CD Markers
CD47


Minor changes: 16 June 2020

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PubMed Search: CD47[TI] review[PT]

Frido Bruehl, M.D.
Christian M. Schürch, M.D., Ph.D.
Page views in 2019: 308
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Cite this page: Bruehl F, Schürch C. CD47. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/cdmarkerscd47.html. Accessed July 7th, 2020.
Definition / general
  • CD47 is a ubiquitously expressed marker of self ("don't eat me" signal) and functions as an antiphagocytic molecule on the cell surface by binding the inhibitory molecule SIRPα on immune cells (e.g. macrophages) (Science 2000;288:2051)
Essential features
  • CD47 is expressed in most tissues and primarily acts as a marker of self 
  • CD47 is overexpressed on solid tumors and hematolymphoid malignancies to evade immune control
  • CD47 has limited diagnostic utility but may be used as a prognostic or predictive marker in the future
Terminology
Pathophysiology
Diagrams / tables

Contributed by Frido Bruehl, M.D.
Proposed mechanism of action of CD47

Proposed mechanism of action of CD47

Clinical features
Interpretation
  • Cell membrane staining
  • Cytoplasmic staining may also be observed but the significance of this finding is unclear
Uses by pathologists
  • Cytological diagnosis of body cavity effusions: a 2 marker panel of CD47 (high expression) and BRCA1 associated protein 1 (BAP1; loss) can discriminate diffuse malignant mesothelioma from reactive pleural effusions with a sensitivity of 78% and a specificity of 100% (Oncoimmunology 2017;7:e1373235)
Prognostic factors
Microscopic (histologic) images

Contributed by Christian M. Schürch, M.D., Ph.D.
Mesothelioma, cell block, CD47

Mesothelioma, cell block, CD47

Positive staining - normal
  • CD47 was first described in red blood cells and other hematopoietic cells (J Cell Biol 1990;111:2785)
  • CD47 is expressed in all tissue types based on mRNA studies and 4 splice variants with different tissue distribution are known (J Cell Sci 1995;108:3419)
Positive staining - disease
Negative staining
Sample pathology report
  • Pleural fluid, thoracentesis:
    • Positive for malignant cells, favor mesothelioma (see comment)
    • Comment: The cytology slide shows numerous three dimensional cell clusters and atypical single cells. Immunostains for calretinin, CK5/6, D2-40 and CD47 are positive. Immunostains for Ber-EP4, TTF1 and BAP1 are negative. The combined morphological and immunohistochemical features are consistent with an atypical mesothelial proliferation, favor malignant mesothelioma. Correlations with the clinical and imaging findings, as well as the patient history are necessary. A pleural biopsy may be valuable to further classify the disease process.
Board review style question #1

Which statement about CD47, calreticulin and SIRPα is true?

  1. Calreticulin is the dominant antiphagocytic protein
  2. CD47 is an innate immune checkpoint and binds SIRPα
  3. CD47 is a marker of activation
  4. CD47 is negative in mesothelioma
  5. CD47 is not expressed on red blood cells
Board review answer #1
B. CD47 is an innate immune checkpoint and binds SIRPα. CD47 can be thought of as an innate immune checkpoint and marker of self. Calreticulin is prophagocytic and its effect is controlled by the expression of CD47. Both molecules are highly expressed in mesothelioma and other cancer types. CD47 was first discovered in erythrocytes.

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Reference: CD47
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