IDH1 and oligodendroglioma: Among IDH1/2-mutant gliomas, TERTp (38.8%), CIC (24.3%), and FUBP1 (15.3%) alterations exhibited a subtype-specific distribution, with CIC/FUBP1 mutations predominant in oligodendrogliomas (62.0%/39.2%) and rare (<2%) in non-oligodendroglial subtypes.