Abstract
Recently, several antibodies have allowed the detection of estrogen receptor beta (ER-β) in paraffin-embedded tissue; however, these attempts have failed to specifically identify the wild-type form and revealed technical difficulties such as the necessity for alterations to standard staining protocols and amplification detection systems. The aim of this study was to generate a monoclonal antibody that could provide enhanced sensitivity for detection of ER-β in paraffin embedded tissues. A 130-amino acid region of the C-terminus of ER-β was expressed as a fusion protein and used as an antigen to generate monoclonal antibodies. Immunohistochemical analysis of ER-β using clone EMR02 in normal and inflamed tissues demonstrated nuclear staining. In benign and malignant tumors, variable intensities of staining and patterns of nuclear reactivity were observed between cases. Intense ER-β positivity was also observed in tumor-infiltrating lymphocytes. Mapping studies by ELISA and Western blotting have identified specific reactivity of EMR02 to a 17-amino acid sequence of the full-length wild-type ER-β protein (ERβwt). Our results show that clone EMR02 is a sensitive tool for the detection of ERβwt in paraffin-embedded tissues. This preliminary study also supports its use in immunohistochemical studies to determine the role of ERβwt as a tumor prognostic marker and a possible therapeutic target.
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