MTOR and glioblastoma: It has been demonstrated that rapamycin- and mTOR siRNA-mediated inhibition of the HIF1α and mTOR signaling pathways may decrease the ability of GBM cells to acquire genetic and/or phenotypic characteristics of endothelial cells and form microvascular channels as a way to enhance blood supply to the tumor, called vasculogenic mimicry or trans-differentiation.