Stains & CD markers
CD117 / KIT


Last author update: 9 June 2022
Last staff update: 9 June 2022

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PubMed Search: CD117 / KIT

See Also: Stains chapter

Leonie Frauenfeld, M.D.
Christian M. Schürch, M.D., Ph.D.
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Cite this page: Frauenfeld L, Schürch CM. CD117. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/cdmarkerscd117.html. Accessed August 10th, 2022.
Definition / general
Essential features
  • Proto-oncogene activated in GISTs (Cureus 2022;14:e20868)
  • Gene at 4q11-21
  • Class III receptor tyrosine kinase
  • Highlights mast cells (normal and abnormal) in the assessment of mast cell neoplasms
Terminology
Pathophysiology
  • Has activating or gain of function mutations in most GISTs, often at exon 11, less often at exons 9 and 13 (Hum Pathol 2002;33:484, Cancer Med 2020;9:6485, Cureus 2022;14:e20868)
  • Tyrosine kinase activity of c-kit in GIST and BCR-ABL overexpression in chronic myeloid leukemia (CML) are inhibited by imatinib mesylate (Gleevec, STI571), a tyrosine kinase inhibitor used to treat these diseases (Clin Cancer Res 2022;28:1672)
  • Mutated in mastocytosis, typically the D816V mutation
Interpretation
  • Cytoplasmic staining
Uses by pathologists
  • Confirming diagnosis of GIST (also see Positive staining - disease) (Cureus 2022;14:e20868)
  • Staining of mast cells
  • Staining of myeloid stem cells (myelodysplastic syndrome [MDS], acute myeloid leukemia [AML]: estimating quantity of blasts)
Microscopic (histologic) images

Contributed by Debra L. Zynger, M.D. and Andrey Bychkov, M.D., Ph.D.
Seminoma with IHC CD117

Seminoma with IHC

Testis

Testis

GIST

GIST

Positive staining - normal
Positive staining - disease
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 (Am J Surg Pathol 2002;26:486)
Sample pathology report
  • Gastric biopsy:
    • Gastrointestinal stromal tumor (see comment)
    • Comment: Infiltrates of a well circumscribed spindle cell tumor with few mitoses (2 / 5 mm2). Immunohistochemically, the tumor is CD117+, DOG1+ and CD34+.
Board review style question #1

Which of the following is the most likely underlying mutation in this gastrointestinal stromal tumor (staining with the associated protein for this mutation)?

  1. ALK
  2. KIT
  3. PDGFRA
  4. PDGFRB
  5. SDHB
Board review style answer #1
B. KIT

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Reference: CD117
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