脑肿瘤中P53蛋白的表达及Ki－67LI的相关性研究

利用突变型Ｐ５３蛋白的单抗及Ｋｉ－６７单抗对５０例冰冻标本进行检测，结果发现，脑肿瘤中突变型Ｐ５３蛋白的表达阳性率为４６％。低恶度胶质瘤、高恶度胶质瘤及转移癌中Ｐ５３蛋白表达的阳性率不同，分别为１８．２％、５３．８％及１００％。Ｐ５３蛋白表达阳性的肿瘤中高Ｋｉ－６７ＬＩ比例为７０％，其中位数及均数为１４．３％、２０．７６±１８．３（％），而无Ｐ５３蛋白表达的脑瘤中，ｋｉ－６７ＬＩ中位数及均数分别为１．３９及５．１９±９．０（％）。结果表明，突变型Ｐ５３蛋白的表达与脑肿瘤的组织类型，分化程度及细胞的增殖有关，而它的高表达又可能是肿瘤恶性表型或转移的标志之一。     

人脑胶质瘤组织中P53基因的突变研究

人脑胶质瘤组织中Ｐ５３基因的突变研究高振强高志萍为了研究Ｐ５３基因在脑肿瘤发生过程中的作用，我们采用目前检测基因突变最先进ＰＣＲ－ＳＳＣＰ技术，对脑胶质瘤组织中Ｐ５３基因进行了研究。一、材料与方法脑胶质瘤来自医院手术标本，共３０例，其中多形性成胶质细...     

儿童恶性脑胶质瘤P53与细胞增殖核抗原表达的预后价值

目的探讨Ｐ５３与细胞增殖核抗原（ＰＣＮＡ）在儿童恶性脑胶质瘤表达的预后价值。方法采用ＡＢＣ免疫组化方法对３３例儿童恶性脑胶质瘤Ｐ５３与ＰＣＮＡ表达进行回顾性研究。结果３３例儿童恶性脑胶质瘤中Ｐ５３表达阳性１５例（４５％），ＰＣＮＡ表达阳性２９例（８８％）。间变性星形细胞瘤、胶质母细胞瘤及髓母细胞瘤Ｐ５３蛋白表达的阳性比例分别为５／１２、９／１６、１／５，肿瘤Ｐ５３蛋白阴性者其细胞增殖活性均较阴性者高（Ｐ＜００５）；ＰＣＮＡ标记指数与肿瘤的恶性程度呈正相关（Ｐｅａｒｓｏｎ列联系数＝０．５６，Ｐ＜００１）。Ｐ５３或ＰＣＮＡ表达阳性者存活率分别显著低于Ｐ５３或ＰＣＮＡ表达阴性者（Ｐ＜００５，Ｐ＜００１）。结论Ｐ５３基因突变以及由此导致的细胞异常增殖与儿童恶性脑胶质瘤的发生和发展有关；ＰＣＮＡ能较好地反映胶质瘤的恶性程度，其表达检测对临床预后判定有重要参考价值。     

100例脑肿瘤中p53基因突变与P53蛋白积聚的研究

目的:研究不同类型脑肿瘤中的p53基因突变与P53蛋白积聚及其相关性。方法:采用聚合酶链反应-单链构象多态性(PCR-SSCP)分析及免疫组化法检测100例脑肿瘤p53基因突变及蛋白表达。结果:p53基因突变率为11%(11/100),其中高恶度胶质瘤为37.5%(6/16),低恶度胶质瘤4.3%(1/23),脑膜瘤6.9%(2/29),转移瘤40.0%(2/5)。P53蛋白表达阳性率为22%(22/100),其中高恶度胶质瘤为62.5%(10/16),低恶度胶质瘤为26.1%(6/23),脑膜瘤10.3%(3/29),转移瘤60%(3/5);其他肿瘤均未发现p53基因突变或蛋白表达。P53蛋白表达阳性的22例中伴有p53基因突变者11例,多见于高恶度肿瘤。结论:p53基因失活在脑肿瘤恶性进展过程中起重要作用。p53基因突变与P53蛋白积聚相关,但并非唯一因素。     

p53,CerbB—2和PCNA在脑胶质瘤中表达的意义及其 …

目的 研究７６例脑质瘤的ｐ５３ＣｅｒｂＢ－２和ＰＣＮＡ表达意义及其相关性。方法 应用ＳＰ微波免疫组化技术和统计学分析。结果 （１）在７６例脑胶质瘤组织中；ｐ５３，ＣｅｒｂＢ－２和ＰＣＮＡ的阳性表达率分别是４４．７４％（３４／７６），３４．２１％（２６／７６）和８０．２６％（６１／７６）。（２）ｐ５３的表达强度与胶质瘤的组织学类型和恶性程度呈显著正相关（Ｐ〈０．０１）。（３）ｐ５３ＣｅｒｂＢ－２和Ｐ     

