CD47 and leukemia: The intracellular SIRPα region possesses typical immunoreceptor tyrosine‐based inhibitory motifs that are phosphorylated after ligation, resulting in cytosolic protein tyrosine phosphatase SHP‐1 and/or SHP‐2 recruitment and activation.1, 2, 3, 4 For certain cells (i.e., erythrocytes, platelets, or leukocytes), surface CD47 can protect against macrophage‐mediated phagocytosis by binding to the inhibitory macrophage receptor SIRPα.5, 6, 7 The interaction of SIRPα on macrophages with CD47 on leukemia and even solid tumor cells also prevents phagocytosis of such neoplastic cells.