CD47 and cancer: We and others have shown that CD47-SIRPα interactions negatively regulate antibody-mediated cytotoxicity by neutrophils both in vitro and in vivo for a number of cancers (i.e., Her2+-breast cancer, EGFR+-carcinoma), and that a blockade of the interaction substantially potentiates the cytotoxic capabilities of these effector cells [33,34,35].