Estrogen and Progesterone Receptors of Human Endometrial Cells in Vivo and in Vitro : Comparative Results of Radiochemical and Histochemical Assays

Abstract

Oncopathologists have been developing histochemical methods of sex steroid receptor determination, essential in therapy selection in breast cancer, based on the binding of labeled hormone to receptor. We have applied the fluorescent hormones available commercially from Lee to endometrium. Our purpose was to compare biochemical and histochemical results, both in fresh tissue and in endometrial tissue cultures. We wished to examine the ability of the technique to determine subcellular localization of hormone binding and to trace the hormone-receptor pathway to the chromatin. Eleven fresh normal endometrial specimens, in culture for 3 months, were used for the determination of receptors. As a control we also used cells from 4 human carcinoma cell lines. In fresh tissue, histological patterns were similar to those described in breast cancer but there was little correlation with radiochemical values. In cultured cells also, there was no similarity between the two techniques. Morphologically the labeled hormone was unable to enter the living cell. After fixation it never got through the nuclear membranes. Moreover, the fluorescent cytoplasmic feature was fibrillar and reticular, which could evoke a non specific fixation on the cytoskeleton. We concluded that this molecule is not useful for subcellular localization of hormone-receptor complexes.