中国成人动脉粥样硬化病变中P53抑癌基因的结构突变及与病…

应用ＰＣＲ－ＳＳＣ方法，系统地研究了中国成人动脉粥样硬化（ＡＳ）病变组织中Ｐ５３抑癌基因结构的突变及与病变程度之间的关系。结果：受检的８９例ＡＳ组织中的９例 ＰＣＲ－ＳＳＣＰ的异常，其中６例经测序证实Ｐ５３基因突变的具体内容。在此基础上，应用高特异性的Ｐ５３蛋白单克隆抗体，证实在有Ｐ５３基因突变的ＡＳ组织中也同时有Ｐ５３突变蛋白的异常表达；对动脉管腔狭窄面积、斑声的相对厚度及二乾与Ｐ５３基因突变之     

肿瘤抑癌基因p53与原发性肝癌

１９８８年,Ｂｅｎ－Ｄａｖｉｄ［１］在小鼠Ｆｒｉｅｎｄ病毒感染的红细胞中发现了Ｐ５３基因的频发失活,提出了Ｐ５３是一个肿瘤抑制基因、研究发现,将人野生型Ｐ５３基因转染到体外培养的肿瘤细胞中,可抑制肿瘤细胞生长。野生型Ｐ５３基因在正常细胞分裂过程中可能并无作用,但在细胞损伤后修复及不可修复细胞的清除过程中却必不可少。１　ｐ５３因异常与肿瘤的发生 ｐ５３基因是许多恶性肿瘤十分常见的共同基因损伤靶位,它的结构改变与表达异常可能是这些肿瘤发生的中心环节。点突变是ｐ５３基因异常表现的主要形式之一。大多数结…     

抑癌基因p53与p16在胆囊癌的表达及意义

本研究,采用免疫组化法测定胆囊癌和胆囊良性病变标本的抑癌基因ｐ53与ｐ16蛋白表达,分析其在胆囊癌发生和发展中的作用以及和预后的关系。材料与方法一、标本来源收集本院近来手术的24例胆囊癌、20例胆囊腺瘤和18例慢性胆囊炎。胆囊癌根据Ｎｅｖｉｎ分期,Ｓ1、Ｓ2、Ｓ3共11例,Ｓ4、Ｓ5共13例。病理分级:Ⅰ级7例,Ⅱ级9例,Ⅲ级8例。所有标本均为石蜡包埋,作4μｍ连续切片。二、免疫组化法ｐ16抗体Ｃ20为ＳａｎｔａＣｒｕ2Ｂｉｏｔｅｃｈ产品,ｐ53抗体Ｄｏ7为Ｄａｋｏ产品。免疫组化采用Ｅｎｖｉｓｉｏｎ法,微波加热后进行抗原修复和暴露。以…     

肝细胞癌抑癌基因p53突变

目的分析重庆地区肝细胞癌ｐ５３基因突变谱．方法住院肝细胞癌患者２０例，皆经病理证实，长期在重庆地区居住，其中早期小肝癌４例，中期６例，晚期１０例．采用ＰＣＲ－ＳＳＣＰ，ＰＣＲ直接测序技术分析ｐ５３基因５，６，７和８外显子突变．结果ｐ５３基因总的突变率为４０％．其中外显子５和６各占１０％，外显子７占２０％，未发现外显子８的突变；测序证实外显子７为第２４９位密码子Ｇ→Ｔ的颠换突变．突变病例多为晚期肿瘤．结论重庆地区肝细胞癌存在明显的ｐ５３基因突变，反映了该地区肝癌与黄曲霉毒素和ＨＢＶ或ＨＣＶ病毒有关     

抑癌基因Mxil在白血病细胞中突变的研究

目的：分析Mxil基因突变在白血病发病中的作用。方法：利用逆转录-聚合酶链反应（RT-PCR）、单链构象多态性（SSCP）分析及DNA序列分析技术检测26例初治急性白血病患者、30名健康对照者和2种髓系白血病细胞株（KG1、K562）Mxil基因表达及突变情况。结果：RT—PCR显示所有标本中均可检测到Mxil基因的表达，在11．5％（3／26）初治急性白血病患者和KG1细胞株中发现四处错义突变，发生突变的3例患者均于确诊后5个月内死亡。结论：首次在急性白血病细胞中发现Mxil基因突变，提示Mxil基因的突变可能与白血病的发病和预后有关。     

