少突-星形细胞瘤病例的临床回顾和整合诊断研究

目的根据2016年WHO中枢神经系统肿瘤分类第4版修订方案(2016年WHO指南),探讨分子标志物对病理诊断和预后的指导意义。方法对既往诊断为少突-星形细胞瘤或间变少突-星形细胞瘤的病例回顾病理检查结果参照2016年WHO指南重新进行整合性诊断。收集2014至2016年,45例经手术切除后组织病理诊断为少突-星形细胞瘤及间变少突-星形细胞瘤的病例。采用直接测序法检测IDH1/2基因突变及TERT启动子区突变,采用荧光原位杂交(FISH)检测1p/19q的共缺失状态,采用甲基化特异性PCR(MSP)方法检测O6-甲基鸟嘌呤-DNA甲基转移酶(MGMT)甲基化水平。分析TERT启动子突变及MGMT甲基化与患者总生存期和无复发生存期的关系。结果依据2016年WHO指南,结合IDH基因突变、1p/19q共缺失等分子标志物特征,45例整合诊断为:少突胶质细胞瘤(IDH突变型和1p/19q共缺失)22例;弥漫性胶质瘤[IDH野生型(IDH野生型和1p/19q共缺失)]2例;弥漫星形细胞瘤(IDH突变型8例,IDH野生型3例)11例;间变少突胶质细胞瘤(IDH突变型和1p/19q共缺失)2例;间变弥漫星形细胞瘤(IDH突变型3例,IDH野生型1例)4例;少突-星形细胞瘤(未知类型)4例。TERT启动子突变及MGMT甲基化的患者总生存期较短,但差异无统计学意义。结论依据2016年WHO指南和更新的修改建议,并不能把既往诊断为少突-星形细胞瘤的患者进行完全分类;此类混合性胶质瘤的生物学和遗传学特征还需进行深入研究。     

人脑胶质瘤 IDH1基因突变与临床病理类别的关系

目的探究不同病理类型和级别的胶质瘤患者中异柠檬酸脱氢酶1（IDH1）基因突变情况及其临床意义。 方法选取厦门大学附属第一医院神经外科自2014年1月至2017年9月收治并实施手术的胶质瘤患者76例,通过免疫组化检测并鉴定各病理组织样本中IDH1基因突变情况,分析不同病理类型、不同WHO级别和不同年龄患者IDH1基因突变率。 结果76例胶质瘤标本中,共检出37例IDH1基因突变,总突变率48.68%。各种病理类型突变率由高至低分别为：弥漫性星形细胞瘤（71.43%）、间变型少突星形细胞瘤（71.43%）、少突胶质瘤（66.67%）、少突星形细胞瘤（66.67%）、间变型星形细胞瘤（63.64%）、胶质母细胞瘤（34.62%）。IDH1基因突变型的年龄普遍较野生型更小,其中,弥漫性星形细胞瘤、少突星形细胞瘤、间变型星形细胞瘤、间变型少突星形细胞瘤及胶质母细胞瘤样本中,IDH1基因突变型患者平均年龄均低于野生型患者,差异具有统计学意义（P<0.05）。 结论IDH1基因突变在WHOⅡ、Ⅲ级胶质瘤中的发生率较高,并在胶质瘤的发生、发展过程中起重要作用。     

胶质瘤1p/19q联合缺失与临床病理因素的相关性分析

目的 本研究旨在筛选与胶质瘤组织1p/19q联合缺失相关的临床病理因素.方法 收集胶质瘤标本56例,采用荧光原位杂交(FISH)方法检测肿瘤组织标本中1p和19q的状态,并用免疫组化对9种肿瘤相关蛋白进行半定量分析,应用统计学方法筛选与1p/19q联合缺失相关的临床病理因素.结果 单因素分析证实病理类型、p53和O6-甲基鸟嘌呤-DNA甲基转移酶(MGMT)表达水平与1p/19q联合缺失相关,Logistic回归进一步证实病理类型和MGMT表达水平与1p/19q联合缺失相关,P值分别为0.001和0.004.结论 在胶质瘤中,通过病理类型和MGMT表达水平可以准确预测部分胶质瘤的1p/19q缺失状态,1p/19q联合缺失有可能通过p53和MGMT的低表达,增强烷化剂化疗疗效和延长存活期.

