SMAD4 and neoplasm: As shown with SMAD4 antigen staining (Figure 8c), the tumors from the sw1990/ RV-miR-301a-3p group expressed less SMAD4 than those from sw1990/ RV-miR-control group, that supported our hypothesis that the increased tumor growth in mice injected sw1990/ RV-miR-301a-3p cells might be partially because of inhibition of SMAD4 expression caused by the up-regulated miR-301a-3p.