H3-G34-mutant diffuse hemispheric gliomas are characterized by missense mutations in codon 34 of the histone H3 gene H3–3A and are classified as grade 4 tumors according to the 2021 WHO Classification[^1].
WHO Classification
In the 2016 WHO Classification, these gliomas were still classified among glioblastomas, IDH-wildtype. However, these gliomas exhibit distinct molecular and clinical features, including a characteristic DNA methylation pattern, as well as a preferential presentation in the cerebral hemispheres[^2], and were therefore classified as a distinct entity in the 2021 WHO Classification.