44例人脑胶质瘤P53基因突变的研究

用ＰＣＲ－ＳＳＣＰ及ＤＮＡ直接测序研究了４４例人脑胶质瘤。发现１３例有Ｐ５３基因突变。３３例星形细胞瘤１２例有Ｐ５３基因突变。１１例非星形细胞瘤１例有Ｐ５３基因突变。ＤＮＡ直接测序证实所有突变均在Ｐ５３基因第５～８外显子，发现了一些新的突变位点，并发现在３例胶质母细胞瘤中存在Ｐ５３基因的多个位点的突变。该结果提示在大多数非星形细胞胶质瘤并不涉及Ｐ５３基因突变，Ｐ５３基因突变对星形细胞瘤的诊断有重要价值。特别是多位点的Ｐ５３基因突变可做为星形细胞瘤进展到胶质母细胞瘤的基因标志。     

脑星形胶质细胞瘤组织P21^WAF1／CIP1mRNA的表达与p53？…

目的：探讨脑星形胶质细胞瘤组织Ｐ２１＾ＷＡＦ１／ＣＩＰ２ｍＲＮＡ的表达与ｐ５３基因突变的关系及其意义。方法：应用ＲＴ－ＰＣＲ、ＰＣＲ－ＳＳＣＰ方法对３８例新鲜脑星形胶质细胞瘤组织中上述两种基因进行研究。结果：ｐ５３基因在脑星形胶质细胞瘤组织中的突变率为２８．９％（１１／３８），且在Ⅲ、Ⅳ级肿瘤突变率显著高于Ⅰ～Ⅱ级者（Ｐ〈０．０５）；Ｐ２１＾ＷＡＦ１／ＣＩＰ１ｍＲＮＡ在Ⅲ，Ⅳ级中的表达显著低于Ⅰ～     

人脑胶质瘤中表皮生长因子受体表达的研究

目的：探讨表皮生长因子受体（ＥＧＦＲ）基因表达与胶质瘤恶性程度的关系。方法：采用Ｎｏｒｔｈｅｒｎ印迹杂交及免疫组织化学技术从ｍＲＮＡ及蛋白水平检测了５０例人脑胶质瘤、４个体外恶性胶质瘤细胞系及８例正常脑组织的ＥＧＦＲ的基因表达。结果：免疫组化检测高恶度胶质瘤（ＷＨＯⅢ－Ⅳ级）ＥＧＦＲ表达６９％（２０／２９），而低恶度胶质瘤（ＷＨＯⅠ－Ⅱ级）表达率为３３％（７／２１），差异显著（Ｐ＜０．０１）；４例细胞系阳性表达１００％；８例正常脑组织无ＥＧＦＲ蛋白表达。ＷＨＯ分级与ＥＧＦＲ蛋白表达呈正相关（ｒ＝０．５５９７，Ｐ＜０．００１）。对５０例胶质瘤进行Ｎｏｒｔｈｅｒｎ印迹杂交，其结果与免疫组化检测结果一致，ＥＧＦＲｍＲＮＡ也随胶质瘤恶性程度的增加而表达增高。结论：ＥＧＦＲ可能在恶性胶质瘤的发生发展中起重要作用，ＥＧＦＲ过表达与胶质瘤分级相关性为从分子水平评估肿瘤的恶性程度及选择基因治疗的靶基因提供了参考。     

抑癌基因p16蛋白在脑胶质瘤中的缺失及意义

目的 研究ｐ１６蛋白的缺失率与脑胶质瘤性程度的关系。方法 应用ＳＰ免疫级化检测７２例人脑胶质瘤，４个人脑体外恶性胶质瘤细胞系及１０例正常脑组织中抑癌基因ｐ１６蛋白的表达，结果 正常脑组织、Ｉ级、ＩＩ级、ＩＩＩ级、ＩＶ级、ＣＬ中ｐ１６蛋白的缺失率分别为０．１０％，３１．８％，６３．２％，７１．４％，１００％，脑胶质瘤细胞系，高恶度脑胶质瘤（ＷＨＯ，ＩＩＩ级～ＩＶ级）与低恶度脑胶质瘤（ＷＨＯ，Ｉ级～Ｉ级）之间差异显（Ｐ〈０．０５），结论 ｐ１６蛋白的缺失率与脑胶质瘤的汪事分极和恶性程度密切相关，提示ｐ１６基因在脑胶质瘤的发生，发展过程中起重要作用。     

