To determine if the BMP and TGF-β pathways are activated in glioblastoma cells in the tumor microenvironment, we performed immunohistochemistry on human glioblastoma specimens (n = 9) for the activated nuclear R-SMADs, pSmad1 (BMP) and pSmad2 (TGF-β). This evidence concerns the gene TGFB1 and glioblastoma.