膀胱癌和肾癌组织中RASSF1A基因的甲基化改变

目的研究RASSF1A基因启动子的甲基化状态及在膀胱癌和肾癌发生中的作用。方法采用甲基化特异性PCR(MSP)技术检测45例手术切除的膀胱癌组织和相应癌旁正常组织标本、9例电切膀胱癌组织、3例非肿瘤患者正常膀胱组织、12例肾癌组织和相应癌旁正常组织标本中RASSF1A基因的甲基化情况。结果膀胱癌组织中RASSF1A基因异常甲基化55.6%(30/54),其中手术切除组57.8%(26/45),电切癌组织异常甲基化4例,癌旁正常组织基因异常甲基化1例;肾癌组织中基因异常甲基化66.7%(8/12),相应癌旁正常组织中未发现基因甲基化。3例正常膀胱组织标本中未发现基因异常甲基化。膀胱癌组织中RASSF1A基因甲基化率有随组织分期升高的趋势,但与临床病理参数间无明显相关性。结论膀胱癌和肾癌组织中RASSF1A基因启动子高度甲基化,表明该基因甲基化可能与2种肿瘤的发生相关。     

RASSF1A在胃癌中的表达及其甲基化状态的研究

目的：研究胃癌组织中RASSF1A基因启动子区甲基化及其蛋白表达情况,分析两者之间的关系及其在胃癌发生发展中的作用。方法：应用免疫组化SP法检测39例胃癌组织,39例相应癌旁组织及30例对照组织中RASSF1A蛋白表达,应用甲基化特异性PCR法检测上述组织RASSF1A启动子CpG岛甲基化状态。结果：1）胃癌组RASSF1A蛋白表达阳性率53.8%明显低于癌旁组97.4%及正常对照组100%（P〈0.05）;2）胃癌组织中RASSF1A基因启动子区甲基化率为64.1%,显著高于癌旁组织甲基化率7.7%及对照组0%（P〈0.05）;3）在胃癌组织中,甲基化组RASSF1A蛋白表达明显低于非甲基化组（P〈0.05）。结论：胃癌组织RASSF1A蛋白表达缺失或低下,与其启动子甲基化程度增高显著相关,RASSF1A启动子甲基化在胃癌发生、发展中起一定作用。     

食管鳞癌RASSF1A基因启动子区甲基化研究

目的 研究肿瘤抑制基因RASSF1A启动子区甲基化所致该基因表达抑制在我国食管鳞癌发生中的作用及可能机制. 方法 用甲基化特异PCR技术(MSP)检测43例原发性食管鳞癌标本及6例对照食管上皮组织标本、食管鳞癌细胞系TE11和TE12中RASSF1A启动子甲基化状态;逆转录(RT)-PCR法检测5-氮-2′-脱氧胞苷(5-Aza-CdR)处理前后食管鳞癌细胞系中RASSF1A mRNA表达水平;Western blot方法检测食管鳞癌细胞系中细胞微管蛋白的表达. 结果 20.9%(9/43)原发性食管鳞癌标本有RASSF1A启动子超甲基化,正常食管上皮组织未发现该基因超甲基化改变.RASSF1A基因甲基化与食管癌患者的性别和TNM分期无关(P＞0.05),但在不同年龄组间的差异有统计学意义(P＜0.05).TE12细胞RASSF1A启动子发生甲基化,RT-PCR检测不到RASSF1A mRNA.TE11细胞系启动子未发生甲基化,RT-PCR检测其有RASSF1A mRNA表达.5-Aza-CdR处理可使TE12重新表达RASSF1A mRNA.TE12细胞的β-微管蛋白水平比TE11细胞低87.8%. 结论 原发性食管鳞癌存在RASSF1A启动子超甲基化,该基因甲基化与年龄相关.RASSF1A在食管鳞癌细胞系表达抑制与其甲基化状态有关.RASSF1A表达缺失可能导致β-微管蛋白减少.     

