中国非小细胞肺癌患者血清DAPK基因、p16基因启动子甲基化的分析

Objective： To evaluate the clinical significance of the aberrant methylation of DAPK gene and p16 gene in sera from 65 NSCLC patients from Nanjing General Hospital of Nanjing Command, China. Methods： A methylation-specific PCR （MSP） was performed for the detection of promoter hypermethylation of DAPK gene and p16 gene in blood DNA from 65 cases of NSCLC, and to analyze the relation of the aberrant methylation of DAPK gene and p16 gene and the clinicopathological data. Results： 30.8% （20/65） of the sera from 65 cases of NSCLC showed hypermethylation for DAPK promoter and 43.1% （28/65） the same for p16 promoter, whereas no methylated DAPK gene promoter and p16 gene promoter were found in sera from the patients with lung benign diseases and normal controls. Methylated DAPK gene promoter and p16 gene promoter in sera were not closely correlated with the pathological classification, stage, metastasis and differentiation in NSCLC. Conclusion： Detection of the aberrant methylation of DAPK gene and p16 gene in blood DNA from NSCLC patients might offer an effective means for the earlier auxiliary diagnosis of the malignancy.     

胰腺组织p15、p16抑癌基因CpG岛甲基化研究

Objective： To detect the aberrant methylation patterns in the CpG islands of p16 and p15 tumor suppressor genes, and to analyze its correlation with pancreatic carcinogenesis and with clinicopathological characteristics of patients with pancreatic cancer （PC）. Methods： The methylation-specific polymerase chain reaction （MSP） method was used to monitor methylation patterns in the CpG islands of p15 and p16 genes from 29 cases of PC and 3 cases of chronic pancreatitis （CP） paraffin-embedded tissue, as well as 2 cases of normal liver tissues and 12 cases of normal blood samples. Results： p15 and p16 genes were detected to show unmethylation patterns and no amplification using methylation-specific primers in control group. The aberrant methylation rates of p16 in carcinoma tissue and adjacent noncarcinoma tissue were 37.9% （11 of 29 cases） and 34.5% （10 of 29 cases） respectively. Of the 11 aberrant methylated samples, 5 showed complete methylation and 6 hemimethylation. The methylation rates of p15 gene in carcinoma tissue and adjacent noncarcinoma tissue were 27.5% （8/29） and 24.4% （7/29） respectively. Of the 8 aberrant methylated samples, 3 showed complete methylation and 5 hemimethylation. In 6 PC samples, aberrant methylation in CpG islands of both p15 and p16 genes existed simultaneously. The aberrant methylation patterns in CpG islands of p15 and p16 genes had no close correlation with the clinicopathological characteristics （age, sex, smoking, volume of primary tumor, differentiation, clinical stage and histological classification） of the patients with PC （P〉0.05）. Conclusion： The aberrant methylation in CpG islands of p15 and p16 genes could be regarded as an early molecular event in PC and had no close correlation with the clinicopathological characteristics of the patients with PC.     

乙肝病毒相关的肝癌p16异常甲基化

Objective： To investigate the potential linkage between high rate of p16 methylation and hepatitis B virus （HBV） infection, methylation status of p16, HBV infection markers in serum and HBV-DNA replication level in cancerous and non-cancerous tissue of 32 cases of hepatocellular carcinomas （HCC） with HBV infection and 12 HCCs without HBV infection were examined. Methods： p16 methylation was detected with methylation-specific polymerase Chain reaction （PCR）, and HBV markers were examined with real-time PCR and immunologic method. Results： Methylation of p16 promoter was found in 31 （70.5%） of 44 cancerous tissues of HCC, 2 （16.7%） of 12 HCC without HBV infection, 29 （90.6%） of 32 HCCs with HBV infection marker, p16 methylation was detected in 5 （83.3%） of 6 HCCs positive for HBsAg and HBeAg, 17 （94.4%） of 18 HCCs positive for HBsAg and negative for HBeAg, 7/8 （87.5%） of HCCs positive for other HBV infection markers, such as HBsAB, HBcAb, HBeAb. p16 methylation products were also found in non-cancerous tissues of 4 cases of HCCs with HBV infection, not detected in non-cancerous tissues without HBV infection. HBV-DNA was detected in cancerous tissues of 29/32 （90%） HCCs with HBV infection. Surprisingly, Methylation product of p16 promoter was found in all cases （29/29） of HCCs with detectable HBV-DNA in neoplastic tissue. Conclusion： Persistent HBV infection may promote p16 hypermethylation, suggesting that HBV, via enhancing the aberrant methylation of p16, indirectly involved in development of HCC.     

