Myeloid malignancies are one of many cancer types that exploit the CD47-SIRPα pathway to suppress the immune response with a “don’t eat me” signal2

Select the labels on the diagram below to explore how CD47 overexpression may prevent macrophages from “eating” malignant cells through phagocytosis2

A graphic showing how CD47 overexpression prevents macrophages from “eating” malignant cells through phagocytosis.
1 2 3 4 5
A graphic showing how CD47 overexpression prevents macrophages from “eating” malignant cells through phagocytosis.
Macrophages are a key cell type in the innate immune system. They use phagocytosis to “eat” and eliminate cells that have been marked with prophagocytic “eat me” signals.1
2“eat me” signals
“Eat me” signals may be expressed when a cell is damaged through stress, DNA damage, or other mechanisms. Malignant cells widely express these signals.1
3malignant cell
While “eat me” signals mark them for elimination, malignant cells can override these signals and hide from macrophages by overexpressing the immune checkpoint protein CD47.1
4CD47 “don’t eat me” signals
After binding to SIRPα, CD47 activates “don’t eat me” signals that can override the “eat me” signals, preventing phagocytosis and allowing cancer to proliferate.1
5SIRPα receptors
SIRPα is the cognate receptor to CD47 that mainly exists on macrophages. When bound to CD47, it transmits the “don’t eat me” signal to the macrophage.1
Image adapted from reference.1

If CD47 signaling were diminished, could “eat me” signals on malignant cells potentially be revealed and lead to phagocytosis?1

Learn more Download information on the CD47 pathway and the immune response

CD47 overexpression has been demonstrated across myeloid malignancies and solid tumors, indicating that cancer cells may exploit the CD47-SIRPα pathway3

Research is exploring if a CD47 blockade could potentially restore phagocytosis and subsequently activate T-cells for a comprehensive immune response.2,3

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CD47, cluster of differentiation 47; PD-L1/PD-1, programmed death-ligand 1/programmed cell death 1 protein; SIRPα, signal-regulatory protein alpha.

References: 1. Chao MP, Takimoto CH, Feng DD, et al. Front Oncol. 2020;9:1380. doi:10.3389/fonc.2019.01380 2. Yang H, Xun Y, You H. Biomark Res. 2023;11(1):15. doi:10.1186/s40364-023-00456-x 3. Liu X, Kwon H, Li Z, et al. J Hematol Oncol. 2017;10(1):12. doi:10.1186/s13045-016-0381-z