TGFB1 and glioblastoma: TGF-β has been reported as a potent inducer of EMT in epithelial cancers.24,27,28 In addition, TGF-β is also an important component of the GBM microenvironment.17,18,20 Taking these facts into consideration, the effects of TGF-β on U87 and U251 cells that have no or low mesenchymal marker expression were tested.