Hypermethylation of promoter 5＇CpG island of p16 gene in glioma tissue and plasma

ObjectiveTo explore the clinical significance of methylation status of promoter CpG island of p16 gene in glioma tissue and plasma.MethodsMethylation specific polymerase chain reaction (MSP) was used to determine the methylation status of the promoter for p16 gene within glioma tissue and plasma.Immunohistochemicel method (SP) was used to analyze the expressions of p16 and Ki-67 proteins.ResultsHypermethylation was found in 17/40 (42.5%) of brain gliomas,in comparison with 11/40 (27.5%) plasma specimens (x2 = 1.9780,P = 0.1596).Loss of p16 expression was associated (P = 0.0229) with hypermethylation of CpG island of promoter regions.Hypermethylation of p16 gene CpG island was significantly related to the increase of malignant grade of brain glioma (TissueX2 = 11.4288,P = 0.0007;PlasmaX2 = 8.9439,P = 0.0028).The Ki-67 index increased significantly (P＜0.05) in brain gliomas methylated in contrast to those unmethylated.ConclusionP16 hypermethylation may be one of the major mechanisms of tumorigenesis of gliomas.Methylated tumor-specific DNA may be as a plasma biomarker for prognosis in patients with glioma.     

PROMOTER HYPERMETHYLATION OF p16 GENE IN PRE- AND POST-OPERATIVE PLASMA OF PATIENTS WITH GASTRIC ADENOCARCINOMA

Objective: To detect promoter hypermethylation of p16 gene in matched pre- and post-operative plasma of patients with gastric adenocarcinoma for evaluating the effectiveness of therapeutic intervention. Methods: Tissue samples, pre- and post-operative plasma of 84 patients were collected. Plasma of 15 healthy people was collected as control. After sodium-bisulfite treatment, extracted DNA was amplified for p16 promoter by methylation-specific polymerase chain reaction (MSP). The PCR products were detected by both gel-ethidium bromide electrophoresis and high performance liquid chromatogram (HPLC). Results: Among 84 patients, p16 hypermethylation was detected in 26 (31.0%) cancer tissues and 2 (0.02%) tumor-adjacent tissues and 12 (14.3%) pre-operative plasma, while negative in plasma of healthy people. For positive plasma cases, the paired tumor tissues were confirmed to be methylated.Within available 30 pairs of matched pre- and post-operative plasma, 6 pre-operative plasma was positive, and only 1 of 6 plasma remained hypermethylated after surgery. The results detected by HPLC exactly matched those by gel-electrophoresis. Conclusion: The alteration of status of p16 hypermethylation in post-operative plasma is considered the consequences of surgical intervention. Although p16 hypermethylation has no role in pre-operative staging of gastric cancer, detecting hypermethylated p16 in plasma could be utilized in monitoring patients after surgery.     

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.     

Detection and clinical significance of <Emphasis Type="Italic">DLC1</Emphasis> gene methylation in serum DNA from colorectal cancer patients

Objective: Deleted in liver cancer 1 (DLC1) is a new candidate tumor suppressor gene, whose down-regulation or even silence will result from promoter hypermethylation in various human cancers including colorectal cancer (CRC). The aim of this study is to evaluate the diagnostic role of DLC1 gene methylation in the serum DNA from CRC patients. Methods: This study enrolled 85 CRC patients and 45 patients with benign colorectal diseases. Methylation-specific polymerase chain reaction (MSP) was used to determin...     

Analysis of Inactivation of hMLH1 by Promoter Hypermethylation and Microsatellite Instability in Gastric Carcinogenesis