肝细胞癌患者血浆FHIT、SLIT2基因启动子甲基化的检测及意义

目的 探讨肝细胞癌(hepatocellular carcinoma,HCC)患者外周血浆中FHIT和SLIT2基因启动子甲基化状态及其临床意义.方法 应用甲基化特异性PCR(MSP)检测36例HCC患者血浆及10例健康对照者血浆中FHIT和SLIT2的基因启动子甲基化状态,并分析其与临床参数的关系.结果 36例 HCC患者外周血浆中FHIT和SLIT2的基因启动子甲基化率分别为50.0%(18/36)和27.8%(10/36);10例健康对照者血浆中均未检出基因甲基化改变.外周血浆中FHIT和SLIT2基因甲基化发生率与性别、年龄、HBV感染、肝硬化、肿瘤大小、甲胎蛋白(AFP)水平、肿瘤病理分级及临床分期、有无癌栓及是否为复发病例之间无统计学相关性.联合AFP和血浆中FHIT和SLIT2基因甲基化检测诊断HCC敏感性达86.1%,高于单独应用AFP检测的诊断敏感性(61.1%)(P＜0.05,χ2=5.79).结论 HCC患者外周血浆中可检测到FHIT、SLIT2基因甲基化改变,与临床参数无相关性.联合AFP及血浆DNA甲基化检测可提高HCC的诊断敏感性.     

膀胱移行细胞癌患者RASSF1A蛋白表达和启动子区甲基化的研究

目的:探讨RASSFlA(RAS association domain family1A)蛋白表达水平与启动子甲基化的关系.方法:应用免疫印迹技术(western-blot)检测10例正常膀胱组织和23例膀胱移行细胞癌(Badder transitional cell carcinoma,BTCC)组织中RASSFlA蛋白表达水平;用甲基化特异性PCR(Methylation-Specific PCR,MSP)方法检测正常膀胱组织,BTCC组织中RASSF1A基因启动子CPG岛甲基化状态.结果:RASSF1A蛋白在正常膀胱组织中全部表达,在BTCC组织中表达率为30.4%(7/23),二组间表达差异有统计学意义(P＜0.05),但各肿瘤分期、病理分级间的表达差异无统计学意义(P＞0.05).在正常膀胱组织中,RASSF1A基因启动子未发生甲基化;在BTCC组织中,RASSF1A基因启动子甲基化频率为60.9%(14/23),二组间表达差异有统计学意义(P＜0.05).在14份启动子异常甲基化的BTCC标本中,13份同时伴有RASSFIA蛋白表达缺失或下调,两者存在明显相关性(P＜0.05).结论:RASSFlA基因启动子在BTCC组织中发生异常甲基化,使RASSF1A蛋白表达缺失,推测RASSFIA基因启动子CPG岛异常甲基化导致RASSF1A基因失活从而引起肿瘤的发生,而与肿瘤的进展可能无关.     

RASSF1A基因在膀胱癌组织中的转录表达及其启动子甲基化状态的研究

Ras相关区域家族1A(RASSF1A)是2000年从3号染色体短臂(3p21.3)上克隆出来的新型候选抑癌基因[1].我们采用半定量逆转录-聚合酶链反应(RTPCR)和甲基化特异性PCR(MSP)检测正常膀胱组织及膀胱癌组织中RASSF1 A基因的表达及其启动子甲基化的状态,探讨RASSF1A基因与膀胱癌生物学行为间的关系.     

pSi2.1-G9a-siRNA 诱导人胆管癌细胞RASSF1A 基因脱甲基化

目的 分析组蛋白甲基转移酶Gga特异性siRNA真核表达质粒pSi2.1-G9a-siRNA对人胆管癌细胞株QBC939中RASSF1A基因启动子甲基化及其表达的影响,探讨组蛋白甲基化和DNA甲基化的关系.方法 构建pSi2.1-G9a-siRNA真核表达质粒并转染QBC939细胞,甲基化特异性PCR(MS-PCR)检测RASSF1A启动子甲基化状态的改变,逆转录-聚合酶链反应(RT-PCR)观察RASSF1A mRNA水平变化,Western blot检测RASSF1A蛋白表达.结果 转染pSi2.1-G9a-siRNA后,QBC939细胞中RASSF1A启动子由甲基化状态转变为非甲基化状态;RT-PCR和Western blot结果 显示转染组细胞中分别出现RASSF1A基因的DNA条带(280 bp)和蛋白质条带(40×103),而转染前没有相应条带出现.结论 pSi2.1-G9a-siRNA质粒能够诱导QBC939中RASSF1A启动子去甲基化并恢复表达,提示DNA甲基化在一定程度上受组蛋白甲基化的调控.     

