PIK3R1 and glioma: The additional features identified in TCGA (CIC, ATRX, PIK3R1, IDH2, GRIN2A, NOTCH1, TP53, EGFR, MUC16) and CGGA (PDGFRA) provide interesting avenues for analysis of progression to a higher grade in glioma via linkage to known signaling pathways of tumor progression and treatment resistance (Table 1, Figure 4).