胃癌形成过程中p16IN4a、Runx3和O-6-甲基鸟嘌呤-DNA甲基转移酶基因甲基化及其表达研究

目的 研究胃癌形成过程中p16INK4a、Runx3和O-6-甲基鸟嘌呤-DNA甲基转移酶(MGMT)基因启动子区的高甲基化状态,同时检测MGMT的蛋白表达情况.探讨抑癌基因启动子区高甲基化与胃癌发生的关系.方法 选择经透明帽法进行首次黏膜病变切除者43例,其中异型增生27例,早期胃癌16例.选择胃镜活检证实为慢性萎缩性胃炎伴肠上皮化生者14例.另取20例正常胃黏膜活检组织作为对照.采用甲基化特异聚合酶链反应(MSP)检测每例组织中p16INK4a、Runx3和MGMT基因启动子区的甲基化状态,对所有甲基化p16INK4a产物进行测序,免疫组化检测MGMT蛋白表达情况.结果 肠上皮化生、异型增生和早期胃癌中p16INK4a基因甲基化率依次为14.3%(2/14)、22.2%(6/27)和37.5%(6/16);Runx3基因甲基化率依次为14.3%(2/14)、48.1%(13/27)和50.0%(8/16);MGMT基因甲基化率依次为7.1%(1/14)、48.1%(13/27)和50.0%(8/16).20名正常对照均未检出基因甲基化,与异型增生和早期胃癌相比差异有统计学意义(P＜0.05).Runx3和MGMT两种基因在异型增生和早期胃癌中的甲基化率显著高于肠上皮化生组(P＜0.05).各组病变中三种基因甲基化联合分析发现,异型增生和早期胃癌中甲基化的基因种类高于肠上皮化生组.差异有统计学意义(P＜0.01).基因甲基化与息者年龄、性别、幽门螺杆菌感染以及病变部位无相关性,但p16INK4a和MGMT基因甲基化与血清癌胚抗原水平升高显著相关(P值分别为0.003和0.039).MGMT基因启动子区高甲基化与其蛋白失表达密切相关(χ2=12.821,P=0.001).结论 抑癌基因启动子区高甲基化是基因失活的主要机制,可能是胃癌发生的早期分子事件.p16INK4a、Runx3和MGMT基因启动子区高甲基化在胃癌形成过程中起着重要的作用.     

胃癌患者p16基因启动子甲基化检测及其临床意义

目的 探讨p16基因启动子CpG岛甲基化在胃癌发生、发展中的作用.方法 应用特异性甲基化PCR(MSP)检测58例胃癌及癌旁组织和30例正常胃黏膜组织中p16基因启动子CpG岛的甲基化状态,分析其与胃癌临床病理参数的关系.结果26例(44.8％)胃癌组织、5例(8.6％)癌旁组织也检测出甲基化的存在,30例正常胃黏膜组织标本中均未检测出p16基因甲基化的存在(P ＜0.05);p16基因甲基化与胃癌淋巴结转密切相关(P＜0.05).结论 p16基因启动子CpG岛甲基化可促进胃癌的发生、发展;此基因的异常甲基化可作为胃癌早期诊断的敏感指标.     

原发胃癌中p16基因及其甲基化状态、表达异常的研究

目的：检测胃癌组织中p16基因及启动了甲基化状态和p16蛋白表达情况。方法：选择p16基因及启动子区域,用PCR－SSCP、MSP（甲基化特异的PCR）法、测序和免疫组化等方法对100例胃癌患者的癌组织和癌旁组织进行检测。结果：71％的病例p16表达阴性,54％的病例具有p16基因启动子区的高甲基化,50％的病例同时有p16表达阴性和p16基因启动子区的高甲基化,无突变和纯合缺失检出。结论：提示p16基因启动子区域高甲基化是胃癌中p16基因失活的主要原因。     

