Estrogen receptor determinations in primary breast cancer. A comparison of a biochemical dextran-coated charcoal and an immunohistological technique.

The present study describes the estrogen receptor (ER) detection by an immunocytochemical assay kit (ER-ICA) on cryostat sections of 78 primary breast carcinomas. Results are compared with quantitatively measured ER levels, which were obtained by the dextran-coated charcoal (DCC) method. An excellent overall correlation between the logarithm of the ER levels, estimated by this technique, and the semiquantitative immunocytochemical evaluation was found, i.e. r = 0.73. Since the ER-ICA can be easily handled without radioactivity being involved and since it is more representative of the total tumor, we conclude (as other groups before us) that the ER-ICA is an easy-to-handle and reliable technique presenting many advantages over the DCC method.