肝细胞癌组织中Ras相关区域家族蛋白1A、肿瘤高甲基化基因1和p73基因的异常甲基化

目的探讨肝细胞癌中RAS相关区域家族蛋白1A(RASSF1A)、肿瘤高甲基化基因1(H IC1)和P73基因启动子异常甲基化状况及其与患者临床和病理因素之间的关系。方法收集肝细胞癌组织标本和对应的远癌组织标本各40例及2例健康人的肝组织标本;通过甲基化特异的聚合酶链反应方法检测这些标本中RASSF1A、H IC1和P73基因启动子区的甲基化状况。结果RASSF1A基因在癌和远癌组织中启动子区的甲基化率分别为90.0%和72.5%,癌组织中的甲基化率高于远癌组织(P<0.05)。H IC1基因在癌和远癌组织中的甲基化率分别为77.5%和70.0%。P73基因在癌组织中甲基化率为5.0%,在远癌组织没有发现甲基化。健康人肝组织中未发现任何上述基因的异常甲基化。远癌组织中H IC1基因甲基化患者的年龄[(48±14)岁]比无甲基化患者[(57±11)岁]小(T=2.049,P=0.047)。3个基因甲基化发生情况与患者性别、是否合并乙型肝炎、肝硬化、甲胎蛋白水平、肿瘤大小、有无包膜和门静脉癌栓以及TNM分期之间未发现有统计学相关性。结论肝细胞癌中RASSF1A和H IC1基因启动子的高甲基化是普遍现象,年轻肝细胞癌患者H IC1甲基化现象更常见。     

散发性肝外胆管癌中RASSF1A基因启动子甲基化状态的研究

目的　检测肝外胆管癌组织中RASSF1A基因启动子甲基化及各CpG位点甲基化发生率。方法　采用甲基化特异性聚合酶链反应 (MS PCR)和半巢式PCR对RASSF1A基因启动子区域进行扩增 ,并对扩增产物克隆测序。结果　在全部 48例肝外胆管癌组织中 ,RASSF1A基因启动子区域存在CpG位点甲基化现象的共 2 8例 ,16个CpG位点甲基化平均发生率为 42 .45 % ,明显高于对照组 (χ2 =11.77,P <0 .0 1)。结论　RASSF1A基因启动子区域CpG岛甲基化是RASSF1A失活的主要机制 ,在肝外胆管癌的发生过程中发挥重要作用。     

肝癌抑癌基因GSTP1、p16、RIZ1、RASSF1A异常甲基化检测及其临床意义

目的 研究肝细胞癌中的GSTP1、p16、RIZ1、RASSF1A 4种基因启动子区域甲基化状态的表达差异,并探讨其在肝癌发生中的作用.方法运用甲基化特异性聚合酶链反应（methylation-specific PCR,MSP）技术,分别检测35例肝癌组织及其相应的癌旁组织和20例正常对照肝组织中4种候选抑癌基因（GSTP1、p16、RIZ1、RASSF1A）启动子区域的甲基化表达情况,并结合临床病理资料进行分析.结果在肝细胞癌、癌旁及正常对照肝组织中检测到GSTP1基因启动子区的甲基化率分别是57.1 （20/35）,25.7％（9/35）,0％ （0/20）;p16基因启动子区甲基化率分别是54.3％ （19/35）,37.1％ （13/35）,0％ （0/20）; RIZ1基因启动子区甲基化率分别是68.6％ （24/35）,14.3％ （5/35）,0％ （0/20）;RASSF1A基因启动子区甲基化率分别是88.6％ （31/35）,74.3％（26/35）,10％ （2/20）,其中癌组织中GSTP1和RIZ1基因甲基化率均显著高于相应的癌旁组（P＜0.01）和正常对照肝组织（P＜0.01）,癌组织中p16、RASSF1A启动子区甲基化率高于癌旁组织,但二者无统计学意义（P＞0.05）,但明显高于正常对照肝组织（P＜ 0.01）.在肝癌组织中肿瘤有包膜侵犯者GSTP1基因甲基化阳性率明显高于无包膜侵犯者（P＜0.05）;乙肝表面抗原（HbsAg）阳性的肝癌患者p16基因甲基化阳性的比率要显著高于HbsAg阴性者（P＜0.05）;而RIZ1、RASSF1A与临床病理资料间均没有统计学意义（P＞ 0.05）.结论RIZ1、GSTP1基因甲基化状态具有肝癌特异性,或可作为临床肝癌辅助诊断的分子标记物.慢性HBV感染可能是导致p16甲基化而失活的原因,GSTP1基因启动子甲基化可能与肝细胞癌的侵袭性有关.     

