The mutations of the fifth,sixth,thirteenth,fifteenth exon of the hMSH2 were analyzed by using PCR-SSCP, and DNA sequencing methods,were analyzed incorporating clinical parameters by compared using the SPSS13.0 software.Results:44 cases of Guangxi sporadic colorectal cancer patients,hMSH2 gene mutation were detected in two cases, the rate of the hMSH2 mutation was 4.55%,one case happened at exon6, codon338(GGA→AGA),the other one happened at exon13, codon710(GCC→TCC). There were no significant differences among hMSH2 mutation rate in patho-Staging of tumour tissue(P>0.05).Conclusion:hMSH2 gene perhaps has a certain effect in occurrence of Guangxi sporadic colorectal cancer, the mutations of hMSH2 can not indicate differentiations and patho-Staging of tumour tissue. In Guangxi sporadic colorectal cancer mutation rate of hMSH2 gene is low, but it suggest that it is not a key gene in occurrence and development of Guangxi sporadic colorectal cancer.