A subtype of GBM, accounting for nearly 10% of all glioblastomas, has been found to display isocitrate dehydrogenase 1 or 2 (IDH) mutations; mutant IDH proteins acquire the enzymatic ability to convert α-ketoglutarate (α-KG) to d-2-hydroxyglutarate (d-2-HG), eventually leading to aberrant DNA and histone methylation. Here, IDH1 is linked to glioblastoma.