少突胶质细胞瘤中染色体1p/19q联合缺失与MGMT基因启动子甲基化的相关性

目的 研究少突胶质细胞瘤染色体1p/19q联合缺失与MGMT基因启动子甲基化的相关性。方法 选取少突胶质细胞瘤35例、间变型少突胶质细胞瘤32例标本作为实验组,星形细胞瘤20例及瘤旁正常脑组织标本20例作为对照组,荧光原位杂交方法检测染色体1p/19q联合缺失情况,巢式甲基化特异性PCR技术检测MGMT基因启动子甲基化情况。结果 少突胶质细胞瘤和间变型少突胶质细胞瘤1p/19q联合缺失率分别为85.71%、75.00%,均显著高于星形细胞瘤及正常脑组织（P<0.05）;少突胶质细胞瘤、间变型少突胶质细胞瘤、星形细胞瘤的MGMT基因启动子甲基化率均显著高于正常脑组织（P<0.05）,但三者组间比较差异无统计学意义（P>0.05）;少突胶质细胞瘤1p/19q联合缺失与MGMT基因启动子甲基化呈正相关性,并且均与患者3年生存率相关（P<0.05）。结论 少突胶质细胞瘤中1p/19q联合缺失与MGMT基因启动子甲基化状态密切相关,联合检测有助于提高临床病理诊断的精确性,更好地评估预后。     

低级别胶质肿瘤的1p/19q缺失研究

背景与目的：近几年来,少枝胶质细胞瘤,特别是有染色体1p/19q的联合缺失者被证实对烷化剂化疗敏感,成为预后良好的标志物。本实验旨在研究低级别胶质瘤中1p/19q的联合缺失率和与标本中1p/19q的缺失百分比相关的分子病理特征。方法：搜集北京天坛医院低级别胶质瘤标本25例,应用免疫荧光原位杂交（fluorescence in situ hybridization,FISH）的方法对1p36和19q13的缺失程度进行定量分析,统计其在低级别胶质瘤中的联合缺失率,并应用Spearman秩相关分析方法分析标本中1p36、19q13缺失百分比与P170、MGMT、MMP-9、PTEN、EGFR、P53、VEGF、Ki-67、TOPO-Ⅱ、GST-π的分子病理结果的关系。结果：在25例低级别胶质瘤标本中,星形细胞瘤10例,少枝胶质细胞瘤3例,少枝星形细胞瘤12例。在星形细胞瘤、少枝胶质瘤和少枝星形细胞瘤中,1p/19q联合缺失率分别为40%、67%和50%。1p36、19q13的缺失程度与MGMT表达呈负相关,（P分别为0.042和0.015）,1p36的缺失程度与GST-π表达呈负相关（P=0.024）。结论：在低级别胶质瘤中,1p/19q的联合缺失率与国外报道相似,MGMT、GST-π的低表达可能与1p、19q的缺失有关。     

DH1基因突变及MGMT基因启动子

摘 要：［目的］ 探讨IDH1基因突变及MGMT基因启动子甲基化状态在指导胶质瘤患者临床化疗和预后判断的意义。［方法］ 运用PCR测序和焦磷酸测序方法对190例胶质瘤患者的肿瘤标本分别进行IDH1基因突变和MGMT基因启动子甲基化状态分析;分析两者与胶质瘤患者临床病理特征及预后的关系。［结果］ 胶质瘤中IDH1基因突变在不同年龄（P=0.026）、病理分级（P=0.020）、KPS评分（P=0.004）组间分布差异有统计学意义;而在不同性别（P=0.900）、p53表达（P=0.878）、肿瘤幕上幕下位置（P=0.106）组间分布差异无统计学意义。MGMT基因启动子甲基化在不同年龄（P=0.488）、性别（P=0.447）、病理分级（P=0.287）、KPS评分（P=0.077）、p53表达（P=0.970）及肿瘤幕上与幕下位置不同（P=0.915）。IDH1基因突变型组与野生型组30个月总生存期差异有统计学意义（P=0.002）,高级别胶质瘤术后化疗患者MGMT基因启动子甲基化组与非甲基化组30个月总生存期差异有统计学意义（P=0.049）。［结论］ IDH1基因突变可作为判断胶质瘤患者预后的指标,而MGMT基因启动子甲基化可作为指导化疗的重要指标。     

