CD47 and neoplasm: However, knockout of signal-regulatory protein α (SIRPα)—regulator that inhibits phagocytosis of tumor cells via interacting with the self-recognition marker CD47 (the so-called ‘do not eat me’ signal)—resulted in infiltration of cytotoxic T cells, NK cells, and inflammatory neutrophils, therefore, enhancing radiotherapy efficiency and promoting tumor elimination [62].