APC promoter methylation and protein expression in hepatocellular carcinoma

Purpose We investigated the impact of promoter methylation on APC protein expression in patients with hepatocellular carcinoma (HCC). Materials and methods 50 patients [HCC (n=19), liver metastasis (n=19), cholangiocellular cancer (n=7), and benign liver tumors (n=5)] were studied for methylation using Methylight analysis. APC mutation was investigated by protein truncation test and direct sequencing of genomic DNA. The protein expression was evaluated by immunohistochemistry and Western blot analysis. Results The APC promoter was hypermethylated in 81.8% of non-cancerous liver tissue samples. All HCC samples and ten patients with liver metastasis (52.6%) exhibited APC promoter methylation. The degree of methylation was significantly higher in samples from HCC compared to the non-cancerous liver tissue samples (63.1% vs. 24.98%; p=0.001). The level of APC protein expression was significantly reduced in HCC samples compared to that of the corresponding non-tumor liver tissue (p<0.05). Conclusions Promoter methylation of the APC gene seems to be of significance in hepatocarcinogenesis and results in reduced protein expression in HCC. Interestingly, APC promoter methylation is also present in the vast majority of non-cancerous liver tissue whose (patho)physiological function remains unresolved.     

Caveolin-1和Caspase-3蛋白在肝细胞癌中的表达及意义

目的研究Caveolin．1和Caspase-3蛋白在肝细胞癌中的表达及意义。方法采用免疫组织化学检测30例肝细胞癌,相应癌旁及10例正常肝组织中Caveolin-1和Caspase-3蛋白的表达。结果（1）Caveolin-1在正常肝组织、癌旁肝组织、肝细胞癌组织中的阳性表达率分别为90％、13．33％、10％。Caspase-3在正常肝组织、癌旁肝组织、肝细胞癌组织中阳性表达率分别为90％、70％、40％。Caveolin．1和Caspase-3在不同性质组织间的表达,差异均有统计学意义（P〈0．05）;（2）Caveolin-1与Caspase-3的表迭在肝细胞癌中无明显相关性（r=0．181,P=0．337）。结论Caveolin-1与Caspase-3在肝细胞癌组织中表达均呈下降,但两者间无明显相关性,提示在肝细胞癌中,Caveolin-1的异常与Caspase-3细胞凋亡紊乱无关。     

人原发性肝细胞癌中总基因组DNA甲基化变化的研究

目的：研究原发性肝细胞癌组织中总基因组DNA甲基化水平及其与病理学及生物学行为的关系。方法：以甲基化酶温育3H-腺苷甲硫氨酸掺入、液闪计数法分析33例中晚期肝癌手术标本的癌灶和癌旁组织细胞内总基因组DNA甲基化水乎，并以10例正常肝组织作对照比较。结果：肝癌灶内的DNA甲基化水平显著低于癌旁组织（P＜0．05）和正常对照肝组织（P＜0．01），其甲基化水平降低程度与肿瘤的大体形态（多发性或单灶性．结节型或区块型）有关，而与组织学改变（Edmondson分级）、门脉癌栓有否及血清AFP水平无明显关系。结论：人原发性肝细胞癌组织中DNA的甲基化水平有显著降低，值得进一步研究肝细胞癌组织个别癌基因片段甲基化及mRNA表达状况。     

DNA methylation in hepatocellular carcinoma

As for many other tumors, development of hepatocellular carcinoma （HCC） must be understood as a multistep process with accumulation of genetic and epigenetic alterations in regulatory genes, leading to activation of oncogenes and inactivation or loss of tumor suppressor genes （TSG）. In the last decades, in addition to genetic alterations, epigenetic inactivation of （tumor suppressor） genes by promoter hypermethylation has been recognized as an important and alternative mechanism in tumorigenesis. In HCC, aberrant methylation of promoter sequences occurs not only in advanced tumors, it has been also observed in premalignant conditions just as chronic viral hepatitis B or C and cirrhotic liver. This review discusses the epigenetic alterations in hepatocellular carcinoma focusing DNA methylation.     

