子宫内膜癌组织中DACH1基因启动子的甲基化状态及其临床意义

摘要

Objective To analyze the status of DACH1 gene promoter methylation and explore its association with the expression of DACH1 gene promoter methylation and clinical significance of endometrium carcinoma(EC).Methods From February 2004 to August 2008,a total of 80 EC tissue samples with comprehensive surgical pathology staging were collected and used for this study.Twenty normal endometrium tissues in 2008 were abtained from the fractional curettage because of dysfunctional uterine bleeding as control.All samples were confirmed pathologically.Methylation specific PCR (MSP) was performed to detect the promoter methylation of DACH1 gene,and analyze its influence on the expression of DACH1 and the relationship between DACH1 promoter methylation and clinicopathological factors in EC.DACH1 protein expression was detected by western blot.Chi-square test and Pearson test were used for statistical analysis.Results The rate of promoter methylation of DACH1 gene in the EC tissues was significantly higher than that in the normal endometrium issues (30％ vs.5％,P ＜ 0.05).There was an association between the expression of DACH1 and DACH1 gene promoter methylation ( r =- 0.30,P ＜ 0.01 ).There was statistical difference between the methylation of DACH1 and the pathological grade ( P ＜ 0.05 ) or histological type ( P ＜0.05).But DACH1 gene methylation was not related with the age,stage,myometrial invasion depth and lymphnode metastasis (P ＞ 0.05 ).Conclusions DACH1 gene promoter methylaion could lead to a decrease or absence in the DACH1 expression in EC.The promoter methylation of DACH1 gene may induce the inhibition of DACH1 expression,which might be one of the mechanisms of DACH1 gene inactivation in human EC.%目的 探讨子宫内膜癌组织中DACH1基因启动子的甲基化状态及其临床意义.方法 选取2004年2月至2008年8月间山东大学齐鲁医院及第二医院行全面分期手术并经病理检查确诊的80份子宫内膜癌组织,以同期(2008年)因功能失调性子宫出血行诊刮并经病理检查确诊为正常子宫内膜的20份组织标本作为对照.采用甲基化特异性PCR (MSP)技术检测子宫内膜癌组织与正常子宫内膜组织中DACH1基因启动子的甲基化状态,蛋白印迹法检测其DACH1蛋白的表达,并分析DACH1基因启动子的甲基化状态与子宫内膜癌临床病理特征的关系.结果 MSP技术检测显示,子宫内膜癌组织中DACH1基因启动子的甲基化阳性率为30％( 24/80),明显高于正常子宫内膜组织(5％,1/20),差异有统计学意义(P＜0.05).DACH1基因启动子甲基化阳性的子宫内膜癌组织中DACH1蛋白为阴性或弱阳性,而DACH1基因启动子甲基化阴性的子宫内膜癌组织和正常子宫内膜组织中DACH1蛋白表达阳性；在24份DACH1基因启动子甲基化阳性的子宫内膜癌组织中,DACH1蛋白表达强度与DACH1基因启动子的甲基化程度呈明显负相关关系(r=-0.30,P=0.008).子宫内膜癌组织中,病理分级为G1～G2的癌组织中DACH1基因启动子的甲基化阳性率为18％ (7/39),显著低于G3者(41％,17/41),差异有统计学意义(P＜0.05)；病理类型为子宫内膜样腺癌的癌组织中DACH1基因启动子的甲基化阳性率为23％( 12/53),显著低于特殊类型子宫内膜癌(包括子宫内膜浆液性乳头状癌和子宫内膜透明细胞癌)的44％( 12/27),差异有统计学意义(P＜0.05)；而DACH1基因启动子的甲基化状态与患者的年龄、手术病理分期、肌层浸润深度及淋巴结转移无关(P＞0.05).结论 子宫内膜癌组织中DACH1基因启动子的甲基化导致DACH1蛋白表达降低或缺失,这可能是导致DACH1基因在子宫内膜癌中失活的分子生物学机制之一.