IDH2 and glioma: The pooled results of the meta-analysis showed that the IDH mutations were independent prognostic markers for improved OS (HR  = 0.33, 95% CI: 0.25–0.42, Pheterogeneity  = 0.204; Figure 2) and PFS (HR  = 0.38, 95% CI: 0.21–0.68, Pheterogeneity  = 0.000; Figure 3) in gliomas (Table 3).