DISEASE CHARACTERISTICS:

• Diagnosis of breast cancer not eligible for potentially curative therapy or studies of higher priority

  • Advanced disease
  • Tumor accessible to biopsy AND not irradiated
• Failed at least 1 prior chemotherapy regimen (not including adjuvant chemotherapy)

• Hormone receptor status:

  • Not specified

PATIENT CHARACTERISTICS:

Age

• 18 and over

Sex

• Female

Menopausal status

• Not specified

Performance status

• ECOG 0-2

Life expectancy

• At least 3 months

Hematopoietic

• Absolute neutrophil count ≥ 1,500/mm^3
• Platelet count ≥ 100,000/mm^3
• Hemoglobin ≥ 9.0 g/dL

Hepatic

• AST ≤ 2 times upper limit of normal (ULN)
• Bilirubin ≤ 1.5 times ULN

Renal

• Creatinine ≤ 1.5 times ULN OR
• Creatinine clearance ≥ 50 mL/min

Other

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• HIV negative
• No active uncontrolled bacterial, viral, or fungal infection
• No poor medical risk from non-malignant systemic disease

PRIOR CONCURRENT THERAPY:

Biologic therapy

• Not specified

Chemotherapy

• See Disease Characteristics
• Prior irinotecan allowed
• Prior carboplatin allowed
• More than 3 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin)

Endocrine therapy

• Not specified

Radiotherapy

• See Disease Characteristics
• More than 4 weeks since prior radiotherapy except for small port radiotherapy for local control

Surgery

• More than 4 weeks since prior major surgery

Other

• No concurrent high-dose IV cyclosporine