P53及其下游靶基因与癫痫

Ｐ５３是一种抑癌基因，其编码产物野生型Ｐ５３蛋白是细胞生长的“监控器”。目前公认Ｐ５３的主要功能是整合细胞对各种危急状况的反应，其信息传递途径上游是各种危急状况的信息，下游是Ｐ５３蛋白的靶基因，Ｐ５３蛋白通过靶基因Ｐ２１ｗａｆ－１及Ｇａｄｄ４５调控Ｇ１关卡，也参加了Ｇ２／Ｍ关卡的调控；Ｐ５３通过上调靶基因Ｂａｘ及ＩＧＦ－ＢＰ－３，抑制Ｂｃｌ－２基因，调控凋亡。ｍｄｍ－２基因是Ｐ５３基因的负调控因子，通过与Ｐ５３基因形成反馈调节环来抑制Ｐ５３的功能。在多种癫痫模型中已经证实，癫痫发作后细胞死亡中存…     

P16基因改变与脑胶质瘤生物学特性相关性的研究

目的 研究Ｐ１６基因改变与脑胶质瘤恶性程度分级及肿瘤细胞增殖活性之间的关系。方法 检测４１例不同级别脑胶质瘤标本和７例正常脑组织Ｐ１６基因改变和ＰＣＮＡ蛋白表达情况。结果 实验组Ｐ１６基因缺失和突变２２例（５４％），ｍＲＮＡ和蛋白表达缺失分别为２３例（５６％）和２７例（６６％），三者改变非一对一关系。Ｐ１６基因改变和ＰＣＮＡ指数随脑胶质瘤恶性程度级别增高呈上升趋势（Ｐ〈０．０５）。Ｐ１６基因改变与     

脑胶质瘤中c—myc基因扩增,H—ras及p53基因突变

研究脑胶质瘤中癌基因c-myc的扩增、H-ras的突变及抑癌基因p53的5～8外显子的突变情况以及与胶质瘤的恶性程度的关系.采用差异性PCR(DPCR)及PCR-SSCP、PCR-RFLP等方法检测22例脑胶质瘤的基因突变情况.22例脑胶质瘤中c-myc扩增率为63.6%(14/22),H-ras的突变率为36.4%(8/22),p53的突变率45.5%(10/22).提示:癌基因c-myc的扩增及抑癌基因p53的突变与脑胶质瘤的恶性程度有关(P<0.05),而癌基因H-ras的突变则与脑胶质瘤的发生有关,与脑胶质瘤的恶性程度无关(P>0.05).各类型脑胶质瘤基因突变未发现不同(P>0.05),可能与标本量少有关.     

人脑胶质瘤中Livin、p53的表达及其与肿瘤恶性程度的关系

目的 探讨Livin、p53在不同级别人脑胶质瘤中的表达及其与肿瘤恶性程度之间的关系.分析二者在胶质瘤细胞凋亡过程中的信号转导机制.方法 应用免疫组织化学技术检测Livin、p53蛋白在41例人脑胶质瘤和10例正常脑组织中的表达.结果 Livin、p53蛋白在10例正常脑组织中均不表达,在41例胶质瘤组织中表达率分别为87.8%和41.5%.Livin和p53蛋白在低级别胶质瘤中表达较低,在高级别胶质瘤中表达较高,两组比较差异有统计学意义(P＜0.05).Spearman等级相关分析显示,Livin蛋白与p53蛋白表达呈正相关(r=1.000,P＜0.01).结论 Livin和p53在人脑胶质瘤组织中表达上调,细胞凋亡受到抑制,引起肿瘤恶性增殖,与胶质瘤病程发展、恶性程度明显相关,这可能是胶质瘤恶性增殖的一个机制.     

