RÉSUMÉ
The estrogen hormone receptor (ER) content of human breast cancer has assumed an important role as a predictor of hormone therapy response and as a prognostic indicator. The conventional technique is the dextran-coated charcoal (DCC) method or a ligand-binding assay (LBA) based on the measurement of radiolabeled steroids in cytosolic extracts of tissue homogenate. The recent introduction of monoclonal antibodies with high specificity for human ERs has allowed the application of immunocytochemical assays (ICA) in human cancer tissue. An extension of the ICA technique to cytologic specimens is also widely used. Our aim was to evaluate the reliability of ER-ICAs on fine needle aspirates(FNA) from breast cancer patients by comparing it with ER-ICAs and ER-LBAs performed on surgically removed tissues. During a recent 6-month period, ER-ICAs and ER-LBAs were performed in 83 cases. Among these 83 cases, only the 40 cases for which the ER-ICA and the ER-LBA were performed simultaneously ere included in this study. As positive cutoff values, we assumed 10 fmol/mg protein for the ER-LBAs and a semiquantitative score of 4 for the ER-ICAs. The results were as follows : 1) The ER positive rate was 55% (22/40) for ICAs and 47.5% (19/40) for LBAs. The concordance rate between the ER of ICAs and that of LBAs was 82.5% (33/40). 2) The Pearson correlation coefficient between ER-ICAs of fine needle aspirates and that of surgically removed tissue was good (r=0.94, p<0.005) 3) The Spearman correlation coefficient between ER-ICAs of fine needle aspirates and ER-LBAs of surgically removed tissue was good (r=0.57, p=0.0001) In conclusion, ER determination by using the fine needle aspirate is a reliable method in palpable breast cancer. FNA-ER may be a useful method when it is difficult to take sufficient breast cancer tissue, i.e., in cases of diffusely recurrent cancer, liver metastasis, malignant pleural effusion, etc.