Peripheral blood stem cells are now considered the standard source of stem cells for autologous stem cell transplants. Unfortunately, there is still a 20-30% chance that inadequate numbers of stem cells will be collected, resulting in prolonged recovery of cell counts after transplantation and increased transfusion dependence. There is also a significant economic burden associated with remobilization and a risk that delays in collecting sufficient numbers of stem cells can result in an increased chance of disease recurrence prior to transplantation.