PPP1R15A and glioblastoma: TCGA contains RNA-Seq data from hundreds of human GBM samples; this database was interrogated with GlioVis for the mRNA expression levels of two hypoxia-responsive kinases involved in the ISR (GCN2, PERK), as well as the SG aggregator G3BP1 and the inducible phosphatase of SG disassembly GADD34 in Grades II, III, and IV (GBM) astrocytomas.