According to the molecular signatures, selected gliomas are classified as follows: (1) IDH-mutant and 1p/19q codel, oligodendroglioma (WHO grade II-III); (2) IDH-mutant, astrocytoma (WHO grade II-III); (3) IDH-mutant, glioblastoma (WHO grade IV); (4) IDH-wildtype, glioblastoma (WHO grade IV); (5) H3K27M-mutant, diffuse midline glioma (WHO grade IV) (Figure 1). This evidence concerns the gene IDH1 and oligodendroglioma.