DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed* breast adenocarcinoma metastatic to the liver

  • Solitary or multiple hepatic metastases

    • No malignant involvement of > 40% of the estimated liver volume NOTE: *Must be from the hepatic tumor designated for study injection
• Metastatic liver tumors must be measurable in ≥ 2 dimensions on CT scan or MRI
• At least 1 metastatic hepatic tumor ≥ 2 cm in diameter must be visualized by ultrasound and accessible for percutaneous injection under ultrasound guidance
• Extrahepatic metastasis allowed
• No solitary hepatic metastasis eligible for liver resection
• No clinical evidence for severe liver disease (e.g., prior or current ascites or portosystemic encephalopathy)
• Hormone-receptor status not specified

PATIENT CHARACTERISTICS:

• Female
• Menopausal status not specified
• Granulocyte count ≥ 1,500/mm^3
• Hemoglobin ≥ 9.0 g/dL
• Platelet count ≥ 100,000/mm^3
• PT ≤ 14.5 sec
• Creatinine ≤ 1.5 mg/dL OR creatinine clearance ≥ 45 mL/min
• Bilirubin ≤ 2 times upper limit of normal (ULN)
• Transaminases ≤ 2.5 times ULN
• Karnofsky performance status ≥ 70%
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception during and for at least 2 months after completion of study treatment
• No active infection or serious intercurrent medical illness
• No HIV infection
• Life expectancy ≥ 16 weeks
• No other malignancy within the past 5 years except inactive nonmelanoma skin cancer, in situ carcinoma of the cervix, or grade 1 papillary bladder cancer
• At highest dose level, patient must weigh ≥ 30 kg

PRIOR CONCURRENT THERAPY:

• No systemic immunosuppressive drugs, including corticosteroids, within 2 months prior to study entry

  • Not require immunosuppressive drugs or anticoagulant therapy with heparin or warfarin for at least 2 months after study treatment
• No chemotherapy within 4 weeks of study entry (6 weeks for nitrosoureas)