Because TMEPAI is a Smad dependent TGF-β target gene [15, 28] and Smad3 but not Smad2 deficiency reduced TMEPAI levels (Figure 3A), we tested the effect of R-Smad deficiency on cell migration and invasion of breast cancer cells by using Boyden chamber coated with matrigel. The gene discussed is SMAD3; the disease is breast cancer.