Halofuginone inhibited cell proliferation of breast and prostate cancer cells in vitro (data not shown) and reduced tumor growth in mice at the orthotopic site, showing that its effects are not limited to bone; unlike the effects of other TGF-β inhibitors, including SD208 and overexpression of Smad7 in melanoma cells [12, 15]. The gene discussed is SMAD7; the disease is prostate carcinoma.