Keratinocyte stem cells: friends and foes

J Cell Physiol. 2010 Nov;225(2):310-5. doi: 10.1002/jcp.22275.


Skin and its appendages provide a protective barrier against the assaults of the environment. To perform its role, epidermis undergoes an ongoing renewal through a balance of proliferation and differentiation/apoptosis called homeostasis. Keratinocyte stem cells reside in a special microenvironment called niche in basal epidermis, adult hair follicle, and sebaceous glands. While a definite marker has yet to be detected, data raised part in humans and part in the mouse system point to a critical role of stem and its progeny transit amplifying cells in epidermal homeostasis. Stem cells are protected from apoptosis and are long resident in adult epidermis. This renders them more prone to be the origin of skin cancer. In this review, we will outline the main features of adult stem cells in mouse and humans and discuss their fate in relation to differentiation, apoptosis, and cancer.

Publication types

  • Review

MeSH terms

  • Animals
  • Apoptosis
  • Biological Products
  • Cell Differentiation
  • Humans
  • Keratinocytes / cytology*
  • Keratinocytes / physiology*
  • Skin Neoplasms / pathology
  • Stem Cells / cytology*
  • Stem Cells / physiology*


  • Biological Products