非小细胞肺癌p16基因甲基化及缺失的研究

目的 研究p16基因在非小细胞肺癌组织中的甲基化和缺失情况，探讨其在肺癌诊断中的价值。方法 应用甲基化相关的PCR及双重PCR，检测50例肺癌组织和54例正常肺组织中p16基因第1外显子5′端启动子区域CpG岛甲基化及第2外显子缺失情况。结果 p16基因在非小细胞肺癌组织中甲基化率为32.0%(16/50)。缺失率为28.0%(14/50);54例正常肺组织甲基化率为3.7%(2/54)，缺失率为0，二组比较，甲基化率（Fisher's exact=0.000)及缺失率（Fisher's exact=0.000)均有显著性差异。结论 甲基化和缺失是非小细胞肺癌p16基因失活的主要形式，检测p16基因甲基化和缺失状态可能有助于肺癌的诊断。     

肺癌血清p16基因启动子畸变甲基化检测

[目的]检测肺癌患者血清DNA中p16基因启动子畸变甲基化,并探讨其在肺癌早期诊断和预后评价中的作用。[方法]收集新鲜的肺癌组织及其对应的血清标本69例,肺良性疾病患者标本25例,健康人血清标本10例。采用PCR技术分别检测肿瘤组织DNA和血清游离DNA中p16基因启动子畸变甲基化的状况。[结果]28.99%(20/69)肺癌组织出现p16高甲基化;出现高甲基化的组织标本相对应的20例血清中有15例(75%)出现p16基因高甲基化。肺良性疾病患者及正常人的血清、DNA中均未见p16基因高甲基化。血清p16基因高甲基化与肺癌TNM分期及分化程度密切相关(P<0.01或P<0.05)。[结论]非小细胞肺癌血清中p16基因甲基化状况的检测,可能有助于非小细胞肺癌的早期诊断或预后评估。     

p16基因5′-CpG岛甲基化对肺癌的早期诊断价值

目的　检测 p16基因在肺癌患者癌组织及相应痰液脱落细胞中甲基化状态 ,以探讨其在肺癌早期诊断中的价值。方法　采用甲基化敏感的核酸内切酶 Sma 、Sac 酶切基因组 DNA,对 5 6份肺癌组织及相应痰液、6 0份非恶性病变肺组织及 2 8份痰液进行 PCR分析。结果　 p16基因在肺癌组织中甲基化率为 30 .4% (17/5 6 ) ,相应的痰液中为 2 8.6 % (16 /5 6 ) ,两组差异无显著性 (χ2 =0 .0 430 ,P=0 .836 )。 6 0份非恶性病变肺组织甲基化率为 3.3% (2 /6 0 ) ,2 8份痰液无 1份发现 p16基因甲基化。结论　肺癌组织及相应的痰液脱落细胞 p16基因 5′- Cp G岛甲基化率相似 ,即痰液脱落细胞 p16基因甲基化状态可以反映肺癌组织 p16基因甲基化状态。因此 ,检测痰液脱落细胞 p16基因甲基化状态有助于肺癌的早期诊断     

FHIT和p16基因甲基化与肺癌的发生

背景与目的:探讨FHIT和p16基因甲基化与肺癌发生之间的关系. 材料与方法:采用甲基化特异性PCR检测59例原发性肺癌组织,相对应的32例正常组织及11例支气管鳞状化生组织中FHIT基因、p16基因启动子区CpG岛甲基化状况.结果:肺癌组织和正常肺组织中的FHIT基因甲基化率分别为37.3%(22/59)、0.0%(0/32),两组间的差异有统计学意义(P<0.01);支气管鳞状化生组织FHIT基因甲基化阳性率为18.1%(2/11).肺癌组织和正常肺组织中的p16基因甲基化率分别为50.8%(30/59)、0.0%(0/32),两组间的差异具有统计学意义(P<0.01);支气管鳞状化生组织p16基因甲基化阳性率为18.1%(2/11).肺癌患者吸烟组中FHIT、p16基因甲基化联合检测的阳性率为90.6%(29/32),与非吸烟组(33.3%.9/27)相比较,其差异具有统计学意义(P<0.05).结论: FHIT基因和p16基因启动子区甲基化可能与肺癌的发生有关.     

