前列腺癌组织中DLC-1启动子甲基化定量检测的HRM方法建立及其应用意义

目的 建立HRM技术定量检测DLC-1启动子甲基化的方法 ,并分析探讨DLC-1甲基化程度与前列腺癌病理参数的相关性.方法 选取89份前列腺癌组织以及10份匹配癌旁组织标本,采用LCM收集肿瘤细胞群,抽提DNA后进行甲基化修饰.以CpGenome Universal Methylated DNA作为100%甲基化样本,以100%非甲基化的健康人外周血DNA作为稀释剂,分别制成100%、80%、50%、30%、10%、0%系列浓度的标准曲线,并进行重复性和灵敏性评价.同时用HRM技术定量检测前列腺癌细胞中DLC-1甲基化水平,探讨DLC-1甲基化程度与前列腺癌患者年龄、PSA水平与前列腺癌TNM的关系.结果 100%、80%、50%、30%、10%、0%甲基化标准品的HRM熔解曲线从右往左依次排列,10份癌旁组织标本、35份前列腺癌组织标本重叠在0%标准曲线上;5份前列腺癌组织标本位于0%～30%区域内,29份位于31%～80%区域内,20份位于81%～100%区域内.HRM技术最低检测限可达10%的甲基化水平,优于MSP检测(30%甲基化水平).DLC-1甲基化水平与前列腺癌患者年龄无明显相关(X~2=3.29,P=0.19),与PSA水平也无相关性(X~2=2.04,P=0.36),但DLC-1甲基化水平与TNM分期显著相关(X~2=9.04,P=0.01),且随TNM分期增高而增高.结论 成功建立的HRM技术定量检测DLC-1甲基化水平的方法 稳定、灵敏、操作简单,DLC-1启动子甲基化有望成为评估前列腺癌TNM的分子指标.

Establishment of HRM method for quantitative determination for methylation level of DLC-1 promoter in prostate cancer and its clinical significance

Objective To establish quantitative method for detection of methylation level of DLC-1 promoter with HRM technology to analyze its association with pathological parameters in prostate cancer.Methods 89 prostate cancer tissue samples and 10 matched normal tissue samples were enrolled into this study.Prostate cancer cells were obtained by LCM.DNA was extracted and modified for methylation determination.CpGenome Universal Methylated DNA was chosen as 100% methylation sample.Then the calibrators representative of 100%,80%,50%,30%,10% and 0% methylation levels were prepared with dilution in a DNA sample of peripheral blood from healthy subjects(100% non-methylation).The DLC-1 methylation levels in prostate cancer tissue samples were detected with HRM.The associations of methylated level with age of patients,PSA value,TNM stage were investigated respectively.ResultsThe melting curves representing 100%,80%,50%,30%,10% and 0% methylation levels were aligned from right to left.The methylation levels of 10 adjacent normal samples and 35 prostate cancer samples were overlapped with 0% methylated calibrator.The methylation levels of 5 cancer samples ranged between 0% and 30%.The methylation levels of 29 cancer samples ranged between 31% and 80%.The methylation levels of 20 cancer samples ranged between 81% and 100%.HRM could be used to reliably detect the as low as 10% methylation for each assay,whereas methylation specific PCR(MSP) could be used to detect 30% methylation level.No significant association between methylation level and patients' age(X~2=3.29,P=0.19),PSA level(X~2=2.04,P=0.36) was found.However,DLC-1 methylation was higher in the prostate cancer tissues with advanced TNM stage(X~2=9.04,P=.01).Conclusions The quantitative method for DLC-1 methylation with HRM is successfully established.It is convenient with good reproducibility and high sensitivity.DLC-1 methylation could be used as the molecular marker for estimation of malignancy in prostate cancer.