To determine whether TGF beta 1 indeed acts on GBM cells to change the expression of SOX4 and TGFBI (GENE ID:7045) and to see whether the change was acted through TGF–β receptor I kinase (TβRI), we stimulated two different GBM cell lines, U87MG and M059J, with TGF−β and then inhibited the TGF−β pathway with a specific inhibitor of the TGF–β receptor I kinase (TβRI). This evidence concerns the gene TGFB1 and glioblastoma.