TGFB1 and hepatocellular carcinoma: Coculture of fibroblasts treated with a TGFR1 inhibitor for 3 days with epithelial hepatoma cells confirmed that fibroblast-derived paracrine TGFb1 is sufficient for the acquisition of metastatic ability by epithelial hepatoma cells (Figs. 1C, 3B, and S6A–C).