影响幕上WHOⅢ胶质瘤预后的相关因素分析

背景与目的:近年来,国外开展了多宗关于胶质瘤预后因素评估的临床研究,而此类研究在国内尚为数不多。本文旨在以中国人群为样本,分析影响胶质瘤预后相关因素,为临床提供理论依据。方法:收集2009年5月至2010年12月北京天坛医院神经外科四病区外科手术治疗的109例原发性WHOⅢ胶质瘤患者的资料。生存分析中单因素分析采用Kaplan-Meier计算生存率,并采用Log-rank检验进行生存率比较;多因素分析使用Cox比例风险模型,采用逐步回归分析法。结果:单因素分析结果显示病理类型、年龄、1p/19q、IDH1、MGMT与患者预后相关(P0.05);多因素分析结果显示病理类型、年龄、1p/19q为独立预后因素,而IDH1、MGMT则不能作为独立预后因素。结论:病理类型、年龄、1p/19q可作为评估幕上WHOⅢ胶质瘤患者的独立预后因素;1p/19q共缺失可能是MGMT低表达作为评估患者预后因素的前提条件,而1p/19q共缺失则很可能是通过降低MGMT表达量而增加了患者化疗、放疗敏感性来延长患者的生存期。     

IDH突变和1p/19q共缺失型少突胶质细胞瘤临床病理特征和预后分析

目的探讨I D H突变和1p/19q共缺失型少突胶质细胞瘤的临床病理特征及预后相关影响因素。方法收集54例IDH突变和1p/19q共缺失型少突胶质细胞瘤病例,分析其临床病理特点,包括年龄、组织学分级和肿瘤部位等因素对无进展生存期和总生存期的影响。结果 54例患者中,肿瘤发生于1个脑叶者46例,发生于2个脑叶以上者8例。肿瘤组织学WHO分级2级12例,3级42例。FISH检测显示54例均为1p/19q共缺失;免疫组织化学检测显示Olig2均为弥漫强阳性;GFAP均为阳性;p53有6例强阳性;48例患者ATRX未缺失;Ki-67增殖指数5%～60%。Sanger测序显示54例均发生IDH基因突变（40例为IDH1突变,14例为IDH2突变）,33例发生TERT启动子突变。16例在治疗过程中发生复发及转移。单因素分析显示,手术后复发转移间隔时间超过2年可以延长患者无进展生存和总生存期。54例患者平均无进展生存期33.5个月,平均总生存期40.7个月。结论 IDH突变和1p/19q共缺失型少突胶质细胞瘤术后联合精准放化疗降低了进展风险,手术后复发转移间隔时间与该型患者预后相关。     

弥漫性较低级别胶质瘤的整合性分子病理分型研究进展*

弥漫性较低级别胶质瘤包含WHOⅡ级和Ⅲ级的星形细胞瘤、少突胶质细胞瘤和少突星形细胞瘤,其临床表现具有高度可变性,目前的组织病理学无法准确地预测其预后。近年来,胶质瘤分子病理取得了重大进展,已经发现一系列与胶质瘤临床特征和预后密切相关的分子标志物如异柠檬酸脱氢酶（isocitrate dehydrogenase ,IDH ）突变、染色体1p/ 19q 共缺失、ATRX 基因突变、TERT启动子突变、MGMT 启动子甲基化等。在此基础上,结合这些分子标志物对弥漫性较低级别胶质瘤进行整合性分子病理分型的研究相继开展,且这些研究的结果一致表明,整合性分子病理分型能够更好地预测弥漫性较低级别胶质瘤的预后和指导治疗。本研究对弥漫性较低级别胶质瘤的整合性分子病理分型研究进展进行综述。      

