CD Markers

Editorial Board Member: Patricia Tsang, M.D., M.B.A.
Deputy Editor-in-Chief: Genevieve M. Crane, M.D., Ph.D.
Frido Bruehl, M.D.
Christian M. Schürch, M.D., Ph.D.

Last author update: 17 May 2023
Last staff update: 18 May 2023

Copyright: 2002-2023,, Inc.

PubMed Search: CD47[TI] review[PT]

Frido Bruehl, M.D.
Christian M. Schürch, M.D., Ph.D.
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Cite this page: Bruehl F, Schürch C. CD47. website. Accessed September 22nd, 2023.
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
  • Expressed in most tissues and primarily acts as a marker of self 
  • Overexpressed on solid tumors and hematolymphoid malignancies to evade immune control
  • Limited diagnostic utility but may be used as a prognostic or predictive marker in the future
Diagrams / tables

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

Proposed mechanism of action of CD47

Clinical features
  • 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
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 antiphagocytic molecule
  3. CD47 is a marker of activation
  4. CD47 is negative in mesothelioma
  5. CD47 is not expressed on red blood cells
Board review style answer #1
B. CD47 is antiphagocytic by binding SIRPα on effector immune cells. CD47 can be thought of as an innate immune checkpoint and marker of self. In contrast, 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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