CD47 and plasma cell myeloma: Mice lacking SLAMF7 show restricted growth of tumors.50 In addition, macrophages selectively phagocytose hematopoietic tumor cells in response to SIRPα–CD47 checkpoint blockade in a SLAMF7-dependent manner.51 In multiple myeloma, SLAMF7 is highly expressed on multiple myeloma cells but has limited expression in a subset of hematopoietic cells among normal tissues, making it a rational target for cancer therapy.52 The SLAMF7 antibody elotuzumab has been approved for the treatment of patients with multiple myeloma.