Targeting distinct amino acid metabolic vulnerabilities in IDH-mutant and IDH-wildtype gliomas

Diffuse gliomas are up till now graded based upon morphology. Recent findings indicate that isocitrate dehydrogenase (IDH) mutation status defines biologically distinct groups of tumors. The role of tumor grade and mitotic index in patient outcome has not been evaluated following stratification by IDH mutation status. To address this, we interrogated 558 WHO grade II-III diffuse gliomas for IDH1/2 mutations and investigated the prognostic impact of WHO grade within IDH-mutant and IDH-wild type tumor subsets independently. The prognostic impact of grade was modest in IDH-mutant [hazard ratio (HR) = 1.21, 95 % confidence interval (CI) = 0.91-1.61] compared to IDH-wild type tumors (HR = 1.74, 95 % CI = 0.95-3.16). Using a dichotomized mitotic index cut-off of 4/1000 tumor cells, we found that while mitotic index was significantly associated with outcome in IDH-wild type tumors (log-rank p < 0.0001, HR = 4.41, 95 % CI = 2.55-7.63), it was not associated with outcome in IDH-mutant tumors (log-rank p = 0.5157, HR = 1.10, 95 % CI = 0.80-1.51), and could demonstrate a statistical interaction (p < 0.0001) between IDH mutation and mitotic index (i.e., suggesting that the effect of mitotic index on patient outcome is dependent on IDH mutation status). Patient age, an established prognostic factor in diffuse glioma, was significantly associated with outcome only in the IDH-wild type subset, and consistent with prior data, 1p/19q co-deletion conferred improved outcome in the IDH-mutant cohort. These findings suggest that stratification of grade II-III gliomas into subsets defined by the presence or absence of IDH mutation leads to subgroups with distinct prognostic characteristics. Further evaluation of grading criteria and prognostic markers is warranted within IDH-mutant versus IDH-wild type diffuse grade II-III gliomas as independent entities.

To evaluate the diagnostic potential of fluid suppression (FS) techniques combined with amide proton transfer-weighted imaging (APTw) for assessment of isocitrate dehydrogenase (IDH) mutation status, glioma subtypes, and tumor proliferation. This retrospective study included 117 patients with adult-type diffuse gliomas. Conventional APTw, FS-APTw, and spillover-corrected FS-APTw (SCFS-APTw) metrics were calculated from 3T MRI data in tumor parenchyma, necrotic or cystic regions, and contralateral normal-appearing white matter. APTw signals were compared across the three techniques within each region, between IDH-mutant and IDH-wildtype gliomas, and among astrocytoma, oligodendroglioma, and glioblastoma subtypes. Diagnostic performance for distinguishing IDH mutation status and glioma subtypes was assessed using receiver operating characteristic (ROC) analysis. Correlations between APTw metrics and Ki-67 expression were also analyzed. Both FS-APTw and SCFS-APTw significantly reduced signal intensity in tumor parenchyma and necrotic or cystic regions, with SCFS-APTw demonstrating a stronger suppression effect. IDH-wildtype gliomas showed significantly higher APTw metrics than IDH-mutant gliomas (all P < 0.001). Glioblastomas exhibited significantly higher metrics than oligodendrogliomas (all corrected P ≤ 0.015) and astrocytomas (all corrected P < 0.001). SCFS-APTw achieved the highest area under the ROC curve (AUC) of 0.846 for identification of IDH mutation status. For differentiation between astrocytomas and glioblastomas, the 90th percentile of APTw yielded the highest AUC (0.860), followed by SCFS-APTw (0.849). For discrimination between oligodendrogliomas and glioblastomas, the highest AUC (0.832) was obtained using the 90th percentile of SCFS-APTw. None of these metrics successfully differentiated oligodendrogliomas from astrocytomas. SCFS-APTw demonstrated the strongest correlation with Ki-67 expression (r = 0.451). FS techniques effectively reduce elevated APTw signals originating from fluid compartments. Their combination with APTw imaging enables evaluation of IDH mutation status, glioma subtypes, and tumor proliferative activity in adult-type diffuse gliomas.

