IDH1 and glioblastoma: Despite these efforts, these mutation-based and transcriptome-based approaches have found limited clinical application, and only a few biomarkers, including IDH mutation (favorable prognoses, secondary GBM)9, MGMT promoter methylation (benefit from temozolomide)10, and 1p/19q co-deletion (chemosensitivity)11 are being used in clinic.