Abstract：

Objective This study aimed to select clinical and pathological aspects correlated with 1p/19q co- deletion in gliomas.Methods Samples of 56 glioma patients were collected.The status of chromosome 1p and 19q was detected by Fluorescence in Situ Hybridization (FISH) and the expression levels of nine tumor- associated proteins were analyzed semi- quantitatively by immunohistochemistry.Then the aspects correlated with 1p/19q co- deletion were chosen by univariate and logistic regression methods.Methods Pathology,expression levels of p53 and MGMT were the factors correlated with 1p/19q co-deletion by univariate analysis,while pathology and expression level of MGMT were further confirmed by logistic regression.Conclusion 1p/19q co- deletion could be predicted by pathology and expression level of MGMT exactly in part of gliomas.It is likely that 1p/19q co-deletion results in hypo-expression of p53 and MGMT in gliomas,which in turn lead to improved alkylator sensitivity and prolonged survival.     

少突胶质细胞肿瘤的分子遗传学改变与其部位的相关性研究

目的 研究少突胶质细胞肿瘤分子遗传学改变和肿瘤部位的相关性.方法 回顾性地研究了105例胶质瘤.根据影像学资料记录每例肿瘤的部位,运用PCR-变性高效液相色谱技术检测肿瘤染色体1p和19q杂合性缺失的情况,用χ2检验和Fisher确切概率法评估肿瘤部位和分子遗传学特征之间的相关性.结果 位于非颞叶的少突胶质细胞肿瘤与位于颞叶的肿瘤相比,更倾向于具有1p和19q联合杂合性缺失,而星形细胞瘤的分子遗传学特征与其部位之间没有相关性.结论 不同分子亚型的少突胶质细胞肿瘤可能发生于不同的脑叶,即具有1p和19q联合杂合性缺失的肿瘤通常发生于非颞叶.     

2021年世界卫生组织中枢神经系统肿瘤分类（第五版）成人型弥漫性胶质瘤分类解读

2021年世界卫生组织中枢神经系统肿瘤分类(第五版,简称新版肿瘤分类)首次将弥漫性胶质瘤分为成人型和儿童型两大类,其中成人型分为3种类型,即星形细胞瘤,IDH突变型;少突胶质细胞瘤,IDH突变和1p/19q共缺失型;胶质母细胞瘤,IDH野生型。为进一步准确理解和应用新版肿瘤分类,本文就成人型弥漫性胶质瘤诊断分类进行解读。     

胶质瘤IDH1和IDH2基因突变研究进展

异柠檬酸脱氢酶1和2(IDH1/2)基因突变主要发生于星形细胞瘤、间变型星形细胞瘤、少突胶质细胞瘤、间变型少突胶质细胞瘤、少突星形细胞瘤、间变型少突星形细胞瘤和继发性胶质母细胞瘤。IDH1/2基因突变改变蛋白酶功能、消耗α-酮戊二酸和还原型烟酰胺腺嘌呤二核苷酸磷酸,从而产生致癌代谢物2-羟基戊二酸,2-羟基戊二酸在细胞内蓄积可引起一系列下游效应并最终导致上述胶质瘤发生。IDH1/2基因突变及伴发的其他分子遗传学改变可用于胶质瘤的鉴别诊断。IDH1/2基因突变也是上述胶质瘤有良好预后的独立预测因子。而针对IDH1/2基因突变的分子靶向治疗也是目前胶质瘤治疗研究的热点。本文对近年来胶质瘤IDH1/2基因突变研究进展简要概述。     

