Expression of transforming growth factor-beta 1 in hepatocellular carcinoma in comparison with the non-tumor tissue

TGF-beta 1 (transforming growth factor-beta 1) has been shown to be overexpressed in various cancer cells including hepatocellular carcinoma cells. In this study, we examined the association of the immunohistochemical expression of TGF-beta 1 in hepatocellular carcinoma tissues with the clinicopathological findings.

Thirty liver tumor biopsy specimens obtained with ultrasound guidance and in which tumor-tissue and non-tumor tissue existed were examined. TGF-beta 1 was stained using rabbit anti-human TGF-beta 1 antibody.

TGF-beta 1 was expressed mainly in the cytoplasm and plasma membrane of the hepatocellular carcinoma cells, while it was stained in the fibrous septa and sinusoidal cells in the non-tumor tissue. When comparing the intensity of TGF-beta 1 staining in the hepatocellular carcinoma tissue with that in the non-tumor tissue, the former was more intense than the latter in 21 (70%) of the 30 cases. Although the expression of TGF-beta 1 in the hepatocellular carcinoma tissue was not related to the tumor size of hepatocellular carcinoma, it was correlated with the histological differentiation: the lower the histological differentiation grade of hepatocellular carcinoma was, the more intense was the TGF-beta 1 staining in hepatocellular carcinoma tissue. In addition, TGF-beta 1 tended to be overexpressed in the trabecular type of hepatocellular carcinoma. To elucidate the relationship of TGF-beta 1 staining with apoptosis in hepatocellular carcinoma cells, we performed terminal deoxynucleotidyl transferase-mediated DUTP biotinnick end labeling (TUNEL) in 11 of the 30 specimens. No positive cells for TUNEL were detected in the hepatocellular carcinoma tissues.

These results indicated that the expression of TGF-beta 1 was associated with the histological differentiation of hepatocellular carcinoma cells.