SOS2 and glioblastoma: Patient survival data based on EXOC5, PPP2R5E, and SOS2 expression levels were available in the TCGA-GBM database, and the analysis with Cox proportional hazard model revealed that the high expression levels of these genes were associated with high survival in patients with proneural GBM at a log-rank P value cutoff of 0.05 (PP2R5E and SOS2) or close to 0.05 (EXOC5) (Supplementary Figure 4).