IDH1 and glioblastoma: For example, point mutations in the isocitrate dehydrogenase-1 (IDH-1) and IDH-2 genes classify glioblastoma into IDH-mutant glioblastomas, characterized by epigenetic hypermethylation and proneural gene expression, and IDH-wildtype glioblastomas (neural, proneural, mesenchymal, or classical gene expression patterns) [1,7].