IDH1 and central nervous system cancer: According to the WHO 2021 glioma classification [11], 12 (21%) cases were IDH-mutant and 1p/19q non-codeleted astrocytomas (66% grade II, 17% grade III and 17% grade IV), 12 (21%) were IDH-mutant and 1p/19q codeleted oligodendrogliomas (100% grade II) and 33 (58%) were IDH-wildtype glioblastomas.