Even among the few reported prognostic mutant genes, the literature contains conflicting findings.11–13 The prognostic significance of EGFRvIII is controversial14,15; for example, PTEN mutation has been associated with poor survival in glioma patients.16CDKN2A and CDKN2B deletions, but not TERT mutation or EGFR amplification, have been recently reported to be an independent prognostic marker for IDH1/2-wildtype glioblastoma.17 Few studies investigating the prognostic value of particular gene alterations have taken into account factors that are known to impact survival. The gene discussed is IDH1; the disease is glioblastoma.