Tamoxifen Pharmacogenetics and Clinical Effects

You may be eligible if

• 1. 18-years or older
• 2. Women with a prior breast cancer or who are at a high risk for developing the disease and about to start tamoxifen therapy.
• 3. Participants must not be treated with concomitant chemotherapy or hormone therapy other than tamoxifen. They must not have ovarian ablation or currently being treated with radiation therapy and/or chronic corticosteroids.
• 4. The participant must not be taking anti-hot flash therapy (clonidine, bellergal, megestrol acetate). Vitamin E, selective serotonin reuptake inhibitors, or herbal remedies are allowed provided that the participant has been taking the remedy for at least 4 weeks and intends to continue the remedy for at least the first month while on the study, and allows for one-month follow up evaluation (hot flash diaries and blood samples).
• 5. The participant must not be pregnant or lactating.
• 6. The participant is able and willing to sign an informed consent.