IDH1 and glioma: Perhaps the most prominent example of newly identified drivers of gliomagenesis are point mutations in either the codon 132 of isocitrate dehydrogenase 1 (IDH1) or infrequently codon 172 of IDH2, which are very common in WHO grade II and III gliomas (70–80%) and rare in primary de novo glioblastomas (WHO grade IV, <10%)4.