Giovanna et al. found that PECAM-1 acts as a checkpoint molecule and can negatively regulate FcγR-mediated phagocytosis by monocytes and macrophages, and downregulation of PECAM-1 correlated with decreased survival of chronic lymphocytic leukemia cells (51, 52). The gene discussed is FCGR2A; the disease is B-cell chronic lymphocytic leukemia.