Increased expression of growth hormone and prolactin receptors in hepatocellular carcinomas

The liver is an essential target tissue for growth hormone (CH) and prolact in (PRL). The aim of this study was to determine the in situ expression of growth hormone receptor (GHR) and prolactin receptor (PRLR) in hepatocellul ar carcinomas and to compare the results with normal liver. For this purpos e, in situ hybridization (ISH)and immunohistochemical techniques were perfo rmed and several tests were conducted to validate the results. By radioacti ve ISH, all the hepatocellular carcinomas studied showed labeling for GHR a nd PRLR mRNAs, Relative expression levels, determined by computer-assisted microdensity, were higher in hepatocellular carcinomas than in normal liver . Immunohistochemistry led us to confirm the constant expression of both re ceptor proteins in hepatocellular carcinomas and normal liver and to demons trate their localization not only in the cytoplasm but also in the nucleus. These results confirm that the liver is a major CH and PRL target tissue a nd suggest that in hepatocellular carcinomas the proliferative effects of t hese hormones may be increased by a higher expression of their receptors.