FCGR2B and neoplasm: Although Fc engineering can enhance FcγRIIB interaction and improve activity (Li and Ravetch, 2012, 2013; White et al., 2013), this approach is limited by the fact that FcγRIIB may not always be available for crosslinking within the tumor microenvironment and may also result in adverse events when FcγRIIB is engaged on endothelial cells (Xu et al., 2003).