抑癌基因p16的研究进展

p16是近年来确定的多肿瘤抑制基因，它对细胞周期的负调控作用尤为重要，其突变或缺失会导致对细胞分裂调控的丧失和紊乱，导致细胞的异常增殖，最终形成肿瘤。该基因在各种肿瘤中的作用，目前正越来越引起人们的重视。     

抑癌基因p53与肿瘤发生及基因治疗的研究进展

概述了抑癌基因p53的结构和特性,以及p53的抑癌作用机理、基因治疗的研究进展.抑癌基因p53是人类细胞中非常重要的基因,野生型p53基因产物具有抑制肿瘤细胞增殖、诱导肿瘤细胞凋亡的作用.在p53基因发生突变或缺失时,可引起多种肿瘤.当人工将野生型p53基因与载体结合成重组DNA分子导入肿瘤患者体内后,有可能达到治疗恶性肿瘤的目的.     

胃上皮内瘤和胃癌组织中p53蛋白表达的意义

探讨胃上皮内瘤和胃癌组织中P53蛋白的表达及其临床意义;应用免疫组化SP法对10例慢性胃炎组、30例胃上皮内瘤组及20例胃癌组中P53的表达进行检测;慢性胃炎中无p53表达,随着异型增生程度的增加,p53阳性表达也在增加,胃癌的阳性率最高;p53蛋白在胃上皮内瘤中即显示异常表达,其突变发生于胃粘膜癌变的早期阶段,提示p53基因的缺失、突变与细胞的异型性密切相关。     

口腔鳞状细胞癌中错配修复基因hMLH1、hMSH2、p53和PCNA表达的相关性及意义

探讨hMLHI、hMSH2、p53和PCNA在OSCC中的表达关系及可能存在的临床意义。运用免疫组织化学S—P法对56例口腔鳞状细胞癌巾hMLH1、hMSH2、μ53和PCNA的表达进行检测。4种基因产物在OSCC中的阳性率均高于正常口腔黏膜,其中,中一低分化癌中的阳性率均高于高分化癌;hMSH2、p53和PCNA的阳性率在有淋巴结转移者中高于无转移者。hMLHI与p53／PCNA表达,hMSH2与p53／PCNA,p53与PCNA表达均呈正相关性。hM—LH1、hMSH2、p53和PCNA的异常表达及其相互之间的调节可能与OSCC的发生发展有关;检测4种蛋白有助于判断OSCC的恶性程度和生物学行为．     

结、直肠癌患者抑癌基因的甲基化检测

目的：评价特异性甲基化PCR（MSP）分析法检测抑癌基因高甲基化对结、直肠癌的诊疗价值。方法：应用MSP法检测36例结、直肠癌患者血清、术中癌旁组织及癌组织中的抑癌基因hMIM1、p15、p16甲基化的发生率。另选择36例健康体检者血清样品作正常对照。结果：36例结、直肠癌患者术前血清及术中癌组织的hMIM1、p15、p16甲基化发生率为59％-97％,癌旁组织略低;术后1周血清中hMIM1、p15、p16与术前比较明显下降（P〈0．01）,而正常对照组抑癌基因甲基化发生率均为0。结论：MSP法的建立,直接检测结、直肠癌患者的抑癌基因的高甲基化状态,有助于临床判断和动态观察治疗的效果。     

Interaction of hepatitis B virus with tumor suppressor gene p53: its significance and biological function

The mechanism of the interaction of hepatitis B virus (HBV) with tumor suppressor p53 and its role in the hepatocar-cinogenesis have been studied by PCR-directed sequencing, gel shift assays and in situ ultraviolet cross-linking assay. The biological function of the interaction of HBV with p53 gene was investigated by co-transfection of chloramphenicol acetyltransferase ( CAT) reporter gene. p53 and HBV DNA. and quantitative PCR. Among the 16 primary hepatocellular carcinoma (PHC) samples. 13 were HBV-DNA positive. 10 HBxAg positive and 9 p53 protein positive. The p53 gene point mutation was found in 5 samples, one of which had a G to T substitution located at codon 249. After analyzing the HBV genome by a computer program, a p53 response element binding sequence was found in HBV genome at upstream of enhancer I. from 1047 to 1059 nucleotides. This sequence could specifically bind to p53 protein, increase p53 protein accumulation in the PHC cells and stimulate the transactivating activity of p53 and HBV replication . The results also revealed that HBxAg could combine with p53 protein to form a complex in the cells and enhance CAT expression. Immunocytochemical staining showed that p53 protein complex was located in the cytoplasm and the process of p53 entry to nuclei was. in part, blocked. From our results, we conclude that the mutation of p53 gene at codon 249 is infrequent in HBV-associated PHC. the DNA-protein binding between HBV and p53. and the protein-protein binding between HBxAg and p53 might lead to the reduction or inactivation of p53 protein, which in turn resulting in HBV-associated hepatocarcinogenesis.     

