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.     

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。     

Characterisation of molecular alterations in microdissected archival gliomas

Classification of gliomas according to their molecular characteristics may be important in future histopathological diagnosis. However, gliomas frequently display heterogeneity at the histological, biological and molecular level. In this study of archival diagnostic gliomas, precision microdissection was used to enrich samples in the most malignant cells or to investigate intratumoural histological heterogeneity. Analysis of tumour samples microdissected from the most aggressive regions, representative of the histopathological diagnosis, revealed PTEN mutations in 4/14 anaplastic astrocytomas, 4/13 glioblastomas and 1 gliosarcoma, but not in 19 low-grade gliomas. Using a novel PCR procedure and direct sequence analysis of the entire coding sequence, TP53 mutations were detected in 1/3 pilocytic astrocytomas, 3/13 astrocytomas, 4/14 anaplastic astrocytomas, 5/13 glioblastomas and 1 gliosarcoma. All but one of the tumours with TP53 mutation showed p53 immunopositivity, but 5 low-grade and 10 high-grade gliomas had p53 protein nuclear accumulation in the absence of detectable mutation. p53 status was unrelated to p21 expression. Neither PTEN nor TP53 mutations influenced the proliferative index or microvessel density of high-grade astrocytomas. Unusual findings include: TP53 mutation in a juvenile pilocytic astrocytoma; TP53 and PTEN mutations in a de novo glioblastoma, a gliosarcoma with identical mutations in gliomatous and sarcomatous components, and an infratentorial anaplastic astrocytoma with an earlier supratentorial grade II astrocytoma bearing the same TP53 mutation but not the PTEN mutation or loss of heterozygosity (LOH) of 10q23. Similarly, the transition to high-grade histology was associated with acquisition of PTEN mutations and 10q23.3 LOH in two de novo high-grade tumours with regions of low-grade histology.     

Absence of hereditary mutations in exons 5 through 9 of the p53 gene and exon 24 of the neurofibromin gene in families with glioma

Inherited mutations of the p53 and neurofibromin genes are thought to cause two distinct neoplastic disorders in which gliomas occur, the Li-Fraumeni syndrome and neurofibromatosis type 1. We investigated the possibility that inherited mutations in specific regions of these genes also contributed to the clustering of gliomas in otherwise normal families. Twenty-six members of 16 families with glioma were screened for germline mutations of exons 5 through 9 of the p53 gene and exon 24 of the neurofibromin gene using a polymerase chain reaction–single-strand conformation polymorphism method. No germline mutations were found, suggesting that the genetic basis of familial glioma is distinct from that of gliomas occurring in the Li-Fraumeni syndrome, and that inherited mutations of the catalytic domain of neurofibromin do not predispose affected glioma families to these tumors.     

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.     

脑肿瘤中P53基因突变与突变型P53蛋白表达的研究

采用聚合酶链反应－单链构象多态性（ＰＣＲ－ＳＳＣＰ）法对４１例脑肿瘤进行Ｐ５３基因突变的检测，并与抗突变型Ｐ５３蛋白单抗的免疫组化染色结果相对照，结果显示脑肿瘤中Ｐ５３基因突变率为３４．１％（１４／４１），胶质瘤为２８％（１０／３６）。Ｐ５３基因突变与突变型Ｐ５３蛋白表达具有高度一致性，且二者均与脑肿瘤的分化程度有关。Ｐ５３基因突变及蛋白的表达不仅出现在高恶度胶质瘤及转移癌，而且可出现在低恶度胶质瘤中，表明Ｐ５３基因的突变在脑瘤的发生、发展过程中起重要作用。     

Evaluation of p53 protein expression and proliferative potential based on the MIB-1 positive index in astrocytic gliomas

