Growing evidence has shown that miR-133a is downregulated and plays tumor suppressor roles in cancer and that it can inhibit proliferation, migration, and invasion of HCC cells by targeting several genes such as IGF-1R, FSCN1, and FOSL2 through the TGF-β/Smad3 signaling pathway [17, 18]. The gene discussed is SMAD3; the disease is cancer.