MICROTITER PLATE IMMUNOENZYMOMETRIC ASSAY FOR ESTROGEN-RECEPTOR

The estrogen receptor (ER) status of breast dancer is used both as a p rognostic factor and as a predictor of response to endocrine therapy. An immunoenzymometric assay for ER was developed an 96-well microtiter plates (EIA96). This technique involves two monoclonal antibodies dir ected against different: epitopes in the B domain of ER. The two-Step protocol (16-18 h and 3 h at 4 degrees C) requires 100 mu L of cytosol . This assay showed a detection limit of 0.58 pmol/L. Intra- and inter assay CVs of clinical specimens were less than or equal to 5% except f or the least concentrated sample (6.5 pmol/L, CV = 6.7%). In a compari son study involving cytosols of breast adenocarcinoma tissue biopsies; we compared the EIA96 with the radioligand assay (RLA) and the Abbott ER-EIA, widely used techniques for determining ER concentration in cy tosols of breast cancer tumors, The two EIAs showed excellent agreemen t; however, two samples showed discrepant results by EIA96 and RLA.