Polymorphisms of mismatch repair gene hMLH1 and hMSH2 and risk of gastric cancer in a Chinese population.

The purpose of this study was to determine the genotype and allele frequencies of hMLH1 (-93G>A and I219V) and hMSH2 (-118T>C and IVS12-6T>C) polymorphisms in patients with gastric carcinoma and normal controls, and to evaluate the association between these polymorphisms and the risk of gastric cancer in a hospital-based Chinese population. Genomic DNA was extracted from peripheral blood lymphocytes. A TaqMan assay was used to determine the genotype and allele frequencies of hMLH1 and hMSH2 polymorphisms in data obtained from 554 gastric cancer cases and 592 controls. Unconditional logistic regression was used to assess the association between the four single nucleotide polymorphisms (SNPs) and gastric carcinoma risk. No evidence of an association among any of the four polymorphisms and the risk of gastric cancer was observed. However, when gastric cancer patients were further stratified by age, gender, smoking status, alcohol use and clinicopathological characteristics, and compared with the control populations, the combined variant genotype hMSH2 -118T>C (TC+CC) was not only associated with an increased risk of gastric cancer in subgroups of younger subjects [ages ≤63years; adjusted odds ratio (OR)=1.51, 95% confidence interval (CI), 1.05-2.16], but also with diffuse tumors (adjusted OR=1.41, 95% CI, 1.01-1.96). These data indicate that the polymorphisms of -93G>A, I219V and IVS12-6T>C are not associated with the risk of gastric cancer. However, hMSH2-118T>C combined with variant genotypes (TC+CC) may confer a potential risk of gastric cancer in the Chinese population.