TGFB1 and glioblastoma: An important mediator of mesenchymal changes in glioblastomas is the transforming growth factor beta (TGFbeta) [27,28], a pleiotropic cytokine which exists in three isoforms (TGFbeta-1, -2, and -3), and by binding to TGFbeta receptors, triggers both Smad and non-Smad TGFbeta-activated intracellular signaling pathways [29,30].