152 Background: Mutations in the metabolic enzyme isocitrate dehydrogenase 1 (IDH1) are found in &gt; 70% of intermediate grade gliomas. Gain-of-function mutations in IDH1 promote diffuse glioma formation through epigenetic reprogramming of a number of genes, including immune-related genes. Tumor-derived exosomes (TEX) accumulate in the tumor microenvironment (TME) and in body fluids of patients. TEX serve as a communication system between tumor and normal cells. Circulating TEX carry a complex molecular and genetic cargo and interfere with functions of immune cells. This study characterizes TEX produced by IDH mutant glioma spheres and TEX from plasma of patients with IDH mutant gliomas. Methods: TEX produced by patient-derived IDH1(mut) or IDH1(wt) glioma spheres or TEX in patient’s plasma were isolated by mini size exclusion chromatography (mini-SEC). TEX morphology, size, numbers and molecular profile were characterized and the crossing of the blood-brain barrier (BBB) and biodistribution was investigated by in vivo imaging of TEX. Interactions of TEX with endothelial cells, astrocytes and immune cells were demonstrated by confocal microscopy. Results: TEX isolated from supernatants of IDH1(mut) or IDH1(wt) glioma spheres by mini-SEC carried TSG101 and showed the typical size and vesicular morphology of exosomes. BCA protein assays and qNano analysis revealed an elevated exosome production by IDH mutant cells ( p&lt; 0.01). TEX carried immunosuppressive proteins (FasL, CTLA-4 and TRAIL) and IDH mutant exosomes carried higher levels of these proteins and of adenosine pathway components CD39 and CD73. Labeled TEX injected in the white matter of mice crossed the BBB and were detectable in distant organs 24h after injection. TEX were rapidly internalized by endothelial cells and astrocytes, but not by T cells, which interacted with TEX by surface signaling. These results were confirmed by investigating TEX isolated from glioma patient’s plasma. Conclusions: The data suggest that TEX play an important role in IDH mutant gliomas and drive tumor progression in part by inducing suppression of immune cells. Future efforts will focus on characterizing immunosuppressive effects of TEX derived from IDH mutant cells vs gliomas without IDH mutations.

Gliomas are the most common malignant brain tumor, have an aggressive behavior, and invariably relapse and progress. Despite the recent advancements, little is known about the role of the epigenome in glioma disease progression and recurrence. To investigate the molecular dynamics over time and in response to therapeutic pressures, the Glioma Longitudinal AnalySiS (GLASS) Consortium, a multinational collaboration, is investigating epigenome-wide molecular data from primary and recurrent matched pairs, including IDH mutant (IDHmut) and IDH wildtype (IDHwt) gliomas. We have compiled a total of 357 samples comprising 143 primary-recurrent pairs profiled by DNA methylation, of which 157 samples have genomic data (WXS/WGS) and 120 have transcriptomic data (RNAseq). IDHwt gliomas have a distinct epigenetic evolution compared to IDHmut after treatment. IDHwt gliomas are more epigenetically stable over time, while IDHmut gliomas display a loss of DNA methylation throughout disease progression. Next, we investigated the molecular drivers of longitudinal gliomas by integration of DNA methylation and gene expression data. We identified epigenetic activation of cell cycle pathways in recurrent IDHmut compared to initial tumors. Transcription factors musculin, ZNF367, and ZNF682 are enriched among recurrent IDHmut gliomas and potentially regulate IDHmut recurrence and/or progression. We next used a DNA methylation-based deconvolution approach to estimate the tumor microenvironment (TME) composition. We found that the TME among IDHmut subtypes (Codel, GCIMP-high, and GCIMP-low) presented less immune infiltration than IDHwt (Classic-like, Mesenchymal-like, and PA-like). Post-treatment, we found a decrease of CD4+T and an increase of CD8+T cells in IDHmut. In conclusion, IDHmut gliomas present a more unstable epigenome, while the epigenome of IDHwt gliomas seems relatively preserved after treatment. We identified potential master regulators of cell cycle deregulation of IDHmut recurrence. Finally, the TME differs across IDHmut and IDHwt gliomas and the cell composition changes over time.

