DISEASE CHARACTERISTICS:

• Histologically confirmed solid tumor that is refractory to standard therapy or for which no standard therapy exists

  • Histologic confirmation not required for brainstem glioma or optic pathway tumor
• Ineligible for therapies of higher priority

• Stratum II only:

  • No bone marrow involvement

PATIENT CHARACTERISTICS:

Age:

• Under 22

Performance status:

• Karnofsky 50-100% (over 10 years of age)
• Lansky 50-100% (10 years of age and under)

Life expectancy:

• At least 8 weeks

Hematopoietic:

• Absolute neutrophil count at least 1,500/mm^3
• Platelet count at least 75,000/mm^3 (transfusion independent)
• Hemoglobin at least 8 g/dL (RBC transfusions allowed)

Hepatic:

• Bilirubin less than 1.5 mg/dL
• ALT less than 5 times normal for age
• Albumin at least 2 g/dL

Renal:

• Creatinine no greater than upper limit of normal for age OR
• Creatinine clearance or radioisotope glomerular filtration rate greater than 70 mL/min

Other:

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• Neurologic deficits related to CNS tumors allowed if relatively stable for at least 2 weeks
• No uncontrolled infection

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• At least 7 days since prior biologic therapy and recovered
• At least 3 months since prior allogeneic stem cell transplantation
• At least 1 week since prior growth factors

• Stratum II only:

  • No prior stem cell transplantation with or without total body irradiation

Chemotherapy:

• At least 2 weeks since prior chemotherapy (4 weeks for nitrosoureas) and recovered

• Stratum II only:

  • No more than 2 prior multi-agent chemotherapy regimens
  • More than 2 single-agent regimens allowed

Endocrine therapy:

• Concurrent dexamethasone allowed for CNS tumors if stable dose for at least 2 weeks

Radiotherapy:

• See Biologic therapy
• At least 2 weeks since prior palliative local radiotherapy
• At least 6 months since prior craniospinal radiotherapy or radiotherapy to at least 50% of pelvis
• At least 6 weeks since prior substantial bone marrow radiotherapy
• Recovered from prior radiotherapy

• Stratum II only:

  • No prior radiotherapy to more than 20% of bone marrow

Surgery:

• Not specified

Other:

• No prior bortezomib
• No concurrent anticonvulsants
• No other concurrent investigational agents