脑胶质瘤低氧诱导因子鄄1α的表达及其意义

目的探讨低氧诱导因子鄄1α在脑胶质瘤中的表达及其意义。方法60例脑胶质瘤标本中Ⅰ级11例(毛细胞型星形细胞瘤8例、脉络丛乳头状瘤2例、黏液乳头状型室管膜瘤1例);Ⅱ级20例(弥漫型星形细胞瘤11例、少突胶质细胞瘤5例、室管膜瘤2例、多形性黄色瘤型星形细胞瘤2例);Ⅲ级21例(间变性星形细胞瘤12例、间变性少突胶质细胞瘤6例、间变性室管膜瘤3例);Ⅳ级8例(均为胶质母细胞瘤)。采用免疫组织化学方法检测胶质瘤标本中低氧诱导因子鄄1α的表达变化,并与胶质瘤体积及患者年龄、性别进行统计学分析。结果(1)胶质瘤组织低氧诱导因子鄄1α表达呈阳性反应,主要位于细胞质和(或)细胞核,具有明显的异质性;肿瘤浸润边缘部的肿瘤细胞表达明显增强;而阴性对照标本和10例对照脑组织标本则无表达。胶质瘤组织中低氧诱导因子鄄1α阳性表达率为71.67%(43/60),其中Ⅰ级为27.27%(3/11),Ⅱ级70.00%(14/20),Ⅲ级85.71%(18/21),Ⅳ级100%(8/8)。高级别胶质瘤者低氧诱导因子鄄1α阳性表达率明显高于低级别者,不同级别间差异有高度统计学意义(χ2=15.907,P<0.01);表达强度与病理级别间呈高度正相关(rs=0.480,P<0.01)。(2)低氧诱导因子鄄1α表达与患者年龄、性别及原发肿瘤体积的大小等均无相关性(均P>0.05)。结论脑胶质瘤低氧诱导因子鄄1α的表达强弱与肿瘤病理分级相关。     

神经导航系统辅助切除邻近重要功能区神经胶质瘤

目的 观察神经导航系统对脑重要功能区附近的神经胶质瘤手术定位的意义。方法2000年6月～2001年10月,在神经导航系统辅助下完成19例邻近脑重要功能区(额后、额顶交界、额颞交界、顶叶和基底节区)神经胶质瘤的切除手术。结果 导航系统对19例患者肿瘤病灶的定位误差为1.2～2.3mm,平均1.7 mm。肿瘤全切除者16例(84.21％),次全切除者3例(15.79％)。术后病理学分类为星形细胞瘤(9例),间变性星形细胞瘤(5例),多形性胶质母细胞瘤(3例),少突胶质细胞瘤(1例),星形-少突混合性胶质细胞瘤(1例)。手术未对患者重要神经功能造成不良影响。结论 借助神经导航系统可明显提高脑神经胶质瘤手术的准确性和安全性,并可显著提高肿瘤的切除程度。     

解读ESMO《高级别胶质瘤的诊断、治疗与随访指南》

高级别胶质瘤主要指胶质母细胞瘤、间变性星形细胞瘤、间变性少突胶质细胞瘤和间变性少突星形细胞瘤,具有高复发率、致残率和致死率的特点。本文结合最新文献,对欧洲肿瘤内科学会制定的高级别胶质瘤指南中所涉及的流行病学、病理分型、分子标志、预后因素、治疗策略和缓解评估等细则进行详细介绍和解读。     