Magnetic resonance imaging criteria for prediction of isocitrate dehydrogenase (IDH) mutation status in patients with grade II-III astrocytoma and oligodendroglioma

Background and Purpose:In-vivo magnetic resonance spectroscopy (MRS) of 2-hydroxyglutarate (2HG) may provide diagnostic and monitoring biomarkers in isocitrate dehydrogenase (IDH)-mutated glioma. A previous meta-analysis has shown good diagnostic accuracy of TE-optimized PRESS for IDH-mutated glioma, but most studies feature IDH-wildtype glioma as a comparison. However, when considering newly identified brain lesions that may mimic glioma, full characterization of its diagnostic utility should also consider the accuracy of 2HG measurement in non-tumor tissue. Therefore, we tested how well TE-optimized 2HG levels distinguish between IDH-mutated glioma and non-tumor tissue, in this case, normal-appearing brain. We further examined the impact of different spectral modeling strategies (baseline stiffness, macromolecule inclusion, and basis set composition).Materials and Methods:48 patients with diagnosed/suspected IDH-mutated glioma were enrolled. 3T MRS data were acquired from tumor and contralateral non-tumor tissue with PRESS localization (TE = 97 ms, optimized for 2HG detection) and analyzed with ‘LCModel’ software. Receiver operating characteristic analysis evaluated 2HG estimates’ ability to distinguish IDH-mutated glioma from non-tumor brain tissue. Modeling interactions between 2HG and other metabolites were evaluated to identify reasons for potential false-positive 2HG detection.Results:TE-optimized PRESS distinguished IDH-mutated glioma from non-tumor tissue with lower sensitivity (range 0.76–0.62) and specificity (0.85–0.78) than literature suggests for IDH-mutated vs. IDH-wildtype glioma. Strong negative correlations between gamma-aminobutyric acid (GABA) and 2HG persisted across all modeling strategies and may lead to false-positive 2HG detection in non-tumor tissue. We further present a cautionary example from a patient on a ketogenic diet, showing that the ketone body acetone can interfere with 2HG detection.Conclusions:Spectral overlap with GABA and acetone can lead to false-positive 2HG detection in non-tumor tissue. Clinicians need to be mindful of these pitfalls when interpreting 2HG estimates.

Mutations in isocitrate dehydrogenase ( IDH) 1 are high-frequency events in low-grade glioma and secondary glioblastoma, and IDH1 mutant gliomas are vulnerable to interventions. Metabolic reprogramming is a hallmark of cancer. In this study, comprehensive metabolism investigation of clinical IDH1 mutant glioma specimens was performed to explore its specific metabolic reprogramming in real microenvironment. Massive metabolic alterations from glycolysis to lipid metabolism were identified in the IDH1 mutant glioma tissue when compared to IDH1 wild-type glioma. Of note, tricarboxylic acid (TCA) cycle intermediates were in similar levels in both groups, with more pyruvate found entering the TCA cycle in IDH1 mutant glioma. The pool of fatty acyl chains was also reduced, displayed as decreased triglycerides and sphingolipids, although membrane phosphatidyl lipids were not changed. The lower fatty acyl pool may be mediated by the lower protein expression levels of long-chain acyl-CoA synthetase 1 (ACSL1), ACSL4, and very long-chain acyl-CoA synthetase 3 (ACSVL3) in IDH1 mutant glioma. Lower ACSL1 was further found to contribute to the better survival of IDH1 mutant glioma patients based on the The Cancer Genome Atlas (TCGA) RNA sequencing data. Our research provides valuable insights into the tissue metabolism of human IDH1 mutant glioma and unravels new lipid-related targets.

Background: Isocitrate dehydrogenase mutant (IDH-mut) gliomas represent a distinct subtype of glioma with a somewhat better prognosis. However, despite this, they remain incurable due to the limited availability of effective treatments. Targeting SHP2, a non-receptor protein tyrosine phosphatase, shows promise as a therapeutic strategy for cancers, including IDH wildtype (WT) glioblastoma (GBM). However, it is unknown whether IDH-mutant gliomas respond to SHP2 inhibition. Methods: Bioinformatic and biological analyses revealed increased expression and activation of the PDGFRα-SHP2-ERK pathway in IDH-mutant gliomas and patient-derived IDH-mut glioma stem-like cells (GSCs). The effects of SHP2 inhibition, alone or with radiation therapy (RT), were assessed through assays including cell growth, sphere formation, cell differentiation, flow cytometry, immunoblotting, orthotopic brain tumor xenografts, and immunohistochemistry. Results: PDGFRα expression was elevated in IDH-mut gliomas and GSCs, activating the SHP2-ERK pathway. SHP099, a SHP2 inhibitor, reduced GSC tumorigenicity in vitro and in vivo by disrupting SHP2-ERK signaling and promoting differentiation. SHP099 also enhanced cytotoxicity of RT, the standard treatment for IDH-mut glioma, on IDH-mut GSCs and orthotopic glioma models. Mechanistically, the PDGFRα-SHP2-ERK axis is activated in IDH-mut gliomas and RT further activates this pathway. Targeting SHP2 suppressed ERK signaling thereby enhancing the therapeutic effect of RT. Conclusion: Combining SHP2 inhibition with RT shows promising therapeutic efficacy for IDH-mut glioma by suppressing the activated SHP2-ERK axis. Citation Format: Xiaozhou Yu, Xiao Song, Deanna Tiek, Runxin Wu, Maya Walker, Craig Horbinski, Bo Hu, Shi-Yuan Cheng. Targeting PDGFRa-SHP2 signaling enhances radiotherapy in IDH1 mutant glioma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 6946.

