OUTLINE: Following a course of mobilization chemotherapy, patients receive priming therapy comprising filgrastim (G-CSF) and interleukin-2 through the completion of leukapheresis. Patients then receive oral busulfan 4 times daily on days -8 through -5, cyclophosphamide IV continuously on days -4 and -3, and etoposide IV over 2 hours on day -4. For patients unable to receive cyclophosphamide and etoposide, melphalan IV is administered instead on days -3 and -2. Autologous peripheral blood stem cells (PBSC) are reinfused on day 0.