子宫内膜癌组织中HOXD10甲基化状态及临床意义

Status and clinical significance of HOXD10 methylation in endometrial carcinoma

目的 探究同源异形盒(HOX)D10在子宫内膜癌(EC)组织中的表达和基因甲基化状态,分析其与临床病理特征及生存预后的关系。方法 采用基因表达谱动态分析(GEPIA)工具分析美国公共癌症基因数据库(TCGA)中HOXD10 mRNA在EC组织和正常组织中的表达差异及预后信息。选取2016年5至2018年4月在我院治疗的EC患者148例,另选同期30例子宫内膜增生症患者作为良性病变组,收集患者临床资料及新鲜组织标本。采用实时荧光定量PCR(qPCR)、甲基化定量PCR、免疫组织化学染色法检测组织HOXD10 mRNA、基因启动子甲基化状态、蛋白表达。结果 TCGA数据集中,174例EC组织中HOXD10 mRNA表达量显著低于91例正常子宫内膜组织中的表达量(P<0.05),但未得出HOXD10 mRNA表达与患者中位总生存期(OS)和无进展生存时间(PFS)之间的关系(P>0.05)。临床研究中,EC组织中的HOXD10 mRNA表达均显著低于良性病变组织(0.229±0.237 vs. 1.018±0.265),但HOXD10 mRNA启动子甲基化水平(0.166±0.237 vs. 0.041±0.033)和甲基化率(50.0%vs. 10.0%)均显著高于良性病变组织(P<0.05)。且HOXD10 mRNA启动子高甲基化的癌组织样本中HOXD10 mRNA及蛋白阳性表达率显著降低(P<0.05)。HOXD10 mRNA甲基化与国际妇产科联合会(FIGO)分期、组织学分级、淋巴结转移、肌层浸润程度相关(P<0.05),HOXD10蛋白阳性表达率在不同FIGO分期、微卫星不稳定的EC患者间存在有统计学意义的差异(P<0.05)。Cox比例风险回归模型分析显示,微卫星不稳定、肌层浸润≥1/2肌层、HOXD10 mRNA启动子高甲基化是影响EC患者OS的独立危险因素(P<0.05)。HOXD10 mRNA启动子高甲基化预示着EC患者更短的OS(P<0.05)。结论 EC组织中HOXD10mRNA启动子甲基化水平明显升高,这可能是导致HOXD10蛋白低表达的部分原因。且其高甲基化状态与EC患者临床病理特征及生存结局相关,可作为EC恶性程度和预后的潜在生物学标志物。

Objective To investigate the expression and gene methylationof homeobox(HOX)D10 in endometrial carcinoma(EC)tissue,and explore their relationship with clinicopathological characteristics and prognosis.Methods Using the Gene Expression Profile Dynamic Analysis(GEPIA)tool to analyze the differential expression and prognostic information of HOXD10 mRNA in EC tissues and normal tissues in the American Public Cancer Gene Database(TCGA).148 EC patients who received treatment in our hospital from May 2016 to April 2018 were selected,while 30 patients with endometrial hyperplasia during the same period were selected as the benign lesion group.Clinical data and fresh tissue samples of the patients were collected.Real time fluorescence quantitative PCR,methylation quantitative PCR,and immunohistochemistry staining were used to detect HOXD10 mRNA,gene promoter methylation status,and protein expression in tissues.Results In the TCGA dataset,the expression of HOXD10 mRNA in 174 EC tissues was significantly lower than that in 91 normal endometrial tissues(P<0.05),but no correlation was found between HOXD10 mRNA expression and median overall survival(OS)and progression free survival(PFS)in patients(P>0.05).In clinical studies,the expression of HOXD10 mRNA in EC tissues was significantly lower than that in benign lesion tissues(0.229±0.237 vs.1.018±0.265),but the levels of HOXD10 mRNA promoter methylation(0.166±0.237 vs.0.041±0.033)and methylation rate(50.0%vs.10.0%)were significantly higher than those in benign lesion tissues(P<0.05).The positive expression rates of HOXD10 mRNA and protein in cancer tissue samples with hypermethylation of HOXD10 mRNA promoter were significantly reduced(P<0.05).The methylation of HOXD10 mRNA was correlated with the International Federation of Obstetrics and Gynecology(FIGO)staging,histological grading,lymph node metastasis,and degree of muscle invasion(P<0.05).The positive expression rate of HOXD10 protein showed statistically significant differences among EC patients with different FIGO staging and microsatellite instability(P<0.05).Cox proportional hazards model analysis showed that microsatellite instability,muscle infiltration≥1/2 of the muscle layer,and hypermethylation of HOXD10 mRNA promoter were independent risk factors for OS in EC patients(P<0.05).Moreover,HOXD10 mRNA promoter hypermethylation indicated a shorter OS in EC patients(P<0.05).Conclusion HOXD10 mRNA promoter methylation in EC tissues is significantly increased,which may be partially responsible for the low expression of HOXD10 protein.Moreover,its hypermethylation status is related to the clinical pathological characteristics and survival outcomes of EC patients,and can serve as a potential biological marker for the malignancy and prognosis of EC.