Estrogen receptor analyses in breast cancer: comparison of monoclonal immunohistochemical and biochemical methods.

The estrogen receptor content in 100 female breast carcinomas was determined using the biochemical dextran-coated charcoal (DCC) method and the monoclonal estrogen receptor immunocytochemical assay (ER-ICA). Great care was taken to make procedures optimal in order to minimize preanalytical errors. A statistically highly significant correlation was found between the results of the two methods, which were qualitatively in accordance in 91 cases, while nine gave a negative ER-ICA but a weak positive DCC result. The quantitative correlations were also statistically significant but varied considerably in individual cases. Under optimal conditions, ER-ICA provides results similar to the DCC method, but it is still uncertain if it can stand alone in routine diagnosis.