细胞老化和p53基因的研究进展

研究发现抑癌基因在抑制肿瘤发生的同时，还调控着细胞老化。细胞老化最初是在40年前防止培养的正常人纤维原细胞分化生长过程中发现的。细胞老化和凋亡被认为在防止类似发生于肿瘤中的不良细胞增殖有相同作用，但细胞凋亡是杀死并消除癌变倾向的细胞，而细胞老化仅仅是不可逆地使其生长停滞。在癌基因刺激应答过程中，细胞老化经常发生，最终导致细胞生长停滞，而不是死亡。细胞老化的机制还不完全清楚，从某种程度上可理解为一系列基因活动变化的结果。     

U6嵌和型Maxizyme对肝癌突变抑癌基因p53的抑制作用

目的探讨U6嵌和型Maxizyme对肝癌突变抑癌基因p53的抑制作用。方法应用计算机设计针对肝癌突变抑癌基因p53(mtp53)249位密码子(AGG→AGT)Maxizyme(Mz)的基因片段,构建其真核表达载体,使抗mtp53的Mz嵌于U6表达系统中,细胞外由T7 RNA聚合酶转录,细胞内由RNA聚合酶Ⅲ高效转录。检测Mz在细胞外对mtp53的切割效率。在LipofectamineTM2000介导下转染肝癌细胞MHCC97,应用逆转录聚合酶链反应(RT-PCR)检测Mz对肝癌细胞mtp53的抑制作用,western blot分析mtp53蛋白表达水平,并用四甲基偶氮唑盐(MTT)法观察肿瘤细胞的生长情况。结果在细胞外,Mz可特异性切割靶基因mtp53,切割效率为42%,而野生型p53(wtp53)没有被切割。RT-PCR和western blot检测结果提示转染Mz的MHCC97内mtp53 mRNA和蛋白(5.3 ×104)表达均明显下降,转染Mz的MHCC97增殖速度明显降低。结论U6表达系统能高效启动核酶等小分子RNA的转录,U6嵌和型Maxizyme在细胞内外均可特异性抑制mtp53表达,抑制肝癌细胞增殖,有望开发为肝癌基因治疗的新方法。     

河南省肝细胞癌患者P53基因点突变研究

肝细胞癌(HCC)与抑癌基因P~(53)突变的关系是近年来分子生物学研究的一个热点,特别是其第7外显子(E7)第249编码区(cd249)的高频率点突变引起了许多学者的兴趣。1999年6月至2000年4月我们对49例HCC患者的癌组织标本进行了P~(53)基因     

Ras oncogene and p53 gene hotspot mutations in colorectal cancers

Abstract Ras oncogene and p53 gene mutations are frequently observed in colorectal cancers. The role of co-operation between these two genes in the tumorigenesis of colorectal cancer was evaluated. Point mutations in K-ras oncogene and hotspot codons of p53 gene of colorectal cancers were evaluated by naturally created or amplified created restriction site method. Nine of 42 cases (21.4%) of colorectal cancer showed K-ras oncogene mutations. Six of 42 cases (14.3%) of colorectal cancer showed p53 gene hotspot point mutations. The low frequency of p53 gene mutation in this series may be due to racial difference or different hotspot codons. When six cases with mutated p53 gene were examined, only one (16.7%) showed concurrent K-ras oncogene codon 12 and p53 gene codon 248 mutations. We concluded that the co-operation between ras oncogene and p53 gene hotspot point mutations in the tumorigenesis of colorectal cancer in Chinese was not common. Other factors such as adenomatous polyposis coli gene mutations, oncogene activation or tumour suppression gene inactivation may be involved.     

Correlation between mutations in p53 gene and protein expression in human lymphomas

