NTRK1 and Hepatic fibrosis: To develop a model for testing the effect of brivanib on mechanisms of liver fibrosis, we first determined the effect of fibrogenic growth factors on proliferation of HSCs by measuring BrdU incorporation after treatment of LX-2 cells with the cytokine TGF-β1 or the receptor tyrosine kinase growth and angiogenesis factor ligands PDGF, VEGF, and FGF2.