KAI1基因表达与肿瘤转移的抑制

就KAI1基因的发现、定位及作用机制：KAI1基因在肿瘤转移过程中的抑制作用；KAI1基因的表达与肿瘤预后之间的关系的意义等方面的研究结果作一综述。     

一个推测的马氏珠母贝肿瘤抑制子QM的cDNA分析

从马氏殊母贝（P．martensif）足的SMARTcDNA文库中得到了一个与肿瘤抑制子QM基因同源的克隆,测序获得了757bp的全长cDNA序列，推测的开放阅读框位于23-673bp，编码217个氨基酸，由20种氨基酸组成，最少的为色氨酸，仅占1．4％，最多的为精氨酸，有24个，占11．1％；同GenBank数据库中查找到的马氏珠母贝（P．fucata）QM基因仅在末尾有4个氨基酸存在差异．P.fucata缺少P．mariensii在开放阅读框的第637处对应的碱基C，导致P．fucala的QM蛋白在3′端多了13个氨基酸和缺乏多聚腺苷酸加尾信号AATAAA．因而，已报道的P.fitcataQM基因很可能由于测序等原因导致在开放阅读框第637处缺失了碱基C．     

FHIT抑癌基因在头颈部鳞癌中的研究进展(综述)

脆性组氨酸三联体基因(FHIT)是1996年新发现的一种定位于人类染色体3p14．2上的抑癌基因，其编码的蛋白质具有ApnA水解酶的特性，可通过水解ApnA(主要是Ap3A)而阻止细胞生长信号传导途径，从而抑制细胞的生长；另有观点认为FHIT可与Ap3A等结合成FHIT底物复合物，这种复合物可能是一种信号物质，其抑癌作用可能比其水解酶作用更重要。研究表明FHIT在肿瘤的发生中起着重要的作用，现就FHIT在头颈部鳞癌中的研究进展作一综述。     

丙型肝炎病毒感染与ras,p53基因表达的相关性

为了探讨丙型肝炎病毒（ＨＣＶ）感染与肝细胞癌（ＨＣＣ）的关系以及ＨＣＶ可能的致癌机理，采用免疫组织化学方法及巢式ＰＣＲ法检测了１３６例肝细胞癌等肝病组织中的ＨＣＶＮＳ３抗原、ＨＣＶＲＮＡ及Ｐ２１、Ｐ５３蛋白。结果表明，肝细胞癌及癌周肝组织中有ＨＣＶＮＳ３抗原及ＨＣＶＲＮＡ检出，支持ＨＣＶ与ＨＣＣ的关联。Ｐ２１在ＨＣＣ、肝炎后肝硬化、慢性肝炎、体质性黄疸各组中的检出率随病变的加重而逐渐增高，在ＨＣＣ的癌及癌周组织中Ｐ２１呈致密的过量表达，提示ｒａｓ癌基因的激活在ＨＣＣ的发生过程中起一定作用。Ｐ５３的阳性率较Ｐ２１低，但ｐ５３的突变似乎也是肝癌发生的协同因素之一。组织中Ｐ２１的过量表达与ＨＣＶＮＳ３抗原阳性检出呈正相关，ＨＣＶＮＳ３抗原与Ｐ２１的这种关联提示，ＨＣＶ感染作为ＨＣＣ的密切相关因素之一，可能通过激活某些癌基因或使某些抑癌基因突变而致肝细胞癌变     

P15——a new tumor suppressor gene

In addition to the tumor suppressor genes such as Rb and p53, it has been found that some molecules of the same class named CKI (cyclin-dependent kinase inhibitor) also play an important role in the inhibition of tumorigenesis and the tumor progression. In the KIP and INK4 families of CKIs, p15 shares extensive homology with p16. Findings in many tumors and their cell lines show that the inactivation of p15 (deletion, mutation, rearrangement, etc.) is very frequent, and inactive p15 is involved in the progress of some tumors. These studies provide evidence that the p15 is a new tumor suppressor gene. Furthermore, the research on the molecular mechanism of p15 in regulation of cell proliferation shows that p15 can inhibit the growth of some kinds of tumor cells, and p15 is the mediator of TGF-β-induced cell arrest. Investigations on p15 in cell differentiation suggest that increased p15 is related to the change of malignant phenotype. These results supply clues for further interpretation about the molecular mechnism of cell cycle control and cell tumorigenesis. And they may provide theoretical and experimental basis for application of p15 to clinical therapy of tumors.     

早期肺癌病人血液中P53的克隆及其pEGFP-N1-p53的构建

首先用RT-PCR方法从早期肺癌病人的外周血中克隆出人抗癌基因p53,经测序确认为野生型后,通过酶切、连接、转化构建出扩增质粒pMD18-T-p53,然后构建出含增强型绿色荧光蛋白(EGFP)基因的真核表达质粒pEGFP-N1-p53.pEGFP-N1-P53经限制性内切酶Hind Ⅲ和BamH Ⅰ酶切,酶切产物电泳结...