非小细胞肺癌组织与癌旁组织SEMA3B基因甲基化分析

目的分析非小细胞肺癌组织与癌旁组织SEMA3B基因启动子区甲基化状况。方法用甲基化特异PCR(MSP)法检测非小细胞肺癌(NSCLC)组织及癌旁组织标本23例,用克隆测序验证。结果非小细胞肺癌组织标本中SEMA3B基因启动子区有19例(82.6%,19/23)发生异常甲基化,相对应的癌旁组织标本中有18例(78.3%,18/23)发生异常甲基化,但与发病年龄、性别、病理分化无关。结论非小细胞肺癌组织与癌旁组织都表现出SEMA3B基因启动子区异常甲基化,癌旁组织细胞中发生SEMA3B基因启动子异常甲基化可能要早于细胞的恶性增生。     

CDKN2/p16基因5′-CpG岛SmaI位点甲基化与肺癌的关系

目的　研究CDKN2 /p16基因 5′端调控序列CpG岛甲基化的状态与肺癌发生发展的关系。方法　采用对甲基化敏感的核酸内切酶SmaⅠ ,酶切基因组DNA的方法 ,对 89例肺癌标本和 10例正常肺组织的CDKN2 /p16基因进行Southern杂交分析。结果　 89例肺癌中 ,CDKN2 /p16基因甲基化者 15例 ,甲基化频率为 16 .9%。 42例p16蛋白阴性的肺癌患者中 ,有 12例发生甲基化 ,甲基化频率为 2 8.6 % ;另有 47例p16蛋白阳性患者中仅有 3例发生甲基化。 10例正常肺组织中均未发现CDKN2 /p16基因有甲基化现象。结论　CDKN2 /p16基因 5′端CpG岛甲基化是该基因失活的重要机制 ,是肺癌细胞区别于正常细胞的分子事件之一 ,可能参与肺癌的发生发展过程     

染色体3p21.3缺失区域11个相关基因在非小细胞肺癌中的表达

背景与目的50%-80%的非小细胞肺癌存在染色体短臂3p21.3上等位基因的丢失,提示可能存在多个潜在的抑瘤基因。本研究通过大规模筛选3p21.3区相关基因在肺癌中的表达,以期找到数个肺癌相关抑瘤基因。方法应用生物信息学方法,选择出11个位于该区与肿瘤密切相关的基因,RT-PCR检测16例非小细胞肺癌及配对组织标本中11个基因的表达,并进行相关统计分析。结果在11个基因中,5个基因[RASSF1A43.8%(7/16),GNAT137.5%(6/16),SEMA3B62.5%(10/16),SEMA3F50%(8/16),Blu56.3%(9/16)]在非小细胞肺癌组织中表达下调或缺失(P<0.05);其余6个基因ZNF35、NPRL2、LTF、AXUD1、BAP1和FUS1的表达,在非小细胞肺癌及配对组织标本的表达无统计学差异。结论肺癌组织中3p21.3区有多个基因参与了肺癌的发生发展。     

