OLIG1 and oligodendroglioma: According to the literature, the activation of the pathways of stem cell growth (SOX2), oligodendrocyte transformation (OLIG1/2), and proliferation (PDGFRA) is the main characteristic of three types of human tumors: glioblastoma (wild-type IDH), H3K27M-mutant glioma (pediatric type), and IDH-mutant oligodendroglioma (1p/19q-codeletion).