Stains & CD markers
CD117 / KIT

Topic Completed: 1 August 2013

Minor changes: 17 September 2021

Copyright: 2003-2022,, Inc.

PubMed Search: CD117[title]

See also Stains chapter

Nat Pernick, M.D.
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Cite this page: Pernick N. CD117. website. Accessed January 28th, 2022.
Definition / general
  • Summary: proto-oncogene activated in GIST tumors
  • Aka c-kit, KIT, stem cell factor receptor
  • Gene at 4q11-21
  • Receptor for kit protein, a 145 kD tyrosine kinase growth factor receptor protein important for development and survival of mast cells, hematopoietic stem cells, melanocytes, germ cells, interstitial cells of Cajal
  • Has activating or gain of function mutations in most GIST tumors, often at exon 11, less often at exons 9 and 13 (Hum Pathol 2002;33:484)
  • Tyrosine kinase activity of c-kit in GIST and bcl-abl overexpression in CML are inhibited by imatinib mesylate (Gleevec, STI571), a tyrosine kinase inhibitor used to treat these diseases (Hum Pathol 2002;33:466)
Uses by pathologists
  • Confirming diagnosis of GIST (but see other CD117+ tumors below)
  • Possibly confirm chronic intestinal pseudo-obstruction (Am J Surg Pathol 2003;27:228)
  • Should be strong and diffuse cytoplasmic staining, like the positive control
Microscopic (histologic) images

Contributed by Debra L. Zynger, M.D.

Seminoma with IHC



Contributed by Andrey Bychkov, M.D., Ph.D.


Positive staining - normal
  • Interstitial cells of Cajal, hematopoietic progenitor cells, melanocytes, embryonic/fetal brain, endothelium, gonads, mast cells, breast epithelium, germ cells
Positive staining - tumors
  • AML, angiomyolipoma (Am J Surg Pathol 2002;26:493), angiosarcomas (50%), clear cell sarcoma, CML, epithelioid sarcoma, Ewing sarcoma, gastrointestinal autonomic tumor (GANT), gastrointestinal stromal tumor (GIST), granulocytic sarcoma, Hodgkin lymphoma (some Reed-Sternberg cells), intraabdominal fibromatosis (depends on antibody used, Am J Surg Pathol 2001;25:549), mast cell disease (also positive for tryptase, CD43, CD68); melanoma, mesenteric fibromatosis (variable, Am J Surg Pathol 2002;26:1296), metanephric adenosarcoma (Am J Surg Pathol 2001;25:1451), omental mesenchymal tumor, osteosarcoma, rhabdomyosarcoma, sclerosing mesenteritis (variable), seminomas /dysgerminomas, small cell lung cancer (Hum Pathol 2002;33:1182), synovial sarcoma (~10%, usually cytoplasmic staining), adenoid cystic carcinoma of salivary gland (strong staining)
Negative staining
  • Alveolar soft part sarcoma, desmoplastic small round cell tumor, glomus tumor, leiomyoma (retroperitoneal, colorectal), leiomyosarcoma, myxoma (cardiac), schwannoma (colorectal), smooth muscle tumor of uncertain malignant potential, solitary fibrous tumor
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