CD Markers

Last author update: 1 September 2013
Last staff update: 14 May 2021

Copyright: 2003-2024,, Inc.

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

Nat Pernick, M.D.
Page views in 2023: 1,721
Page views in 2024 to date: 641
Cite this page: Pernick N. CD13. website. Accessed May 19th, 2024.
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

Contributed by Leica Microsystems

Prostate: normal

Images hosted on other servers:
Missing Image

CNS: glioblastoma & colon: carcinoma

Missing Image

Colon: normal

Missing Image Missing Image

Liver: left-normal, right-hepatocellular carcinoma

Missing Image Missing Image

Prostate: carcinoma

Missing Image

Skin (inflammatory), tonsil

Missing Image

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
Back to top
Image 01 Image 02