MGMT and glioblastoma: In clinicopathological features, the proportion of WHO grade 4 tumors grew from cluster 1 to cluster 4, which were characterized by glioblastomas and gliomas with unmethylated MGMT promoter, while TERT promoter wild-type tumors occupied the majority of cluster 3 gliomas, suggesting a potential connection between these tumors and alternative telomere lengthening (Figures 2E–H).