Genistein in Preventing Breast Cancer in Women at High Risk for Breast Cancer

Inclusion Criteria

• No known soy intolerance
• At increased risk of developing breast cancer in >= 1 previously unaffected breast, as defined by any of the following:
• Estimated 5-year risk of developing breast cancer using the Gail model, as defined by 1 of the following:
• Gail score >= 1.66%
• Gail score >= 0.1% for women age 20-29 years
• Gail score >= 1.0% for women age 30-39 years
• Estimated 5-year risk of developing breast cancer using the Claus model:
• Claus score >= 1.66%
• Claus score >= 0.1% for women age 20-29 years
• Claus score >= 1.0% for women age 30-39 years
• Prior diagnosis of unilateral in situ or invasive breast cancer OR history of atypical hyperplasia, BRCA 1 and/or BRCA 2 positivity
• History of lobular carcinoma in situ
• No evidence of breast cancer, as determined by a negative mammogram within the past 6 months and a history and physical
• No previously diagnosed breast cancer unless all systemic therapy (including endocrine therapy) was completed at least 1 year ago
• Pre- or postmenopausal
• ECOG performance status 0-1
• Hemoglobin > 10.0 g/dL
• Platelet count > 100,000/mm^3
• Absolute neutrophil count > 1,000/mm^3
• Creatinine 2 years
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective barrier contraception
• Must be willing to keep a dietary diary
• No venous thrombosis within the past year
• No unrecognized or poorly controlled thyroid disease
• No other cancer within the past 5 years except nonmelanomatous skin cancer or noninvasive cervical cancer
• No other medical condition that, in the opinion of the investigator, would jeopardize either the patient or the integrity of the data obtained
• None of the following for >= 2 weeks before the first random fine needle aspiration and during study participation:
• Oral contraceptives
• Soy supplements
• High soy-containing foods
• Fish oil supplements
• Multivitamins
• Vitamins C and E
• Daily aspirin or nonsteroidal
• Anti-inflammatory drugs
• No other concurrent investigational agents
• No concurrent warfarin or other blood thinners
• Female patient

Exclusion Criteria

Women previously diagnosed with breast cancer will not be eligible unless all systemic therapy (including endocrine therapy) was completed at least one year previously

• Currently pregnant, or planning to become pregnant during the study period
• History of venous thrombosis within past year
• Medical conditions, which, in the opinion of the investigators would jeopardize either the patient or the integrity of the data obtained
• History of other cancer within the past five years, excluding non-melanomatous skin cancer, and non-invasive cervical cancer
• Known soy intolerance
• Unrecognized or uncontrolled thyroid disease, subjects may be on synthroid, but thyroid function must be in normal range or the patient's physician must document that the patient's thyroid is controlled.
• Currently receiving any other investigational agents
• Currently on coumadin, or other blood thinners
• History of breast augmentation implants.
• Rusults from patients who have <4000 epithelial cells in either the first or the second random Fine-needle aspiration (rFNA) will not be included in the study.