A discordance between p53 protein overexpression and the presence of mutations in the gene has been observed in many types of tumors, including human lymphomas. To probe this finding, we have studied a large series of 94 lymphomas of different pathologic types and histologic differentiation. Analyzing exons 5–9, we have found mutations in the p53 gene in 7 of 94 cases distributed in different subtypes: 4/12 (33%) high-grade B-cell non-Hodgkin's lymphomas (B-NHLs), in 1 of 5 (20%) high-grade mucosa-associated lymphomas (MALT), in 1 of 22 (4.5%) anaplastic large cell lymphoma (ALCL), and in 1 of 24 (4%) T-cell NHLs. Immunostaining with anti-p53 antibody DO-7 was possible in 87 lymphomas, and overexpression of p53 protein was observed in 16 cases (18%). A discrepancy between the results of SSCP and immunostaining was detected in 18 tumor samples. Two cases with mutations in the gene showed no altered protein expression and 16 cases overexpressed p53 protein had no point mutations. In these cases, the possibility that mutations occur outside the exons studied has been tested and the entire coding sequence analyzed. Only one case showed a mutation in exon 10, and we found two cases carrying a polymorphism in exon 4 and in intron 10. We conclude that mutations in p53 occur mainly in high-grade B-cell NHLs. Although not limited to a specific subtype of lymphoma, they may be rare in Hodgkin's disease and in low-grade lymphomas. The discrepancies between overexpression and presence of mutations suggest (1) the existence of another mechanism to stabilize the p53 protein, and (2) that the immunohistochemistry cannot be used to predict mutations in the gene. Am. J. Hematol. 55:1-8, 1997. © 1997 Wiley-Liss, Inc.     

p53 gene mutations and expression of p53 and mdm2 proteins in invasive breast carcinoma

The aim of the study was to analyzep53 gene mutations and the expression of p53 and mdm2 proteins in 31 randomly selected invasive breast carcinomas. The results were then correlated with tumor grade, stage, estrogen receptor status, nodal status, and DNA ploidy. The expression of the proteins p53 and mdm2 was determined immunohistochemically using formalin-fixed, paraffin-embedded material. Screening for p53 mutation involved analysis of the highly conserved regions of thep53 gene (exons 5–9) by the polymerase chain reaction/single-strand conformation polymorphism (PCR-SSCP) technique. PCR products with band shifts were directly sequenced. Immunohistochemical staining of p53 was positive in 9 cases (29.0%), only 2 of which showed ap53 gene mutation. These were identified as a CG transversion at the second position of codon 278 in exon 8 and an AG transition at the second position of codon 205 in exon 6. A third case with a mutation was observed (CT transition, position 1 of codon 250 in exon 7) that did not show p53 immunohistochemically. Of the 9 p53-positive tumors, 2 were moderately differentiated (grade II). The remaining tumors were poorly differentiated (7/9). By contrast, p53-negative carcinomas were well differentiated (grade I) in most cases (P=0.02). DNA cytometry in 8 of the 9 p53-positive carcinomas revealed an aneuploid stem line. The majority of the p53-negative tumors were diploid (P=0.01). Mdm2 oncoprotein was detected in 10 tumors (32.2%), 4 of which were p53-positive, including the 3 with mutations. The grading of the mdm2-positive tumors was moderate or poor, G1 carcinomas were always noted to be mdm2-negative (P=0.04). Overexpression of p53 protein is a complex mechanism and does not merely indicate the detection of mutations in thep53 gene. This study has shown that p53 expression correlates with tumor grade and DNA ploidy. Mdm2 expression was also associated with the tumor grade. Immunohistological demonstration of the p53 protein alone is insufficient as a basis for comment on the functional state of thep53 gene and gene product. The interrelation between recognition of the p53 protein and gene mutation needs more careful assessment to define their roles in the control of neoplasia.     

胰腺癌ras癌基因及p53抑癌基因表达的临床意义

目的研究ras癌基因及p53抑癌基因在在胰腺癌表达的临床意义．方法胰腺石蜡包埋标本55例，包括胰腺癌32例，癌切缘未受浸润的胰腺组织12例，急慢性胰腺炎7例，正常胰腺4例，标本均经病理学证实，用免疫组织化学ABC法对上述标本的ras癌基因及p53抑癌基因表达进行检测．结果在32例胰腺癌中，ras和p53基因的阳性表达率分别为71．9％和28．1％，高于胰腺炎和癌切缘组织（P＜0．05）ras，p53基因表达与患者性别、年龄、肿瘤所在部位及大小和初发症状无关（P＞0．05），p53基因表达与临床分期和病理分级相关（P＜0．05），p53基因表达阳性者其临床分期较晚期，细胞分化较差，而ras基因表达仅与病理分级有关（P＜0．05）．P53基因表达与癌肿可切除率相关（P＜0．05），凡癌肿能切除者多为p53基因表达阴性者.p53基因表达亦与淋巴结转移有关（P＜0．05），其表达阳性者多已有淋巴结转移．ras与p53基因表达之间存在正相关关系．结论ras与p53基因表达可以反映胰腺癌的生物学行为，对胰腺癌的诊断和治疗有一定指导意义．     