非小细胞肺癌INK4a和ARF基因甲基化与其蛋白共表达关系的探讨

目的:分析INK4a和ARF基因启动子甲基化与其蛋白共表达之间的关系.方法:选择前期实验中p14ARF和p16INK4a蛋白共表达阴性的非小细胞肺癌(NSCLC)患者35例,共表达阳性的NSCLC患者20例作为研究对象,分别称为(p14 p16)阴性组和(p14 p16)阳性组.运用甲基化特异性PCR(MSP)方法对两组患者癌组织INK4a和ARF基因启动子的甲基化状态进行检测.结果:(p14 p16)阴性组有18例发生INK4a基因甲基化,(p14 p16)阳性组有2例发生INK4a基因甲基化,两组差异有显著意义(P＜0.01).(p14 p16)阴性组有8例发生ARF基因启动子甲基化,(p14 p16)阳性组有2例发生ARF基因启动子甲基化,两组差异无显著意义(P＞0.05).INK4a和ARF基因异常申基化相互之间无显著相关性(P＞0.05).结论:NSCLC患者肺癌组织INK4a基因甲基化是导致p16INK4a蛋白表达阴性的重要机制;INK4a和ARF基因甲基化可能是相对独立的事件.     

肺癌组织中p16基因缺失的初步研究

目的　探讨p16基因缺失与肺癌发生的关系。方法　采用PCR方法检测 48例肺癌组织标本中p16基因缺失的情况 ,其中包括 2 3例原发性小细胞肺癌 (SCLC)和 2 5例原发性非小细胞肺癌 (NSCLC)。结果　在 2 3例SCLC中没发现p16基因缺失 ,而 2 5例NSCLC中 ,7例存在p16基因缺失 ,缺失率达 2 8%。结论　结果提示p16基因的变异与原发性非小细胞肺癌的发生及发展相关。     

血浆中检测FHIT、p16、MGMT和RASSF1A基因甲基化在肺癌诊断中的价值

目的:探讨血浆中脆性组氨酸三连体基因(fragile histidine triad,FHIT)、p16基因、O6-甲基鸟嘌呤-DNA甲基转移酶基因(O6-methyl-guanine-DNA methyltransferase,MGMT)及信号转导通路基因(rasassociation domain family1A,RASSF1A)等抑癌基因启动子异常甲基化及其联合检测在肺癌筛查及早期诊断中的价值。方法:采用甲基化特异性PCR(methylation specifi c PCR,MSP)法,检测53例肺癌组织和对应的血浆标本以及24例肺良性病变组织中FHIT、p16、MGMT和RASSF1A4种基因启动子区甲基化状态。结果:肺癌组织中FHIT、p16、MGMT和RASSF1A基因启动子区甲基化检出率分别为39.6%(21/53)、49.1%(26/53)、35.8%(19/53)和18.9%(10/53);其对应的血浆标本中这4个基因的甲基化检出率分别为35.8%(19/53)、49.1%(26/53)、28.3%(15/53)和17.0%(9/53),两组标本甲基化检出率存在着较好的一致性(P>0.05)。24例肺良性病变组织标本和血浆标本中分别有同1例(0.04%)出现p16基因甲基化,与肺癌组比较差异有统计学意义(P<0.05)。4项指标联合检测可显著提高肺癌检测的敏感度(73.6%)和特异度(95.8%)。p16基因在血浆中甲基化检出率与患者吸烟指数有明显相关性(P<0.05)。结论:血浆中多个肺癌相关基因甲基化联合检测有望成为肺癌筛查、早期诊断简便有效的指标。     

CYP1A1基因多态性与p16基因甲基化对中国人肺癌发病的影响

Objective:To investigate the relationship between the genetic polymorphism of CYP1A1 and the genetic susceptibility to lung cancer as well as to study the effects of the methylation in p16 gene on the risk of lung cancer in a Chinese population.Methods:A case control study was conducted among 47 cases of lung cancer and 94 controls.The genetic polymorphism of CYP1A1 was tested with method of PCR-RFLP,and a methylation-specific PCR(MSP)was performed to detect p16 methylation.Results:It showed that there was no significant difference in frequencies of the genotypes of CYP1A1 between the two groups(P>0.05).Synergistic effects were not found between smoking and CYP1A1.Methylated p16 gene was found in 44.7%(21/47)of lung cancer tissues and in 17.0%(8/47)of normal lung tissues with significant difference(P< 0.05).Conclusion:The genetic polymorphism of CYP1A1 does not increase the risk of lung cancer in a Chinese population. The methylation in p16 gene may be the most common mechanism to inactivate p16 gene in lung cancer,and is not significantly associated with genotype of CYP1A1.     

