The participants will be consented following diagnostic core needle biopsy at the time of initial surgical consultation. Baseline assessments include medical history, nipple aspirate fluid (NAF) collection, explanation of gel application, BESS questionnaire (symptom assessment) and blood draw for clinical and research labs including plasma estradiol, progesterone and FSH (rushed), CBC, chemistry profile, liver and renal function tests, Factor VIII, von Willebrand Factor, Factor IX, and total protein S, plasma for insulin-like growth factor (IGF-1) and sex hormone-binding globulin (SHBG), and DNA extraction for assessment of polymorphisms in tamoxifen metabolism genes. At Northwestern plasma and RNA from blood will be collected pre- and post-treatment and will be stored for future proteomic and gene expression fingerprinting