Because gliomas with concurrent IDH mutations and TERT promoter most possibly have a coexisting 1p/19q codeletion 22, it suggests that co-occurrence of mutations in TERT promoter and IDH plays a role in the genesis of oligodendroglioma and the favorable prognostic effect of the triple-positive tumors(IDH, 1p/19q and TERT) might be caused by 1p/19q codeletion which trump over the negative effects of TERT promoter mutation 58. This evidence concerns the gene IDH2 and oligodendroglioma.