SIRPA and cancer: CD47 (integrin associated protein (IAP), MER6, OA3) is expressed on normal tissue cells, cancer cells, and immune cells.135,136 It primarily exerts innate immune inhibitory effects through the signal-regulatory protein (SIRP) family proteins, especially SIRPα and SIRPγ expressed on myeloid cells137–141 to inhibit phagocytosis signals (Fig. 2).