CD47 and cancer: Cancer cells can evade macrophage-mediated phagocytosis by upregulating cell-surface expression of “don’t eat me signals”, such as CD47, PD-L1, β2M, and CD24, which bind to the phagocytosis-inhibiting receptors SIRPα, PD-1, LILRB1 and Siglec-10, respectively1,3–6.