Patients undergo a core biopsy and mammogram of the contralateral breast at baseline and after 6 months for histological evaluation, IHC analysis, and mammographic density reading. Core biopsy tissue is assessed for proliferative changes and presence of atypia using standardized histological criteria. Core biopsy tissue is also analyzed by IHC for the following proteins: Ki-67 (proliferation index), p53, EGFR, HER2/neu, cleaved caspase-3 (apoptosis marker), and estrogen receptor (ER). Blood and urine samples are collected at baseline and every 2 months during treatment to measure drug effect biomarkers: serum estradiol, testosterone, insulin-like growth factor-1 (IGF-1), IGF binding protein-3 (IGFBP-3), and sex hormone-binding globulin (SHBG) by immunological laboratory methods; urine prostaglandin levels (PGE-M) by tandem mass spectrometry; urine oxidative damage markers (8-OHdG, isoprostane) and serum C-reactive protein (CRP) by ELISA; and catechol-O-methyltransferase (COMT) genotype (at baseline only).