胶质瘤染色体1p和19q杂合性缺失与O6-甲基鸟嘌呤DNA甲基转移酶p53和Ki-67蛋白表达的关系

目的 探讨胶质瘤染色体1p和19q杂合性缺失(LOH)与O6-甲基鸟嘌呤DNA甲基转移酶(MGMT)、p53和Ki-67蛋白表达的关系.方法 采集146例胶质瘤(45例少突胶质细胞瘤、42例少突星形细胞瘤和59例星形细胞瘤)的肿瘤组织和血液标本,采用聚合酶链反应结合变性高效液相色谱技术检测染色体1p和19q LOH,免疫组化法检测肿瘤组织中MGMT、p53和Ki-67蛋白的表达,并进一步分析其与胶质瘤临床病理特征的关系.结果 少突胶质细胞肿瘤和星形细胞瘤中,1p LOH的发生率分别为59.8％和33.9％,差异有统计学意义(P=0.002);1p和19q LOH的发生率分别为42.5％和16.9％,差异有统计学意义(P=0.001).MGMT低表达和Ki-67高表达多发生于少突胶质细胞肿瘤中,发生率分别为65.5％和54.0％,而p53高表达多发生于星形细胞瘤和少突星形细胞瘤中,发生率为75.2％.在87例少突胶质细胞肿瘤中,1p LOH和MGMT蛋白低表达多发生于Ⅱ级少突胶质细胞肿瘤中,发生率分别为72.5％和87.5％,而p53和Ki-67蛋白高表达多发生于Ⅲ级少突胶质细胞肿瘤中,发生率分别为83.0％和76.6％.1p和19q LOH在非颞叶和颞叶肿瘤的发生率分别为55.6％和21.2％(P=0.002).1p LOH与19q LOH、MGMT蛋白表达与p53蛋白表达、MGMT蛋白表达与Ki-67蛋白表达、1p和19q LOH与p53蛋白表达、1p LOH与Ki-67蛋白表达均有关(均P＜0.05).结论 1p和19q LOH及MGMT、p53和Ki-67的蛋白表达与胶质瘤的临床病理学特征有关,检测其LOH状态和表达水平对胶质瘤的诊断和治疗具有指导作用.     

高级别胶质瘤手术联合术后辅助放化疗的疗效分析（附56例）

目的:探讨高级别胶质瘤的手术和术后放化疗的治疗效果。方法:回顾性分析56例高级别胶质瘤患者的临床资料,均采用手术、术后同步放化疗及6个周期以上的替莫唑胺化疗,对其治疗效果和不良反应进行评价分析。结果:56例患者手术全切除10例（17.9%）,次全切除35例（62.5%）,部分切除11例（19.6%）。分子病理提示IDH1132H突变19例;MGMT基因启动子甲基化20例。随访过程中13例未见明显复发;35例复发;1例出现脊髓的多发转移灶;7例出现放射性脑损伤,其中3例再次手术减压,4例保守治疗。12个月、24个月和36个月总生存率分别为66.1%、50.0%和32.1%;无进展生存率分别为57.1%、39.3%和25.0%。结论:高级别胶质瘤预后不佳,术后残留、复发、转移和放射性损伤是治疗的重点和难点;MGMT基因启动子甲基化患者总体生存率和无进展生存率高于MGMT启动子未甲基化患者。     

63例高级别胶质瘤中IDH1和TERT突变状态的预后价值

目的:探讨异柠檬酸脱氢酶-1（IDH1）和端粒酶逆转录酶（TERT）启动子突变对高级别胶质瘤患者的预后价值。方法:选取2014年9月至2017年6月于我院行手术切除且术后病理提示为高级别胶质瘤的患者63例（WHO Ⅲ级27例，Ⅳ级36例），完善临床资料、随访资料、分子检测结果。应用Sanger测序法检测样本中IDH1和TERT启动子突变情况，根据结果将患者分为不同亚组，通过比较其生存期的差异，分析基因突变与患者预后的关系。结果:63例高级别胶质瘤中，IDH1突变型和野生型患者的中位生存期分别为24和10个月，差异有统计学意义（P＜0.01）；TERT突变型和野生型的中位生存期无明显差异（P＞0.05）。IDH1突变为高级别胶质瘤患者预后良好的因素，TERT突变不能单独提示预后，二者联合分析提示:IDH1突变／TERT突变组预后最好，IDH1野生／TERT突变组预后最差，IDH1突变／TERT野生组预后稍好于IDH1野生／TERT野生组，四组间预后有明显差异。结论:IDH1突变的高级别胶质瘤患者有较好的临床预后，在此基础上，TERT启动子突变检测有助于进一步划分其预后分层。     

