OUTLINE: Patients receive high-dose oral busulfan every 6 hours on days -8 to -5, cyclophosphamide IV twice a day on days -4 and -3, and cyclosporine IV over 6 hours on day -1 and then 10 hours on day 0 for 2 doses (allogeneic only). Allogeneic peripheral blood progenitor cells IV are administered on day 0.