NHE1 mRNA在肝癌组织的表达及意义

目的 探讨钠氢交换蛋白1（NHE1）mRNA在原发性肝细胞肝癌组织及癌旁组织的表达及意义。方法采用RT—PCR检测诊断为HCC患者34例的肝癌及癌旁组织中NHE1mRNA的表达情况。结果所有肝癌组织和癌旁组织NHE1均有表达,相对表达量分别为2．892±0．882和0．802±0．206,两者存在显著性差异（P〈0．001）。作为对照的21例肝组织NHE1的相对表达量为0．872±0．186。肝癌组织与对照肝组织比较存在显著性差异（P〈0．001）;癌旁组织与对照肝组织比较差异无统计学意义（P〉0．10）。将从同一患者取材的肝癌组织和癌旁组织检测到的NHE1mRNA的表达量进行配对t检验,两者间存在显著性差异（P〈0．001）。结论NHE1mRNA在肝癌组织的表达增高,可能在肝癌的发生中起一定的作用。     

DKK-1在非小细胞肺癌中的研究进展

DKK-1是DKK家族的一员,为一种分泌型糖蛋白.它通过与其相应的受体结合来调控细胞内的信号传导,进而来决定细胞的分化、增殖、生存、凋亡、迁移等特性,在肿瘤发生方面发挥重要作用.DKK-1可能成为非小细胞肺癌早期诊断及判断预后的一种非常有前景的标志物.     

Clinicopathological significance of RASSF1A reduced expression and hypermethylation in hepatocellular carcinoma

Purpose  

Protein downregulation and hypermethylation of Ras association domain family 1A (RASSF1A) has been recognized as an important early event in different classes of carcinogenesis, but clinicopathological significance of RASSF1A protein expression and methylation in hepatocellular carcinoma (HCC) remains largely unknown. The aim of the study was to investigate the expression of RASSF1A protein and methylation in HCC and their clinical significance.     

TRA1 mRNA在肝硬化及肝癌组织中表达的研究

目的探讨肝癌(hepatocellular carcinoma,HCC)组织、肝硬化(liver cirrhosis,LC)组织及正常对照组织中肿瘤排斥抗原1(tumor rejection antigen 1,TRA1)mRNA的表达及关系。方法采用逆转录-聚合酶链反应的方法检测34例肝癌患者肝癌组织、癌旁肝硬化组织、非肝癌的肝硬化患者活检组织、肝血管瘤及肝内胆管结石等对照组织中TRA1 mRNA的表达,用捷达801分析软件对结果进行相对定量分析。结果肝癌组织、肝硬化组织、对照组织TRA1 mRNA表达率分别为95.00%、84.21%、50.00%,肝癌组与对照组间表达率的比较,差异有统计学意义(P0.05),肝硬化组织、对照组织表达率之间差异无明显统计学意义(P0.05);肝癌组织、肝硬化组织、对照组织TRA1 mRNA表达量分别为1.67±0.96、1.49±0.53、0.57±0.27;扩增产物表现出表达量的不同,呈现渐变趋势,肝癌组织、肝硬化组织与对照组之间差异有统计学意义(P0.05),肝癌组织与肝硬化组织比较,差异无统计学意义(P0.05)。结论 TRA1参与了肝硬化、肝癌的发生、发展,TRA1可能是肝硬化和肝癌潜在诊断标志物和治疗靶点。     

RhoC和IQGAP1蛋白在原发性肝细胞癌中的表达及意义

目的:探讨RhoC和IQGAP1蛋白在原发性肝细胞癌(hepatocellular carcinoma,HCC)组织中的表达及其临床病理意义.方法:采用免疫组织化学法分别检测56例原发性肝细胞癌和15例正常肝组织中RhoC及IQGAP1蛋白的表达,并分析两者的相关性及与临床病理因素的关系.结果:RhoC和IQGAP1在...     

DNA methylation,microRNAs,and their crosstalk as potential biomarkers in hepatocellular carcinoma

Epigenetic alterations have been identified as a major characteristic in human cancers.Advances in the field of epigenetics have contributed significantly in refining our knowledge of molecular mechanisms underlying malignant transformation.DNA methylation and microRNA expression are epigenetic mechanisms that are widely altered in human cancers including hepatocellular carcinoma(HCC),the third leading cause of cancer related mortality worldwide.Both DNA methylation and microRNA expression patterns are regulated in developmental stage specific-,cell type specific-and tissue-specific manner.The aberrations are inferred in the maintenance of cancer stem cells and in clonal cell evolution during carcinogenesis.The availability of genome-wide technologies for DNA methylation and microRNA profiling has revolutionized the field of epigenetics and led to the discovery of a number of epigenetically silenced microRNAs in cancerous cells and primary tissues.Dysregulation of these microRNAs affects several key signalling pathways in hepatocarcinogenesis suggesting that modulation of DNA methylation and/or microRNA expression can serve as new therapeutic targets for HCC.Accumulative evidence shows that aberrant DNA methylation of certain microRNA genes is an event specifically found in HCC which correlates with unfavorable outcomes.Therefore,it can potentially serve as a biomarker for detection as well as for prognosis,monitoring and predicting therapeutic responses in HCC.     

