The diagnosis of glioblastoma is based either on the absence of IDH mutation in a diffuse glioma with endothelial-capillary proliferation and/or necrosis, or in the absence of these histopathological criteria, by the identification of at least one of the following three alterations: mutation of the TERT promotor, the combination of a gain of chromosome 7 and a loss of chromosome 10 (+7/10), or amplification of EGFR (3). This evidence concerns the gene IDH1 and glioblastoma.