甘油醛-3-磷酸脱氢酶与人脑胶质瘤的相关性研究

目的探讨甘油醛-3-磷酸脱氢酶在神经胶质瘤中的表达及其临床意义。方法选择1999年11月-2004年1月手术切除,经病理证实的胶质瘤标本51例(胶质瘤组)、脑膜瘤9例(脑膜瘤组)、垂体瘤5例(垂体瘤组)。根据WHO2000年分级标准,胶质瘤组Ⅱ级胶质瘤16例(星形细胞瘤13例、少突胶质细胞瘤1例、室管膜瘤1例、混合性星形-少突胶质细胞瘤1例);Ⅲ级胶质瘤17例(间变性星形细胞瘤9例、间变性少突胶质细胞瘤7例、间变性室管膜瘤1例);Ⅳ级胶质瘤18例(均为胶质母细胞瘤)。脑膜瘤组为Ⅰ级脑膜瘤6例(纤维型脑膜瘤),Ⅱ级脑膜瘤3例(非典型性脑膜瘤)。垂体瘤组中垂体生长激素/催乳素细胞腺瘤1例,垂体催乳素细胞腺瘤1例,垂体多激素细胞腺瘤3例。采用免疫组化方法检测脑肿瘤组织中甘油-3-磷酸脱氢酶的表达程度。结果(1)胶质瘤Ⅱ～Ⅳ级标本免疫组化染色均呈阳性反应,脑膜瘤、垂体瘤和正常对照组则为阴性反应。(2)不同病理分级的胶质瘤标本中甘油醛-3-磷酸脱氢酶表达水平各异,其中胶质瘤Ⅱ级者甘油醛-3-磷酸脱氢酶阳性细胞检出率为12.8%,Ⅲ级22.9%,Ⅳ级44.5%,三者间差异具有显著性意义(P<0.05);而且甘油醛-3-磷酸脱氢酶阳性细胞检出率与胶质瘤的病理分级呈线性正相关(r=0.606,P<0.05)。结论甘油醛-3-磷酸脱氢酶蛋白表达水平的增高在胶     

α-Internexin in the diagnosis of oligodendroglial tumors and association with 1p/19q status

α-Internexin (INA) has been proposed to be a surrogate marker for the 1p/19q codeletion in oligodendroglial tumors (OTs). We analyzed INA expression in 83 glioma and 21 oligodendroglial phenotype-mimicking tumors (OMT) to assess its usefulness in differential diagnosis and its correlation with 1p/19q status; in particular, INA expression in gliomas with isolated/partial 1p or 19q deletions was assessed. α-Internexin expression and 1p/19q codeletion were present in 92% (34/37) of codeleted tumors (p < 0.0001). By contrast, INA was found in only 20% of cases with isolated/partial 1p aberrations and 36% of cases without 1p/19q deletions; it was also foundin 63% (10/16) of cases with isolated/partial 19q aberrations. α-Internexin expression was more specific in high-grade than in low-grade gliomas (66% vs 31%). Notably, a subset of tumors (10/83) displayed a biphasic INA expression pattern that was significantly associated with proliferation rate, whereas all areas harbored the 1p/19q codeletion. Only no or weak INA expression was seen in OMTs. In summary, INA is a useful marker to differentiate OTs from astrocytic tumors and OMTs, but INA expression is not exclusively linked to OTs harboring the 1p/19q codeletion. Moreover, it can sometimes be heterogeneously distributed within tumors, which emphasizes the need for 1p/19q analysis by molecular genetic techniques for diagnosis.     

Genetic alterations and biomarkers for glioma

Over the last decade, significant progress has been made in understanding glioma on a molecular level. However, optimal incorporation of molecular markers into clinical care is still controversial. Here, the potential utility of genetic alterations found in gliomas in refining histological diagnosis, prognosis, and predictive values for treatment selection is reviewed. Among all, O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation, 1p/19q codeletion, and isocitrate dehydrogenase 1 (IDH1) mutations have been identified as favorable prognostic markers. MGMT promoter methylation is the only potential predictive marker for response to temozolomide and alkylating agents in glioblastoma (GBM), but it is not of assistance in diagnostics. IDH1 mutations and 1p/19q codeletion are also useful for classifying and grading gliomas, since 1p/19q codeletion is tightly linked to oligodendroglial lineage, and IDH1 mutations are restricted to grade II/III gliomas, while not to primary GBM. BRAF fusion is a good marker for pilocytic astrocytoma. High-throughput profiling techniques for gene expression and epigenetic modification have provided new subtype classifications for GBM as well as lower grade gliomas, which may be of prognostic and predictive values. Efforts to identify molecular markers that predict the benefits of novel molecularly targeted treatments will enable better patient stratification and individualization of treatment.     

