 REINDUCTION BLOCK 2: Patients receive etoposide phosphate IV over 1-2 hours on days 1-5; cyclophosphamide IV over 15-30 minutes on days 1-5; bortezomib IV over 3-5 seconds on days 1, 4, and 8; filgrastim G-CSF subcutaneously SC or IV daily beginning on day 6 and continuing until blood counts recover; high-dose methotrexate IV over 24 hours on day 22; and leucovorin calcium PO or IV every 6 hours on days 23 and 24. Patients with CNS-negative disease also receive methotrexate IT on days 1 and 22; patients with CNS-positive disease receive TIT on days 1 and 22. After completion of reinduction block 2, patients proceed to reinduction block 3 immediately or when blood counts recover. Patients with disease progression are removed from the study. 