Anti-Proliferative Effects and Genomic Alterations of Abiraterone Acetate Compared to an Aromatase Inhibitor in Post-menopausal HR+ Operable Breast Cancer

This study is being offered to patients who are post-menopausal, have breast cancer with a positive estrogen and/or progesterone hormone receptor test and are currently awaiting surgery for breast cancer. The purpose of this study is to determine whether abiraterone acetate has different hormonal and genomic effects than non-steroidal aromatase inhibitors in the treatment of post-menopausal hormonal receptor positive primary operable breast cancer