非小细胞肺癌中hMLH1基因完全失活机制

Research of hMLHI gene in non-small cell lung cancer

目的研究hMLH1基因完全失活机制及蛋白表达与非小细胞肺癌的关系。方法应用PCR-变性聚丙烯酰胺凝胶电泳-银染方法检测hMLH1基因杂合性缺失(LOH),利用甲基化敏感性限制性核酸内切酶HpaⅡ/MspⅠ酶切-PCR方法检测异常甲基化;通过免疫组化染色方法分析hMLH1基因蛋白表达情况。结果40例NSCLC中,hMLH1基因LOH发生率为65%,甲基化发生率为67.5%,72.5%hMLH1蛋白表达阴性,均与对照组之间存在显著性差异。29例hMLH1蛋白表达缺失中有21例(72.4%)同时发生LOH和异常甲基化。结论hMLH1基因异常在NSCLC发生中起着重要作用,其完全失活机制可能主要为:LOH+异常甲基化。

Purpose To study complete devitalization mechanism and exprssion of hMLH1 gene in NSCLC（includes squamous cancer and adenoid cancer）.Methods Detected hMLH1 gene＇s LOH（lost of heterozygote） with the way of PCR-Electrophoresed（denatured polyacrylamide gel）-sliver staining,analyzed the methylation of hMLH1 promoter by restriction endonuclease and specific PCR,detected the exprssion of hMLH1 with immunohistochemistry in abnormal/NSCLC lung tissue.Results The result showed that the incidence of LOH was 65%,the frequency of hMLH1 methylation was 67.5% and the frequency of aberrant hMLH1 exprssion was 72.5% in NSCLC group.LOH、methylation and aberrant hMLH1 exprssion were far more higher in the fronter than the latter.72.4% exhibiting aberrant hMLH1 exprssion displayed LOH and methylation.Conclusions The abnormality of hMLH1 gene takes effects on carcinogenesis and development of NSCLC.LOH and methylation were mainly the complete devitalization mechanism of hMLH1 gene.It is important for the early diagnosis of NSCLC.