PIK3R2 and glioblastoma: The GBM dataset consisted of 69 samples and 15 genes (IDH1, PTEN, FGFR1, EGFR, NF1, RB1, TP53, PIK3R1, PIK3R2, PIK3CA, PIK3CB, PIK3C2G, FGFR3, PIK3C2A, ATRX).