Detection of Ki-ras and p53 gene mutations in tissue and pancreatic juice from pancreatic adenocarcinomas

Pancreatic carcinomas have a high incidence of Ki-ras mutations, and the genetic change is thought to occur at an early stage in the carcinogenesis. The aim of this study was to evaluate the usefulness of detecting genetic mutations in pure pancreatic juice (PPJ). DNA was extracted from tissue specimens of pancreatic carcinomas and from cells in PPJ, and subjected to polymerase chain reaction-single-strand conformation polymorphism analysis. Two types of mobility shifts that indicate Ki-ras mutations were observed in 13 of the 20 (65%) tissue specimens obtained by operation or autopsy. Ten of 15 specimens (67%) of PPJ collected from patients with pancreatic carcinomas showed two types of mobility shifts. Conventional imaging techniques did not show two in 10 of these patients. PPJ from patients with non-cancerous pancreatic diseases showed no Ki-ras mutations. The p53 tumor suppressor gene, examined by PCR-SSCP analysis, was mutated in 8 of the 20 tissue specimens obtained by operation or autopsy (40%). The detection of Ki-ras and p53 mutations in PPJ could be useful for the early diagnosis of pancreatic carcinomas, especially for neoplastic lesions of the intraductal type. (Received Jan. 29, 1997; accepted Sept. 26, 1997)     

p53 Mutations in human cholangiocarcinoma: a review.

The reported mortality from intrahepatic bile duct tumours is increasing markedly in industrialised countries, for reasons that remain unknown. Inactivation of the tumour suppressor gene p53, is the commonest genetic abnormality in human cancer and has been implicated in the genesis of cholangiocarcinoma in various immunohistochemical and molecular epidemiological investigations, including gene sequencing studies. The structure and function of p53 and its role in linking cancer to specific carcinogens by way of mutational signatures is reviewed. The findings of previous p53 studies and their relevance in human cholangiocarcinoma are summarised.     

p16、p53、p21基因对肺癌细胞增殖的影响

目的 观察肿瘤抑制基因ｐ１６,ｐ５３及细胞周期信赖激酶抑制物ｐ２１基因单独或联合应用时对肺癌细胞增殖的影响。方法 应用十八酰基胺阳离子脂质体介导ｐ１６,ｐ５３,ｐ２１基因单独或共转染到非小细胞肺癌细胞系Ａ５４９和小细胞肺癌细胞系ＳＨ７７,观察转染后１,３,５日该细胞增殖的活力。采用四甲基偶氮唑 盐微量酶反应比色法（ＭＴＴ法）测定吸光度（Ａ）,以检测细胞增殖活力,结果 Ａ５４９细胞系：Ａ均值分别为：     

Poor prognosis in non-villous splenic marginal zone cell lymphoma is associated with p53 mutations

We have recently reported a series of 15 non-villous splenic marginal zone lymphoma patients, six of whom showed p53 mutations (40%). This molecular alteration did not correlate with any particular clinico-pathologic feature at diagnosis. After a median follow-up of 56 months, four cases evolved into aggressive fatal non-Hodgkin's lymphoma (NHL) and two had refractory progressive disease; interestingly, p53 mutations were demonstrated in five of these patients at diagnosis. As the patients with wild-type p53 presented responsive or indolent disease, this genetic alteration may be an early marker of aggressive transformation or refractoriness. p53 evaluation at diagnosis could be advisable in this particular subset of NHL.     

PCR—SSCP方法研究血液系统肿瘤的p53d基因突变

目的：探讨p53基因突变在血液系统肿瘤发病及进展中的作用。方法：采用PCR－SSCP方法对34例血液系统肿瘤患者p53基因第5、8显子进行研究。结果：从1例急性粒细胞白血病（AML）（1／12,8．33％）,1例急性淋巴细胞白血病（ALL）（1／5,20％）,2例非霍奇金淋巴瘤（NHL）（2／5,40％）,2例多发性骨髓瘤（MM）（2／8,25％）中发现了p53基因突变。其中1例AML,1例NHL及1例MM,均在检测后3个月内死亡。结论：p53基因突变在血液系统肿瘤的发病及疾病发展中起着一定的作用。