Building on the basis of above-mentioned landmark findings, the current version of the WHO Classification of Tumours of the Central Nervous System 5th edition (WHO CNS 5) classifies GBM as diffused astrocytic glioma, characterised by isocitrate dehydrogenase (IDH)-WT with the presence of other key genetic alterations, such as mutations in TERT promoter, amplification of EGFR, and concurrent gain of chromosome 7 and loss of chromosome 10 [8]. The gene discussed is IDH2; the disease is glioblastoma.