IDH1 and oligodendroglioma: Several major molecular alterations have been found, such as IDH1/IDH2 (Isocitrate dehydrogenase) mutations in diffusely infiltrating gliomas, mutations of TP53 (tumor suppressor protein 53) and ATRX (Alpha-thalassemia/mental retardation syndrome X-linked) in astrocytomas, 1p/19q co-deletion in oligodendrogliomas, mutations of TERT (telomerase reverse transcriptase) promoter in oligodendrogliomas and IDH wild-type glioblastomas, and mutations or fusions of BRAF in circumscribed astrocytomas [19].