Does human liver contain estrogen receptors? A comparative study of estrogen binding in human and rodent liver

Role of sex steroid receptors in pathobiology of hepatocellular carcinoma

The striking gender disparity observed in the incidence of hepatocellular carcinoma (HCC) suggests an important role of sex hormones in HCC pathogenesis. Though the studies began as early as in 1980s, the precise role of sex hormones and the significance of their receptors in HCC still remain poorly understood and perhaps contribute to current controversies about the potential use of hormonal therapy in HCC. A comprehensive review of the existing literature revealed several shortcomings associated with the studies on estrogen receptor (ER) and androgen receptor (AR) in normal liver and HCC. These shortcomings include the use of less sensitive receptor ligand binding assays and immunohistochemistry studies for ERα alone until 1996 when ERβ isoform was identified. The animal models of HCC utilized for studies were primarily based on chemical-induced hepatocarcinogenesis with less similarity to virus-induced HCC pathogenesis. However, recent in vitro studies in hepatoma cells provide newer insights for hormonal regulation of key cellular processes including interaction of ER and AR with viral proteins. In light of the above facts, there is an urgent need for a detailed investigation of sex hormones and their receptors in normal liver and HCC. In this review, we systematically present the information currently available on androgens, estrogens and their receptors in normal liver and HCC obtained from in vitro, in vivo experimental models and clinical studies. This information will direct future basic and clinical research to bridge the gap in knowledge to explore the therapeutic potential of hormonal therapy in HCC.

Estrogen receptors in hepatocellular carcinoma: is endocrine therapy for hepatocellular carcinoma likely to be effective?

Specimens of human liver obtained at the time of operation were assayed for cytosolic estrogen receptors by the binding assay and enzyme immunoassay (EIA). Mean estrogen receptor contents determined by the binding assay were 17.8 fmol/mg protein in non-cirrhotic liver, 7.1 in cirrhotic liver, and 0.7 in hepatocellular carcinoma, by EIA the contents were 12.1, 5.9, and 0.8 fmol/mg protein, respectively. There were significant differences among the three groups. In particular, hepatocellular carcinoma specimens contained very little or no detectable amounts of estrogen receptors in either assay. The correlation between the estrogen receptor content determined by the binding assay and that determined by EIA was significant (r = 0.822, p less than 0.001). It is suggested that the estrogen receptor content decreases with the development of liver cirrhosis and hepatocellular carcinoma and that antiestrogen endocrine therapy for hepatocellular carcinoma may be ineffective.

Estrogen receptors in hepatocellular carcinoma

Estrogen receptors (ER) were assayed on hepatocellular carcinoma (HCC) and surrounding liver tissue in 30 adult patients. All specimens were obtained at the time of surgery. Cirrhosis of the liver was associated with 28 patients and chronic hepatitis in 2 patients. ERs were detected in 12 of 30 HCCs. The value ranged from 1.4 to 9.2 fmol/mg cytosol protein with the dissociation constant (Kd) value less than 1 nanomol. On the other hand, 13 of 28 cirrhotic livers had measurable amounts of the receptors that ranged from 1.5 to 4.1 fmol/mg cytosol protein. Two livers with chronic hepatitis did not have detectable amounts of ERs. The receptors were not detected in both the tumor and liver in ten patients. The ER titers in HCC did not have any correlation with serum levels of alpha-fetoprotein or carcinoembryonic antigen, hepatitis B virus profiles, and histologic types of the tumor. In the light of the current results, it would be of great interest whether hormone therapy can be used or not as a treatment of naturally occurring HCC in humans.

Estrogen receptors in hepatocellular carcinoma

Estrogen receptors (ER) were assayed on hepatocellular carcinoma (HCC) and surrounding liver tissue in 30 adult patients. All specimens were obtained at the time of surgery. Cirrhosis of the liver was associated with 28 patients and chronic hepatitis in 2 patients. ERs were detected in 12 of 30 HCCs. The value ranged from 1.4 to 9.2 fmol/mg cytosol protein with the dissociation constant (Kd) value less than 1 nanomol. On the other hand, 13 of 28 cirrhotic livers had measurable amounts of the receptors that ranged from 1.5 to 4.1 fmol/mg cytosol protein. Two livers with chronic hepatitis did not have detectable amounts of ERs. The receptors were not detected in both the tumor and liver in ten patients. The ER titers in HCC did not have any correlation with serum levels of alpha-fetoprotein or carcinoembryonic antigen, hepatitis B virus profiles, and histologic types of the tumor. In the light of the current results, it would be of great interest whether hormone therapy can be used or not as a treatment of naturally occurring HCC in humans.

Steroid receptor status of focal-nodular hyperplasia of the human liver

As with normal human liver, both focal nodular hyperplasia (FNH) of the liver and a hepatocellular carcinoma were found to contain low levels of high affinity estrogen-binding components. In low-salt sucrose gradients the estrogen binders sedimented at 4S and 8S. Specificity studies indicated a requirement for estrogenic hormones. Progestin-binding studies using labeled and unlabeled ORG 2058 revealed high levels of specific binding in FNH and normal liver cytosol, whereas only insignificant amounts of ORG 2058 binding was found in the hepatocellular carcinoma. As judged by the high apparent dissociation constant (4-14 X 10(-8) mol/l) of the ORG 2058 - binder complex, the apparent lack of 8S binding in low-salt sucrose gradients and the atypical ligand specificity, the progestin receptor nature of these binding entities is unlikely. In contrast, normal liver, FNH, and the hepatocellular carcinoma were found to contain significant quantities of glucocorticoid receptors.