人胃癌,肝癌的c—myc癌基因甲基化的研究

目的：了解人胃癌和肝癌相关癌基因的甲基化情况。材料与方法：将22例进展期胃癌的癌区、癌旁和外周正常区组织和33例原发性肝癌的癌区、癌旁区及10例正常肝组织的DNA，以限制性内切酶Hpall／Mspl消化、Southernblot分析其c－myc癌基因片段的甲基化情况。结果：发现47％（10／22）的胃癌区、59％（13／22）的胃癌旁和30％（10／33）的肝癌区、13％（4／33）的肝癌旁组织的c－myc癌基因呈低甲基化状态。结论：在消化系常见的恶性肿瘤的发生中，某些癌基因甲基化水平降低。     

肝癌组织中ZHX2基因启动子甲基化及其与临床病理特征的关系

目的 运用变性高效液相色谱(Denature High-Performance Liquid Chromatography,DHPLC)法检测原发性肝癌细胞中ZHX2基因启动子甲基化的情况,为进一步探讨其与原发性肝细胞癌(HCC)临床病理特征之间的关系奠定基础.方法 采用亚硫酸氢钠-DHPLC技术,以体外甲基化的DNA和人类胎盘DNA分别为甲基化和非甲基化对照,建立ZHX2基因启动子甲基化DHPLC分析方法.在55℃部分变性条件下,对ZHX2基因启动子重要区域甲基化水平进行检测,并对24例HCC癌组织及癌旁肝组织和6例正常肝组织标本进行检测.结果 建立了ZHX2基因启动子甲基化DHPLC分析方法,使用该方法检测结果显示正常肝组织未检测到甲基化,24例HCC癌组织中有11例存在甲基化(45.8％),而24例HCC癌旁组织中有3例(16.6％)存在甲基化.结论 本研究建立了ZHX2基因启动子甲基化DHPLC分析方法,并首次将其应用于肝癌组织标本的检测,为深入探讨ZHX2基因与HCC发生发展之间关系奠定了基础.     

POLD1基因在原发性肝癌中的表达及其意义

目的:探讨DNA聚合酶δ催化亚基基因(DNA polymerase delta catalytic subunit gene 1,POLD1)及其编码蛋白p125在原发性肝癌中的表达及意义.方法:选用原发性肝癌患者手术切除标本20例,分别采用逆转录聚合酶链反应(RT-PCR)法和Western blot法检测POLD1...     

Clinical implications of DNA methylation in hepatocellular carcinoma

Background

Epigenetics is a rapidly evolving field of genetic study applicable to nearly every aspect of genome-related research. The importance of epigenetics has been recognised in human hepatocellular carcinoma (HCC). Changes in DNA methylation patterns, including global hypomethylation and promoter hypermethylation, are thought to be early events in hepatocarcinogenesis.

Objectives

This review aimed to summarise the role of epigenetics in HCC, to describe the mechanisms of epigenetic changes in HCC and to examine the clinical relevance of epigenetics in HCC.

Methods

This review examines the role of CpG-rich regions and DNA methylation, and describes an epigenetic model of cancer, tumour type-specific methylation, the relationships among methylation, cirrhosis and hepatocarcinogenesis, and the role of DNA methylation in HCC. The clinical implications of epigenetics in HCC are discussed.

Results

A multivariate predictor model based on traditional clinical factors and DNA methylation profile may have important applications in the early detection of neoplastic transformation in populations at high risk for HCC. CpG methylation may be valuable in HCC prognostics. DNA methylation profiles may enable clinical prediction in pre-therapy patient biopsies, paraffin-embedded samples or plasma DNA.

Conclusions

Epigenetic changes and profiles may correlate to the biological behaviour of tumours and clinical outcome of HCC patients. The use of DNA methylation profiles as a surrogate biomarker remains an active area of clinical cancer research.     

肝细胞癌患者PBMCs中T-bet、GATA3和Foxp3 mRNA水平及其意义

目的探讨肝细胞癌患者外周血单个核细胞(PBMC)中T-bet、GATA3和Foxp3 mRNA水平变化及意义。方法在肝细胞癌患者20例和健康对照人群10例,采用RT-PCR法检测PBMC中T-bet、GATA3和FoxP3mRNA水平。结果 HCC患者和健康对照T-bet水平分别为0.554±0.030和0.514±0.071(P=0.391);HCC患者和健康对照GATA3水平分别为0.956±0.030和0.535±0.028(P<0.01);HCC患者和健康对照FoxP3水平分别为0.976±0.073和0.772±0.083(P<0.01);HCC患者和健康对照T-bet/GATA3比值分别为0.697±0.078和0.963±0.133(P<0.01)。结论肝细胞癌患者PBMC中GATA3和FoxP3 mRNA水平上调,可能参与了HCC的发生和发展过程。