散发性大肠癌错配修复基因hMLH1的突变及甲基化研究  

Research on Mutation and Methylation of Mismatch Repair Gene hMLH1 in Sporadic Colorectal Cancer

作　　者：范凯[1] 马坚妹[2] 王彦[1] 吕申[1] 

机构地区：[1]大连医科大学附属第二医院分子生物学实验室 [2]大连医科大学解剖学教研室,辽宁大连116027

出　　处：《癌变．畸变．突变》2005年第3期167-170,共4页Carcinogenesis,Teratogenesis & Mutagenesis

摘　　要：背景与目的:研究散发性大肠癌hMLH1(humanmutlhomologlgene,hMLH1)基因突变和启动子甲基化的状况。材料与方法: 采用毛细管电泳-单链构象多态性分析(Capillaryelectrophoresis_singlestrandconformationpolymorphism,CE_SSCP)结合基因序列分析的方法,对50例散发性大肠癌标本hMLH1基因第3、8、12、13、15和16号外显子进行突变检测;利用HapⅡ和MspⅠ酶切结合聚合酶链反应(Reversetranscriptase_polymerasechainreaction,RT_PCR)方法对hMLH1基因启动子区进行甲基化检测。结果: ①50例标本有3例hMLH1基因第12号外显子检出突变,突变率为6 %。突变位点均是12号外显子的第1151位碱基发生杂合型突变T→A ,使该碱基所处的第384位密码子发生错义突变(GTT→GAT,Val384Asp) ,其他外显子均未发现突变。②9例标本出现hMLH1基因启动子区甲基化,占18 %。结论:散发性大肠癌hMLH1基因突变可能是偶发事件;hMLH1基因第12号外显子第384位密码子的错义突变可能增加罹患大肠癌的危险性;hMLH1基因启动子甲基化与肿瘤临床病理参数间无明显相关关系。BACKGROUND&AIM: To investigate the mutation and methylation status of mismatch repair gene human mutl homolog l gene( hMLH1 )in sporadic colorectal cancer. MATERIAL AND METHODS: Genomic DNA extracted from50sporadic colorectal cancer tissues was subjected to the mutation analysis of exon3,8,12,13,15,16in hMLH1gene by capillary electrophoresis-single strand conformation polymorphism(CE-SSCP)followed by DNA sequencing technology,and methylation of hMLH1promotor was measured by HapⅡ,MspⅠenzyme and reverse transcriptase-polymerase chain reaction(RT-PCR)technology. RESULTS: ①Among the50cases,3cases showed the missense mutation in exon12(GTT→GAT,Val384Asp),and the mutation rate was6%.②9cases showed methylation of hMLH1promotor,and methylation rate was18%. CONCLUSION: Mutation of hMLH1gene in sporadic colorectal cancer may be casual events;people with the missense mutation in exon12of hMLH1gene may be subject to sporadic colorectal cancer;there is no significant correlationship between hMLH1gene methylation and clinicopathology in sporadic colorectal cancer.

关 键 词：HMLH1基因 突变 甲基化 大肠癌 

分 类 号：R730.2[医药卫生—肿瘤]