In accordance with previous reports4, 6, the association was strong in oligodendrogliomas, regardless of the IDH-status of tumors (OR = 10.55 in IDH-mutant vs. 11.02 in IDH-wt tumors; p < 0.0001 vs. p = 0.0043; n = 67 vs. 8, respectively (Supplementary Table 2). Here, IDH2 is linked to oligodendroglioma.