EGR1 and glioblastoma: In most solid tumours treated with the prototype HOX/PBX inhibitor HXR9 cell death is mediated by apoptosis which we also demonstrated in GBM and has been shown to be activated, at least in part, from a rapid upregulation in cFOS expression To assess the apoptotic pathways that were activated from disrupting HOX/PBX dimers using HTL-001, the protein expression of cFOS, DUSP1 and EGR1 was quantified using western blot analysis.