title: Hematopoietic stem cells and hematopoiesis.
abstract: BACKGROUND
  The highly orchestrated process of blood cell development and homeostasis is termed "hematopoiesis." Understanding the biology of hematopoietic stem cells as well as hematopoiesis is important to developing improved treatments for hematologic malignancies, congenital disorders, chemotherapy-related cytopenias, and blood and marrow transplants.
  
  
  METHODS
  The author reviews the current state of the art regarding hematopoietic stem cells and hematopoiesis.
  
  
  RESULTS
  Several new concepts, including stem cell plasticity, suggest the possibility that stem cells may have the ability to differentiate into other tissues in addition to blood cells.
  
  
  CONCLUSIONS
  While much is known about hematopoietic stem cells and hematopoiesis, much remains to be clarified about the environmental and genetic processes that govern the growth and development of the blood system. In addition, careful studies remain to be conducted to determine whether hematopoietic stem cells can differentiate into extra-hematopoietic tissues.
authors.affiliation: Blood and Marrow Transplant Program, H. Lee Moffitt Cancer Center Research Institute, Tampa, FL 33612, USA. smithca@moffitt.usf.edu
authors.forename: Clayton
authors.initials: C
authors.lastname: Smith
mesh_terms: D000818:Animals; D002468:Cell Physiological Phenomena; D006410:Hematopoiesis / Q000502:physiology*; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000502:physiology*; D006801:Humans