TGFB1 and hepatocellular carcinoma: The analysis of TGF-β1-induced targeted expression revealed that the induction of IL-11 and CTGF mRNA and protein expression was attenuated in SMMC-7721 cells with shSmad4–2 compared with the control, whereas the opposite results were found in Smad4-overexpressing HCC-LM3 cells (Additional file 6: Figure S3C-F).