title: Biochemistry of epidermal stem cells.
abstract: BACKGROUND
  The epidermis is an important protective barrier that is essential for maintenance of life. Maintaining this barrier requires continuous cell proliferation and differentiation. Moreover, these processes must be balanced to produce a normal epidermis. The stem cells of the epidermis reside in specific locations in the basal epidermis, hair follicle and sebaceous glands and these cells are responsible for replenishment of this tissue.
  
  
  METHODS
  A great deal of effort has gone into identifying protein epitopes that mark stem cells, in identifying stem cell niche locations, and in understanding how stem cell populations are related. We discuss these studies as they apply to understanding normal epidermal homeostasis and skin cancer.
  
  
  CONCLUSIONS
  An assortment of stem cell markers have been identified that permit assignment of stem cells to specific regions of the epidermis, and progress has been made in understanding the role of these cells in normal epidermal homeostasis and in conditions of tissue stress. A key finding is the multiple stem cell populations exist in epidermis that give rise to different structures, and that multiple stem cell types may contribute to repair in damaged epidermis.
  
  
  CONCLUSIONS
  Understanding epidermal stem cell biology is likely to lead to important therapies for treating skin diseases and cancer, and will also contribute to our understanding of stem cells in other systems. This article is part of a Special Issue entitled Biochemistry of Stem Cells.
authors: Department of Biochemistry and Molecular Biology, The University of Maryland School of Medicine, USA. reckert@umaryland.edu
authors: Richard L
authors: RL
authors: Eckert
authors: Gautam
authors: G
authors: Adhikary
authors: Sivaprakasam
authors: S
authors: Balasubramanian
authors: Ellen A
authors: EA
authors: Rorke
authors: Mohan C
authors: MC
authors: Vemuri
authors: Shayne E
authors: SE
authors: Boucher
authors: Jackie R
authors: JR
authors: Bickenbach
authors: Candace
authors: C
authors: Kerr
mesh_terms: D000078404:Epidermal Cells; D004817:Epidermis / Q000378:metabolism; D006801:Humans; D013234:Stem Cells / Q000166:cytology*