SMAD3 and hepatocellular carcinoma: SMAD3 binds to the protein tyrosine phosphatase receptor ε (PTPRε) promoter to activate its expression and, in turn, PTPRε interacts with TGF-βR1/SMAD3 to promote the recruitment of SMAD3 to TGF-βR1, resulting in a sustained state of SMAD3 activation that promotes HCC cell migration, invasion, and metastasis in vitro and in vivo [66].