HYPERMETHYLATION OF p14^ARF PROMOTER REGION AND EXPRESION OF p14^ARF GENE PRODUCT IN NON-SMALL CELL LUNG CANCER

Objective： This study was designed to investigate promoter methylation status and protein expression of p14^ARF gene in non-small cell lung cancer, and value the role of p14^ARF promoter methylation in carcinogenesis of non-small cell lung cancer. Methods： Promoter methylation status and protein expression of p14^ARF gene in 40 cases of non-small cell lung cancer were analyzed by methylation specific polymerase china reaction （MSP）, restriction enzyme-related polymerase chain reaction （RE-PCR） and immunohistochemistry （IHC）. Results： The positive rates of p14^ARF promoter methylation in tumor tissues and normal tissues adjacent to cancer were 17.5% （7/40） and 2.5% （1/40） respectively. There were statistically significant differences between them, P〈0.05. The results of RE-PCR were consistent with that of MSP. The expression rate of p14^ARF protein in tumor tissues was significantly lower than that in normal tissues adjacent to cancer, p〈0.01. Promoter methylation status and protein expression of p14^ARF gene in non-small cell lung cancer showed significantly an inverse correlation （r=-0.56, P〈0.01）, and both of them did not relate statistically with the clinicopathologic characteristics of patients such as histological classification, clinical stage, differentiation grade and lymph node involvement. Conclusion： Promoter methylation is a crucial mechanism of inactivation of p14^ARF gene. Promoter methylation of p14^ARF gene might he involved in carcinogenesis of non-small cell lung cancer, and is an early event in development process of non-small cell lung cancer. It might be used as a new target in gene treatments in the future.     

RASSF1A和p16 转录本在非小细胞肺癌中的表达及启动子区甲基化

 目的 研究RASSF1A和p16基因在国人非小细胞肺癌（NSCLC）组织中的转录及启动子区甲基化情况，探讨其转录失活的机制，为NSCLC的诊断和治疗寻找新的途径。方法 应用半定量RTPCR和甲基化特异性PCR法分析96例NSCLC及远癌正常肺组织中RASSF1A和p16基因mRNA的表达和启动子区甲基化情况。结果 （1）53．12％（51／96）的NSCLC中RASSF1A表达明显下调或缺失；36．46％（35／96）的p16表达下调或缺失，而远癌正常肺组织均表达良好。（2）96例NSCLC中RASSF1A甲基化率48．96％（47／96），该基因表达明显下调或缺失的51例中39例（76．5％）出现甲基化，表达正常的45例中8例（17．8％）出现甲基化，两组对比差异有统计学意义（P〈0．05）；96例NSCLC中33例（34．38％）检测到p16启动予区甲基化，p16基因表达明显下调的35例中20例（57．1％）出现该基因CPG岛的甲基化，而表达正常的61例中13例（21．3％）出现甲基化，两组比较差异显著（P〈0．05）。96例远癌正常肺组织均未检测到此两基因启动子有甲基化。结论 RASSF1A和p16基因mRNA在国人NSCLC中较高比例的表达下调或缺失；甲基化可能是两基因表达失活的主要原因。     

Characterization of a multiple epigenetic marker panel for lung cancer detection and risk assessment in plasma

