[Problems posed by the morphologic demonstration of estrogen receptors]

The different morphological methods that can be used to detect and localize estrogen receptors into the cell are reviewed. Sex steroid receptors measurements are useful for clinicians and studies on breast cancer demonstrated their predictive value in the management of patients. Beside the routinely used radiochemical assay, morphological detection of receptors can be realized by two different ways: an indirect way, using markers of estrogen and its detection when linked to the receptor. One can use radioactive estrogen and autoradiography; fluorescent estrogen and U-V microscope; or anti-estrogen antibody linkage and immunocytodetection. All these methods face two complex problems: the large diffusibility of steroid hormone and their affinity for many other ligands than their specific receptor; a direct way, irrespective of the presence or absence of hormone, using a monoclonal antibody generated against receptor protein from human breast cancer. Using this antibody, estrogen receptors are strictly localized into the nuclei of cells (no cytoplasmic localization). This appears to be the best morphological method and a useful complement of radiochemical assay.