CD276 and neoplasm: developed MGA271, a B7-H3-reactive, Fc-engineered mAb that mediates potent antitumor activity in vitro and in tumor xenografts; this characteristic, together with the favorable safety profile of MGA271 in cynomolgus monkey toxicology studies, supports its exploration in the treatment of B7-H3-positive cancers (79) (Figure 4).