IDH2 and central nervous system cancer: Among the 573 cases of Grade II-IV gliomas, 103 (18.0%) were triple-positive, 19 (3.3%) had mutations in both IDH and TERT, 108 (18.8%) had IDH mutation only, 144 (25.1%) were triple-negative, 155 (27.1%) had TERT mutation only, and 44 (7.7%) had other combinations of the three biomarkers (Figure 1A).