Increase sensitivity in detecting superficial,low grade bladder cancer by combination analysis of hypermethylation of E-cadherin,p16, p14, RASSF1A genes in urine

ObjectivesTo identify a better set of DNA methylation markers to detect superficial, low grade cancer cell in urine sediment for improving cancer treatment, morbidity, and mortality.Materials and MethodsMethylation-specific PCR (MSP) assay was used to detect promoter hypermethylation in 4 genes (E-cadherin, p16, p14, and RASSF1A) to identify reliable biomarkers for bladder cancer diagnosis in primary tumor DNA and urine sediment DNA from 57 bladder cancer patients. Urine DNA was compared with 20 healthy controls.ResultsFifty-one (90%) tumor DNA and 47 urine DNA (83%) samples from bladder cancer patients revealed hypermethylation in at least 1 of the 4 analyzed genes, whereas all urine samples from normal controls were negative. The sensitivity of MSP assay for detecting E-cadherin, p16, p14 and RASSF1A in tumor cells in voided urine was 35%, 35%, 33%, and 65%, respectively. Diagnostic sensitivity was 75% for combining RASSF1A and p14, and 83% for RASSF1A, p14 and E-cadherin. Urine cytology, however, detect only 13 (28%) cases of cancer or suspicious cancer. For detecting superficial and invasive bladder tumor, urine cytology revealed a sensitivity of 23% (6/26) and 35% (7/20), respectively. In contrast, MSP detected hypermethylation in the urine of 80% (37/46) bladder cancer patients. Moreover, hypermethylation analysis of E-cadherin, p14 or RASSF1A genes in urine sediment DNA detected in 85% (22/26) of superficial, 85% (11/13) of low grade, 75% (15/20) of invasive and 79% (26/33) of high grade bladder cancers. Importantly, hypermethylation was detected in the urine DNA of 90% (18/20) superficial tumors with negative or atypia cytology.ConclusionsHypermethylation of E-cadherin, p14 or RASSF1A in urine sediment DNA is a potential biomarker for detecting superficial, low grade cancer. Besides, hypermethylation of these 3 genes is a valuable adjunct diagnostic marker to urine cytology, which can enhance the diagnostic accuracy and follow-up treatment of bladder cancer patients.     

肝细胞肝癌中外周血浆DNA基因甲基化检测及意义

目的评估外周血浆DNA甲基化检测在肝细胞肝癌(HCC)诊断中的作用,筛选血浆灵敏度及特异性高的甲基化抑癌基因。方法采用甲基化特异性PCR(MSP)检测34例经病理检查证实的HCC患者血浆及其配对癌组织中的SLIT2及DAPK基因启动子甲基化状态,并分析其与HCC临床病理特征的关系。结果 34例HCC患者癌组织中SLIT2和DAPK基因甲基化率分别为70.6%(24/34)和79.4%(27/34),相应外周血浆中SLIT2和DAPK基因甲基化率分别为44.1%(15/34)和50.0%(17/34)。血浆SLIT2和DAPK基因甲基化检测的灵敏度分别为62.5%和63.0%,特异度均为100%,阴性预测值分别为52.6%和41.2%,阳性预测值均为100%。HCC癌组织和外周血浆中SLIT2及DAPK甲基化检出率与HCC各临床病理特征无关(P>0.05)。在AFP<400μg/L患者中SLIT2和DAPK基因甲基化联合检出率达61.1%(11/18)。结论基于MSP方法,血浆中SLIT2及DAPK基因甲基化仍有较高的检出率,HCC癌组织和血浆中SLIT2及DAPK基因甲基化具有明显的一致性。血浆DNA甲基化可作为一种独立非侵入性诊断HCC的标志物,尤其对AFP阴性者可提高HCC的诊断率。HBV感染可能仅与部分抑癌基因甲基化相关。     

前列腺癌组织RASSF2基因甲基化及蛋白表达的检测及意义

目的:通过检测Ras相关序列家族2(RASSF2)基因在前列腺癌及前列腺增生组织中的甲基化及其蛋白表达情况,探讨该基因的表观失活在前列腺癌发生发展中的作用及意义。方法:获取前列腺癌石蜡包埋组织标本30例(实验组),前列腺增生石蜡包埋组织标本30例(对照组),石蜡组织标本切片后获取相应组织基因组DNA,通过甲基化特异性PCR技术(MSP)检测两组组织中RASSF2基因甲基化情况,通过免疫组织化学技术检测两组组织中RASSF2蛋白表达情况。结果:实验组中,RASSF2基因甲基化发生率为66.7%(20/30),RASSF2蛋白表达缺失发生率为70.0%(21/30);对照组中RASSF2基因甲基化发生率为6.7%(2/30),RASSF2蛋白表达缺失发生率为3.3%(1/30)。实验组RASSF2基因甲基化发生率显著高于对照组,差异有统计学意义(P<0.05);实验组RASSF2蛋白表达缺失发生率显著高于对照组,差异亦有统计学意义(P<0.05)。RASSF2基因异常甲基化与其蛋白表达缺失具有显著相关性(P<0.05)。结论:RASSF2基因的表观失活与前列腺癌的发生具有相关性,RASSF2基因的表观失活有望成为前列腺癌的分子诊断及治疗靶点。     

