From stem cells to cancer stem cells: HIF takes the stage.

Hypoxia, a condition of insufficient oxygen availability, occurs during normal development as well as tumorigenesis. Cellular responses to hypoxia are primarily mediated by hypoxia-inducible factors (HIFs). Recent studies have revealed that dormant hematopoietic stem cells (HSCs) reside within hypoxic regions of the bone marrow and that HIF is a critical player in HSC homeostasis. The functional significance of HIF in maintaining stemness also applies to cancer stem cells in hematological malignancies. These findings indicate that better understanding of the mechanisms underlying HIF functions in stem cells should permit the development of new therapies for tissue regeneration and cancer.