OBJECTIVE To study the microsatellite instability (MSI) and methylation state of the hMLH1 gene promoter and their mechanisms underlying the development of gastric cancer. METHODS Forty-one gastric cancer samples were obtained from patients undergoing surgery and 46 chronic atrophic gastritis tissues with dysplasia or intestinal metaplasia (IM) were obtained from patients undergoing gastro-endoscopy. Fourteen normal gastric mucosal samples were used as controls. Genomic DNA was extracted from the samples and 5 microsatellite markers were used to measure MSI. Methylation-specific PCR (MSP) was used to screen the methylation state of the samples. DNA sequencing and immunohistochemistry were performed to verify the results. RESULTS MSI was identified in 22 out of the 41 (53.7%) gastric cancers, of which 8 cases showed high-level MSI (2 or more loci altered) and 14 showed low-level MSI (1 locus altered). MSI was also detected in 12 out of 46 (26.1%) pre-cancerous lesions of the stomach, whereas it was not seen in the normal tissue. Moreover, hMLH1 hypermethylation was detected in 17 out of the 41 (41.5%) gastric cancers, 9 out of the 46 (19.6%) pre-cancerous lesions and 0 out of the 14 normal tissue. Significant differences in frequency of MSI and hMLH1 promoter methylation were observed among gastric cancers, precancerous lesions and normal gastric tissue. Gastric samples with MSI had a tendency to be hypermethylated in the hMLH1 promoter. DNA sequencing and immunohistochemistry results also confirmed that hMLH1 promoter methylation could lead to loss of the hMLH1 protein and gene silence which sequentely resulted in gene mismatch and MSI. CONCLUSION Accumulation of MSI and hMLH1 promoter methylation may be important early molecular events during gastric carcinogenesis and may contribute to the acquisition of a transformed cell phenotype and the development of gastric cancer.     

原发性肝癌患者血清p16和DAPK基因启动子甲基化的研究

 目的研究原发性肝癌患者血清p16和DAPK基因启动子甲基化的改变状况及其临床意义。方法运用甲基化特异性PCR技术,检测64例PLC患者血清p16基因和DAPK基因启动子甲基化,并分析与临床病理资料的关系。结果PLC患者血清p16基因和DAPK基因甲基化检出率分别为76.6%(49/64)和40.6%(26/64),而正常对照组和良性肝部疾病组血清未检出p16基因和DAPK基因甲基化;p16基因和DAPK基因甲基化检出率与HBsAg、分期及转移状态无明显关系,而与AFP有关联。结论p16基因和DAPK基因启动子异常甲基化参与了PLC的发生发展过程,并可作为PLC早期辅助诊断的分子标志物之一。     

中国非小细胞肺癌患者血清DAPK基因、p16基因启动子甲基化的分析(英文)

目的分析65名中国南京军区南京总医院的非小细胞肺癌(NSCLC)住院患者血清中DAPK、p16启动子区域甲基化的改变状况及其临床意义。方法运用甲基化特异性PCR技术,检测65例NSCLC患者血清DAPK、p16基因启动子区域甲基化的改变情况,并分析与临床病理资料的关系。结果 NSCLC患者血清DAPK基因甲基化检出率为30．8％(20/65),p16基因甲基化检出率为43．1％(28/65),而正常对照组和良性肺部疾病组血清未检出DAPK基因、p16基因甲基化,DAPK基因、p16基因甲基化检出率与NSCLC病理类型、分期及转移状态无明显关系。结论 DAPK基因、p16基因检出启动子区域异常甲基化是NSCLC早期辅助诊断的分子标志物之一。     

乳腺癌患者外周血清中APC基因启动子甲基化异常的检测及其意义

背景与目的:检测肿瘤患者外周血中肿瘤相关标志物是当前肿瘤研究的热点之一,恶性肿瘤患者外周血中存在游离的肿瘤相关DNA已引起肿瘤学界的极大关注,人们曾在多种肿瘤患者血清中发现与原发肿瘤相同的DNA变异.本研究以APC(adenomatous polyposis coli)基因启动子甲基化作为肿瘤标志物,探讨乳腺癌患者外周血清中游离的肿瘤相关DNA与肿瘤组织及临床病理参数的相关性.方法:采用甲基化特异性PCR(methylation specific-PCR,MSP)方法,分别检测84例乳腺癌组织、癌旁正常腺体组织及外周血清中游离DNA APC基因启动子甲基化状况.结果:84例乳腺癌组织APC基因启动子甲基化频率为45.2%(38/84),相应外周血清中同样DNA变异阳性检出率为31.0%(26/84).外周血清中DNA甲基化变异与肿瘤组织的甲基化状况显著相关(r=0.977,P=0.002).检测外周血清中APC基因甲基化的敏感性为68.4%,特异性为97.8%.肿瘤组织及外周血清中游离DNA甲基化异常与临床分期、病理类型、肿块大小及受体状况无相关性(P＞0.05).肿瘤组织未检测到甲基化患者的血清中及健康人血清中均未检测到该基因甲基化变异.结论:乳腺癌患者外周血清中肿瘤相关DNA甲基化与肿瘤组织中相同基因的变异显著相关.     