NSCLC患者血浆p16和MGMT基因甲基化检测及临床意义

目的：检测非小细胞肺癌（non—small cell lung cancer，NSCLC）患者外周血血浆中p16基因、O^6-甲基乌嘌呤-DNA甲基转移酶（O^6-methylguanine—DNA methyhransferase，MGMT）基因启动子的甲基化状态，探讨p16、MGMT基因启动子的异常甲基化在NSCLC筛查及早期诊断中的意义。方法：利用巢式甲基化特异性聚合酶链反应法检测NSCLC患者外周血血浆p16、MGMT基因启动子的甲基化状态。结果：65例NSCLC血浆样品中分别发现19例（29．23％）p16基因启动子异常甲基化和16例（24．62％）MGMT基因启动子异常甲基化，45例正常对照血浆组未检测到p16、MGMT基因启动子的异常甲基化（P〈0．05），血浆中两基因甲基化检出率与NSCLC的分型及临床分期无明显相关性（P〉0．05）。结论：利用巢式甲基化特异性PCR法检测外周血血浆中p16、MGMT基因启动子的甲基化，可为NSCLC的筛查、早期诊断及预后判断提供有价值的信息。     

Molecular prognostic factors of anaplastic oligodendroglial tumors and its relationship: a single institutional review of 77 patients from China

The increased chemosensitivity of oligodendroglial tumors has been associated with loss of heterozygosity (LOH) on chromosomes 1p and 19q. Other clinical and molecular factors have also been identified as being prognostic and predictive for treatment outcome. Seventy-seven patients with anaplastic oligodendroglioma (AO) or anaplastic oligoastrocytoma (AOA), treated in Beijing Tiantan Hospital from 2006 through 2008, were reviewed. LOH 1p, LOH 19q, IDH1 mutation, O(6)-methylguanine-DNA methyltransferase (MGMT) promoter methylation, and protein expression level of MGMT, P53, EGFR, and Ki-67 were evaluated. Age at diagnosis, LOH 1p and 19q, IDH1 mutation, P53 expression level, reoperation when progression, and adjuvant chemotherapy were statistically significant factors for overall survival (OS) in univariate analysis. Further multivariate analysis showed that age at diagnosis (P = .010), LOH 1p and 19q (P = .016), IDH1 mutation (P = .011), and reoperation after progression (P = .048) were independent predictors for longer survival in these patients. Nonrandom associations were found between LOH 1p and LOH 19q, MGMT promoter methylation and LOH 1p or 19q, IDH1 mutation and LOH 1p and 19q, IDH1 mutation and MGMT promoter methylation, whereas mutual exclusion was found between MGMT promoter methylation and MGMT expression level. The present study confirmed that age at diagnosis, LOH 1p and 19q, IDH1 mutation, and reoperation after progression were independent significant prognostic factors for patients with anaplastic oligodendroglial tumors. Inter-relationship between LOH 1p, LOH 19q, IDH1 mutation, MGMT promoter methylation, and MGMT expression level were also revealed. Future clinical trials for AO and AOA should consider the molecular alterations of patients.     

Quantitative analysis of O<Superscript>6</Superscript>-methylguanine DNA methyltransferase (MGMT) promoter methylation in patients with low-grade gliomas

Methylation of the MGMT promoter is supposed to be a predictive and prognostic factor in glioblastoma. Whether MGMT promoter methylation correlates with tumor response to temozolomide in low-grade gliomas is less clear. Therefore, we analyzed MGMT promoter methylation by a quantitative methylation-specific PCR in 22 patients with histologically verified low-grade gliomas (WHO grade II) who were treated with temozolomide (TMZ) for tumor progression. Objective tumor response, toxicity, and LOH of microsatellite markers on chromosomes 1p and 19q were analyzed. Histological classification revealed ten oligodendrogliomas, seven oligoastrocytomas, and five astrocytomas. All patients were treated with TMZ 200 mg/m² on days 1–5 in a 4 week cycle. The median progression-free survival was 32 months. Combined LOH 1p and 19q was found in 14 patients; one patient had LOH 1p alone and one patient LOH 19q alone. The LOH status could not be determined in two patients and was normal in the remaining four. LOH 1p and/or 19q correlated with longer time to progression but not with radiological response to TMZ. MGMT promoter methylation was detectable in 20 patients by conventional PCR and quantitative analysis revealed the methylation status was between 12 and 100%. The volumetric response to chemotherapy analyzed by MRI and time to progression correlated with the level of MGMT promoter methylation. Therefore, our retrospective case series suggests that quantitative methylation-specific PCR of the MGMT promoter predicts radiological response to chemotherapy with TMZ in WHO grade II gliomas.     

