IDH1 and central nervous system cancer: We defined tumors with IDH1/2 mutation and either 1p/19q codeletion or TERTp mutation as ‘IDHmut-OT’ gliomas, tumors with IDH1/2 mutation only as ‘IDHmut’ gliomas, tumors with wild-type IDH1/2 and either TERTp mutation or EGFR amplification as ‘IDHwt-ET’ gliomas, and tumors without any of the four molecular markers as ‘IDHwt’ gliomas.