Differential DNA methylation associated with hepatitis B virus infection in hepatocellular carcinoma

Gene inactivation through DNA hypermethylation plays a pivotal role in carcinogenesis. This study aimed to profile aberrant DNA methylation in different stages of liver disease, namely noncirrhosis, cirrhosis and hepatocellular carcinoma (HCC), and also to clarify the influence of hepatitis B virus (HBV) infection on the aberrant DNA methylation in HCCs. Promoter methylation in p14(ARF), p16(INK4a), O(6)-methylguanine-DNA methyltransferase (MGMT), glutathione S-transferase pi (GSTP1) and E-cadherin (E-Cad) genes of 58 HCCs paired with adjacent nontumorous tissues was assayed by methylation-specific PCR. HBV infection was determined using a hepatitis B virus surface antigen (HBsAg) serological assay. The frequency of p16(INK4a) promoter methylation increased from noncirrhotic, cirrhotic, to HCC tissues (noncirrhotic vs. HCC, p < 0.001), while that of GSTP1 promoter methylation increased in cirrhotic tissues compared to noncirrhotic ones (p = 0.029). The frequency of GSTP1 promoter hypermethylation is significantly higher in HCC than in nontumorous tissues (p = 0.022) from HBsAg-positive patients, but not the HBsAg-negative controls (p = 0.289). While the frequency of E-Cad promoter hypermethylation remained high in both nontumorous tissues and HCCs from HBsAg-positive patients (p = 0.438), it was lower in HCCs than in nontumorous tissues from HBsAg-negative patients (p = 0.002). In contrast, the frequency of p16(INK4a), MGMT and p14(ARF) promoter hypermethylation in HCCs was unrelated to HBsAg status. In conclusion, aberrant DNA methylation may begin at different stages of liver disease in a gene-dependent manner. Moreover, HBV infection may enhance or maintain GSTP1 and E-Cad promoter methylation and thereby affect hepatocarcinogenesis.     

宫颈癌中p16基因启动子异常甲基化的检测

目的:探讨宫颈癌组织及外周血浆中p16基因启动子异常甲基化的状况及其在宫颈癌诊断中的价值.方法:用甲基化特异性PCR技术对宫颈癌组织,正常宫颈组织及相对应血浆中p16基因进行甲基化的检测.结果:45例宫颈癌组织中p16基因异常甲基化率为33.3％(15/45),相对应血浆中p16基因甲基化的检出率为20％(9/45),而正常对照组织未检出甲基化.血浆中甲基化的改变与宫颈癌组织甲基化状态显著相关(P＜0.05).p16基因甲基化发生率与年龄、病理分级、临床分期之间无统计学相关性(P＞0.05).结论:p16基因CpG岛甲基化是宫颈癌发生的高频事件,其甲基化检测在宫颈癌早期诊断中有一定的应用价值.     

河南林州地区贲门癌和癌旁组织中p16基因启动子甲基化及蛋白表达

目的探讨贲门癌变过程中p16基因启动子区甲基化和p16蛋白表达变化特征和规律及其相互关系。方法采用甲基化特异PCR（MSP）及免疫组化方法,检测林州地区32例贲门癌患者癌组织、癌旁不典型增生组织和正常组织p16基因启动子区甲基化状态及蛋白表达情况。结果p16基因在癌组织中表达缺失18例（56%）,不典型增生组织中表达缺失8例（73%）;26例（81%）癌组织、7例（64%）不典型增生组织和18例（67%）正常组织发生了p16基因启动子区的甲基化。贲门癌组织中p16基因甲基化与表达缺失一致率为56%。差异无统计学意义,P〉0.05。结论p16蛋白表达缺失可能是贲门癌变过程中的重要分子事件,p16基因启动子区甲基化可能是导致其蛋白表达缺失的机制之一。     

Predicting hepatocellular carcinoma by detection of aberrant promoter methylation in serum DNA.

