CD47 and cancer: CD47 belongs to the immunoglobulin superfamily and is expressed on the surface of various cancer cells, with SIRPα on macrophages serving as its ligand.[81] Cancer cells are thought to avoid being phagocytosed through expression CD47, thereby activating a “do not eat me” signaling pathway that enables immune escape for cancer cells.[82] Consequently, blocking the CD47–SIRPα inhibitory signal can promote macrophage phagocytosis of cancer cells.