CD34
Template:PBB CD34 molecule is a cluster of differentiation molecules present on certain cells within the human body. It is a cell surface glycoprotein and functions as a cell-cell adhesion factor. It may also mediate the attachment of stem cells to bone marrow extracellular matrix or directly to stromal cells. CD34 is also the name for the human gene that encodes the protein.[1][2][3]
Function
The CD34 protein is a member of a family of single-pass transmembrane sialomucin proteins that show expression on early hematopoietic and vascular-associated tissue. However little is known about its exact function.[4]
CD34 is also an important adhesion molecule and is required for T cells to enter lymph nodes. It is expressed on lymph node endothelia whereas the L-selectin to which it binds is on the T cell.[5][6]
Tissue distribution
Cells expressing CD34 (CD34+ cell) are normally found in the umbilical cord and bone marrow as hematopoietic cells, a subset of mesenchymal stem cells, endothelial progenitor cells, endothelial cells of blood vessels but not lymphatics (except pleural lymphatics), mast cells, a sub-population dendritic cells (which are factor XIIIa negative) in the interstitium and around the adnexa of dermis of skin, as well as cells in soft tissue tumors like DFSP, GIST, PNSTs etc.
Clinical applications
CD34+ cells may be isolated from blood samples using immunomagnetic or immunofluorescent methods.
Antibodies are used to quantify and purify hematopoietic progenitor stem cells for research and for clinical bone marrow transplantation. However, counting CD34+ mononuclear cells may overestimate myeloid blasts in bone marrow smears due to hematogones (B lymphocyte precursors) and CD34+ megakaryocytes.
Cells observed as CD34+ and CD38- are of an undifferentiated, primitive form; i.e. they are pluripotential hemopoietic stem cells. Thus, because of their CD34+ expression, such undifferentiated cells can be sorted out.
In tumors, CD34 is found in alveolar soft part sarcoma, preB-ALL (positive in 75%), AML (40%), AML-M7 (most), dermatofibrosarcoma protuberans, gastrointestinal stromal tumors, giant cell fibroblastoma, granulocytic sarcoma, Kaposi’s sarcoma, liposarcoma, malignant fibrous histiocytoma, malignant peripheral nerve sheath tumors, mengingeal hemangiopericytomas, meningiomas, neurofibromas, schwannomas, and papillary thyroid carcinoma.
A negative CD34 may exclude Ewing's sarcoma/PNET, myofibrosarcoma of the breast, and inflammatory myofibroblastic tumors of the stomach.
Interactions
CD34 has been shown to interact with CRKL.[7]. It also interacts with L-selectin, important in inflammation.
References
- ^ "Entrez Gene: CD34 CD34 molecule".
- ^ Simmons DL, Satterthwaite AB, Tenen DG, Seed B (1 January 1992). "Molecular cloning of a cDNA encoding CD34, a sialomucin of human hematopoietic stem cells". J. Immunol. 148 (1): 267–71. PMID 1370171.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Satterthwaite AB, Burn TC, Le Beau MM, Tenen DG (1992). "Structure of the gene encoding CD34, a human hematopoietic stem cell antigen". Genomics. 12 (4): 788–94. doi:10.1016/0888-7543(92)90310-O. PMID 1374051.
{{cite journal}}: Unknown parameter|month=ignored (help)CS1 maint: multiple names: authors list (link) - ^ Furness SG, McNagny K (2006). "Beyond mere markers: functions for CD34 family of sialomucins in hematopoiesis". Immunol. Res. 34 (1): 13–32. doi:10.1385/IR:34:1:13. PMID 16720896.
- ^ Berg EL, Mullowney AT, Andrew DP, Goldberg JE, Butcher EC (1998). "Complexity and differential expression of carbohydrate epitopes associated with L-selectin recognition of high endothelial venules". Am. J. Pathol. 152 (2): 469–77. PMC 1857953. PMID 9466573.
{{cite journal}}: Unknown parameter|month=ignored (help)CS1 maint: multiple names: authors list (link) - ^ SSuzawa K, Kobayashi M, Sakai Y, Hoshino H, Watanabe M, Harada O, Ohtani H, Fukuda M, Nakayama J (2007). "Preferential induction of peripheral lymph node addressin on high endothelial venule-like vessels in the active phase of ulcerative colitis". Am. J. Gastroenterol. 102 (7): 1499–509. doi:10.1111/j.1572-0241.2007.01189.x. PMID 17459027.
{{cite journal}}: Unknown parameter|month=ignored (help)CS1 maint: multiple names: authors list (link) - ^ Felschow, D M (2001). "The adapter protein CrkL associates with CD34". Blood. 97 (12). United States: 3768–75. doi:10.1182/blood.V97.12.3768. ISSN 0006-4971. PMID 11389015.
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Further reading
- Bellini A, Mattoli S (2007). "The role of the fibrocyte, a bone marrow-derived mesenchymal progenitor, in reactive and reparative fibroses". Lab. Invest. 87 (9): 858–70. doi:10.1038/labinvest.3700654. PMID 17607298.
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External links
- Antigens,+CD34 at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
- Mouse CD Antigen Chart
- Human CD Antigen Chart