PROMOTER HYPERMETHYLATION OF p16 GENE AND DAPK GENE IN SERA FROM HEPATOCELLULAR CARCINOMA （HCC） PATIENTS

Objective： To analyze the aberrant methylation of p16 gene and DAPK gene in sera from primary liver cancer patients ad to evaluate the clinical significance. Methods： A methylation-specific PCR was performed for the detection of promoter hypermethylation of p16 gene and DAPK gene in blood DNA from 64 cases of HCC patients, and to analyze the relation of the aberrant methylation of p16 gene and KAPK gene and the clinical pathological data. Results： 76.6%（49/64） of the sera from 64 cases of HCC patients showed hypermethylation for p16 promoter and 40.6% （26/64） for KAPK promoter, whereas no methylated p16 gene promoter and DAPK gene promoter were found in sera from benign liver diseases patients and normal control. Methylated p16 gene and KAPK gene promoters in sera did not strongly correlated with HBsAg, stage, metastasis and differentiation in HCC; but strongly correlated with AFP. Conclusion： Detection of the aberrant methylation of p16 gene and KAPK gene in blood DNA from HCC patients might offer an effective means for the earlier auxiliary diagnosis of the malignancy.     

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.     

CLINICAL STUDY OF T-PA AND U-PA EXPRESSION IN PATIENTS WITH GASTROINTESTINAL CANCER

Objective: To study the changes of tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA) expressions and fibrinolysis molecular markers in patients with gastrointestinal cancer in order to elucidate their clinical significance. Methods: The plasma levels of t-PA, u-PA, urokinase-type plasminogen activator receptor (u-PAR) and plasmin anti-plasmin complex (PAP) were measured by ELISA. t-PA and u-PA mRNAs were detected by Real-time RT-PCR. Results: The plasma levels of u-PA, u-PAR and PAP were elevated in gastrointestinal cancer patients, while u-PA was markedly elevated in patients with local infiltration, lymph node involvement or distal metastasis. U-PA mRNA was higher and t-PA was lower in gastrointestinal cancer compared to normal tissue. Conclusion: Hyperfibrinolysis is an important factor related with metastasis potential of gastrointestinal cancer, t-PA may be a character of well differentiated tissue.     

HYPERMETHYLATION STATUS OF E-CADHERIN AND p16^INK4a IN GASTROINTESTINAL STROMAL TUMOR

Objective： To investigate the methylation status of CpG island in E-cadherin（CDHl）, P16^INK4a（ P16）promoter region ,and to analyze their role in gastrointestinal stromal rumor （GISTs）. Methods： A total of 56 surgically resected GISTs were obtained from January 2003 to December 2005. The routine H＆E-stained sections and CD117, CD34-immunoreactions were reviewed to verify the morphologic diagnosis. Methylation status of the CDH1, P16^INK4a promoter region was analyzed by methylation specific polymerase chain reaction （MSP） from chemically modified DNA after Na-bisulfite treatment. Results： The frequency of CDHlgene methylation was 32% （18 of 56） in GISTs. The rate was 9% （1 of 11）, 21% （4 of 19）, 41.6% （5 of 12）, and 57% （8 of 14） for very low risk, low risk, intermediate risk, and high risk GISTs; P16^INK4a methylation was found in 19 of 56（34%） cases. The rate was 0% （0 of 11）, 16% （3 of 19）, 50% （6 of 12）, and 71% （10 of 14） for very low risk, low risk, intermediate risk, and high risk GISTs. Statistical analysis indicated that of the 56 cases, there was significant association of CDH^INK4a and/or P16^INK4a methylation status with tumor malignant behavior （methylation rate 23/56, 41%, P〈0.01） and site （P〈0.05）. Conclusion： E-cadherin （CDHI） and/or P16^INK4a promoter hypermethylation is strongly associated with risk grade, may be a useful biomarker for GISTs risk assessment, and may shed light on new therapeutic options to treat GISTs     

