TP53 and glioblastoma: Combination treatment with γIR and the dual PI3K/mTOR inhibitor PI-103, but not single treatments, caused the downregulation of stem and progenitor cell markers as well as of FoxO1 and FoxO3 in GBM-SCs with functional p53 (Figure 1A and 1C) but not in those with non-functional p53 (Figure 1B and 1C).