Diffuse Midline Glioma, H3 K27-Altered (DMG)

Overview

Diffuse midline glioma, H3 K27-altered (DMG) is a high-grade pediatric brain tumor defined by histone H3 K27M (or equivalent K27-altering) mutations and a diffuse midline location (brainstem, thalamus, spinal cord). It carries a uniformly poor prognosis; RT is the primary therapeutic modality. The tumor’s relatively low mutational burden makes it a tractable model for studying intra-tumoral heterogeneity and RT response variability.

Cohorts in the corpus

  • ROBIN KIDSROBIN PNOC023 cooperative study (Harvard University and University of California, San Francisco) — 33 patients accrued to arms A and B; biospecimen collection ongoing. PMID:41941260
  • KIDSROBIN radiomics cohort — 2,039 serial MRI scans from 253 DMG patients secured for radiomics and NLP studies; 8,057 clinical notes from 99 DMG patients for NLP. PMID:41941260

Recurrent alterations

No corpus-specific gene-level variant frequencies are reported; KIDSROBIN targets intra-tumoral heterogeneity rather than recurrence frequencies of individual mutations.

  • DMG is noted for relatively low mutational burden, making it a genetically simple model for deep mechanistic study of RT response. PMID:41941260
  • ICGC PedBrain pilocytic astrocytoma WGS study found one PAST case (ICGC_PA69) with the FGFR1 + H3-3A K27M + NF1 triple-mutation constellation classified as histologically ambiguous between PAST and diffuse midline glioma; H3-3A K27M co-occurred with FGFR1 activation in 3/48 pediatric GB samples from an independent cohort PMID:23817572

Subtypes

No molecular subtypes distinguished in the corpus beyond the H3 K27-altered definition.

Therapeutic landscape

  • ROBIN KIDSROBIN center (U54 CA274516; Harvard University and UCSF) uses single-cell genomics, spatial transcriptomics (Xenium 10x Genomics), epigenetics, and proteomics integrated with computational biology to elucidate how intra-tumoral heterogeneity drives variable RT responses in DMG. The central hypothesis is that RT response variability is largely driven by intra-tumoral heterogeneity, with both cell-intrinsic and cell-extrinsic (e.g., tumor-nervous-system interaction / Cancer Neuroscience) components. PMID:41941260
  • PNOC023 provides accrued biospecimen infrastructure (33 patients) while clinical data are maturing; analyses are underway for single-cell spatial profiling, auto-segmentation, volumetric analysis, and radiomics feature extraction from paired pre-/post-induction MRI scans. PMID:41941260
  • Insights from DMG are positioned as broadly translatable to more common adult cancers — the low-mutational-burden “high C/low N” deep-dive approach is a deliberate model for the consortium’s radiobiology methodology. PMID:41941260

Sources

This page was processed by crosslinker on 2026-05-09.