Fifty-seven patients with infiltrative astrocytic gliomas, comprising 29 cases of glioblastoma, 13 cases of anaplastic astrocytoma and 15 cases of low-grade astrocytoma, were examined. In 12 cases of astrocytic glioma, the p53 gene mutation was investigated by polymerase chain reaction (PCR)-single strand conformation polymorphism (SSCP). p53 overexpression was observed in 20 (35%) of the 57 patients with astrocytic gliomas. The occurrence of p53 overexpression was apparently correlated with the histological grading of the astrocytic gliomas. Of the 20 patients with glioblastoma who were less than 60 years old (mean age ± SD, 39.2 ± 15.0 years), 50% demonstrated p53 overexpression, whereas only 2 (22%) patients with glioblastoma who were more than 60 years old (mean age ± SD, 65.1 ± 5.8 years) had p53 overexpression. A substantial difference in survival associated with glioblastoma was noted between the p53-positive group (mean survival 28.9 months) and the p53-negative group (mean survival 11.3 months) based on Kaplan-Meier survival curves (P= 0.01). Even among patients with glioblastoma who were less than 60 years old, a better survival rate was recognized in those with p53 overexpression than in those without p53 (P= 0.03). The MIB-1 indices tended to increase with tumor malignancy, and a poor survival time was significantly associated with elevated values for the MIB-1 index. A substantial difference in survival between the two groups of patients who had MIB-1 indices of above 5% and below 5% was evident from the Kaplan-Meier survival curves (P= 0.04). The group that had no p53, and MIB-1 indices of above 5%, was found to show the malignant gliomas most frequently. Although most of the gliomas with p53 overexpression demonstrated MIB-1 indices of above 5%, there was no significant correlation between p53 protein expression and the MIB-1 index. Of the 12 patients with astrocytic glioma who were examined by PCR-SSCP, 3 (one glioblastoma and 2 anaplastic astrocytomas) revealed p53 gene mutation correlated with p53 (DO-7) overexpression.     

Germline mutations of p53 but not p16/CDKN2 or PTEN/MMAC1 tumor suppressor genes predispose to gliomas. The ANOCEF Group. Association des NeuroOncologues d'Expression Française

Constitutional DNA from 44 selected patients suspected of being genetically predisposed to develop astrocytic tumors was analyzed for germline mutations of the p53, p16, and PTEN genes. Six constitutional missense mutations of the p53 gene were identified (13.6%), but no mutations of the p16 and PTEN genes were found, suggesting that (1) germline p53 mutations contribute to a small portion of astrocytic tumors, (2) inherited mutations of the p16 and PTEN gene do not predispose to the development of gliomas, and (3) other genes are involved in glioma predisposition.     

人脑胶质瘤PTEN基因变异的研究

目的进一步了解PTEN基因突变和缺失在人脑胶质瘤发生和恶性进展中的作用。方法应用聚合酶链反应-单链构象多态性(PCR-SSCP)结合银染技术和双重PCR分别检测10例正常脑组织、10例脑膜瘤、80例胶质瘤PTEN基因第5和第8外显子区域上的突变与缺失情况。结果发现10例正常脑组织和10例良性脑膜瘤均无PTEN基因点突变发生,80例胶质瘤分别有11例(13.75%)和27例(33.75%)发生基因点突变和基因缺失,且PTEN基因失活与星形细胞瘤病理分级明显相关(P<0.05),其中高恶性度胶质瘤(III、IV级)突变率(24.44%)和缺失率(60%)明显高于低恶性度(I、II级)胶质瘤(P<0.05)。结论PTEN基因突变或缺失与胶质瘤病理分级关系密切,可能属于胶质瘤恶性进展的后期事件。     

The p53 gene and its role in human brain tumors

Mutation of the p53 gene is among the most common lesions in a variety of human tumors, including those of the central nervous system. In most instances, mutation of one p53 allele is followed by loss of the remaining wild-type allele, resulting in cells with a complete absence of functional wild-type p53 protein. However, in some situations, such as at initiation of spontaneously arising gliomas or as the germline configuration of patients with the Li-Fraumeni syndrome, cells clearly carry both wild-type and mutant p53 alleles. These observations lead to the hypothesis that p53 mutations can give rise to loss of tumor suppressor functions as well as to gain of oncogenic transformation capabilities. In this review, we define the types of mutations that occur in the p53 gene in various glial tumors, contrast that with the spectra described in other human tumor types, and discuss the biochemistry and physiology of the p53 protein and its ability to regulate and be regulated by other gene products. We use this information to propose roles for p53 in the initiation and progression of human gliomas. © 1995 Wiley-Liss, Inc.     

lncRNA MIR4435-2HG的表达水平及甲基化状态与脑胶质瘤病理分级的关系

目的 探讨长链非编码RNA MIR4435-2HG的表达水平及甲基化状态与脑胶质瘤病理分级的关系.方法 选取2019年1～12月手术切除的脑胶质瘤组织110例和颅脑损伤内减压术中切除正常脑组织20例(对照组).采用实时荧光定量PCR和甲基化特异性PCR检测组织和血清MIR4435-2HG水平及甲基化状态.结果 110例...     

