[Comparative studies of estrogen receptor determinations by enzyme immuno-assay using the monoclonal antibody, dextran-coated charcoal, and sucrose density gradient methods].

Estrogen receptor (ER) determination in human mammary tumors was performed by enzyme immunoassay (EIA) using monoclonal antibody, and the results were compared with those obtained using the dextran-coated charcoal (DCC) and sucrose density gradient (SDG) method. Twenty ER-positive tumors by the DCC method were all ER-positive by EIA, when determined in the same cytosol fraction. Three out of 21 ER-negative tumors by the DCC method were ER-positive by EIA. Estrogen receptors of 8S, 8S + 4S, and 4S determined by the SDG method were all shown to be ER-positive using EIA. Between the values of estrogen receptors determined by the DCC method and by EIA, a high correlation was observed (r = 0.868). Values of ER less than 13.5 fmol/mg protein were considered as negative ER.