The Biological Behavior of High-Grade Glioma in H3K27M Mutant Circumscribed Midline Gliomas

Abstract Purpose: Due to the prognosis of circumscribed midline gliomas（CMGs）with H3K27M mutation is still unclear. This study explored the prognostic stratification of （CMGs） with H3K27M mutation. Methods: One hundred and sixty midline gliomas（MGs）were identified over 10 years. Immunohistochemistry was done for H3K27M, ATRX, IDH1, and P53, and Sanger sequencing performed for IDH and H3 genes. The clinicopathological characteristics were reviewed and survival analysis performed. Results: 1. For H3K27M mutant MGs, there was no difference in prognosis between diffuse midline gliomas (DMGs) and CMGs (p = 0.211), also between the CNS WHO grades.2. The prognosis of H3K27M mutant CMGs of CNS WHO grade 1 was worse than that of H3K27M wild-type CMGs (p = 0.0024), even worse than of DMGs without H3K27M mutation of CNS WHO grade 2(p = 0.0066). Conclusions: The weight value of H3K27M affecting prognosis is affected by location and age. CMGs with H3K27M mutation have biological behavior similar to high-grade gliomas. It is recommended that Treatment management was referenced to high-grade glioma for CMGs with H3K27 mutation.