Simple SummaryGliomas represent the vast majority of primary brain tumours and are of significant medical importance due to the poor clinical course of affected patients. The isocitrate dehydrogenase 1 (IDH1) mutation is associated with improved prognosis, compared to patients with IDH1-wildtype lesions of the same stage. In this proof-of-concept study, Fourier transform infrared spectroscopy was used to determine the IDH1 molecular status in fixed glioma sections. Classification algorithms successfully distinguished the two IDH1 classes with high accuracies (>80%). Knowledge of the IDH1 status would be beneficial, as maximum resection may be preferred in patients with IDH1-mutant gliomas, whilst a more limited resection can be best for IDH1-wildtype gliomas. Furthermore, we examined blood serum in an attempt to identify the biomolecular alterations caused by the IDH1 mutation. Non-invasive approaches that can detect the molecular status may guide some patients to an alternative treatment prior to surgery.Mutations in the isocitrate dehydrogenase 1 (IDH1) gene are found in a high proportion of diffuse gliomas. The presence of the IDH1 mutation is a valuable diagnostic, prognostic and predictive biomarker for the management of patients with glial tumours. Techniques involving vibrational spectroscopy, e.g., Fourier transform infrared (FTIR) spectroscopy, have previously demonstrated analytical capabilities for cancer detection, and have the potential to contribute to diagnostics. The implementation of FTIR microspectroscopy during surgical biopsy could present a fast, label-free method for molecular genetic classification. For example, the rapid determination of IDH1 status in a patient with a glioma diagnosis could inform intra-operative decision-making between alternative surgical strategies. In this study, we utilized synchrotron-based FTIR microanalysis to probe tissue microarray sections from 79 glioma patients, and distinguished the positive class (IDH1-mutated) from the IDH1-wildtype glioma, with a sensitivity and specificity of 82.4% and 83.4%, respectively. We also examined the ability of attenuated total reflection (ATR)-FTIR spectroscopy in detecting the biomolecular events and global epigenetic and metabolic changes associated with mutations in the IDH1 enzyme, in blood serum samples collected from an additional 72 brain tumour patients. Centrifugal filtration enhanced the diagnostic ability of the classification models, with balanced accuracies up to ~69%. Identification of the molecular status from blood serum prior to biopsy could further direct some patients to alternative treatment strategies.

Background: Dynamic susceptibility contrast perfusion MRI (DSC-MRI) is a promising non-invasive examination to predict histological and molecular characteristics of brain gliomas. However, the diagnostic accuracy of relative cerebral blood volume (rCBV) is heterogeneously reported in the literature. This systematic review and meta-analysis aims to assess the diagnostic accuracy of mean rCBV derived from DSC-MRI in differentiating Isocitrate Dehydrogenase (IDH)-mutant from IDH-wildtype gliomas. Methods: A comprehensive literature search was conducted in PubMed, Web of Science, and EMBASE up to January 2025, following PRISMA guidelines. Eligible studies reported mean CBV values in treatment-naïve gliomas with histologically confirmed IDH status. Pooled estimates of standardized mean differences (SMDs), diagnostic odds ratios (DOR), and area under the receiver-operating characteristic curve (AUC) were computed using a random-effects model. Heterogeneity was assessed via I2 statistic. Meta-regression analyses were also performed. Results: An analysis of 18 studies (n = 1733) showed that mean rCBV is significantly lower in IDH-mutant gliomas (SMD = -0.86; p < 0.0001). The pooled AUC was 0.80 (95% CI, 0.75-0.90), with moderate sensitivity and specificity. Meta-regression revealed no significant influence of DSC-MRI acquisition parameters, although a flip angle showed a trend toward significance (p = 0.055). Conclusions: Mean rCBV is a reliable imaging biomarker for IDH mutation status in gliomas, demonstrating good diagnostic performance. However, heterogeneity in acquisition parameters and post-processing methods limits generalizability of results. Future research should focus on standardizing DSC-MRI protocols.

