HER-2 Protein Vaccine in Treating Women With Breast Cancer

DISEASE CHARACTERISTICS: * Histologically confirmed adenocarcinoma of the breast, meeting criteria for 1 of the following: * Metastatic disease currently in complete or partial response or stable disease * Have been receiving a stable endocrine therapy regimen (e.g., aromatase inhibitor, tamoxifen, fulvestrant, or gonadotropin-releasing hormone agonist) for at least 30 days OR status post oophorectomy * Completed a course of local and adjuvant systemic therapy for high-risk stage II or III disease (i.e., anticipated 5-year relative survival is no greater than 50%) meeting any of the following staging criteria: * Stage IIB with involvement of at least 4 nodes * Stage IIIA (T3 disease with involvement of at least 4 nodes) * Any stage IIIB or IIIC disease * Stage IV with no evidence of disease (e.g., prior resection of local chest wall recurrence with no evidence of disease elsewhere) * 1+, 2+, or 3+ HER2/neu expression by immunohistochemistry * Treatment with trastuzumab (Herceptin®) not clinically indicated * Hormone receptor status: * Not specified PATIENT CHARACTERISTICS: Age * 18 and over Sex * Female Menopausal status * Not specified Performance status * ECOG 0-1 Life expectancy * At least 6 months Hematopoietic * Platelet count at least 100,000/mm\^3 * Hemoglobin at least 10 g/dL * Absolute neutrophil count at least 1,500/mm\^3 Hepatic * ALT or AST no greater than 2.5 times upper limit of normal (ULN) (5 times ULN for patients with liver metastases) * Bilirubin no greater than 2 mg/dL (unless due to Gilbert's disease) Renal * Creatinine no greater than 2 mg/dL Cardiovascular * No history of significant cardiovascular disease * No myocardial infarction within the past 6 months * No poorly controlled cardiac arrhythmia * No New York Heart Association class III or IV heart disease * LVEF at least 50% by MUGA Other * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * No other malignancy except basal cell skin cancer or adequately treated carcinoma in situ of the cervix * No concurrent severe autoimmune disease * No other clinically significant or serious medical disease that would preclude study participation or compromise patient safety or the results of this study PRIOR CONCURRENT THERAPY: Biologic therapy * More than 4 months since prior trastuzumab * No prior anticancer vaccine therapy * No concurrent trastuzumab * No concurrent immunomodulators (e.g., thalidomide or interferons/interleukins) Chemotherapy * More than 4 weeks since prior chemotherapy * No concurrent low-dose methotrexate or cyclophosphamide * No concurrent cytotoxic chemotherapy Endocrine therapy * See Disease Characteristics * No concurrent corticosteroids * Topical or inhaled steroids are allowed * No changes to current endocrine therapy regimen (e.g., discontinuation or addition of an agent) Radiotherapy * More than 3 months since prior radiotherapy involving more than 25% of the bone marrow * No concurrent radiotherapy Surgery * See Disease Characteristics * No prior bilateral breast procedures Other * More than 4 weeks since prior immunosuppressive therapy * More than 30 days since prior investigational agents or clinical trial participation * No other concurrent experimental or investigational agents * No concurrent cyclosporine * No concurrent immunosuppressive agents