Given that both Grade III and Grade IV gliomas were successfully stratified into distinct subgroups based on TERT promoter and IDH1/2 mutational status, and that each signature was associated with a similar median OS within grade, the effect of histology and genetic signature on OS was also examined across the Grade III and IV gliomas together (Fig. 3, Table 5A). The gene discussed is IDH1; the disease is central nervous system cancer.