SIRPA and neoplasm: Antibodies targeting the CD47/SIRPα axis induce enhanced macrophage phagocytosis of tumor cells.14 16 17 Moreover, targeting the CD47/SIRPα axis suppresses tumor growth in vivo, or synergizes with tumor-targeting monoclonal antibodies, as well as immune checkpoint inhibitors.18–21 Numerous CD47/SIRPα blocking agents have been explored and are currently being evaluated in clinical trials, including anti-CD47 antibodies, anti-SIRPα antibodies and SIRPα-Fc fusion proteins.