外源性p16基因表达可抑制人胃癌细胞的恶性增殖

目的探讨ｍｔｓｌ／ｐ１６基因在肿瘤发生发展过程中的作用及在临床基因诊断和基因治疗中的应用前景。方法构建ｍｔｓｌ／ｐ１６基因的表达载体并导入表达水平下调的ＰＡＭＣ８２细胞,用ＰＣＲ、Ｎｏｒｔｈｅｒｎ杂交、ｍＲＮＡ原位杂交和Ｗｅｓｔｅｒｎ杂交对获得Ｇ４１８抗性的细胞进行外源性ｍｔｓｌ／ｐ１６基因整合及表达的鉴定。对导入外源性ｐ１６基因的细胞进行裸鼠致瘤能力及病理学特性分析。结果转染ｐ１６基因的ＰＡＭＣ８２细胞（命名为ＰＡＭＣｐ１６）有外源性ｍｔｓｌ／ｐ１６基因的整合及表达,在裸鼠中的致瘤性显著降低。肿瘤组织病理分析结果显示,ＰＡＭＣｐ１６细胞形成的肿瘤,其分化程度优于ＰＡＭＣ８２细胞。结论导入外源性ｍｔｓｌ／ｐ１６基因可抑制肿瘤细胞的恶性增殖和促进细胞分化。     

p16基因抑制食管癌细胞生长的研究

目的 探讨ｐ１６基因对食管癌细胞生长的抑制作用,为食管癌致癌机理的研究和基因治疗提供理论基础。方法 我们采用基因转染技术,将全长野生型ｐ１６ ｃＤＮＡ转染到经亚硝胺诱发的人胎儿食管癌细胞系中,该细胞内源性ｐ１６基因已发生纯合性缺失。结果 转染ｐ１６基因的食管癌细胞生长受到抑制,其在软琼脂上克隆形成能力降低了大约４倍。对细胞周期分析表明,处在Ｇ０￣Ｇ１期的细胞由３３．７％增加到６８．６％。经Ｄｏｔ     

p16基因在胃癌中的表达及其意义

ｐ１６是最近发现的一个比ｐ５３更直接参与细胞周期调控的抑癌基因,又称为多肿瘤抑制基因。本文用流式细胞术对ｐ１６在胃癌和癌旁组织的表达进行了定量分析,以探讨ｐ１６在胃癌发生中的作用及其与胃癌临床病理特点的关系。１材料与方法本院手术切除经病理证实胃癌标本...     

p16基因在鼻咽癌中缺失和表达改变的研究：p16基因在鼻咽癌中的改变系列研

目的：探讨ｐ１６基因是否在鼻咽癌活检组织中存在高频的失活,以确定该基因在鼻咽癌发病过程中所起的作用。方法：首先利用免疫组化的方法检测了１４例鼻咽癌活检组织中;ｐ１６基因的表达状况。并用比较多重ＰＣＲ－Ｓｏｕｔｈｅｒｎ杂交的方法检测了这１４例鼻咽癌活检组织中ｐ１６基因外显子１α和外显子２可能的缺失,以了解导致ｐ１６基因表达下调的机制。     

胃肠道肿瘤p16、cyclinD1基因表达的研究

[目的]探讨p16、cyclinD1在胃肠道肿瘤发生、分化中的变化规律。[方法]病人430例,用原位杂交技术观察不同病变状态胃肠道粘膜（正常粘膜、慢性炎症、癌前病变及肿瘤）中p16、cyclinD1的基因表达。[结果]正常胃、结肠粘膜p16阳性表达率为90.9％、86％,cyclinD1均为阴性,萎缩性胃炎、不典型增生、胃癌中p16阳性率分别为78.6％、37.5％、26.25％,cyclinD1阳性率依次为21％、58％、73.75％（P<0.05）;p16与cyclinD1有交叉共存现象,胃癌30％,结肠癌26.7％;同时,有反向表达现象,胃癌占70％,结肠癌为73.8％;p16阳性表达率与cyclinD1的阳性表达率呈显著负相关。[结论]p16的缺失、cyclinD1的激活,可单独或协同促进胃肠肿瘤的发生、发展;两者的反向表达趋势提示两者可能存在相互抑制机制。     

