PIK3R1 and glioblastoma: Targeted sequencing across NF1-mutant, IDH wild-type glioblastomas identified recurrent alterations occurring in at least 10% of tumors, including the TERT promoter and genes associated with cell cycle (CDKN2A/B, RB1, CDK4), PI3K signaling (PTEN, PIK3CA, PIK3R1), or apoptosis (TP53, MDM2, MDM4), consistent with prior glioblastoma genomic analysis (Figure 1A) (1–3).