O^6-甲基鸟嘌呤-DNA甲基转移酶基因多态性与胃癌遗传易感性的关系

目的探讨O6-甲基鸟嘌呤-DNA甲基转移酶(MGMT)基因第3外显子上第84和第53密码子上的多态性改变与胃癌易感性的关系以及与环境因素在胃癌发生中的交互作用。方法应用以人群为基础的病例对照研究,采用PCR-RFLP技术检测191例胃癌病例组与251例健康对照组MGMT-Leu53Leu和MGMT-Leu84Phe多态改变的频率。结果MGMT-Leu84Phe各基因型在胃癌病例组(CC 74.3%,CT 23.6%,TT 2.1%)和对照组(CC 74.1%,CT 23.5%,TT 2.4%)的分布情况与MGMT-Leu53Leu基因型相似,差异无显著性;MGMT-Leu53Leu各基因型在胃癌病例组中的分布分别为CC型(75.4%)、CT型(21.5%)、TT型(3.1%),对照组分布为CC型(72.1%)、CT型(24.7%)、TT型(3.2%),两组比较差异无显著性;分别按年龄、性别、吸烟、饮酒、H.pylori感染以及胃癌家族史等因素分层分析也没有发现两个位点的突变基因型与胃癌遗传易感性的相关性。结论结果显示MGMT-Leu53Leu、Leu84Phe与胃癌的发生没有显著关联。

Study on the association between the role of polymorphisms of the O6-methylguanine-DNA methyltransferase gene and gastric cancer hereditary susceptibility

Objective To explore the association between the role of polymorphisms in codons 53 and 84 of the O~6-methylguanine-DNA methyltransferase gene(MGMT) and gastric cancer hereditary susceptibility.Methods Population based case-control study was employed and the polymerase chain reaction-restriction fragment length polymorphisms(PCR-RFLP) was used to genotype two variants in 191 non-cardia gastric cancer patients and 251 controls.Results The frequencies of genotypes CC,CT,and TT of Leu53Leu were(75.4%),(21.5%) and(3.1%) respectively in cases and were(72.1%),(24.7%) and 3.2% respectively in controls.The proportion of genotypes for Leu53Leu and Leu84Phe in cases was similar to that of controls.The frequency of Leu84Phe CC homozygotes was 74.3% in cases and 74.1% in control,the frequencies of Leu84Phe CT,TT were 23.6%,2.1% respectively in cases and 23.5%,2.4% respectively in controls stratified by sex,age,area,smoking,alcohol use,H.pylori infection and family history of gastric cancer in the multivariate logistic regression analysis did not find an association between Leu53Leu or Leu84Phe and gastric cancer.Conclusions These results suggested that the two polymorphisms could not affect the susceptibility to gastric cancer.