Transferrin receptor expression in human hepatocellular carcinoma: an immunohistochemical study of 34 cases

Using a panel of five monoclonal anti-transferrin receptor antibodies, we investigated the transferrin receptor expression in 34 human hepatocellular carcinomas of Belgian (n = 6), Italian (n = 7) and South African (n = 21) origin. For comparison the tumours were also stained with the monoclonal antibody BK 19.9, recognizing an antigen biochemically similar to the transferrin receptor, and with a monoclonal antibody against the epidermal growth factor receptor. Hepatocellular carcinomas express large amounts of transferrin receptors as demonstrated by the intense transferrin receptor immunostaining in 33/34 cases. Differences in staining pattern between and within the tumours were not related to the degree of tumour differentiation, nor to the origin or race of the patient. In 15 cases which included non-tumoural tissue, the tumour was more intensely stained than the surrounding liver parenchyma. The BK 19.9 immunoreactivity was generally weaker and mainly involved stromal cells, except in three cases where an intense staining of the tumour cells was seen. The epidermal growth factor receptor staining was also weaker and only in four cases was the immunoreactivity of the tumour stronger than the surrounding parenchyma. Demonstration of the transferrin receptor may be useful for the detection of malignant foci in liver biopsies. This may be of particular interest in the histological investigation of minute hepatocellular carcinomas.