SMAD4 and meningioma: TGFβ signaling pathway was also found activated in fibroblastic meningioma, since multiple key genes in the pathway were up-regulated in tumor tissues by qRT-PCR, including TGFB2 (4.95-fold), TGFBR1 (2.43-fold), SMAD2 (2.82-fold), and SMAD4 (3.24-fold) (Figure 2A).