IDH1 and astrocytoma (excluding glioblastoma): Mutations in the isocitrate dehydrogenase (IDH) 1 and 2 genes are essential requirements for the diagnosis of astrocytoma, combined IDH1 and IDH2 mutations in combination with the complete loss of chromosomes 1p and 19q (loss of heterozygosity, LOH 1p/19q) are requirements for the diagnosis of oligodendroglioma, and IDH1/2 as well as H3F3A (Histone H3 Family 3A), HIST1H3B/C wildtype status in combination with TERT (telomerase reverse transcriptase) mutations or EGFR (epithelial growth factor receptor) amplifications are requirements for the diagnosis of glioblastoma [1].