Estradiol and progesterone receptors in cultured normal human breast epithelial cells and fibroblasts: immunocytochemical studies.

The estradiol (E2) and progesterone (P) receptors (ER and PR) were studied in normal human breast epithelial (HBE) cells and fibroblasts cultured separately in our laboratory from surgical reductive mammoplasty samples. Immunocytochemical studies were performed on cytospun cells using the anti-ER antibody H222 Sp gamma and the anti-PR antibodies JZB39 and KD68. A specific immunostaining was observed for ER and PR in HBE cells. This immunostaining was nuclear, varying from cell to cell in positivity and intensity of staining. Moreover, ER and PR immunostaining was hormone-modulated: it increased in E2-treated cells and decreased after addition of the progestin R5020. In fibroblasts, a weak ER immunostaining and a stronger PR immunostaining could be observed; however it was not modified by either E2 or progestogen treatment. Thus, in normal breast epithelial cells, E2 stimulates both its own receptor and PR, whereas the progestin R5020 lowers ER and PR content. In contrast, ER and PR content in normal breast fibroblasts seem to be independent of E2 or P action.