title: Cancer stem cell markers: what is their diagnostic value?
abstract: BACKGROUND
  Cancer resistance to conventional therapies has been attributed to cancer stem cells (CSCs). Although a variety of markers have been reported, a universal marker has not yet been found to identify CSCs. Better identification of these CSCs may lead to new therapies that selectively target these cells and thereby result in more effective treatment. This article categorizes the types of marker that have been identified and explores their potential diagnostic and therapeutic value.
  
  
  METHODS
  A focused literature review of studies relating to CSCs and their identification was conducted. Databases evaluated include MEDLINE and Web of Science through 2009.
  
  
  RESULTS
  The ideal identification method needs to be effective and practical in terms of application. The measurement of aldehyde dehydrogenase activity is simple to accomplish compared with other reported identification methods; however, cell surface antigens have been studied most frequently in the therapeutic targeting of CSCs.
  
  
  CONCLUSIONS
  Although specific targeting methods have been reported for various cancers, there does not appear to be a proven universal marker for CSCs that would apply to all cancers. Each particular identification method appears to have advantages and disadvantages. From a therapeutic standpoint, targeting of these CSCs should improve prognosis.
authors.affiliation: University of Michigan Medical School, Spine Research Laboratory, Department of Neurosurgery, Biomedical Science Research Building, Room 5007, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200, USA +1734 615 0371 ; +1734 763 7322 ; lincy@umich.edu.
authors.forename: Chia-Ying
authors.initials: CY
authors.lastname: Lin
authors.forename: Lin
authors.initials: L
authors.lastname: Wang
authors.forename: Khoi
authors.initials: K
authors.lastname: Than
authors.forename: Frank La
authors.initials: FL
authors.lastname: Marca
authors.forename: Paul
authors.initials: P
authors.lastname: Park