DISEASE CHARACTERISTICS: Histologically or cytologically confirmed locally advanced or metastatic solid tumors refractory to standard therapy or for which no standard therapy exists (surgery, radiotherapy, and/or chemotherapy) Measurable or evaluable disease by medical photograph, plain x-ray, CT, MRI, palpation, or serum tumor markers at least 2 times upper limit of normal No symptomatic, progressive brain metastases by CT or MRI scan No cerebral edema No leukemia or multiple myeloma