PITX2启动子甲基化及其与膀胱癌临床病理的关系

Methylation of PITX2 promoter and relationship with clinical pathology of bladder cancer

目的:由于近些年表观遗传学的发展,基因启动子甲基化检测在预测癌症诊断预后方面拥有巨大的潜力。PITX2启动子的高CpG岛增加其甲基化程度,其能够成为新的膀胱癌预测因子。方法:QRT-PCR检测永生化膀胱上皮细胞系(SV-HUC)和3种膀胱癌细胞系(EJ、5637、T24)以及癌组织和癌旁组织的差异性表达。通过DNA甲基化测定实验对33例全膀胱切除术切除癌组织进行甲基化程度测定,分为大于50%甲基化,小于50%甲基化建立甲基化程度与肿瘤分期分级的联系。结果:使用实时定量RT-PCR(Q-PCR)证明PITX2在膀胱癌细胞中高表达。癌组织中甲基化程度明显高于癌旁组织。PITX2启动子甲基化与肿瘤大小(P=0.0267)、高级别(P=0.0277)和TNM分期(0.0160)显着相关。在预测肿瘤侵袭(T2-T4肿瘤)中,PITX2启动子甲基化的ROC曲线下面积(AUC)为0.867。Kaplan-Meier生存分析表明,与低PITX2甲基化表达的肿瘤相比,高PITX2启动子甲基化表达的肿瘤与较短的总体存活相关。结论:PITX2在膀胱癌组织中异常高表达,并且PITX2启动子区域在癌组织中存在高甲基化是患者不良预后的独立危险因素,因此,PITX2启动子甲基化可能成为膀胱癌肿瘤发生进展有效的预测因子。

Objective:Due to the development of epigenetics in recent years,gene promoter methylation detection has great potential in predicting the prognosis of cancer.The high CpG island of the PITX2 promoter increases its rate of methylation,which can be a new predictor of bladder cancer.Methods:QRT-PCR was used to detect differential expression of immortalized bladder epithelial cell line(SV-HUC)and three bladder cancer cell lines(EJ,5637,T24)as well as cancerous and paracancerous tissues.The methylation rates of 33 cases of total cystectomy was determined by DNA methylation assay,which was divided into more than 50%methylation,less than 50%methylation to establish the degree of methylation and tumor staging.Results:Real-time quantitative RT-PCR(Q-PCR)was used to demonstrate hypermethylation of the PITX2 promoter in bladder cancer cells.The degree of methylation in bladder cancer tissues is significantly higher than that in adjacent tissues.PITX2 promoter methylation was significantly associated with tumor size(P=0.0267),high grade(P=0.0277),and TNM stage(0.0160).In the prediction of tumor invasion(T2-T4 tumor),the area under the ROC curve(AUC)of the PITX2 promoter methylation was 0.867.Kaplan-Meier survival analysis indicated that tumors with high PITX2 promoter methylation expression were associated with shorter overall survival compared to tumors with low PITX2 methylation expression.Conclusion:Our results suggest that hypermethylation of the PITX2 promoter region is highly expressed in bladder cancer tissues,and high expression is an independent risk factor for poor prognosis in patients.Therefore,PITX2 promoter methylation may be a treatment for high-grade bladder.An effective predictor of cancerous tumors.