SMAD2 and hepatocellular carcinoma: For example, miR-30a-5p targeted astrocyte elevated gene 1 (AEG-1) to inhibit cell growth and promote the apoptosis of HCC cells [23]; miR-519a accelerated tumor growth via regulation of phosphatase and tensin homolog/phosphatidylinositol-3-OH kinase/protein kinase B (PTEN/PI3K/AKT) signaling in HCC [24]; and miR-125b attenuated epithelial-mesenchymal transition (EMT) by targeting small mothers against decapentaplegic (SMAD)-2 and -4 in HCC [25].