We exemplified this by comparing mutant allele frequencies of IDH1 or IDH2 and the TERT promoter, as well as deleted allele frequencies on 1p and 19q in a cohort of 20 IDH-mutant and 1p/19q-codeleted oligodendrogliomas (Additional file 1: Fig. S7; Table S10). The gene discussed is IDH2; the disease is oligodendroglioma.