ESTROGEN-RECEPTORS PROGESTERONE RECEPTORS AS AN INDEX OF ESTROGEN-RECEPTOR TRANSCRIPTION ACTIVITY IN BREAST-CANCER

Background: The aim of this study was to determine whether the induction of progesterone receptors (PR) for estrogen receptors (ER) in variable in breast cancer, whether it differs among pre and post menopausal women and whether the ER/PR quotient may be an index of tumoral biology. Methods: The ER and PR content was determined by enzymoimmunoassay in 814 breast tumors and the ER/PR quotient was calculated in the ER+PR+ tumors (n=395). Results: ER/PR values < 1 were more frequent in premenopausic women (66%) than in post menopausic women (38%). No influence was observed with regard to age. Conclusions: The highest ER/PR values were found in post menopausic women indicating decreased estrogen receptor transcriptional activity in this subgroup contrary to that found in premenopausic women.