卵巢粘液性肿瘤hMLH1启动子甲基化及微卫星不稳定性

Hypermethylation of hMLH1and Microsatellite Instability in Ovarian Mucinous Tumors

目的观察卵巢粘液性肿瘤中错配修复基因hMLH1启动子甲基化,及与微卫星不稳定性(MSI)间的关系。方法1995～2001年浙江大学医学院附属妇产科医院卵巢粘液性肿瘤组织块共107例(恶性49例,交界性35例和良性23例)。选取BAT-25、BAT-26、BAT-40、D5S346、D17S250和D2S1236个位点用PCR法进行MSI分析;限制性内切酶聚合酶链反应(PCR)法分析hMLH1启动子甲基化。结果良性、交界性和恶性肿瘤的hMLH1启动子甲基化阳性率分别为4.3%(1/23)、14.3%(5/35)和36.7%(18/49)。其中恶性组与交界性、良性组之间存在显著性差异(P=0.023和P=0.004),交界性和良性组之间无显著性差异(P=0.438);良性、交界性和恶性肿瘤的MSI表型阳性率分别为4.3%(1/23)、8.6%(3/35)和16.3%(8/49),有上升趋势,但无统计学意义;75%(9/12)MSI表型阳性的肿瘤存在hMLH1启动子甲基化,MSI表型阴性的肿瘤中84.2%(80/95)不存在hMLH1启动子甲基化,MSI表型阳性和hMLH1启动子甲基化之间显著相关(P=0.000),在恶性组和交界性组中两者均存在相关性(P=0.004,P=0.047)。结论卵巢粘液性肿瘤存在hMLH1启动子甲基化,且可能是造成MSI表型阳性的主要因素,两者可能在卵巢粘液性囊腺癌发生过程中起关键作用。

To investigate the role of hMLH1promoter hypermethylation and microsatellite instability (MSI)in the development of ovarian mucinous tumors.Methods One hundred and seven of paraffin-embedded specimens of ovarian mucinous tumors (malignant 49,borderline35,and benign23)were collected from Women' s Hospital,School of Medicine,Zhejiang University from1995to2001.The assessment of MSI was based on the use of a panel of six microsatellite markers(BAT-25,BAT-26,BAT-40,D5S346,D17S250,and D2S123)by polymerase chain reaction (PCR).Hyper-methylation of hMLH1promoter region was detected using restriction cut analysis.Results4.3%(1/23),14.3%(5/35),and36.7%(18/49)of benign tumors,borderline tumors,and malignant tumors respectively displayed hypermethylation of the hMLH1promoter.The hMLH1promoter hypermethylation rate of malignant group was significantly higher than that of borderline and benign group (P=0.023,0.004),but no significant difference between the borderline group and the benign group(P=0.438);4.3%(1/23),8.6%(3/35),and16.3%(8/49)of benign tumors,borderline tumors,and malignant tumors showed MSI positive phenotype.But there were no significant differences each other in the MSI positive phenotype rate;75%(9/12)MSI positive phenotype ovarian mucinous tumors were hypermethylated at hMLH1promoter,while the MSI -phenotype tumors were unmethylated in84.2%(80/95)of cases.There was significant correlation between MSI positive phenotype and hMLH1 promoter hypermethylation (P=0.000).Conclusions In ovarian mucinous tumors,malignant,borderline,and benign tumors exist hMLH1promoter hypermethylation.Hypermethylation of hMLH1promoter results MSI in ovarian mucinous tumors.Methylation of hMLH1promoter and MSI may be involed in the carcinogenesis of ovarian mucinous cancer.