It has been demonstrated that GBM stem cells irradiated in vivo within orthotopic xenografts are less susceptible to double strand brakes induction and have greater capacity to repair damage as compared to same tumour cells irradiated under in vitro growth conditions.24 Moreover, close correlation between CD133+ GBM cells and hypoxia15, vascular structures25, extracellular matrix (ECM) components7, as well as inflammation and immunoregulatory markers26 have been reported. This evidence concerns the gene PROM1 and glioblastoma.