DISEASE CHARACTERISTICS: Histologically proven advanced solid tumor for which no standard curative therapy exists Must be amenable to biopsy At least 1 site of measurable disease outside of irradiated field No brain metastases by CT or MRI scan

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-1 Life expectancy: Not specified Hematopoietic: WBC greater than 3,000/mm3 Absolute neutrophil count greater than 1,500/mm3 Platelet count greater than 100,000/mm3 Hemoglobin greater than 10 g/dL Hepatic: Bilirubin less than 1.5 times upper limit of normal (ULN) ALT and AST less than 2.0 times ULN PT/PTT less than 1.5 times ULN Renal: Creatinine less than 1.5 mg/dL OR Creatinine clearance greater than 60 mL/min Other: Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No concurrent uncontrolled medical or psychiatric disorder No history of bleeding diathesis

PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent over the counter biologic agents (e.g., shark cartilage) Chemotherapy: At least 3 weeks since prior chemotherapy (6 weeks since nitrosoureas or mitomycin) No more than 3 prior chemotherapy regimens for metastatic or recurrent disease (ECOG 1) Prior adjuvant chemotherapy for nonmetastatic disease allowed Endocrine therapy: Concurrent stable dose of hormone replacement therapy allowed Radiotherapy: At least 3 weeks since prior radiotherapy No concurrent radiotherapy Surgery: At least 24 hours since minor surgery (e.g., central venous placement) At least 4 weeks since major surgery (e.g., laparotomy, thoracotomy, or craniotomy) Other: At least 30 days since other prior investigational agents No concurrent herbal remedies No concurrent usage of products containing heparin No other concurrent anticancer therapy Concurrent multivitamins allowed