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CD Markers

CD26


Reviewer: Nat Pernick, M.D. (see Reviewers page)
Revised: 19 January 2011, last major update January 2011
Copyright: (c) 2002-2011, PathologyOutlines.com, Inc.

General
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● Widely expressive dipeptidase with various clinical features (see below)
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Terminology
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● Also called dipeptidyl-peptidase IV, DDPIV, adenosine deaminase complexing protein 2

Physiology
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● Costimulatory molecule in T cell activation and proliferation
● Also regulates various chemokines and cytokines
● Cleaves amino-terminal dipeptides; plays a role in cell spreading and migration
● Either soluble in plasma or present on cell surface

Clinical features
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● May have protective role against HIV infection (Virol J. 2010 Nov 25;7:343)
● Acute kidney transplant rejection is associated with increased serum CD26 activity, and CD26 inhibition reduces acute and accelerated rejection (Adv Exp Med Biol 2003;524:133)
● Reduced expression in melanoma, endometrial (Am J Obstet Gynecol 2003;188:670) and prostatic carcinoma but increased expression in thyroid carcinoma (Diagn Cytopathol 2002;26:366, Am J Clin Path 1991;96:306)
● Functions as a tumor suppressor in non small cell lung carcinoma (Int J Cancer 2004;109:855)
● Blastocyst implantation may occur by binding of endometrial CD26 to embryonal fibronectin (Mol Hum Reprod 2006;12:491)
● Normally CD26 inactivates cutaneous SDF-1 which binds to CXCR4 in Sezary cells (Blood 2006;107:1108)

Uses
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● Absence of CD26 staining on peripheral blood CD4+ T cells by flow cytometry is useful to diagnose T cell lymphoma (Am J Clin Path 2001;115:885, but see Am J Clin Pathol 2008;129:146)

Positive staining - normal
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● Activated T and B cells, basophils, macrophages, NK cells, thymocytes (mature)
Epithelium: endometrium, hepatocytes, lung, prostate, renal proximal tubular cells, small intestine
● Also cytotrophoblast and extravillous trophoblast (J Clin Endocrinol Metab 2002;87:4287), biliary canaliculae, endothelial cells, fibroblasts, mesothelial cells (Oncology 2002;63:158), splenic sinus lining cells

Micro images
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Renal proximal tubules

Melanoma versus deep penetrating nevi

Positive staining - disease
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● Esophageal adenocarcinoma and Barrett’s metaplasia (Hum Pathol 1999;30:1291)
● Prostate carcinoma, thyroid anaplastic carcinoma (reduced expression in undifferentiated vs. differentiated areas (Am J Clin Path 2006;125:399)
● Wilm’s tumor (Hum Pathol 1990;21:536)

Negative staining
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● Normal thyroid gland, T cells in peripheral blood of mycosis fungoides / cutaneous T cell lymphoma (40%, BMC Clin Pathol 2002 Dec 10;2(1):5)

Additional references
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MIM 102720

End of CD Markers > CD26


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