his to path dog^ zyxwvutsrqponm 1990, zyxwvutsrq 16. 59-62 Transferrin receptor expression in benign tumours and in hepatoblastoma of the liver R.SCIOT, zyxwvutsrq P.VAN EYKEN zyxwvu 81 V.J.DESMET zyxwvu Department of Patholology, Laboratory for Histo- and Cytochemistry. Catholic University of Leuven, Leuven. Belgium Accepted for publication 22 May 1989 SCIOT R., VAN EYKEN P. & DESMET V.J. (1990) Histopathology 16, 59-62 Transferrin receptor expression in benign tumours and in hepatoblastoma of the liver To further investigate the possible usefulness of anti- transferrin receptor staining in the differential diagnosis between benign and malignant primary liver tumours, we examined the transferrin receptor expression in ten cases of focal nodular hyperplasia, six of nodular regenerative hyperplasia, two adenomas and six hepa- toblastomas. In focal nodular hyperplasia, the ductular structures were always positive and the parenchymal cells displayed three staining patterns of moderate intensity. In nodular regenerative hyperplasia there was scattered, relatively weak transferrin receptor stain- ing. The tumour cells in the adenomas were only weakly positive. Three hepatoblastomas showed an intense staining of tumour cells: one was weakly positive and two were negative. A high intensity of transferrin receptor staining, as previously described in hepatocellu- lar carcinomas, was only observed in the hepatoblasto- mas. This gives further credence to the usefulness of strong transferrin receptor expression in evaluating the malignant nature of tumour foci in liver biopsies. Keywords: primary liver tumour, transferrin receptor, immunohistochemistry Introduction In an immunohistochemical study, we recently de- scribed intense transferrin receptor expression in hepa- tocellular carcinomas (Sciot et al. 1988). In all the specimens which included non-tumoural liver tissue, the tumours were more intensely stained than the surrounding liver parenchyma. In view of these findings, we speculated on the possible usefulness of transferrin receptor staining in identifying malignant foci in liver biopsies (Sciot et al. 1988). In an extension of this study, we have now investigated the expression of transferrin receptors in other primary tumours and tumour-like lesions of the liver, including focal nodular hyperplasia, nodular regenerative hyperplasia. adenoma and hepa- toblastoma. Materials and methods The specimens included ten cases of focal nodular hyperplasia, six of nodular regenerative hyperplasia, Address for correspondence: Dr. Raf Sciot.Universitair Ziekenhuis Sint- Rafael,Laboratorium voor Histo- & Cytochemie. Minderbroedersstraat 1 2 , 8 3 0 0 0 Leuven. Belgium. two adenomas and six hepatoblastomas. All specimens were received fresh. A part of each specimen was frozen in nitrogen-cooled isopentane and stored at - 75OC. Five micron thick cryostat sections were stained with haema- toxylin and eosin and an indirect immunoperoxidase procedure was applied on serial sections to demonstrate transferrin receptors (Sciot et al. 1988). Three commer- cially available monoclonal anti-transferrin receptor antibodies were used: OKT9 (Ortho Raritan. New Jersey, USA, dilution 1 : 10). B3/25 (Hybritech, San Diego, USA, dilution 1 : 400) and TUG 7 (Biotest, Dreieich, Germany dilution 1 : 2). Results and discussion FOCAL NODULAR HYPERPLASIA The numerous ductular structures along the septa and portal tract-like structures displayed strong immuno- reactivity for the transferrin receptor in all cases (Figure 1). This corresponds to previous findings in specimens characterized by a ductular reaction (Sciot et al. 1987, 1988). An overall moderately dense staining of hepato- cytes was observed, occuring in three topographical 59