Histomolecular classification of adult diffuse gliomas: the diagnostic value of immunohistochemical markers

Adult gliomas are most often infiltrative. The World Health Organization (WHO) has classed them into three major groups according to the presomptive cell of origin: astrocytoma, oligodendroglioma and mixed oligoastrocytoma. Depending on the presence or absence of a small number of signs of anaplasia (mitosis, nuclear atypia, cell density, microvascular proliferation and necrosis) the WHO distinguishes grade II (LGG), III (anaplastic), and IV (glioblastomas, GBM). Mutation in the isocitrate deshydrogenase I and II (IDH1 and 2) genes distinguishes grade II, III and secondary GBM from primary GBM. Moreover two additional genetic alterations are recorded in grade II and III gliomas: TP53 mutations that characterize astrocytomas and 1p19q codeletion (as the result of t(1;19)(q10;p10) translocation) recorded in oligodendrogliomas. Mixed gliomas, the most non-reproducible category, share with astrocytomas and oligodendrogliomas the same genetic alterations. Interestingly TP53 mutation (p53+) and 1p19q codeletion (1p19q+) are mutually exclusive and involve IDH mutated (IDH+) glial precursor cells. According to IDH, TP53, and 1p19q status, four major subtypes of LGG are recorded: IDH+/p53−/1p19q−, IDH+/p53+/1p19q−, IDH+/p53−/1p19q+ and triple negative, this last subgroup having the worst prognosis. Interestingly, p53 expression and internexin alpha (INA) expression can replace to some extent TP53 mutation and 1p19 codeletion, respectively. Moreover the antibody directed against the IDH1R132H isoform is highly specific. Because this mutation is the most frequent it is sufficient to assess IDH status in more than 80% of grade II and III gliomas. Taken together these three immunohistochemical markers are contribute greatly to the classification of gliomas and should be tested routinely as diagnostic markers. Finally, although GBM are genetically heterogeneous, the vast majority display EGFR amplification, often associated with EGFR expression, which can be helpful for diagnosis in certain cases.     

Molecular diagnostics of gliomas: the clinical perspective

Significant progress has been made in the molecular diagnostic subtyping of brain tumors, in particular gliomas. In contrast to the classical molecular markers in this field, p53 and epidermal growth factor receptor (EGFR) status, the clinical significance of which has remained controversial, at least three important molecular markers with clinical implications have now been identified: 1p/19q codeletion, O ⁶-methylguanine methyltransferase (MGMT) promoter methylation and isocitrate dehydrogenase-1 (IDH1) mutations. All three are favorable prognostic markers. 1p/19q codeletion and IDH1 mutations are also useful to support and extend the histological classification of gliomas since they are strongly linked to oligodendroglial morphology and grade II/III gliomas, as opposed to glioblastoma, respectively. MGMT promoter methylation is the only potentially predictive marker, at least for alkylating agent chemotherapy in glioblastoma. Beyond these classical markers, the increasing repertoire of anti-angiogenic agents that are currently explored within registration trials for gliomas urgently calls for efforts to identify molecular markers that predict the benefit derived from these novel treatments, too.     

