It has demonstrated that transforming growth factor-β (TGF-β) signaling plays a key role in progression and metastasis of HCC [48,49], and it influences the expression of smad4, smad2/3, and β-catenin proteins and regulates cell activities [49], which indicates that it is important in liver cells. The gene discussed is TGFB1; the disease is hepatocellular carcinoma.