While the histological features of GBM are relatively consistent between different cases, genetic studies revealed the existence of several molecular pathways driving this disease as a function of age and repertoire of oncogenic mutations.92 For example, in younger patients, GBM may be characterized by mutation of the isocitrate dehydrogenase 1 gene (IDH1), which could be coupled with mutation of the TP53 tumor suppressor in the pathway leading to LGG, AA, and secondary GBM. The gene discussed is IDH1; the disease is glioblastoma.