SMAD3 and neoplasm: MiR-18a restoration, TGFBR3 knockdown or co-culture with miR-18a mimics, or si-TGFBR3-transfected M2 macrophages promoted SUNE-1 cell progression, tumor growth in mice, decreased p-Smad1/t-Smad1, and elevated p-Smad3/t-Smad3.