SIRPA and neoplasm: It’s possible that relieving the function of other immune cells by blocking immune checkpoints (PD-L1, PD-L2, B7-H4, VISTA, B7–1, and B7–2) on macrophages may be beneficial.368 Interactions between CD47 on tumors and SIRP on macrophages, eliminating the macrophage blockade, assist tumor cells in evading phagocytosis.369 Antibodies directed against CD47 or SIRP could be able to clear the obstruction.