IDH1 and oligodendroglioma: In IDH-wildtype low-grade tumors, up to 60% of patients are TERT mutated, while only approximately 6% of IDH-mutant oligodendrogliomas are positive for TERT. TERT-mutant tumors are less responsive to surgical resection with poor survival outcomes similar to that of malignant grade IV glioblastoma across glioma subtypes, implying its prognostic role in other midline gliomas (38).