EGFR and neoplasm: Indeed, FcγRIIa was reported to be involved in the myeloid effector cell-mediated cytotoxicity by panitumumab, a human IgG2 mAb against EGFR.[27] Therefore, it is important to evaluate the mAb-dependent activation of FcγRIIa as well as that of FcγRIIIa in the development of tumor-targeting therapeutic mAbs of both the IgG1 and IgG2 subclasses.