Elevated Levels of Transforming Growth Factor β Messenger RNA and Its Polypeptide in Human Hepatocellular Carcinoma

Malignant cells in culture express elevated levels of transforming growth factor AŸ\ (TGF-01) mRNA and secrete an abundant amount of TGF-0 protein, but little is known about the production of TGF-/8 in human malignant tissues in vivo. We estimated the levels of TGF-01 mRNA expression by Northern hybridization and measured TGF-0 pro tein using a radioreceptor assay in tumor tissues surgically obtained from six patients with hepatocellular carcinoma (HCC). TGF-01 mRNA was expressed at much higher levels in HCC tissues from all the cases compared with normal human liver, suggesting an association of the activated TGF-/91 gene transcription with hepatocarcinogenesis. The content of TGF-0 was 207 ±121ng/g wet tissue in the HCC tissue, and it showed correlation with the level of TGF-01 mRNA in the tissue (r = 0.69; P < 0.05). An immunohistochemical study demonstrated that TGFti\ staining could be observed in HCC cells. These observations suggest that human HCC strongly expresses TGF-01 mRNA in vivo, leading to a high content of TGF-/3 protein.