PURPOSE: Most hepatocellular carcinomas (HCC) are diagnosed at an advanced stage. Hypermethylation of CpG islands in promoter regions is now recognized as an important early event in carcinogenesis and detection of methylated DNA has been suggested as a potential biomarker for early detection of cancer. There are no studies on epigenetic changes in samples from HCC patients before diagnosis. We explored the possible diagnostic value of aberrant promoter hypermethylation of three tumor suppressor genes in serum DNA for early detection of HCC. EXPERIMENTAL DESIGN: Aberrant promoter hypermethylation was investigated in DNA isolated from the serum of 50 HCC patients who provided repeated blood samples before diagnosis and 50 controls enrolled in a cancer screen program in Taiwan. Methylation-specific PCR was used to determine the methylation status of p16, p15, and ras association domain family 1A (RASSF1A). RESULTS: Among cases, aberrant methylation was found in serum DNA 1 to 9 years before clinical HCC diagnosis. RASSF1A had the highest frequency of hypermethylation with 35 (70%) cases having at least one positive sample compared with 22 (44%) for p16 and 12 (22%) for p15. Six subjects were hypermethylation negative for all three genes. For the 50 controls, promoter hypermethylation was found in three and two subjects for RASSF1A and p16, respectively; none had methylation of p15. A receiver operating characteristic curve that included clinical risk factors (age, HBsAg status, anti-hepatitis C virus status, smoking, and alcohol status) and hypermethylation biomarkers gave an overall predictive accuracy of 89% with sensitivity and specificity 84% and 94%, respectively. CONCLUSIONS: The analysis of epigenetic changes on RASSF1A, p16, and p15 tumor suppressor genes in serum DNA may be a valuable biomarkers for early detection in populations at high risk of HCC.     

Aberrant Promoter Methylation Profile in Pleural Fluid DNA and Clinicopathological Factors in Patients with Non-small Cell Lung Cancer

The aim of this study was to investigate the prognostic value of hypermethylation of tumor suppressor genesin patients with non-small cell lung cancer (NSCLC). In samples from 34 lung patients with malignant pleuraleffusions, we used a methylation-specific polymerase chain reaction to detect aberrant hypermethylation of thepromoters of the DNA repair gene O6-methylguanine-DNA methyltransferase (MGMT), p16INK4a, rasassociation domain family 1A (RASSF1A), apoptosis-related genes, death-associated protein kinase (DAPK),and retinoic acid receptor ß (RARß).There is no association between methylation status of five tumor suppressorgenes including MGMT, p16INK4a, RASSF1A, DAPK and RARß in pleural fluid DNA and clinicopathologicalparameters including clinical outcome. Aberrant promoter methylation of tumor suppressor genes in pleuralfluid DNA could not be a valuable prognostic marker of NSCLC patients with malignant pleural effusion.     

Aberrant promoter methylation in pleural fluid DNA for diagnosis of malignant pleural effusion

Accumulating evidence implicates epigenetic changes such as hypermethylation in carcinogenesis. We investigated whether DNA methylation of 5 tumor suppressor genes in pleural fluid samples could aid in diagnosis of malignant effusion. In samples from 47 patients with malignant pleural effusions and 34 with nonmalignant effusions, we used a methylation-specific polymerase chain reaction to detect aberrant hypermethylation of the promoters of the DNA repair gene O(6)-methylguanine-DNA methyltransferase (MGMT), p16(INK4a), ras association domain family 1A (RASSF1A), apoptosis-related genes, death-associated protein kinase (DAPK), and retinoic acid receptor beta (RARbeta). Promoter hypermethylation was associated with malignant effusion for MGMT (Odds ratio (OR) = infinity), p16(INK4a) (OR = infinity), RASSF1A (OR = 13.8; CI, 1.71-112), and RARbeta (OR = 3.17; CI, 1.10-9.11), but not for DAPK. Instead, DAPK methylation was associated with the length of smoking (p < 0.05). Patients with hypermethylation of MGMT, p16(INK4a), RASSF1A or RARbeta were 5.68 times more likely to have malignant effusions than patients without methylation (p = 0.008). Methylations per patient were more numerous for lung cancer than nonmalignant pulmonary disease (0.915 vs. 0.206, p < 0.001). Sensitivity, specificity, and positive predictive value of methylation in one or more genes for diagnosis of malignant effusion were 59.6%, 79.4%, and 80.0% respectively. In conclusion, aberrant promoter methylation of tumor suppressor genes in pleural fluid DNA could be a valuable diagnostic marker for malignant pleural effusion.