TGFB1 and hepatocellular carcinoma: As we speculated, following exposure of HCC cells to hypoxia, downregulation of Tg737 is required for a significant increase in invasion and migration in vitro via the downregulation of polycystin-1 expression/secretion and the upregulation of interleukin-8 (IL-8) secretion and active and total transforming growth factor β 1 (TGF-β1) levels.