食管癌组织中p16基因突变及其产物表达的研究

目的 探讨ｐ１６基因变异及其产物表达与食管癌生物学行为的关系。方法 应用ＰＣＲ－ＳＳＣＰ和ＰＣＲ方法检测了林县食管癌标本中ｐ１６／ＣＤＫＮ２基因１、２外显子的突变和缺失情况。并用免疫组化方法检测其产物表达情况。结果 在４７例标本中,３例出现了突变,其中第１外显子１例,第２外显子２例,突变率为６．４％（３／４７）。有１２例出现纯合性缺失,缺失率率２５．５％,其叫变异率为３１．９％。免疫组经染色显示,     

肺癌患者外周血血浆中p16基因异常甲基化的检测

目的 分析肺癌患者外周血血浆中p16基因启动子区异常甲基化发生情况,探讨血浆中p16基因异常改变作为肺癌临床辅助诊断分子生物学标志物的可能性。方法 利用半巢式甲基化特异性PCR技术,检测了137例肺癌患者血浆和112例相对应肿瘤组织DNA p16基因的异常甲基化情况。结果 在血浆和肿瘤组织中的p16基因甲基化检出率分别为75．2％和80．4％;其中鳞癌、腺癌、腺鳞癌和小细胞肺癌患者血浆标本的阳性率分别为77．9％,65．1％,75．1％和91．7％。血浆DNAp16基因甲基化仅在肿瘤组织存在同样甲基化的病例中被检出。血浆和肿瘤组织中,p16基因的甲基化异常改变与肿瘤的分期、分型无明显相关性。结论 分析血浆DNA的p16基因异常甲基化有可能成为辅助肺癌诊断的有效方法之一。     

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

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.     

肺癌患者组织样品中p16基因的异常甲基化

目的 分析肺癌患者组织样品中p16基因启动子区域异常甲基化的改变情况,评价该指标作为辅助临床诊断的分子标记物的价值。方法 运用甲基化特异性PCR技术,检测51例原发性肺癌患者的肿瘤组织、外周血血浆和痰标本中p16基因启动子区域的异常甲基化改变。结果 在43例肿瘤组织、36例血浆和39例痰标本中检测到了p16基因异常甲基化。凡在肿瘤组织检出p16基因甲基化阳性的病例,其血浆和(或)痰标本也为阳性;而肿瘤组织p16基因甲基化阴性的病例,其血浆和痰标本也为阴性。将血浆和痰标本的p16甲基化分析与痰细胞学检查相结合,可以发现92．2％的肺癌病例。结论 利用半巢式甲基化特异性PCR进行的血浆和痰标本p16基因甲基化分析,有可能成为辅助肺癌诊断的分子生物学指标。     

Detection of p53 gene mutation in plasma of patients with gastric cancer

Objective:To investigated p53 gene mutation in plasma of gastric cancer patients. Methods: DNA extracted from plasma and matched tumor and tumor-adjacent non-cancerous tissues of 96 gastric cancer patients, and DNA from 20 healthy volunteers were studied. Exon 5, 6, 7, and 8 of p53 were amplified by Polymerase Chain Reaction (PCR). The mutation status was analyzed by denaturing high-performance liquid chromatography (DHPLC), followed by direct sequencing of cases with aberrant chromatographic patterns. Results: Heterozygous mutations of p53 gene were detected in 19.9% (19/96) of primary tumor tissues and 5.2% (5/96) of corresponding plasma. All p53 gene mutations detected in plasma DNA consisted with mutations in the matched primary tumor samples.Neither the tumor-adjacent gastric mucosa tissues nor control plasma from healthy volunteers showed p53 gene mutation. No correlation was found between p53 mutation status and clinicopathological features of gastric cancer patients. Conclusion: p53 gene mutation in plasma can be detected in tissues and plasma of gastric cancer patients, which could be applied in screening and surveillance of this disease.     