p16基因高甲基化在胃癌发展中的作用

目的:通过检测胃癌、癌前病变和正常对照组中p16基因启动子区CpG岛甲基化水平及其表达,并结合临床病理资料,分析他们在胃癌发生、发展中的作用.方法:用甲基化特异性聚合酶链反应(methylation-specific PCR,MSP)检测41例胃癌组织、40例癌前病变组织和38例正常对照组织中p16基因启动子5′CpG岛甲基化;应用免疫组化检测基因的蛋白表达.结果:胃癌组织中p16基因甲基化阳性率为56.1%(23/41),癌前病变组织中为17.5%(7/40),而正常对照组织中为2.6%(1/38),前组与后两组之间的差异有显著性(P<0.05).胃癌组织中p16基因表达阳性率为51.2%,癌前病变组织中为90.0%,正常对照组织中为100.0%,前组与后两组之间的差异有显著性(P<0.05).低分化型胃癌组织中的p16基因甲基化阳性率明显高于高分化型(81.3%vs 40.0%,P<0.05).有淋巴结转移的胃癌组织中,p16基因甲基化阳性率与无转移组的差异有显著性(81.0%vs 30.0%,P<0.05).浸润深达浆膜层的胃癌组织中,甲基化阳性率与未达浆膜层组无统计学差异(60.0%vs 52.4%,P>0.05).胃癌组织中p16基因甲基化阳性组的蛋白表达阳性率显著低于甲基化阴性组(26.1%vs 83.3%,P<0.01).结论:胃癌组织中存在有p16基因启动子5′CpG岛高甲基化,并导致其基因表达率显著低于正常对照及癌前病变组织.p16基因的高甲基化与胃癌分化程度、淋巴结转移相关.p16基因甲基化的发生,从正常、癌前病变到胃癌有逐渐增加的趋势,提示其基因CpG岛高甲基化有可能作为诊断早期胃癌的一项较为敏感的指标.     

5-氮杂-2′-脱氧胞苷对肺癌SPC-A-1细胞p16、MGMT基因甲基化及其表达的影响

目的观察5-氮杂-2′-脱氧胞苷（5-Aza-CdR）对体外培养的肺癌SPC-A-1细胞p16、MGMT基因启动子区DNA甲基化状态及其表达的影响,探讨肺癌细胞p16、MGMT基因失活的机制及去甲基化制剂对p16、MGMT基因表达的调控。方法 5-Aza-CdR处理体外培养的肺癌SPC-A-1细胞,甲基化特异性PCR（MSP）法检测用药前后细胞p16、MGMT基因的甲基化状态,RT-PCR法检测用药前后细胞p16、MGMT mRNA。结果加入5-Aza-CdR前,SPC-A-1细胞p16、MGMTmRNA表达缺失,其启动子区域表现为DNA甲基化。加入5-Aza-CdR后,SPC-A-1细胞中p16、MGMT基因呈现DNA去甲基化,而且表达缺失的p16、MGMT mRNA重新表达。结论启动子区高甲基化是肺癌细胞p16、MGMT基因失活的主要原因之一,去甲基化制剂5-Aza-CdR能逆转p16、MGMT基因甲基化状态,从而调控p16、MGMT基因表达。     

胃癌组织中MGMT基因甲基化与DNMT1蛋白表达的关系

背景:研究表明MGMT基因启动子区甲基化与包括胃癌在内的多种恶性肿瘤密切相关。DNA甲基转移酶1(DNMT1)在多种肿瘤组织中的表达上调。但目前关于胃癌组织中MGMT基因甲基化状态与DNMT1表达关系的研究少见。目的:探讨MGMT基因甲基化、DNMT1蛋白表达与胃癌的关系。方法:采用甲基化特异性PCR(MSP)技术检测60例胃腺癌组织及其相应癌旁组织中MGMT基因启动子区甲基化状态,RT-PCR、免疫组化法分别检测MGMT、DNMT1 mRNA和蛋白表达。结果:胃癌组织中MGMT基因启动子区甲基化率明显高于癌旁组织(45.0%对13.3%,P0.001)。胃癌组织中MGMT mRNA阳性表达率显著低于癌旁组织(41.7%对93.3%,P0.001),而DNMT1 mRNA阳性率明显升高(76.7%对18.3%,P0.001)。MGMT mRNA阴性表达的胃癌组织中其基因启动子甲基化率较阳性表达者升高(57.1%对28.0%,P0.05)。胃癌组织中MGMT蛋白表达与DNMT1蛋白表达呈负相关(r=-0.795,P0.01)。结论:MGMT基因启动子区高甲基化和DNMT1高表达可能与胃癌的发生、发展有关。DNMT1可能调控MGMT基因的甲基化过程。     

