miR-139-3p inhibited metastasis process in vivo. (A) HCC subcutaneous tumor tissues (SNU-449-control, SNU-449-anti-miR-139-3p, HepG2-control, and HepG2-miR-139-3p) were implanted into nude mouse to establish the xenograft HCC models. Twenty-five days after implantation, the mice were euthanized, and tumor volumes were assessed. **p < 0.01 compared with control cells. (B) Quantification of lung metastatic foci showed that downregulation of miR-139-3p significantly accelerated pulmonary metastasis of SNU-449-anti-miR-139-3p compared to SNU-449-control tumors. Few pulmonary metastases occurred in HepG2-miR-139-3p xenografts based on quantification of metastatic foci. **p < 0.01 compared with control cells.