BACKGROUND: Methylation patterns may be useful biomarkers of cancer detection and risk assessment. METHODS: The methylation status of 6 genes, including a candidate tumor suppressor gene (BLU), the cadherin 13 gene (CDH13), the fragile histidine triad gene (FHIT), the cell cycle control gene p16, the retinoic acid receptor beta gene (RARbeta), and the Ras association domain family 1 gene (RASSF1A), was examined in plasma samples, corresponding tumor tissues, and normal lung tissues from a group of 63 patients with lung cancer and in plasma samples from 36 cancer-free individuals. The detection rate of the p16 gene was validated in a test group of 20 patients with lung cancer. RESULTS: The concordance of methylation in tumor tissues and plasma samples was 86%, 87%, 80%, 75%, 76%, and 84% for the BLU, CDH13, FHIT, p16, RARbeta, and RASSF1A genes, respectively. The test group showed a similar concordance for p16 methylation detection. Multiple logistic regression analysis showed that the odds ratio for having lung cancer was 10.204 for individuals with p16 methylation (P = .013) and 9.952 for individuals with RASSFIA methylation (P = .019). After several trial tests, the authors established that methylation for >/=2 of the 6 markers met the criterion for an elevated risk of cancer. Comparisons yielded a sensitivity of 73%, a specificity of 82%, and a concordance of 75% between the methylation patterns in tumor tissues and in corresponding plasma samples. The detection rate was relatively high in cigarette smokers with advanced squamous cell lung cancer. CONCLUSIONS: The current results indicated that multiple epigenetic markers in the plasma, especially the p16 and RASSF1A genes, can be used for lung cancer detection. This methylation marker panel should improve the detection of cancer or the risk assessment for lung cancer in combination with conventional diagnostic tools.     

Promoter hypermethylation of tumor suppressor and tumor-related genes in non-small cell lung cancers

Aberrant methylation of promoter CpG islands is known to be a major inactivation mechanism of tumor suppressor and tumor-related genes. To determine the clinicopathological significance of gene promoter methylation in non-small cell lung cancer (NSCLC), we examined the promoter methylation status of the APC, DAP-kinase, E-cadherin, GSTP1, hMLH1, p16, RASSF1A and RUNX3 genes in 75 NSCLCs and corresponding non-neoplastic lung tissues by methylation-specific PCR (MSP). The frequencies of methylation in NSCLCs and corresponding non-neoplastic lung tissues were: 37% (28 of 75) and 48% (36 of 75) for APC , 28% (21 of 75) and 13% (10 of 75) for DAP-kinase , 29% (22 of 75) and 15% (11 of 75) for E-cadherin , 1% (1 of 75) and 0% (0 of 75) for GSTP1 , 7% (5 of 75) and 0% (0 of 75) for hMLH1 , 31% (23 of 75) and 0% (0 of 75) for p16 , 43% (32 of 75) and 4% (3 of 75) for RASSF1A , and 20% (15 of 75) and 3% (2 of 75) for RUNX3 , respectively. Methylation of p16 was more frequent in squamous cell carcinomas than in adenocarcinomas ( P <0.05), and was associated with tobacco smoking ( P <0.05). On the contrary, methylation of APC and RUNX3 was more frequent in adenocarcinomas than in squamous cell carcinomas ( P <0.05). Thus, a different set of genes is thought to undergo promoter methylation, which leads to the development of different histologies. In addition, methylation of p16, RASSF1A and RUNX3 was mostly cancer-specific ( P <0.05), and may be utilized as a molecular diagnostic marker of NSCLCs.     

