SMAD3 and neoplasm: The TGF-β1 signaling pathway is critical to cell differentiation, development, proliferation, and migration.38 Constitutive activation of TGF-β1 signaling seems to promote tumor progression through tumor-host cell interactions.39, 40 Smad3 is a central downstream modulator, which plays important roles in TGF-β1/Smad pathway.