前列腺癌的p16基因甲基化程度定量分析

目的 建立和评价基因组DNA甲基化的定量分析方法,并比较正常前列腺组织和前列腺癌组织中的p16抑癌基因的DNA甲基化差异.方法 提取正常前列腺组织和前列腺癌组织中的基因组DNA,用亚硫酸氢钠将未甲基化的胞嘧啶转化为尿嘧啶,经过PCR扩增后,用BstUⅠ和HpaⅡ限制性内切酶消化,通过电泳分离消化的片段,定量分析基因组中...     

乳腺癌患者血清中ｐ１６基因甲基化状态的研究

目的　选取ｐ１６基因启动子甲基化这一指标来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　应用甲基化特异性聚合酶链反应（ＭＳ-ＰＣＲ）检测８２例乳腺癌患者组织及其配对血清中游离ＤＮＡｐ１６基因启动子区域甲基化状况。结果　８２例乳腺癌组织ｐ１６基因启动子甲基化阳性率为３０.５％（２５／８２）,相应外周血清中ｐ１６基因启动子甲基化阳性率为１９.５％（１６／８２）。２５例呈现甲基化阳性的癌组织中有１６例其配对血清中也监测到ＤＮＡ甲基化阳性,而８２例乳腺癌组织中甲基化阴性的５７例患者、３０例乳腺良性病变患者以及２４例健康人,其外周血清均为ｐ１６基因启动子甲基化阴性。外周血清中ｐ１６基因启动子区域甲基化异常与乳腺癌组织中的甲基化状况显著相关（ｒ＝０.７４３５,Ｐ＜０.０５）。乳腺癌组织及外周血清中ｐ１６基因启动子区域甲基化状态与肿瘤分期、肿块的大小、病理类型、月经状况、淋巴结转移、激素受体、家族史无关。结论　乳腺癌患者外周血清中ｐ１６基因启动子甲基化与肿瘤组织中相同基因的变异显著相关,可用血清替代癌组织检测ｐ１６基因启动子区域甲基化状态。     

NSCLC患者血浆p16和MGMT基因甲基化检测及临床意义

目的：检测非小细胞肺癌（non—small cell lung cancer，NSCLC）患者外周血血浆中p16基因、O^6-甲基乌嘌呤-DNA甲基转移酶（O^6-methylguanine—DNA methyhransferase，MGMT）基因启动子的甲基化状态，探讨p16、MGMT基因启动子的异常甲基化在NSCLC筛查及早期诊断中的意义。方法：利用巢式甲基化特异性聚合酶链反应法检测NSCLC患者外周血血浆p16、MGMT基因启动子的甲基化状态。结果：65例NSCLC血浆样品中分别发现19例（29．23％）p16基因启动子异常甲基化和16例（24．62％）MGMT基因启动子异常甲基化，45例正常对照血浆组未检测到p16、MGMT基因启动子的异常甲基化（P〈0．05），血浆中两基因甲基化检出率与NSCLC的分型及临床分期无明显相关性（P〉0．05）。结论：利用巢式甲基化特异性PCR法检测外周血血浆中p16、MGMT基因启动子的甲基化，可为NSCLC的筛查、早期诊断及预后判断提供有价值的信息。     

胶质瘤患者血浆与肿瘤组织P16基因甲基化的检测及意义

Objective:To explore the clinical significance of methylation status of promoter CpG island of p16 gene in glioma tissue and plasma.Methods:Methylation 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.Results:Hypermethylation 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 (Tissue:X2 = 11.4288,P = 0.0007;Plasma:X2 = 8.9439,P = 0.0028).The Ki-67 index increased significantly (P＜0.05) in brain gliomas methylated in contrast to those unmethylated.Conclusion:P16 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.