Immunochemical analyses of estrogen receptors in human breast tumors by a novel monoclonal estrogen receptor antibody (EVG F9)

The objective of this study was to assess the potential utility of a new site-directed, monoclonal anti-estrogen receptor antibody (EVG F9) in detection and analyses of human breast tumor estrogen receptor (ER alpha), using immunoblotting and immunohistochemical assays. Using Western Blot analyses, we demonstrated that EVG F9 monoclonal antibody binds specifically to ER alpha and does not cross-react with ER beta. Furthermore, binding of EVG F9 to ER alpha was effectively displaced with the immunogenic peptide in Western Blots and in immunohistochemical analyses. In Western Blot analyses, EVG F9 detected ER alpha at low concentrations approaching 5 to 10 fmol/sample. Determination of ER alpha status of a series of human breast tumor samples by Western Blot analyses or immunohistochemistry using EVG F9 correlated well with ER alpha values measured by ligand binding assays. These observations suggest that EVG F9 monoclonal anti-ER alpha antibody is a valuable immunochemical tool for detection and analyses of ER alpha in human breast tumors. (C) 2000 Elsevier Science Inc. All rights reserved.