肝细胞癌患者血浆和癌组织中RASSF1A基因甲基化及临床意义

目的探讨肝细胞癌(hepatocellular carcimona,HCC)患者外周血浆和肿瘤组织中RASSF1A基因甲基化及其临床意义。方法应用甲基化特异性PCR(MSP)检测36例HCC患者血浆及其对应癌组织中的RASSF1A基因启动子甲基化状态,并分析其与临床参数的关系。结果癌组织和外周血浆中RASSF1A基因甲基化率分别为83.3%(30/36)和61.1%(22/36),二者相关系数为r=0.561(P=0.0004)。外周血浆和肿瘤组织中RASSF1A基因甲基化率与患者性别、年龄、HBV/HCV感染、肝硬化、肿瘤大小、AFP水平、肿瘤病理分级及临床分期、有无癌栓及是否为复发病例等之间无统计学相关性。以AFP≥400 ug/L为阳性,本组病例AFP阳性率为44.4%;以AFP≥20 ug/L为阳性,本组病例阳性率为69.4%。全部患者中,血浆RASSF1A基因甲基化检出率为61.1%,AFP联合血浆RASSF1A基因甲基化检测HCC的检出率为75%(27/36)。结论 HCC患者血浆和肿瘤组织中RASSF1A基因甲基化率有良好的一致性。血浆DNA甲基化联合AFP检测对HCC早期诊断具有一定意义。癌组织和血浆中基因甲基化改变与各临床参数无相关性。     

散发性结直肠癌患者血RASSF2和sFRP1启动子区甲基化检测

目的检测散发性结直肠癌患者血清RASSF2和sFRP1启动子区甲基化情况．从而为散发性结直肠癌的早期筛查提供参考。方法使用甲基化特异性PCR检测59例散发性直结肠癌患者和59例健康对照血清sFRP1和RASSF2基因启动子区甲基化的情况,并分析其与结直肠癌临床病理特征的关系。结果59例结直肠癌患者中RASSF2和sFRP1甲基化者分别为16例（27．1％）和18例（30．5％）;而59例健康对照无一例发现RASSF2或sFRP1基因甲基化,差异有统计学意义（均P〈0．01）。29例（49．2％）结直肠癌患者有至少1个基因甲基化,其甲基化率明显高于RASSF2和sFRP1单-基因甲基化率（均P〈0．05）。结直肠癌患者血清RASSF2和sFRP1基因甲基化率与结直肠癌临床病理特征均无明显关系（均P〉0．05）。结论血清RASSF2和sFRP1基因启动子区甲基化水平在结直肠癌组织异常升高,联合两基因的血清甲基化检测可为散发性结直肠癌的早期筛查提供参考。     

Interest of methylated genes as biomarkers in urothelial cell carcinomas of the urinary tract

