[Determination of estrogen and progesterone receptors in cancer of the breast. Frequency of presentation and prognostic significance].

The assay of estrogen and progesterone receptors (RE and RP) is used to know the hormone dependency of breast tumors and to predict the response to endocrine therapy. In this study 68 per 100 of the patients were RE(+) within a range of 5 to 180 fmol/mg, and 45 per 200 were RP(+) between 10 and 400 fmol/mg. The frequency and concentration increase with age. Significative variations were not observed in RE(+) for either frequency or concentration between primary and metastatic samples. There is a correlation between phenotypes RE(+) and RE(-) and histopathologic prognostic features.