To determine whether diffusion- and perfusion-weighted MRI-based radiomics features can improve prediction of isocitrate dehydrogenase (IDH) mutation and tumor aggressiveness in lower grade gliomas (LGGs) METHODS: Radiomics features (n = 6472) were extracted from multiparametric MRI including conventional MRI, apparent diffusion coefficient (ADC), and normalized cerebral blood volume, acquired on 127 LGG patients with determined IDH mutation status and grade (WHO II or III). Radiomics models were constructed using machine learning-based feature selection and generalized linear model classifiers. Segmentation stability was calculated between two readers using concordance correlation coefficients (CCCs). Diagnostic performance to predict IDH mutation and tumor grade was compared between the multiparametric and conventional MRI radiomics models using the area under the receiver operating characteristics curve (AUC). The models were tested using a temporally independent validation set (n = 28). The multiparametric MRI radiomics model was optimized with a random forest feature selector, with segmentation stability of a CCC threshold of 0.8. For IDH mutation, multiparametric MR radiomics showed similar performance (AUC 0.795) to the conventional radiomics model (AUC 0.729). In tumor grading, multiparametric model with ADC features showed higher performance (AUC 0.932) than the conventional model (AUC 0.555). The independent validation set showed the same trend with AUCs of 0.747 for IDH prediction and 0.819 for tumor grading with multiparametric MRI radiomics model. Multiparametric MRI radiomics model showed improved diagnostic performance in tumor grading and comparable diagnostic performance in IDH mutation status, with ADC features playing a significant role. • The multiparametric MRI radiomics model was comparable with conventional MRI radiomics model in predicting IDH mutation. • The multiparametric MRI radiomics model outperformed conventional MRI in glioma grading. • Apparent diffusion coefficient played an important role in glioma grading and predicting IDH mutation status using radiomics.

Prior studies suggested glutamine metabolism in cancers may be altered to meet the high demands of nucleotide biosynthesis in cancers. We conducted 1H MR spectroscopy in 18 glioma patients and analyzed the metabolic data together with post-gadolinium MRI and cell proliferation rate (MIB-1 label index). The optimized MRS (TE 97 ms PRESS) provided well discernible signal of glutamine at 2.45 ppm and a negative-polarity signal of citrate at 2.6 ppm, without considerable overlaps with neighboring signals. The 18 patients had biopsy-proven anaplastic gliomas or glioblastomas. Concurrent elevation of glutamine and citrate was identified in 15 gliomas. These gliomas presented with enhancement in post-gadolinium MRI, indicative of broken blood-brain barrier (BBB). The 15 gliomas were grouped as subset-1 while the other 3 gliomas that had elevated citrate without elevation of glutamine were grouped as subset-2. Citrate level was significantly different between the two subsets of gliomas (1.4+/-0.5 vs. 1.6+/-0.4 mM). However, subst-1 had significantly higher choline (4.7+/-1.8 vs. 1.6+/-0.3 mM, p&amp;lt; 0.01) and higher MIB-1 compared with subset-2. Given that choline is a cellularity marker, a finding of high choline and high MIB-1 with elevation of glutamine and citrate suggests that the tumors have high tumor cellularity and cell multiplication competence. Of the 18 gliomas, 13 were IDH mutated with elevated 2HG. The glutamine and citrate levels in IDH-mutant gliomas were not significantly different from those in IDH wildtype gliomas. In conclusion, high-grade gliomas undergo a metabolic rearrangement of concurrent elevation of glutamine and citrate to attain malignant characters such as high cellularity, rapid cell proliferation, and BBB breakdown. IDH mutant and IDH wildtype gliomas may share a common metabolic rearrangement of glutamine-mediated citrate elevation to attain malignancy. Measurements of glutamine and citrate may serve a potential imaging biomarker for aggressive gliomas.

