In summary, most experiments demonstrated the promoting effect of the TGF-β pathway on hepatocellular carcinoma, however, the inhibitory effect exhibited by the TGF-β pathway in a few experiments cannot be ignored, showing the complex and critical role of the TGF-β pathway in tumours, and SMADs, as key mediators of the TGF-β pathway, are an important entry point for future studies of the TGF-β pathway. This evidence concerns the gene TGFB1 and hepatocellular carcinoma.