Diagnostic and prognostic values of 1p and 19q deletions in adult gliomas: critical review of the literature and implications in daily clinical practice

Losses of chromosomes 1p and 19q are deemed correlated with diagnosis of oligodendroglioma, higher chemosensitivity and better prognosis. We reviewed the literature to evaluate the usefulness of these correlations in daily clinical practice. The rates of deletions relative to histology (WHO classifications) were extracted from 33 studies, including 2666 patients. The 1p deletions and 1p19q codeletion mean rates were respectively 65.4 and 63.3% in oligodendrogliomas, 28.7 and 21.6% in oligoastrocytomas, 13.2 and 7.5% in astrocytomas, 11.6 and 2.9% in glioblastomas. The presence of 1p deletion and 1p19q codeletion were strongly correlated with the histological diagnosis corresponding to oligodendroglioma. Calculation of specificity, sensitivity, predictive positive values and false negative rates suggests that presence of deletion 1p or codeletion represents a strong argument in favor of the diagnosis of oligodendroglioma. However, considering the high false negative rate, absence of such deletions does not rule out the diagnosis. In grade 3 oligodendroglial tumors, the probability of responding to chemotherapy, and the duration of response, were higher when codeletions were present. This suggests that, in these tumors, the presence of codeletion is a strong argument in favor of adjuvant chemotherapy. However, chemotherapy should not be systematically excluded when codeletions are absent, as the chances of response are about 33% in this situation. Data concerning low-grade gliomas were more controversial. Oligodendroglial tumors with 1p deletion or 1p19q codeletion seemed to have a better prognosis, as five-year survival rates were 50% higher than in tumors without deletion. This might be explained by the correlation between 1p deletion and other identified prognosis factors: (1) higher chemosensitivity, (2) tumor location more frequently in the frontal lobe, leading to better resection and lower risk of neurological deficit, (3) slower growth rate, (4) higher risk of epilepsy, leading to an early detection.     

The importance of 10q status in an outcomes-based comparison between 1p/19q fluorescence in situ hybridization and polymerase chain reaction-based microsatellite loss of heterozygosity analysis of oligodendrogliomas

1p/19q codeletion is a favorable prognostic marker of oligodendrogliomas. Although fluorescence in situ hybridization (FISH) and microsatellite-based polymerase chain reaction (PCR) for loss of heterozygosity (LOH) are common methods to test for 1p/19q codeletion, it is unclear which test is better at prognostic stratification. This study analyzed outcomes of 111 oligodendrogliomas with both 1p/19q FISH and LOH done at the time of diagnosis. Overall concordance between the 2 assays was 81.1%. In grade III oligodendrogliomas, LOH was better than FISH at survival stratification (p < 0.0001 for LOH vs p = 0.02 for FISH), although increasing the stringency of FISH interpretation criteria improved concordance and prognostic power. Oligodendrogliomas that were 1p/19q-codeleted by FISH but also had 10q LOH were negative for 1p/19q codeletion by PCR analysis in more than 70% of cases, with very poor survival in the grade III subset. Thus, although PCR-based LOH is a better stratifier of 1p/19q status, FISH still has clinical and prognostic utility, especially if 10q data can be incorporated.     

Dynamic history of low-grade gliomas before and after temozolomide treatment

OBJECTIVE: To evaluate the natural progression and the impact of temozolomide in low-grade gliomas and to correlate these changes with the profile of genetic alterations. METHODS: The mean tumor diameter (MTD) of low-grade gliomas was evaluated on serial magnetic resonance images before (n = 39), during, and after (n = 107) treatment with neoadjuvant temozolomide. MTD growth curves were correlated with chromosomes 1p-19q loss and p53 overexpression in the tumors. RESULTS: Before temozolomide onset, MTD increased linearly over time, indicating a continuous growth that was significantly slower in 1p-19q deleted tumors (3.4 vs 5.9mm/year; p = 0.0016) and in tumors that did not overexpress p53 (4.2 vs 6.3mm/year; p = 0.05). During temozolomide treatment, almost all patients (92%) experienced initial decrease of MTD. Subsequently, some tumors started to resume growth despite continuous administration of temozolomide, with a lower rate of relapse in 1p-19q deleted tumors (16.6 vs 58%; p = 0.0004) and in tumors that did not overexpress p53 (26 vs 68%; p = 0.003). When temozolomide was discontinued in the absence of tumor progression, a majority of tumors resumed their progressive growth within a year. INTERPRETATION: Untreated low-grade gliomas grow continuously at a rate that is influenced by the genetic alterations of the tumors. Temozolomide reverses this pattern at the onset, but this effect is often brief in patients whose tumors overexpress p53 and do not harbor the 1p-19q codeletion, suggesting acquired chemoresistance. A majority of tumors will resume their growth when treatment is discontinued, raising the issue of the optimal duration of treatment in continuously responding patients.     

