While GBM is nearly always fatal, there is overwhelming evidence that the prognosis of patients with GBM varies with patient age2; clinical features [ECOG score, addition of temozolomide, bilateral spread], performance score2, extent of surgical resection2,3, and molecular characteristics4, e.g., the mutational status of the isocitrate dehydrogenase (IDH) genes, and the methylation status of the O6-methylguanine-DNA methyltransferase (MGMT) promoter5. The gene discussed is IDH1; the disease is glioblastoma.