Fc-Gamma Receptors (FcγRs) bind the Fc portion of antibodies and can impact ICI anti-tumor efficacy.<h4>Methods</h4>A pharmacokinetic study of human IgG1 (hIgG1) and hIgG1 with D265A (D265A) mutation, to abrogate all FcγR binding, was performed in mice that were either LLC tumor bearing (TB) or tumor free (TF). The gene discussed is FCGR2A; the disease is neoplasm.