Dehydroepiandrosterone sulfate causes proliferation of estrogen receptor-positive breast cancer cells despite treatment with fulvestrant.

Hypothesis: Dehydroepiandrosterone sulfate (DHEA-S) causes a proliferation of estrogen receptor (ER)-positive breast cancer cells, even with tamoxifen citrate blockade. The ER antagonist ICI 182780 (fulvestrant) will more effectively stop the proliferative effect of DHEA-S on breast cancer cells.

Design: Examination of in vitro breast cancer cell growth in the presence of fulvestrant and DHEA-S.