To investigate the dynamic expressions of TGF-beta 1 and TGF-beta 1 mRNA at different stages of hepatocellular carcinoma (HCC) development and their use in clinical diagnosis.Hepatoma models were developed with 2-FAA using male Sprague-Dawley (SD) rats. Morphological changes of the rat liver histological preparations (H and E stained) were studied. The fragment of TGF-beta 1 gene obtained was amplified by nested RT-PCR. Dynamic change of TGF-beta 1 level was quantitatively analyzed by ELISA. The distribution of TGF-beta 1 in the cells and its gene expression were detected in human HCC tissues.The progressive increases of hepatic TGF-beta 1 and TGF-beta 1 mRNA were observed in rat hepatocytes which progressed from granular degeneration, atypical hyperplasia and finally to HCC development induced by 2-FAA. The expression levels in HCC tissues were significantly higher than those in the normal and degenerative ones. TGF-beta 1 was shown in rat hepatocytes by immunohistochemistry. Plasma TGF-beta 1 was detected in 89.5% of all the patients with HCC, but it was detected in 93.3% of them who had an AFP less than 400 microg/L. TGF-beta 1 mRNA showed a stronger expression in HCC tissues. TGF-beta 1 mRNA was found in peripheral blood mononuclear cells from all HCC patients with extrahepatic metastasis.TGF-beta 1 may participate in hepatocyte canceration. The overexpression of TGF-beta 1 and TGF-beta 1 mRNA could be useful markers for early diagnosis and predicting prognosis of HCC.