The oncogenic IDH1R132H protein, resulting from disease-defining IDH driver mutations in more than 80% of astrocytoma and oligodendroglioma WHO grade 2–4 cases [5], displays a neomorphic enzymatic activity that causes intratumoral accumulation of the oncometabolite R-2-hydroxyglutarate (R-2-HG) [6]. Here, IDH1 is linked to oligodendroglioma.