title: From pericytes to perivascular tumours: correlation between pathology, stem cell biology, and tissue engineering.
abstract: OBJECTIVE
  Pericytes were once thought only to aid in angiogenesis and blood pressure control. Gradually, the known functions of pericytes and other perivascular stem cells (PSC) have broadly increased. The following review article will summarize the known functions and importance of pericytes across disciplines of pathology, stem cell biology, and tissue engineering.
  
  
  METHODS
  A literature review was performed for studies examining the importance of pericytes in pathology, stem cell biology, and tissue engineering.
  
  
  RESULTS
  The importance of pericytes most prominently includes the identification of the perivascular identity of mesenchymal stem cells (or MSC). Now, pericytes and other PSC are known to display surface markers and multilineage differentiation potential of MSC. Accordingly, interest in the purification and use of PSC for mesenchymal tissue formation and regeneration has increased. Significant demonstration of in vivo efficacy in bone and muscle regeneration has been made in laboratory animals. Contemporaneously with the uncovering of an MSC identity for pericytes, investigators in tumour biology have found biologically relevant roles for pericytes in tumor formation, lymphovascular invasion, and perivascular tumor spread. As well, the contribution of pericytes to perivascular tumors has been examined (and debated), including glomus tumour, myopericytoma and solitary fibrous tumour/hemangiopericytoma. In addition, an expanding recognition of pericyte mimicry and perivascular tumour invasion has occurred, encompassing common malignancies of the brain and skin.
  
  
  CONCLUSIONS
  In summary, pericytes have a wide range of roles in health and disease. Pericytes are being increasingly studied for their role in tumour formation, growth and invasion. Likewise, the application of pericytes/PSC for mesenchymal tissue engineering is an expanding field of interest.
authors.affiliation: Orthopaedic Hospital Research Center, University of California, Los Angeles, CA, USA.
authors.forename: Marco
authors.initials: M
authors.lastname: Mravic
authors.forename: Greg
authors.initials: G
authors.lastname: Asatrian
authors.forename: Chia
authors.initials: C
authors.lastname: Soo
authors.forename: Claire
authors.initials: C
authors.lastname: Lugassy
authors.forename: Raymond L
authors.initials: RL
authors.lastname: Barnhill
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Dry
authors.forename: Bruno
authors.initials: B
authors.lastname: Peault
authors.forename: Aaron W
authors.initials: AW
authors.lastname: James
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D019070:Cell Lineage; D004195:Disease Models, Animal; D006801:Humans; D059630:Mesenchymal Stem Cells; D009361:Neoplasm Invasiveness / Q000473:pathology / Q000503:physiopathology; D009383:Neoplasms, Vascular Tissue / Q000473:pathology / Q000503:physiopathology*; D010336:Pathology / Q000639:trends*; D020286:Pericytes / Q000473:pathology / Q000502:physiology*; D057905:Stem Cell Research; D023822:Tissue Engineering / Q000639:trends*