Figure 1. CD47-SIRPα blockade in activating the “don’t eat me” signal and enhancing anti-tumor immunity. (A) The interaction between CD47, expressed on the surface of cancer cells, and SIRPα on macrophages sends a “don’t eat me” signal, inhibiting phagocytosis of the cancer cell by the macrophage. This binding of CD47 and SIRPα allows cancer cells to evade detection by macrophages, which perceive them as “self” and do not attack them. (B) Disrupting the CD47-SIRPα interaction between cancer cells and macrophages promotes phagocytosis. Treatment with either anti-CD47 or anti-SIRPα mAbs blocks the CD47-SIRPα interaction, leading to the activation of an “eat me” signal that enables macrophages to recognize cancer cells as non-self and initiates phagocytosis. Targeted therapies that disrupt the CD47-SIRPα interaction have the potential to improve the efficacy of cancer immunotherapy by enabling macrophages to overcome the “don’t eat me” signal and phagocytose cancer cells.