ESRRA and breast cancer: Therefore, future studies should include treating ERα (+) cells with combinations of tamoxifen, faslodex or an aromatase inhibitor with Compound A. Additionally, it would be of great interest to treat both ERα (-) and tamoxifen resistant cells with Compound A. In the future it will be interesting to study the effects of knocking-down or antagonizing both ERα and ERRα in breast cancer cells.