Dynamic regulation of stem cell specification and maintenance by hypoxia-inducible factors.

Stem cells are characterized by the capacity for both self-renewal and generation of all other cell types (pluripotency) or differentiated cells within a particular lineage (multipotency). Stem cells are often localized to hypoxic niches within tissues and hypoxia inducible factors (HIFs) play key roles in the maintenance of pluripotent and multipotent stem cells, as well as cancer stem cells, which are also known as tumor-initiating cells. HIF inhibitors target cancer stem cells and improve the responses to angiogenesis inhibitors and cytotoxic chemotherapy in mouse models of breast cancer.