Autocrine BMP4 Signaling Enhances Tumor Aggressiveness via Promoting Wnt/β-Catenin Signaling in IDH1-mutant Gliomas

BackgroundT cell-based immunotherapies have had limited success in glioma thus far. Here, we evaluate the literature on abundance, spatial distribution and phenotypical characteristics of T cells in the tumor micro-environment (TME) of IDH-mutant and IDH-wildtype glioma, with the aim to understand how these measures relate to immunotherapy resistance and to aid the development of immunotherapies for glioma.MethodsMedline, Embase, Web of Science Core Collection, Google Scholar and the Cochrane Central Register of Controlled Trials were systematically searched up to May 6, 2025. Out of 4303 articles screened, 85 studies examining T cell immunity in human glioma were selected. We collected information about tumor subtype, grade, methods, T cell abundance, spatial distribution, phenotypes and prognostic significance.ResultsT cells are present in the glioma TME, but densities are heterogeneous and generally low, especially in IDH-mutant glioma. T cell abundance increases with higher WHO grade and upon recurrence. T cells cluster around blood vessels, especially in IDH-mutant glioma. Glioma-infiltrating T cells largely display a late-differentiated phenotype (CD45RA-CCR7-C62L-), expressing markers that signify sustained antigen activation and exhaustion (PD-1, CTLA-4, TIM-3, LAG-3, CD39, and TIGIT). This phenotype coincides with decreased anti-tumor cytotoxicity and is spatially enriched in the myeloid-rich, hypoxic tumor core. Prognostic significance remains controversial.ConclusionsT cells in glioma are scarce, generally fully differentiated and functionally inert. Understanding and reinvigorating the deficient T cell response will be essential for successful immunotherapies. Future research should incorporate functional and spatial immune profiling to optimize and personalize immunotherapeutic strategies for glioma patients.

BackgroundRoughly 50% of adult gliomas harbor isocitrate dehydrogenase (IDH) mutations. According to the 2021 WHO classification guideline, these gliomas are diagnosed as astrocytomas, harboring no 1p19q co-deletion, or oligodendrogliomas, harboring 1p19q co-deletion. Recent studies report that IDH-mutant gliomas share a common developmental hierarchy. However, the neural lineages and differentiation stages in IDH-mutant gliomas remain inadequately characterized.MethodsUsing bulk transcriptomes and single-cell transcriptomes, we identified genes enriched in IDH-mutant gliomas with or without 1p19q co-deletion, we also assessed the expression pattern of stage-specific signatures and key regulators of oligodendrocyte lineage differentiation. We compared the expression of oligodendrocyte lineage stage-specific markers between quiescent and proliferating malignant single cells. The gene expression profiles were validated using RNAscope analysis and myelin staining and were further substantiated using data of DNA methylation and single-cell ATAC-seq. As a control, we assessed the expression pattern of astrocyte lineage markers.ResultsGenes concordantly enriched in both subtypes of IDH-mutant gliomas are upregulated in oligodendrocyte progenitor cells (OPC). Signatures of early stages of oligodendrocyte lineage and key regulators of OPC specification and maintenance are enriched in all IDH-mutant gliomas. In contrast, signature of myelin-forming oligodendrocytes, myelination regulators, and myelin components are significantly down-regulated or absent in IDH-mutant gliomas. Further, single-cell transcriptomes of IDH-mutant gliomas are similar to OPC and differentiation-committed oligodendrocyte progenitors, but not to myelinating oligodendrocyte. Most IDH-mutant glioma cells are quiescent; quiescent cells and proliferating cells resemble the same differentiation stage of oligodendrocyte lineage. Mirroring the gene expression profiles along the oligodendrocyte lineage, analyses of DNA methylation and single-cell ATAC-seq data demonstrate that genes of myelination regulators and myelin components are hypermethylated and show inaccessible chromatin status, whereas regulators of OPC specification and maintenance are hypomethylated and show open chromatin status. Markers of astrocyte precursors are not enriched in IDH-mutant gliomas.ConclusionsOur studies show that despite differences in clinical manifestation and genomic alterations, all IDH-mutant gliomas resemble early stages of oligodendrocyte lineage and are stalled in oligodendrocyte differentiation due to blocked myelination program. These findings provide a framework to accommodate biological features and therapy development for IDH-mutant gliomas.