Compared to patients with H3-wildtype gliomas, H3 K27M-mutant gliomas (n = 14) showed a lower ratio of GTR (21% vs 81%, P < 0.0001), a higher ratio of Ki-67-positive samples (57% vs 19%, P = 0.0108), and a lower survival rate (P < 0.0001) only in histological grade II astrocytomas, but not in histological grade III and histological grade IV astrocytomas. This evidence concerns the gene MKI67 and astrocytoma (excluding glioblastoma).