肺鳞癌、腺癌中p14 ARF基因启动子区甲基化及蛋白表达的研究

背景与目的 p14^ARF基因是新近发现的抑癌基因，其异常表达与多种人类肿瘤发生有关，启动子区异常甲基化作为p14^ARF基因失活的重要形式可能参与了肿瘤的发生。本研究通过检测肺鳞癌、腺癌中p14^ARF启动子区甲基化状态和蛋白表达，探讨p14^ARF启动子区甲基化与肺癌的关系。方法 通过免疫组织化学（IHC）、甲基化特异性PCR（MSP）和相关限制性内切酶PCR（RF-PCR）方法，检测40例肺鳞癌、腺癌组织中p14^ARF启动子区甲基化状态和蛋白表达水平。结果 癌组织及癌旁正常组织中p14^ARF启动子区甲基化阳性率分别为17．5％（7／40）和2．5％（1／40）（P-0．025）。RE-PCR检测结果相同。癌组织及癌旁正常组织中p14^ARF蛋白阳性率分别为70．0％（28／40）和95．0％（38／40）（P-0．003）。p14^ARF基因启动子区甲基化和蛋白表达均与肿瘤分期、组织类型、分化程度、淋巴结转移等临床病理特征无明显关系（P＜0．05）。p14^ARF启动子区甲基化与蛋白表达呈负相关（r=-0．56，P=0．001）。结论 启动子区甲基化是p14^ARF基因失活的重要机制。p14^ARF启动子区异常甲基化可能参与了非小细胞肺癌的发生，是肺癌发生过程的早期事件。     

Quantitative p16 and ESR1 methylation in the peripheral blood of patients with non-small cell lung cancer

Inactivation of the p16 and ESR1 tumor suppressor genes by promoter lesion methylation has been reported in many tumor types, including lung cancer. We examined the blood of 95 non-small cell lung cancer patients (66 cases of adenocarcinoma, 23 of squamous cell carcinoma and 6 of large cell carcinoma) and 30 controls consisting of normal subjects and benign disease patients to determine the methylation ratios of p16 and ESR1 using real-time PCR. For both genes, there was a statistically significant difference in the methylation ratio between non-small cell lung cancer patients and controls (p16; p<0.01, ESR1; p<0.001). In addition, there was a strong correlation between the methylation ratio of each gene and old age (p16; p<0.01, ESR1; p<0.001 and p16 or ESR1; p<0.001), and between p16 or ESR1 methylation rate and smoking history (p<0.01). Moreover in Stage I cases, the methylation positive rate of each gene (p16, ESR1 and p16 or ESR1) was higher than the CEA positive rate (p<0.05, p<0.001, p<0.001). Evaluation of p16 and ESR1 promoter methylation in blood using real-time PCR appears to be very useful for lung cancer diagnosis and there is some possibility that these methylated genes might come to represent useful biomarkers for the early detection of lung cancer. Our study results also suggested that comparative evaluation of the methylation ratio before and after surgery might be a powerful tool to predict the prognosis of lung cancer patients.     

Association of Methylation of the RAR-β Gene with Cigarette Smoking in Non-Small Cell Lung Cancer with Southern-central Chinese Population

Pathogenesis of lung cancer is a complicated biological process including multiple genetic and epigeneticchanges. Since cigarette smoking is confirmed as the most main risk factor of non-small cell lung cancer (NSCLC),the aim of this study was to determine whether tobacco exposure plays a role in gene methylation. Methylationof the RAR-β gene were detected using methylation-specific polymerase chain reaction in DNA from 167 newlydiagnosed cases with NSCLC and corresponding 105 controls. A significant statistical association was found inthe detection rate of the promoter methylation of RAR-β gene between NSCLC and controls (x2=166.01; p<0.01),and hypermethylation of the RAR-β gene was significantly associated with smoking status (p=0.038, p<0.05). Norelationship was found between RAR-β gene methylation and pathologic staging including clinical stage, celltype, gender and drinking (p>0.05), and the methylation of RAR-β gene rate of NSCLC was slightly higher instages Ⅲ+Ⅳ (80.0%) than in Ⅰ+Ⅱ (70.8%). Similar results were obtained for methylation of the RAR-β genebetween squamous cell carcinoma (77.9%) and other cell type lung cancer (73.9%). These results showed thatthe frequency of methylation increased gradually with the development of clinical stage in smoking-associatedlung cancer patients, and tobacco smoke may be play a potential role in RAR-β gene methylation in the earlypathogenesis and process in lung cancer, particularly squamous cell carcinoma. Aberrant promoter methylationis considered to be a promising marker of previous carcinogen exposure and cancer risk.