Vaccine Therapy and QS21 in Treating Patients With Metastatic Breast Cancer

DISEASE CHARACTERISTICS: * Histologically confirmed stage IV breast cancer meeting 1 of the following criteria: * No evidence of disease * Stable disease on hormonal therapy * Stable disease must be present for ≥ 2 months and include \< 30% decrease or \< 20% increase in the sum of the longest diameter of target lesion * No new target lesions or unequivocal progression of non-target lesions * Elevation in the CA 153 (BR2729) or CEA values allowed * Hormone receptor status not specified PATIENT CHARACTERISTICS: * Female or male * Menopausal status not specified * Karnofsky performance status 80-100% * Lymphocyte count ≥ 500/mm³ * WBC ≥ 3,000/mm³ * Creatinine ≤ 1.5 times upper limit of normal (ULN) * AST ≤ 1.5 times ULN * Alkaline phosphatase ≤ 1.5 times ULN * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * No history of allergy to seafood * No NYHA class III-IV cardiac disease * No other active cancers except basal cell or squamous cell carcinoma of the skin * No active infection requiring antibiotic treatment * No known history of immunodeficiency or autoimmune disease PRIOR CONCURRENT THERAPY: * See Disease Characteristics * At least 4 weeks since prior chemotherapy * At least 4 weeks since prior radiotherapy * At least 4 weeks since prior surgery * At least 6 weeks since prior immunotherapy * No prior sialyl Lewisª antigen * No concurrent immunosuppressive medications (i.e., corticosteroids) * Concurrent hormonal therapy allowed