MGMT基因甲基化水平与恶性胶质瘤细胞对烷化剂耐药性的相关性

目的探讨DNA修复蛋白6-O-甲基鸟嘌呤-DNA甲基转移酶(MGMT)基因甲基化状态与恶性胶质瘤细胞对烷化剂抗肿瘤药物耐药性的相关性。方法选择36例经手术后病理学检查确诊的恶性胶质瘤患者作为研究组,选取同期脑卒中患者10例作为对照组,比较两组患者术前、术后脑组织中的MGMT蛋白表达水平、MGMT甲基化状态差异,并分析MGMT甲基化与治疗效果的关系。结果研究组的MGMT蛋白表达阳性率显著高于对照组,去甲基化水平显著高于对照组(P<0.05)。有效组16例患者,无效组20例患者,有效组MGMT蛋白表达阳性率显著低于无效组,甲基化水平显著高于无效组(P<0.05)。Ⅲ级患者17例,Ⅳ级19例,两种不同病理分级患者的MGMT蛋白、MGMT启动子基因表达率上无差异(P>0.05)。MGMT蛋白表达阳性的20例患者中仅有3例甲基化表达(15%),MGMT蛋白表达阴性的16例患者中有14例甲基化表达(87.5%),MGMT蛋白表达与MGMT启动子基因甲基化状态具有关联性(χ2=18.747,P=0.000)。结论 MGMT蛋白表达与MGMT启动子基因甲基化状态呈负相关性,MGMT基因去甲基化状态会增加恶性胶质瘤细胞的耐药性。     

胃癌p16基因启动子异常甲基化的临床意义

目的 观察胃癌组织中p16基因启动子区异常甲基化状态,并探讨其甲基化改变与临床特征的关系.方法 采用甲基化特异的聚合酶链反应检测胃癌组织及相应癌旁正常组织中p16基因启动子区甲基化状态.结果 胃癌组织p16基因的异常甲基化率显著高于相应的癌旁正常组织(P＜0.01).胃癌组织中该基因的异常甲基化与患者年龄、性别、肿瘤大小、病理分期、组织分化程度、肿瘤浸润深度及淋巴结转移等临床特征无显著相关性.结论 p16基因启动子区的异常甲基化是胃癌发生发展中的频繁事件,在胃癌的发生中具有肿瘤特异性.     

p16基因启动子区甲基化在人嗜铬细胞瘤和副神经节瘤中的变化

目的 检测嗜铬细胞瘤(PHEO)和副神经节瘤(PGL)中p16基因突变和启动子区DNA甲基化改变,分析其与患者临床特征之间的关系.方法收集34例(PHEO 20例、PGL14例)组织标本及患者临床资料,通过甲基化特异性PCR(MSP)测定p16基因启动子区甲基化状态,DNA测序检测基因序列以及RT-PCR方法测定其mRNA表达.结果 (1)34例肿瘤组织中未发现p16基因纯合缺失及点突变;(2)35.3%(12/34)的患者存在p16基因高甲基化,p16基因甲基化阳性标本中,PHEO和PGL分别占25%和75%,两者差异有统计学意义(P=0.005);p16基因甲基化在恶性、单发肿瘤、发病年龄早的亚组中有增高趋势(P＞0.05);(3)甲基化与非甲基化肿瘤组织之间p16 mRNA表达无统计学差异;不同特点的肿瘤中其mRNA表达亦无统计学差异,但恶性肿瘤p16 mRNA表达与良性肿瘤相比有下降的趋势(0.83±0.65对1.12±0.81,P=0.278).结论人PHEO和PGL中,p16基因纯合缺失和突变并不常见,但p16基因启动子区甲基化是其失活的主要形式.     

错配修复基因hMLH1甲基化与胃癌的关系

目的:通过研究散发性胃癌中错配修复基因hMLH1 mRNA的表达及其启动子区5'CpG岛甲基化状态,探讨hMLH1基因异常甲基化在胃癌发生过程中的作用.方法:应用甲基化特异性PCR(methylation specific PCR,MSP)检测60例胃癌组织及其癌旁黏膜组织中hMLH1基因启动子区的甲基化状态,逆转录PCR(RT-PCR)检测两种组织中hMLH1 mRNA表达情况.结果:胃癌组织hMLH1 mRNA表达水平明显低于癌旁组织(t=4.082,P<0.01),hMLH1基因启动子区高甲基化18例(30%),其癌旁黏膜组织中未发现有甲基化.hMLH1基因启动子区甲基化与胃癌的临床病理参数之间无明显的相关性.hMLH1 mRNA表达阴性的21例病例中,17例(81%)发生甲基化,而hMLH1 mRNA表达阳性的39例中仅有1例(2.5%)发生甲基化,hMLH1 mRNA表达降低与甲基化之间存在明显的相关性(χ2=8.0182,P=0.0046).结论:胃癌组织中hMLH1基因启动子区甲基化与其mRNA表达缺失密切相关,是导致hMLH1基因错配修复功能缺陷的重要原因之一.     

