IDH2 and glioblastoma: It is known that the important prognostic factors of GBM include age; performance status; extent of resection; treatment; and various molecular markers, i.e., epidermal growth factor receptor, methylation status of the gene promoter for O6-methylguanine-DNA methyltransferase (MGMT), and isocitrate dehydrogenase (IDH)-1/2 mutations (2–8).