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Updated: May 26, 2026
Enhanced Reduced Representation Bisulfite Sequencing for Assessment of DNA Methylation at Base Pair Resolution
Published on: February 24, 2015
DNA methylation profiling reveals a novel subtype harboring IDH mutation in H3-altered gliomas
Minjie Fu1, Yuan Feng1, Pin Sun1,2
1Department of Neurosurgery, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
Background:
H3-altered gliomas, now recognized by WHO CNS5 as grade 4 neoplasms driven by histone H3 mutations (notably H3K27M and H3G34R/V), exhibit marked molecular heterogeneity, dismal survival, and resistance to standard therapies. Despite their classification as WHO grade 4 neoplasms, current stratification fails to capture their clinical and epigenetic diversity.
Methods:
We performed genome-wide DNA methylation profiling on 49 representative cases from a clinical cohort of 375 H3-altered gliomas and validated subtype classifications using TCGA data. Single-cell RNA sequencing, ChIP-seq, and spatial transcriptomic analyses were employed to elucidate tumor-intrinsic programs and microenvironmental niches across subtypes.
Results:
Unsupervised clustering identified four robust DNA methylation-defined subtypes: DMG_K27M, GBM_RTK, GBM_G34, and IDH/H3_comut, a novel subtype harboring co-occurring IDH and H3 mutations. The IDH/H3_comut subtype exhibited global DNA hypermethylation and significantly improved survival. In contrast, GBM_RTK tumors showed hypomethylation of cell-cycle enhancers and aggressive phenotypes, while GBM_G34 and DMG_K27M displayed subtype-specific epigenetic features. Single-cell transcriptomics revealed distinct lineage compositions and microenvironments, with IDH/H3_comut tumors enriched in NPC-like cells and GBM_RTK in astrocyte-like and vascular mimicry programs. Clonal and spatial analyses uncovered a compartmentalized coexistence of IDH- and H3-mutant cells, suggesting cooperative rather than exclusive evolution.
Conclusions:
Our study redefines H3-altered gliomas through methylation-based taxonomy, identifies a novel IDH/H3_comut subtype with favorable prognosis, and reveals subtype-specific therapeutic vulnerabilities, including potential responsiveness to hypomethylating agents or CDK4/6 inhibitors.
Insights
Histone H3-altered gliomas show diverse subtypes. A novel IDH/H3 co-mutant subtype has better survival and may respond to specific therapies.
Area of Science:
- Neuro-oncology
- Epigenetics
- Cancer Genomics
Background:
- H3-altered gliomas are WHO grade 4, but show molecular heterogeneity and poor outcomes.
- Current classification doesn't capture clinical and epigenetic diversity.
Purpose of the Study:
- To redefine H3-altered gliomas using DNA methylation profiling.
- To identify novel subtypes and understand their molecular and clinical characteristics.
Main Methods:
- Genome-wide DNA methylation profiling of 375 H3-altered gliomas.
- Single-cell RNA sequencing, ChIP-seq, and spatial transcriptomics.
- Validation using TCGA data.
Main Results:
- Identified four DNA methylation subtypes: DMG_K27M, GBM_RTK, DHG_G34, and a novel IDH/H3_comut subtype.
- IDH/H3_comut subtype shows global hypermethylation, neurodevelopmental gene enrichment, and improved survival.
- GBM_RTK tumors exhibit hypomethylation and aggressive phenotypes; distinct lineage compositions and microenvironments were observed across subtypes.
Conclusions:
- Methylation-based taxonomy redefines H3-altered gliomas.
- A novel IDH/H3_comut subtype with a favorable prognosis was identified.
- Subtype-specific vulnerabilities suggest potential therapeutic strategies, including hypomethylating agents or CDK4/6 inhibitors.