Molecular genetic markers as predictors of response to chemotherapy in gliomas

PURPOSE OF REVIEW: This review summarizes recent studies on applications of molecular markers such as chromosome 1p/19q codeletion and MGMT status in the treatment of glioma. RECENT FINDINGS: Prospective trials confirmed that 1p/19q codeletion represents a strong and independent favourable prognostic factor in anaplastic oligodendroglial tumours. Other retrospective studies have suggested that 1p/19q loss is also predictive of chemosensitivity to alkylating agents (nitrosoureas and temozolomide) in low-grade gliomas. Recent reports have provided evidence that 1p and 19q deletions are mediated by unbalanced translocation. The targeted genes remain to be identified, however. Promoter methylation of MGMT gene silencing has been shown to predict benefit from chemotherapy in glioblastoma. MGMT promoter methylation and low expression of MGMT-encoded protein are frequently observed in low-grade gliomas and anaplastic oligodendroglial tumours. In such tumours, however, preliminary studies have yielded contradictory results on the predictive value of MGMT status regarding objective response to chemotherapy and correlation with 1p/19q deletion. SUMMARY: There is mounting evidence that 1p/19q deletion and MGMT inactivation are relevant prognostic markers and predictors of chemosensitivity in gliomas. Although such markers remain to be formally validated by ongoing and planned prospective trials, it is likely that they will soon become essential for optimizing treatment decisions.     

Comparison of 1p and 19q status of glioblastoma by whole exome sequencing,array-comparative genomic hybridization,and fluorescence in situ hybridization

According to the 2016 World Health Organization classification of tumors of the central nervous system, detecting 1p/19q co-deletion became essential in clinical neuropathology for gliomas with oligodendroglioma-like morphology. Here, we assessed genomic profiles of glioblastoma in 80 cases including 1p/19q status using fluorescent in situ hybridization (FISH), array-comparative genomic hybridization (aCGH), and/or whole exome sequencing (WES). Paraffin-embedded tumor tissues were subjected to FISH analysis, and the corresponding frozen tissues from the same tumors were evaluated for aCGH and/or WES for 1p/19q co-deletion and other genetic parameters, which included IDH1-R132H, ATRX, TP53, CIC, and NOTCH1 mutations and MGMT methylation status. We also evaluated correlations between 1p/19q co-deletion status and molecular markers or clinical outcomes. The FISH analyses revealed 1p/19q co-deletion in two cases, isolated deletion of 1p in six cases, and 19q in two cases, whereas the aCGH and WES results showed isolated deletion of 19q in four cases and 19 monosomy in only one case. Eleven cases showed discordant 1p/19q results between aCGH/WES and FISH analysis, and in most of them, 1p and/or 19q deletion on FISH analysis corresponded to the partial deletions at 1p36 and/or 19q13 on aCGH/WES. Our cohort exhibited IDH1-R132H mutations (5.4%), MGMT promotor methylation (34.6%), and mutations in ATRX (9.5%), TP53 (33.3%), and NOTCH1 (3.8%) but not in CIC (0%). In addition, MGMT methylation and ATRX mutation were significantly associated with clinical prognosis. In glioblastomas, partial deletions of 1p36 and/or 19q13 were uncommon, some of which appeared as 1p and/or 19q deletions on FISH analysis.     

