Considerations for targeting malignant stem cells in leukemia.

BACKGROUND Malignant stem cells have been identified in acute myelogenous leukemia, chronic myeloid leukemia, and some types of acute lymphoblastic leukemia. Like normal stem cells, these leukemic stem cells (LSCs) are able to self-renew, differentiate, and proliferate extensively. Evidence suggests that LSCs are critical for the initiation and perpetuation of leukemic disease. METHODS We reviewed the literature describing the characteristic features of LSCs in various leukemias and the novel molecular approaches being used to specifically ablate the LSC population. RESULTS Studies have demonstrated the potential importance of ablating LSCs when treating leukemia. The unique characteristics of LSCs that differentiate them from their normal counterparts can be exploited to specifically target the malignant population. CONCLUSIONS Current therapeutic strategies may not effectively ablate the LSC, leaving the potential for disease progression or relapse. A better understanding of LSC cell and molecular biology will allow the design of more effective therapies.