In a recent work we demonstrated that hypoxia may preserve GBM-derived cells in a more proliferative and less committed cell stage, by down-regulating endogenous BMP signaling in tumor cells and particularly SMAD 1/5/8 activation [3], providing evidence that HIF-1α may counter-act BMP signaling activation under hypoxia. This evidence concerns the gene HIF1A and glioblastoma.