IDH1 and glioma: Other diffuse gliomas, such as glioblastomas (GBM, 65% of gliomas) and IDH1/2-mutant oligodendrogliomas (OD, 10% of gliomas), typically maintain their telomeres by reactivating the telomerase enzyme through mutations in TERT (telomerase reverse transcriptase) promoter (pTERTmt), which leads to TERT re-expression [14].