Update on molecular findings, management and outcome in low-grade gliomas

Low-grade infiltrating gliomas in adults include diffuse astrocytoma, oligoastrocytoma and oligodendroglioma. The current gold standard diagnosis of these tumors relies on histological classification; however, emerging molecular abnormalities discovered in these tumors are playing an increasingly prominent part in the process of tumor diagnosis and, consequently, patient management. The frequency and clinical importance of tumor protein p53 (TP53) abnormalities, deletions involving chromosomes 1p and 19q, O(6)-methylguanine-DNA methyltransferase (MGMT) promoter methylation status, abnormalities in the PTEN tumor suppressor gene and the BRAF oncogene, and isocitrate dehydrogenase (IDH) mutations have become better defined. Molecular markers have not, historically, had an important role in determining the course of treatment for patients with low-grade gliomas, but ongoing phase III clinical trials incorporate 1p deletion or 1p19q codeletion status-and future trials plan to incorporate MGMT promoter methylation status-as stratification factors. Future trials will need to incorporate IDH mutational status in addition to these factors. Ultimately, molecular marker assessment will, hopefully, improve the accuracy of tumor diagnosis and enhance the effectiveness of treatment to achieve improved patient outcomes.     

Integrated DNA methylation and copy-number profiling identify three clinically and biologically relevant groups of anaplastic glioma

The outcome of patients with anaplastic gliomas varies considerably. Whether a molecular classification of anaplastic gliomas based on large-scale genomic or epigenomic analyses is superior to histopathology for reflecting distinct biological groups, predicting outcomes and guiding therapy decisions has yet to be determined. Epigenome-wide DNA methylation analysis, using a platform which also allows the detection of copy-number aberrations, was performed in a cohort of 228 patients with anaplastic gliomas (astrocytomas, oligoastrocytomas, and oligodendrogliomas), including 115 patients of the NOA-04 trial. We further compared these tumors with a group of 55 glioblastomas. Unsupervised clustering of DNA methylation patterns revealed two main groups correlated with IDH status: CpG island methylator phenotype (CIMP) positive (77.5 %) or negative (22.5 %). CIMP^pos (IDH mutant) tumors showed a further separation based on copy-number status of chromosome arms 1p and 19q. CIMP^neg (IDH wild type) tumors showed hallmark copy-number alterations of glioblastomas, and clustered together with CIMP^neg glioblastomas without forming separate groups based on WHO grade. Notably, there was no molecular evidence for a distinct biological entity representing anaplastic oligoastrocytoma. Tumor classification based on CIMP and 1p/19q status was significantly associated with survival, allowing a better prediction of outcome than the current histopathological classification: patients with CIMP^pos tumors with 1p/19q codeletion (CIMP-codel) had the best prognosis, followed by patients with CIMP^pos tumors but intact 1p/19q status (CIMP-non-codel). Patients with CIMP^neg anaplastic gliomas (GBM-like) had the worst prognosis. Collectively, our data suggest that anaplastic gliomas can be grouped by IDH and 1p/19q status into three molecular groups that show clear links to underlying biology and a significant association with clinical outcome in a prospective trial cohort.