Analysis of p53 gene mutations in low- and high-grade astrocytomas by polymerase chain reaction-assisted single-strand conformation polymorphism and immunohistochemistry

Using polymerase chain reaction-assisted single-strand conformation polymorphism (PCR-SSCP) and immunohistochemical analyses, mutations in the p53 tumor suppressor gene were examined in 19 low-and high-grade gliomas. By PCR-SSCP and nucleotide analyses, p53 gene mutation was seen in 7 gliomas. Out of the 7 mutations, 3 were located at the CpG site of the previously proposed hot-spot codons 248 and 273, 2 were at codons 171 and 214 and the other 2 were in intron 5, 1 at the splice acceptor site and the other in the vicinity of the splice donor site. The latter 4 mutations have not, or only rarely, been observed in gliomas or in other tumors. However, their effect on the structural and functional alteration of the p53 protein was suggested by positive intranuclear p53 immunostaining in neoplastic cells in 3 mutations including the 1 at the splice acceptor site. In connection with glioma grading, the p53 gene mutation was shown to have occurred in both low- and high-grade gliomas, often in most of the neoplastic cells, as suggested by lack of distinct normal bands and ladders in SSCP and direct sequencing, respectively. The absence of recurrence and malignant transformation over a considerably long postoperative time in our low-grade glioma cases suggested that the p53 gene mutation might not be sufficient for the progression from low- to high-grade gliomas. The frequency of detection of mutation was 7/19(37%) by PCR-SSCP, 8/19(42%) by immunohistochemistry and 10/19(53%) by both methods. The results of PCR-SSCP and immunohistochemistry were consistent in 14 cases(73.7%), but not in 5 cases(26.3%). Thus, the use of both methods was recommended to survey the occurrence of p53 gene mutation more accurately.Supported in part by the Fujisawa Foundation     

Clinicopathologic Characteristics of Brain Tumors are Associated with the Presence and Patterns of TP53 Mutations: Evidence from the IARC TP53 Database

Biological diversity in the development and progression of brain tumors may be based on the consequences of the nature of the TP53 mutation in the cancer sample. This study was designed to estimate the possible impact of the presence and spectrum of TP53 mutations on clinical variability of brain tumors using the IARC TP53 Database (R17). Somatic and germline mutation patterns differ in brain tumor carriers. The most frequent mutation in sporadic brain tumors is mutation R273C, which is relatively rare in grade 4 tumors compared with lower-grade tumors (p = 1.2 × 10^?5, OR 0.43, 95 % CI 0.29–0.63). Mutations at all hot spots, DNA contact mutations, and mutations in the conserved regions of the TP53 gene are also more common in grade 1–3 tumors than in grade 4 tumors. The frequencies of missense mutations at hotspot codons and DNA contact mutations gradually decrease in all three age groups studied, indicating the role of these mutations in early-onset tumors. The role of TP53 somatic mutations in the development of brain tumors has been elucidated in the individual-participant meta-analysis that provided, for the first time, strong evidence that mean age at the onset of sporadic brain tumor is significantly lower in patients with mutated compared with wild-type TP53 in all groups stratified by tumor grade. The presence and patterns of TP53 mutations are associated mainly with the age at the onset and with the development of less malignant brain tumors. Malignant degeneration of brain tumors may depend on other genetic determinants.     

Accumulation of wild-type p53 in astrocytomas is associated with increased p21 expression

Approximately one quarter of human astrocytomas show immunohistochemical positivity for p53 protein but lack p53 gene mutations, which could reflect either an accumulation of wild-type p53 protein or an inadequate sensitivity of mutation detection. Since wild-type p53 up-regulates p21 expression, increased p21 expression in those astrocytomas with p53 accumulation in the absence of mutations would argue that the protein was wild type in these tumors. We therefore compared p21 expression with p53 gene and protein status in 48 primary human astrocytomas. Single-strand conformation polymorphism analysis and direct sequencing of the p53 gene showed mutations in 11 tumors (22.9%), while immunohistochemistry revealed positive staining in 19 cases (39.6%). Those tumors with p53 immunopositivity in the absence of p53 mutation had significantly increased p21 expression when compared to either mutant p53 or p53-immunonegative cases. Neither p53 nor p21 status correlated with proliferation indices, as assessed by Ki-67 immunohistochemistry. These results support the hypotheses that functionally wild-type p53 accumulates in some astrocytomas, and that alternative cell cycle checkpoints (such as the p16 pathway) may be more important than p21 in regulating proliferation in astrocytomas. Received: 11 October 1996 / Revised, accepted: 17 January 1997