Urothelial cell carcinomas (UCC), including bladder cancer and upper urinary tract cancer, are the second most common malignancy of the urogenital tract after prostate cancer. It is a critical issue to differentiate accurately those patients whose tumour will recur and/or progress after initial treatment from those without recurrence and/or progression because tumours with a similar morphology behave differently. Patients undergo lifelong cystoscopic and cytology surveillance to detect subsequent tumour recurrence. New noninvasive methods for the diagnosis and surveillance of UCCs are required. DNA methylation is an important epigenetic mechanism of gene regulation and plays essential roles in tumour initiation and progression. Currently, aberrant promoter hypermethylation has been investigated in specific genes, i.e. tumour‐suppressor genes, proto‐oncogenes, genes involved in cell adhesion, and genes of cell cycle regulation. E‐cadherin has been shown to be an independent marker of prognosis. Other genes, e.g. APC, RASSF1a, TNFRSF25, EDNRB, and p14, are implicated in tumour progression. IGFBP3 and APAF‐1 are independent markers of recurrence. APAF‐1 is also correlated with tumour stage and grade. In urine, hypermethylation of DAPK, RARβ, E‐cadherin and p16 has been shown to have a good sensitivity and specificity for bladder cancer detection. Several studies found that analysis of hypermethylation using a panel of tumour‐suppressor genes yielded superior results to cytology in the detection of bladder cancer and its progression. Hence, the different panels (e.g. RASSF1a/APC/p14, RAR_/DAPK/E‐cadh/p16, p16/p14/MGMT/GSTP1, and RASSF1a/E‐cadh/APC) are of interest in the detection of bladder cancer. The last panel and RASSF1a/E‐cadh/APC/TNFRSF25/EDNRB are also interesting for tumour progression. There is evidence that the extent of the mutator and methylator phenotypes in UCCs differs with tumour location, perhaps suggesting that carcinogens affect the urinary tract in different ways. For all loci studied except DAPK, there was more frequent methylation in UUT‐UCCs than in the bladder cancers; this difference was statistically significant for hMLH1, RARB, E‐cadherin, p16 and MINT31. In contrast to UUT‐UCCs, hMLH1 and MINT31 were rarely methylated in bladder tumours, suggesting that they play a role in UUT carcinogenesis but not bladder cancer.     

5-Aza-CdR调控胃癌细胞系RASSF1A基因表达及对细胞生长的抑制作用

目的观察去甲基化制剂5-Aza-CdR对体外培养的胃癌细胞SGC7901RASSF1A基因的去甲基化和表达调控及生长抑制作用。方法5-Aza-CdR处理SGC7901细胞后,应用MTT法、流式细胞术、AnnexinV．FITC染色法检测细胞增殖活性、细胞周期分布及细胞凋亡率;应用MSP、RT-PCR及Westem印迹法检测RASSF1A基因的甲基化状态、mRNA及蛋白表达。结果5-Aza-CdR处理后,胃癌细胞SGC7901生长受到抑制（P〈0．05）,细胞周期呈现G1期阻滞,细胞凋亡率显著增加（P〈0．05）。RASSF1A基因在SGC7901中呈异常甲基化状态,在mRNA及蛋白水平表达阴性：5-Aza-CdR处理后RASSF1A基因呈去甲基化状态,在mRNA及蛋白水平重新表达。结论去甲基化制剂5-Aza-CdR调控胃癌细胞SGC7901RASSF1A基因去甲基化及重新表达．对SGC7901细胞具有生长抑制作用。     

Identification and Validation of the Methylated TWIST1 and NID2 Genes through Real-Time Methylation-Specific Polymerase Chain Reaction Assays for the Noninvasive Detection of Primary Bladder Cancer in Urine Samples

Background

Accumulating evidence suggests that DNA methylation markers could serve as sensitive and specific cancer biomarkers.

Objective

To determine whether a panel of methylated genes would have the potential to identify primary bladder cancer (BCa) in voided urine samples.

Design, setting, and participants

A pharmacologic unmasking reexpression analysis in BCa cell lines was initially undertaken to unveil candidate methylated genes, which were then evaluated in methylation-specific polymerase chain reaction (MSP) assays performed on DNA extracted from noncancerous and cancerous bladder tissues. The most frequently methylated genes in cancerous tissues, with 100% specificity, were retained for subsequent MSP analysis in DNA extracted from urine samples to build and validate a panel of potential methylated gene markers. Urine samples were prospectively collected at three urologic centres from patients with histologically proven BCa and processed for use in real-time MSP and cytologic analysis. Patients with nonmalignant urologic disorders were included as controls.

Measurements

A urine sample was classified as valid when ≥10 copies of the gene encoding ß-actin were measured in the urine sediment genomic DNA. Sensitivity, specificity, and predictive values of the MSP and cytology tests were assessed and compared.

Results and limitations

MSP assays performed on 466 of the 496 (94%) valid urine samples identified two genes, TWIST1 and NID2, that were frequently methylated in urine samples collected from BCa patients, including those with early-stage and low-grade disease. The sensitivity of this two-gene panel (90%) was significantly better than that of cytology (48%), with comparable specificity (93% and 96%, respectively). The positive predictive value and negative predictive value of the two-gene panel was 86% and 95%, respectively.

Conclusions

Detection of the methylated TWIST1 and NID2 genes in urine sediments using MSP provides a highly (≥90%) sensitive and specific, noninvasive approach for detecting primary BCa.

Trial registration

BlCa-001 study – EudraCt 2006-003303-40.