CD47 and neoplasm: These inhibitors include 1) monoclonal antibodies (CD47 monoclonal antibody Hu5F9-G4, human IgG4 subclass; SIRPα monoclonal antibody FSI-189), which are mainly to block the anti-phagocytosis signal and reactive macrophages to attack and destroy tumor cells (65, 66); 2) recombinant fusion proteins (TTI-621, SIRPα-Fc fusion protein, human IgG1 subclass; TTI-622, SIRPα-Fc fusion protein, human IgG4 subclass), which are composed of the N-terminal V domain of human SIRPα and the human IgG Fc region.