S.E.D. function of CD34 has yet to be elucidated, but by analyzing and understanding links between CD34+ cells, we hope to be able to offer an insight into the overlapping properties of cells that express CD34. Stem Cells em 2014;32:1380C1389 /em strong class=”kwd-title” Keywords: CD34, Stem cell, Progenitor, Mesenchymal, Stromal, Epithelial, Endothelial Introduction CD34 is predominantly regarded as a marker of hematopoietic stem cells (HSC) and hematopoietic progenitor cells. However, CD34 is now also established as a marker of several other nonhematopoietic cell types, including vascular endothelial progenitors 1 and embryonic fibroblasts 2. Accumulating evidence demonstrates CD34 expression on several other cell types, including multipotent mesenchymal stromal cells (MSC), interstitial dendritic cells, and epithelial progenitors 3C6, but there remains limited recognition of the role of CD34-positive (CD34+) cells outside of each individual specialty. Despite consistent evidence of expression by many cell types, there is still a misconception that CD34 represents a cell of hematopoietic origin, and experimentally, CD34+ cells are often regarded as hematopoietic contamination and subsequently disregarded. This review presents evidence establishing CD34 as a general marker of progenitor cells. We explore common characteristics, such as marker expression, morphology and differentiation potential, C25-140 and endeavor to draw focus toward the many, disparate cell types that express CD34, and in the process spotlight key similarities. CD34 expression across different cell types and the associated implications has not previously been presented, although selected literature has reviewed expression within individual cell groups. Although a common function of CD34 has yet to be elucidated, analyzing and understanding the links between cells offers an insight into the role of CD34 in identifying progenitor cells from many tissue types. A summary of the properties of all the CD34+ cell types discussed in this review can be found in Table?Table11. Table 1 Summary of different CD34+ cell types thead th align=”left” rowspan=”1″ colspan=”1″ CD34+ cell type /th th align=”center” rowspan=”1″ colspan=”1″ Associated markers /th th align=”center” rowspan=”1″ colspan=”1″ Differentiation potential /th th align=”center” rowspan=”1″ colspan=”1″ Properties /th th align=”center” rowspan=”1″ colspan=”1″ Reference /th /thead HSC and progenitorsHLA-DR, CD38, CD117 (c-kit), CD45, CD133Hematopoietic cells, cardiomyocytes, hepatocytesLarge nucleus, little cytoplasm, high proliferative capacity7, 8MSCStro-1, BABL CD73, CD90, CD105, CD146, CD29, CD44, CD271Adipogenic, osteogenic, chondrogenic, myogenic, angiogenicCD34+ MSC form a higher proportion of CFU-f colonies than CD34?. CD34+ MSC exhibit a high proliferative capacity. Fibroblastic cells9C13Muscle satellite cellsCD56, Myf5, Desmin, M-cadherin, CD90, CD106, Flk-1, VEGFR, MyoD, CD146Myogenic, adipogenic, osteogenic, chondrogenicThe CD56+CD34+ populace may represent a more primitive or pluripotent stem cell. In vivo, CD34+ cells are located near the basal lamina. Small and round14C17KeratocytesCD34, CD133, l-selectin, keratocan, ALDHFibroblastic, myofibroblastic, adipogenic, osteogenic, chondrogenic, corneal epithelial, corneal endothelialDendritic morphology. In vitro populace acquires an MSC phenotype18C21Interstitial cellsCD117, vimentin, Desmin, Connexin-43, PDGFRNot yet fully elucidatedTriangular or spindle-shaped with large nucleus and long cytoplasmic processes. CD34+ populace may have a stem cell/progenitor role in the bladder, intestine, C25-140 and reproductive organs22C24FibrocyteCD45, CD80, CD86, MHC class I and IIFibroblastic, myofibroblastic, adipogenic, osteogenic, chondrogenicSmall spindle form. Compact disc34 is dropped in tradition and upon maturation25C27Epithelial progenitorsCD49f, Compact disc10, Compact disc146, Compact disc71, S100a4, Dkk3, Compact disc133, Compact disc117, ALDH, Compact disc90Dermal epithelial cells, neural referred to in HF market in pores and skin28C33Endothelial cellsCD146 mesenchymalPredominantly, VE-cadherin, Compact disc133, Compact disc117, Compact disc14, Compact disc31AngiogenesisElongated with filopodia. Lack small junctions. Compact disc34 exists on luminal membrane procedures and it is indicated on C25-140 filopodia during in vivo angiogenesis. Quiescent in vivo/low proliferation activity1, 34, 35 Open up in another windowpane Abbreviations: ALDH, aldehyde dehydrogenase; Compact disc, cluster of differentiation; CFU-F, colony developing devices fibroblast; Flk-1, fetal liver organ kinase-1; HF, locks follicle; HLA-DR, human being leukocyte antigen-DR; HSC, hematopoietic stem cells; MSC, multipotent mesenchymal stromal cells; Myf5, myogenic element 5; C25-140 MyoD, myogenic differentiation 1; MHC, main histocompatibility complicated; PDGFR, platelet produced growth element receptor ; VEGFR, vascular endothelial development factor receptor. Function and Framework of Compact disc34 Compact disc34 can be a transmembrane phosphoglycoprotein, 1st determined in 1984 about hematopoietic progenitor and stem cells 36. It has.