title: Concise review: the surface markers and identity of human mesenchymal stem cells.
abstract: The concept of mesenchymal stem cells (MSCs) is becoming increasingly obscure due to the recent findings of heterogeneous populations with different levels of stemness within MSCs isolated by traditional plastic adherence. MSCs were originally identified in bone marrow and later detected in many other tissues. Currently, no cloning based on single surface marker is capable of isolating cells that satisfy the minimal criteria of MSCs from various tissue environments. Markers that associate with the stemness of MSCs await to be elucidated. A number of candidate MSC surface markers or markers possibly related to their stemness have been brought forward so far, including Stro-1, SSEA-4, CD271, and CD146, yet there is a large difference in their expression in various sources of MSCs. The exact identity of MSCs in vivo is not yet clear, although reports have suggested they may have a fibroblastic or pericytic origin. In this review, we revisit the reported expression of surface molecules in MSCs from various sources, aiming to assess their potential as MSC markers and define the critical panel for future investigation. We also discuss the relationship of MSCs to fibroblasts and pericytes in an attempt to shed light on their identity in vivo.
authors.affiliation: Department of Orthopaedics and Traumatology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, People's Republic of China; Stem Cell & Regenerative Medicine Consortium, The University of Hong Kong, Hong Kong SAR, People's Republic of China; Center for Reproduction, Development and Growth, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, People's Republic of China.
authors.forename: Feng-Juan
authors.initials: FJ
authors.lastname: Lv
authors.forename: Rocky S
authors.initials: RS
authors.lastname: Tuan
authors.forename: Kenneth M C
authors.initials: KM
authors.lastname: Cheung
authors.forename: Victor Y L
authors.initials: VY
authors.lastname: Leung
mesh_terms: D015415:Biomarkers / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D002469:Cell Separation; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism*
chemical_list: D015415:Biomarkers
keywords: CD146; CD271; Markers; Mesenchymal stem cells; Niche; Pericytes; Regenerative medicine; Surface epitopes