Stem cell purging: an intriguing dilemma

Autologous stem cell transplantation (ASCT) is a therapeutic approach that permits the administration of high-dose chemoradiotherapy followed by the infusion of the patient's own hemotopoietic cells, previously collected during remission and cryopreserved [1-4]. The long-term outcome of ASCT is mainly affected by relapse of the underlying disease that represents the major cause of failure of ASCT. The contribution of reinfused tumor cells to relapse is suggested by several clinical studies and has been recently demonstrated by autografting genetically marked cells. In this minireview, advantages and limitations of currently available purging techniques will be analyzed. In addition, the potential clinical implications of new technological approaches for purging will be discussed.