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

Abstract 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 (ERα), using immunoblotting and immunohistochemical assays. Using Western Blot analyses, we demonstrated that EVG F9 monoclonal antibody binds specifically to ERα and does not cross-react with ERβ. Furthermore, binding of EVG F9 to ERα was effectively displaced with the immunogenic peptide in Western Blots and in immunohistochemical analyses. In Western Blot analyses, EVG F9 detected ERα at low concentrations approaching 5 to 10 fmol/sample. Determination of ERα status of a series of human breast tumor samples by Western Blot analyses or immunohistochemistry using EVG F9 correlated well with ERα values measured by ligand binding assays. These observations suggest that EVG F9 monoclonal anti-ERα antibody is a valuable immunochemical tool for detection and analyses of ERα in human breast tumors.