# H3 K27M mutation

Source: https://onco.cc/biomarkers/h3-k27m/  
OnCo record `h3-k27m` (Biomarker). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

H3 K27M is a single change in a histone that defines diffuse midline glioma, including the brain-stem tumour DIPG. In 2025 dordaviprone became the first drug approved for tumours carrying it.

## Summary

The K27M substitution in H3-3A (or H3C2/H3C3, the H3.1 genes) is detected by a mutation-specific antibody on immunohistochemistry or by sequencing; WHO CNS5 groups these tumours as diffuse midline glioma, H3 K27-altered, grade 4. Dordaviprone (Modeyso, August 2025, accelerated approval) is labelled for adult and paediatric patients from one year with diffuse midline glioma harbouring an H3 K27M mutation and progressive disease after prior therapy. Radiotherapy remains the first treatment; the ACTION trial (NCT05580562) tests dordaviprone after radiotherapy.

## Fields

- Kind: Biomarker
- Last checked: 2026-09-23
- Also known as: H3 K27M; H3K27M; H3F3A K27M; H3-3A K27M; K27M; H3 K27-altered; H3 K27M-mutant diffuse midline glioma
- Tags: biomarker; glioma; paediatric

## Sources

- MODEYSO prescribing information (DailyMed): https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=ad45b43e-fdef-47ad-9c34-055b41bdc576

## Connected records

- biomarkers: [IDH1 R132 mutation](https://onco.cc/biomarkers/idh1-r132/), [MGMT promoter methylation](https://onco.cc/biomarkers/mgmt-promoter-methylation/)
- cancers: [Diffuse midline glioma, H3 K27-altered (including DIPG)](https://onco.cc/cancers/dipg-dmg/), [Paediatric high-grade glioma (excluding diffuse midline glioma)](https://onco.cc/cancers/paediatric-high-grade-glioma/)
- drugs: [Dordaviprone](https://onco.cc/drugs/dordaviprone/)
- terms: [H3 K27M (diffuse midline glioma)](https://onco.cc/terms/h3k27m/)
- targets: [Histone H3.3 (H3-3A)](https://onco.cc/targets/h3-3a/)

---
JSON: https://onco.cc/api/v1/entities/h3-k27m.json