Radioligand-labeled binding assay and immunochemical assay for estrogen receptor in 115 human breast cancers

The aim of this study was to evaluate the results obtained from a new enzyme immunoassay (Abbott-ER-EIA) for the determination of estrogen receptor levels in tumor cytosols in comparison with the currently used DCC method. One hundred and fifteen consecutive primary breast cancer specimens were examined; 66 of the women were postmenopausal and 49 were premenopausal. A good correlation (r = 0.88, p less than 0.001 and a slope of 1.3) was found between ER-EIA and the steroid binding assay (DCC). When these data were analyzed according to menopausal status, no differences were observed for the slopes and correlation coefficients in pre' and postmenopausal groups. The ER-EIA appears to produce results comparable to those obtained with the conventional DCC method for the determination of ER in breast tumor cytosols.