Analysis of Isocitrate Dehydrogenase 1 Mutation in 97 Patients with Glioma

The objective of this study is to investigate the expression and significance of isocitrate dehydrogenase 1 (IDH1) mutation in different subtypes of human gliomas. Direct DNA sequencing, western blot, and immunohistochemistry were used to detect IDH1 mutation and IDH1 gene expression levels in 97 cases of glioma and 9 cases of other CNS tumors. IDH1 mutation was heterozygous, with wild-type arginine 132 replaced by histidine (R132H). Expression in different glioma subtypes was (1) 0 out if 5 in pilocytic astrocytoma; (2) 15 out of 22 in diffuse astrocytoma, 6 out of 9 in oligodendroglioma, 4 out of 6 in oligoastrocytoma, and 0 out of 4 in ependymoma; (3) 11 out of 19 in anaplastic astrocytoma, 4 out of 7 in anaplastic oligodendroglioma, 3 out of 4 in anaplastic oligoastrocytoma, and 0 out of 3 in anaplastic ependymoma; and (4) 1 out of 6 in primary glioblastoma, 8 out of 10 in secondary glioblastoma, and 0 out of 2 in medulloblastoma. IDH1 mutation is a somatic mutation that is found only in some glioma subtypes. It can be used as a molecular marker for glioma subtypes. For example, it can be used to distinguish primary glioblastoma from secondary glioblastoma, combining TP53 mutation and loss of heterozygosity involving 1p/19q. It can also be used as a marker for some gliomas. For example, it can be used to distinguish pilocytic astrocytoma from diffuse astrocytoma, combining detected BRAF proto-oncogene mutations.     

人脑胶质瘤IDH1突变状态与MGMT启动子甲基化、P53和TERT突变相关性

目的 探讨脑胶质瘤异柠檬脱氢酶1（IDH1）突变与O6-甲基鸟嘌呤-DNA甲基转移酶 （MGMT）启动子甲基化状态、P53和端粒酶逆转录酶（TERT）突变之间的相关性。方法 收集2016年6月至2017年9月手术切除并经病理诊断为胶质瘤标本72例（WHO Ⅱ级14例,Ⅲ级19例,Ⅳ级39例）。采用PCR荧光探针法检测MGMT基因启动子甲基化状态,毛细管电泳法检测基因IDH1、P53、TERT突变情况;采用列联系数分析IDH1突变与MGMT基因启动子甲基化、P53、TERT突变状态的相关性。采用多因素Logistic回归分析检验IDH1突变的相关因素。结果 72例中,IDH1突变率为29.2%,MGMT启动子甲基化率为47.2%,P53突变率为41.4%,TERT突变率为50%。相关性分析发现IDH1突变与MGMT启动子甲基化（列联系数=0.44;P<0.001）、P53突变（列联系数=0.32;P<0.05）均有显著相关性,但与TERT启动子突变无明显相关性（P>0.05）。IDH1野生型胶质瘤中MGMT启动子甲基化与TERT启动子基因突变具有相关性（列联系数=0.28,P<0.05）。IDH1突变型胶质瘤中MGMT启动子甲基化与P53基因突变具有相关性（列联系数=0.27,P<0.05）。多因素Logistic回归分析,结果显示病人年龄、MGMT启动子甲基化是IDH1突变独立相关因素（P<0.05）。结论 胶质瘤IDH1突变可能与MGMT启动子甲基化、P53和TERT突变之间存在复杂的相互调节作用。     

Molecular pathways in the formation of gliomas

The past few years have seen remarkable progress in understanding the molecular genetic basis of glioma formation. Affected oncogenes and tumor suppressor genes have been identified and putative tumor suppressor loci have been mapped. These studies have illustrated distinct molecular pathways for different glial neoplasms. We summarize the findings of an ongoing study initiated to characterize human gliomas on a molecular basis. The data are compiled from 150 astrocytic, oligodendroglial, and mixed gliomas that were assessed for genomic alterations characteristic of these neoplasms, i.e., loss of portions of chromosomes 1p, 9p, 10, 17p, 17q, and 19q, mutations of the p53 tumor suppressor gene, and amplification of the EGF receptor (EGFR) gene. Our findings support the hypothesis that distinct genetic pathways result in the formation of astrocytic and oligodendroglial neoplasms of different malignancy grades, and that glioblastoma multiforme may be subdivided into genetically distinct subsets. Such findings may not only lead to a better understanding of neoplastic transformation in glial cells, but may also have a major impact on clinical neuro-oncology. © 1995 Wiley-Liss, Inc.