CYP19A1 and breast cancer: This testosterone-induced response of the expression of estrogen-responsive gene pS2 is inhibited by the aromatase inhibitor 7α (4′-amino) phenylthio-1,4-androstadiene-3,17-dione (7α-APTADD) and by 10 μM tamoxifen in breast cancer MCF-7 cells [41].