TGFB1 and breast neoplasm: To investigate the role of breast tumor-derived TGF-β1 for metastasis, and whether naringenin can suppress metastasis by blocking TGF-β1 secretion from breast tumor cells, we constructed a Tgf-β1 overexpressing breast tumor cell line (4T1/TGF-β1) and examined its metastatic potential in both in vitro and in vivo models.