Comethylation of p16 and MGMT genes in colorectal carcinoma： Correlation with clinicopathological features and prognostic value

AIM: To investigate the significance of p16 and O6- methylguanine-DNA methyltransferase (MGMT) genes promoter hypermethylation and K-ras mutations on colorectal tumorigenesis and progression. METHODS: p16 and MGMT methylation status was examined on 47 tumor samples, and K-ras mutational status was examined on 85 tumor samples. For methylation analysis, a methylation specific PCR (MS-PCR) method was used. RESULTS: p16 and MGMT promoter methylation was found in 51% (24/47) and 43% (20/47) of CRCs, respectively, and the K-ras mutation was found in 44% (37/85) of CRCs. Comethylation of p16 and MGMT genes was significantly associated with lower aggressiveness of the disease within a two-year period of observation. Only 27% of patients with simultaneous p 16 and MGMT methylation showed the detectible occurrence of metastasis and/or death, compared to 67% of patients without double methylation or with no methylation (3/11 vs 22/33, P < 0.05, χ2-test). In addition, p16 and MGMT comethylation showed a trend toward an association with longer survival in patients with CRCs (35.5 ± 6.0 mo vs 23.1 ± 3.2 mo, P = 0.072, Log-rank test). Progression of the disease within a two-year period was observed in 66% of patients carrying the K-ras mutation, compared to only 19% of patients with wild type K-ras (29/44 vs 7/37, P < 0.001, χ2-test). The presence of the K-ras mutation significantly correlated to shortened overall survival (20.0 ± 1.9 mo vs 37.0 ± 1.8 mo, P < 0.001, Log-rank test). The comethylation of p16 and MGMT genes was significantly associated with lower aggressiveness of the disease even when K-ras mutations were included in the analysis as an independent variable. CONCLUSION: Our data suggest that comethylation of promoters of p 16 and MGMT genes could have a prognostic value in patients with CRC. Specifically, concurrent methylation of both genes correlates with better prognosis.     

An inverse correlation between Interleukin-6 and select gene promoter methylation in patients with gastric cancer

BACKGROUND: Both serum IL-6 levels and CpG island methylation have been shown to have prognostic significance in gastric cancer, it was suggested that an important link existed between IL-6 and methylation of cancers. AIM: To investigate the prognostic value of IL-6 serum level and the association between serum IL-6 levels and CpG island methylation at p16, DAPK, MGMT and E-cadherin in patients with gastric cancer. PATIENTS AND METHODS: Methylation status was assessed by MSP in 75 surgical specimens of gastric adenocarcinoma. IL-6 serum levels were measured by chemiluminescent enzyme immunoassay (CLEIA). RESULTS: Methylation of p16, DAPK, MGMT, and E-cadherin were present in 53, 48, 32, and 59% of patients. Patients with tumors methylated at p16 and DAPK had lower serum levels of IL-6 compared to unmethylated tumors (1.8 vs. 4.8 pg/ml, p = 0.01 for p16; 1.5 vs. 6.2 pg/ml, p = 0.0001 for DAPK). But there was no difference with MGMT and E-cadherin methylation status. Serum IL-6 levels were also associated with TNM stage (p = 0.001), depth of tumor invasion (p = 0.002), lymphatic invasion (p = 0.01), vascular invasion (p = 0.008), metastasis (p = 0.002) and signet cell histology (p = 0.001). Conclusion: IL-6 is of prognostic value for patients of gastric cancer. Low serum IL-6 levels were associated with p16 or DAPK gene methylation in patients with gastric cancer.     

p16 promoter hypermethylation： A useful serum marker for early detection of gastric cancer

