Ras相关域家族蛋白1A基因甲基化在子宫内膜异位症组织中的表达及意义

Relationship between methylation of Ras association domain family-1A and protein expression in ;endometriosis

目的：分析子宫内膜异位症（EMS）中Ras相关域家族蛋白1A（RASSF1A）基因的表达情况及其与启动子甲基化状态的关系。方法选择45例卵巢EMS患者的异位内膜及相对应的在位内膜组织和20例非 EMS 患者的正常子宫内膜组织。免疫组化法检测组织标本中RASSF1A基因的表达情况，甲基化特异性聚合酶链反应（PCR）法检测RASSF1A启动子甲基化状态。结果异位内膜、在位内膜及正常内膜组织中RASSF1A表达率依次升高，分别为37.78%（17/45）、60.00%（27/45）、85.00%（17/20），差异有统计学意义（χ2=13.136，P=0.001）。异位内膜、在位内膜组织中 RASSF1A 启动子甲基化率分别为55.56%（25/45）、33.33%（15/45）、0，三组RASSF1A启动子甲基化率比较差异有统计学意义（χ2=18.770，P=0.000）。异位内膜组织中RASSF1A启动子甲基化率在增生期、分泌期分别为66.67%（14/21）、45.83%（11/24）；在位内膜组织中RASSF1A启动子甲基化率在增生期、分泌期分别为38.10%（8/21）、29.17%（7/24），差异均无统计学意义（P＞0.05）。异位内膜组织中，Ⅲ～Ⅳ期RASSF1A启动子甲基化率明显高于Ⅰ～Ⅱ期（χ2=5.940，P=0.015）。在异位内膜和在位内膜组织中，RASSF1A表达水平与RASSF1A启动子甲基化状态呈负相关（r=-0.594、-0.577，P〈0.01）。结论 RASSF1A启动子甲基化导致的基因转录沉默与EMS的发生、发展密切相关。评估在位内膜组织RASSF1A启动子甲基化水平可作为EMS的表观遗传学标志物，有助于EMS的早期诊断。

Objective To analyze the methylation status and protein expression of Ras association domain family- 1A （RASSF1A） in endometriosis （EMS）. Methods The ectopic and corresponding eutopic endometrium tissues were collected from 45 women with EMS and normal endometrium tissues of 20 women without EMS. The methylation status of RASSF1A was examined by methylation specific PCR （MSP）. Immunohistochemistry was performed to measure the level of RASSF1A in endometrium tissues. Results The RASSF1A protein expression rate in ectopic endometrium, eutopic endometrium, and normal endometrium was 37.78%（17/45）, 60.00%（27/45） and 85.00%（17/20）, and there was significant difference （χ2 = 13.136, P = 0.001）. The frequency of aberrant methylation of RASSF1A was 55.56%（25/45）, 33.33%（15/45） and 0 in ectopic endometrium , eutopic endometrium, and normal endometrium, and there was significant difference （χ2 =18.770, P = 0.000）. The frequency of aberrant methylation of RASSF1A had no significant differnce throughout the menstrual cycle in ectopic endometrium and eutopic endometrium： 66.67%（14/21） vs. 45.83%（11/24）, 38.10%（8/21） vs. 29.17%（7/24）, P〉0.05. In ectopic endometrium, the frequency of aberrant methylation of RASSF1A inⅢ-Ⅲstage was significantly higher than that in Ⅰ-Ⅱstage （χ2=5.940, P=0.015）. Innbsp;ectopic endometrium and eutopic endometrium, the RASSF1A protein expression had negative correlation with aberrant methylation of RASSF1A （r =- 0.594、- 0.577, P〈0.01）. Conclusions Epigenetic inactivation of RASSF1A through aberrant promoter methylation may be strongly correlated with the formation and progression of EMS, and assessment of RASSF1A methylation status in eutopic endometrium may be a potentially useful biomarker to enhance the early detection of EMS.