EGF and glioblastoma: Aside from EGF, platelet-derived growth factor (PDGF) has also been shown to activate NFκB in GBM cells [55] and both EGF and PDGF can activate NFκB via PI3K–IKK-dependent mechanisms [47,56] and PDGF-induced PI3K signaling has been demonstrated to directly phosphorylate REL-A [50].