AIM： TO determine p15 promoter hypermethylation in gastric tumoral tissue and serum samples, its impact on p16-protein expression, and correlation with clinical and histological features. METHODS： Samples were obtained from 52 histologically confirmed cases of gastric adenocarcinoma. Gastric tissue and serum of 50 age- and sex-matched individuals with normal gastroscopy and biopsy were obtained as control samples. Methylation-specific polymerase chain reaction （MSP） was used to evaluate methylation status of p16 promoter, p16-protein expression was analyzed by immunohistochemical staining on paraffin-embedded sections. RESULTS： Methylation was detected in 44.2% （23/52） of tumoral tissues. 60.9% of them were also methylated in serum, i.e., 26.9% of all patients （14/52）. Methylation was not detected in tissue and sera of control samples. p16-protein expression was decreased in 61.5% of cases （32/52）, and was significantly associated with promoter hypermethylation （P 〈 0.001）. Methylation was significantly more frequent in higher pathological grades （P 〈 0.05）. Methylation was not associated with other clinicopathological features and environmental factors including Hpylori infection and smoking. CONCLUSION： p16 promoter hypermethylation is an important event in gastric carcinogenesis. It is the principle mechanism of p16 gene silencing. It is related to malignant tumor behavior. Detection of DNA methylation in serum may be a biomarker for early detection of gastric cancer.     

Clinical application of methylation specific-polymerase chain reaction in serum of patients with gastric cancer

BACKGROUND/AIMS: We previously reported that aberrant methylation of p16 and/or E-cadherin genes in serum DNA could serve together as a tumor marker in gastric cancer. We presently investigated whether sensitivity could be increased by consideration of a third gene, which encodes retinoic acid receptor-1 (RARbeta). METHODOLOGY: We performed a methylation-specific polymerase chain reaction (MSP) in serum DNA to detect aberrant methylation of RARbeta from 109 preoperative gastric cancer patients, in which the first two genes had been characterized. We also examined all three genes in sera from 10 outpatients during postgastrectomy follow-up. RESULTS: Aberrant methylation of RARbeta was demonstrated in 26 preoperative patients (24%). Considering this with previous results, 52 patients (48%) of the 109 preoperative showed hypermethylation of at least one gene (p16, E-cadherin, and/or RARbeta). No aberrant methylation was detected in control sera. In the follow-up group, aberrant methylation was demonstrated in 2 of the 3 patients who had definite radiologic evidence of recurrences. One of the patients showing promoter hypermethylation without definite findings of recurrence at the time of analysis developed peritoneal recurrence 6 months later. CONCLUSIONS: Including the MSP assay in conventional follow-up could facilitate early detection of recurrent disease in gastric cancer patients.     

Aberrant p16 methylation, a possible epigenetic risk factor in familial esophageal squamous cell carcinoma

AIM: Detection of methylation in the p16 gene, an inhibitor of cyclin D-dependent protein kinase, as a new tumor marker for early detection of esophageal squamous cell carcinoma (ESCC) in DNA derived from blood and serum. METHOD: A large family with clustering of ESCC was assessed in Khorasan province in northeastern Iran. The family had three histologically proven cases of ESCC in two consecutive generations and several other deceased cases with histories of ESCC. DNA from blood of 28 living family members in three consecutive generations, 30 sporadic ESCC cases (from serum, blood, and tumor tissues), and 30 healthy volunteers (from blood) were examined for the methylation status of p16 promoter using methylation-specific PCR (MSP). RESULTS: Aberrant p16 promoter methylation was found in 64.3% (n = 28) of ESCC family members and none (n = 30) of our normal volunteers. Five of the 28 family members with esophageal cancer symptoms had negative endoscopy results for ESCC, while four of these members had p16 hypermethylation in their blood. The family members with negative endoscopy and positive p16 promoter methylation are being monitored closely for signs of ESCC development through regular check-ups and chromoendoscopies. In sporadic ESCC in northeastern Iran, 73.3% (n = 30) of tumor tissue samples had p16 hypermethylation. Serum and blood samples from the same patients showed p16 hypermethylation in 26.6% and 43.3% of the samples, respectively. CONCLUSION: Aberrant p16 methylation may be a valuable diagnostic tool as a tumor marker for the early identification of individuals in high risk ESCC families.     

