SLAMF1 and plasma cell myeloma: Elotuzumab, a humanized IgG1 monoclonal antibody (mAb) approved by the US Food and Drug Administration (FDA) in 2014 to be used with dexamethasone and lenalidomide against relapsed or refractory multiple myeloma (MM), has been recently discovered to depend on antibody-dependent cellular phagocytosis with macrophages over NK cellular activation by signaling lymphocytic activation molecule (SLAM)F7 interaction for high anti-tumor efficacy.48