Molecular profile of oligodendrogliomas in young patients

Several studies on molecular profiling of oligodendrogliomas (OGs) in adults have shown a distinctive genetic pattern characterized by combined deletions of chromosome arms 1p and 19q, O6-methylguanine-methyltransferase (MGMT) methylation, and isocitrate dehydrogenase 1 (IDH1) mutation, which have potential diagnostic, prognostic, and even therapeutic relevance. OGs in pediatric and young adult patients are rare and have been poorly characterized on a molecular and biological basis, and it remains uncertain whether markers with prognostic significance in adults also have predictive value in these patients. Fourteen cases of OGs in young patients (age, ≤ 25 years) who received a diagnosis over 7 years were selected (7 pediatric patients age ≤ 18 years and 7 young adults aged 19-25 years). The cases were evaluated for 1p/19q status, MGMT promoter methylation, p53 mutation, and IDH1 mutation. None of the pediatric cases showed 1p/19q deletion. In young adults, combined 1p/19q loss was observed in 57% and isolated 1p loss in 14% of cases. The majority of cases in both subgroups (71% in each) harbored MGMT gene promoter methylation. TP53 and IDH1 mutations were not seen in any of the cases in both the groups. To our knowledge, this is the first study to show that molecular profile of OGs in pediatric and young adult patients is distinct. Further large-scale studies are required to identify additional clinically relevant genetic alterations in this group of patients.     

Usefulness of MS-MLPA for detection of MGMT promoter methylation in the evaluation of pseudoprogression in glioblastoma patients

Pseudoprogression is a major diagnostic dilemma in current treatment protocols for malignant gliomas that involve concurrent chemoradiotherapy. We hypothesized that methylation-specific multiplex ligation probe amplification (MS-MLPA), an assay that permits semiquantitative evaluation of promoter methylation, may be used to diagnose pseudoprogression based on the quantification of the methylation status of the O(6)-methylguanine DNA methyltransferase (MGMT) promoter. We examined the methylation ratio of the MGMT promoter with MS-MLPA in 48 samples from glioblastoma patients. The results were compared with those from methylation-specific polymerase chain reaction (MSP), and protein levels were confirmed by immunohistochemical staining. We then evaluated the correlation between those molecular signatures and clinical outcomes. With regard to radiological progression after chemoradiotherapy, the diagnostic accuracy of the MS-MLPA method was 80% (using a cut-off value of 0.2). These results are better than those obtained with MSP (diagnostic accuracy of 68%). Combining the MS-MLPA and MSP methods resulted in a diagnostic accuracy of 93% for the identification of pseudoprogression among patients to whom these results were coherent. These results demonstrate that MS-MLPA is a useful method to predict radiological progression vs pseudoprogression in glioblastoma patients and that the interpretation of these results in combination with MSP results will provide good practical guidelines for clinical decision making in glioblastoma treatment.     

Longitudinal assessment of genetic and epigenetic markers in oligodendrogliomas.

PURPOSE: Because little is known about the evolution of genetic and epigenetic changes that occur during tumor progression in oligodendrogliomas, we evaluated these changes in paired early and progressive oligodendrogliomas. EXPERIMENTAL DESIGN: 1p36, 19q13, 10q22-26, and O(6)-methylguanine-DNA methyltransferase (MGMT) promoter methylation status were assessed in 46 paired early and progressive oligodendrogliomas from 23 patients. RESULTS: In early tumors, 60.8% were of low grade compared with only 17% low-grade tumors at recurrence. Of 17 early tumors described as pure oligodendrogliomas, 76.5% remained in this lineage, regardless of their grade, whereas others changed to astrocytic tumors. Oligoastrocytic tumors had a significantly higher tendency to transform to astrocytic tumors. All pure oligodendrogliomas with 1p/19q codeletions remained phenotypically unchanged, unlike mixed tumors with codeletions, of which 83% changed their cell lineage. Of tumors with early 1p deletion, 80% remained oligodendroglial at progression, whereas 75% of tumors with an intact 1p changed to astrocytic phenotype. 10q loss was uncommon in both early and progressive tumors. The proportional gain in methylation at progression was 31% for tumors with early 1p deletion, unlike tumors with an intact 1p, which had an 87.5% gain of methylation at progression. CONCLUSIONS: Pure oligodendrogliomas with 1p/19q deletion tend to retain their cell phenotype and genetic profile unlike tumors with no deletions or mixed histology. MGMT promoter methylation is more pronounced at tumor progression, particularly in tumors with an intact 1p. These observations suggest that MGMT promoter methylation is a late event in progressive oligodendrogliomas, and therefore, their chemosensitivity is not necessarily related to MGMT methylation status.