IDH1 and central nervous system cancer: For example, on the basis of mutations in the genes encoding the isocitrate dehydrogenases IDH1 and IDH2, co-deletion of 1p19q (oligodendroglioma) and methylation of O6-Methylguanine-DNA methyltransferase (MGMT) have been subclassified as molecular diagnostics and prognostic markers for gliomas [4].