Glioblastoma can be defined as an IDH wild-type, H3 wild-type tumor with TERT promoter mutation, EGFR amplification, +7/-10 chromosome copy-number alterations, microvascular proliferation, or necrosis, illustrating the aggressive nature of IDH wild-type tumors that were previously categorized only as Grade 2 or 3 based on histological appearance (73). Here, IDH1 is linked to glioblastoma.