Folate levels in mucosal tissue but not methylenetetrahydrofolate reductase polymorphisms are associated with gastric carcinogenesis

INTRODUCTION Methylation of gene regulatory elements is a well-documented epigenetic change that can lead to gene inactivation. Human gastric carcinogenesis is suggested to be associated with the decrease of total genomic DNA methylation, hypomethylation …     

Methylation pattern of DNA repair genes and microsatellite instability in hepatocelluar carcinoma]

BACKGROUND/AIMS: Epigenetic silencing of DNA repair genes, O6-methylguanine-DNA methyltransferase (MGMT), hMLH1 and hMSH3, by promoter hypermethylation have been observed in various cancers. However, the relationship between hypermethylation of DNA mismatch repair genes and microsatellite instability (MSI) has not been studied in hepatocellular carcinoma (HCC) associated with cirrhosis. METHODS: We investigated the methylation pattern of CpG islands of 3 genes using methylation-specific PCR (MSP) and MSI in 40 patients with paired hepatocellular carcinoma and associated cirrhosis. RESULTS: hMSH3 and MGMT were the most methylated genes in both cirrhosis (70% and 68%, respectively) and HCC (75% and 73%, respectively). The methylation of hMLH1 was rarely found in both cirrhosis (8%) and HCC (5%). Gene promoters methylated in cirrhosis were also methylated in HCC with the exception of 9 cases found to be methylated either in cirrhosis or HCC. Of 40 cases of HCC associated with cirrhosis, three had MSI-positive phenotype in which two were MSI-low and one was MSI-high. One MSI-positive phenotype was present both in cirrhosis and in HCC, while two were only in HCC. There was no significant correlation between aberrant DNA methylation of mismatch repair genes and MSI status in HCC associated with cirrhosis. Immunohistochemical expressions of hMLH1, MGMT, and hMSH3 proteins were present in 16 (40%), 6 (15%), and 11 (28%) of 40 cases of HCC respectively. There was no significant correlaton between the aberrant DNA methylation of mismatch repair genes and clinical characteristics such as histological differentiation, postoperative recurrence and mortality. CONCLUSIONS: The methylation of MGMT and hMSH3 among DNA repair genes are frequent, but those of hMLH1 and MSI is very rare in both cirrhosis and HCC. There is no significant correlation between the methylation of DNA repair genes and clinical characteristics of HCC.     

胃癌患者血清RASSF1A基因启动子区甲基化检测

Ras相关结构域家族1A（RASSF1A）基因是近年发现的新型抑癌基因，其启动子区甲基化可能与胃肠道肿瘤的发生、发展密切相关。目的：检测胃癌患者血清RASSF1A基因启动子区甲基化情况，探讨其在胃癌早期诊断和预后评估中的可能作用。方法：以甲基化特异性聚合酶链反应（MSP）检测47例胃腺癌患者、30例胃良性病变患者和30名健康对照者的血清RASSF1A基因启动子区甲基化情况，其中16例胃腺癌患者同时留取手术切除癌组织、癌旁组织标本以及术前、术后血标本行对照研究。结果：胃腺癌患者血清RASSF1A基因启动子区甲基化率为34．0％（16／47），显著高于胃良性病变患者（3.3％，1／30）和健康对照者（0％）（P〈0．01）。16例胃腺癌组织中5例（31．2％）检测到RASSF1A基因启动子区甲基化，其中4例（80．0％）术前、术后血清标本均检测到RASSF1A基因启动子区甲基化。血清RASSF1A基因启动子区甲基化与胃癌患者性别、年龄、肿瘤分化程度、有无转移以及血清癌胚抗原（CEA）水平均无相关性。结论：血清RASSF1A基因启动子区甲基化检测可望为胃癌的早期诊断和预后判断提供依据。     

非小细胞肺癌患者血清O6-甲基鸟嘌呤-DNA-甲基转移酶基因异常甲基化检测及其临床意义

目的 探讨非小细胞肺癌(non-small cell lung cancer,NSCLC)患者血清中O6-甲基鸟嘌呤-DNA-甲基转移酶(O6-methylguanine-DNA-methyhransferase,MGMT)基因启动子区域甲基化的改变状况及其临床意义.方法 基因测序法检测62例NSCLC患者、30例肺部良性疾病患者和16例健康体检者血清中MGMT基因启动子区域甲基化状况,并分析其与临床特征的关系.结果 NSCLC患者血清MGMT基因甲基化检出率为27.42%(17/62),而肺部良性疾病患者和健康体检者血清未检出MGMT基因甲基化(Fisher精确概率法,P＜0.01).MGMT基因甲基化检出率与NSCLC患者年龄、性别、病理类型、分化程度无明显相关,但在晚期患者中检出率较高(P＜0.05).MGMT基因甲基化患者吸烟指数(年·支)明显高于非甲基化患者(P＜0.01).结论 MGMT基因异常甲基化可能在NSCLC发生、发展中起重要作用,有望成为NSCLC辅助诊断的分子标记.