TGFB1 and hepatocellular carcinoma: The treatment with TGF-β1 alone within a relatively short period of time could promote the apoptosis in HCC cells as shown by our data and others [29], whereas the apoptosis was reduced after prolonged stimulation, possibly due to the inefficiency of TGF-β1 in inducing the sustained activation of Smad pathway and the proliferation of surviving cells.