CD Markers

Topic Completed: 1 September 2013

Minor changes: 30 July 2019

Revised: 13 December 2018, last major update September 2013

Copyright: (c) 2003-2018,, Inc.

PubMed Search: CD13[title], Aminopeptidase N[title]

Nat Pernick, M.D.
Page views in 2019: 2,663
Page views in 2020 to date: 2,089
Cite this page: Pernick N. CD13. website. Accessed September 23rd, 2020.
Definition / general
  • Myeloid antigen, although CD33 is more specific (OMIM #151530)
  • Also called aminopeptidase N (APN)
Clinical features
  • Cleaves peptides at brush border of small intestine, renal proximal tubules and placenta
  • Cleaves antigen peptides bound to MHC class II molecules of presenting cells
  • Degrades neurotransmitters at CNS synaptic junctions
  • Regulates sperm motility (Asian J Androl 2010;12:899)
Uses by pathologists
Microscopic (histologic) images

Images hosted on PathOut server:

Prostate: normal
(contributed by Leica Microsystems)

Images hosted on other servers:
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CNS: glioblastoma & colon: carcinoma

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Colon: normal

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Liver: left-normal, right-hepatocellular carcinoma

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Prostate: carcinoma

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Skin (inflammatory), tonsil

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Various tumors

Positive staining - normal
  • Granulocytes (most, but low levels in newbornss, Mod Pathol 1993;6:414), interdigitating dendritic cells, large granular lymphocytes (some), macrophages, mast cells, monocytes, myelomonocytes and osteoclasts
  • Also bile duct canaliculi, central nervous system synapses, endothelial cells, endometrial stromal cells, fibroblasts, liver, perineurium of peripheral nerves, placenta, prostate secretory cells, renal proximal tubules (PLoS One 2013;8:e66750), respitatory epithelium, small intestine and sperm
Positive staining - disease
Negative staining
Flow cytometry images

Images hosted on other servers:

CD13+ anaplastic large cell lymphoma

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