Furthermore, among the activating FcγRs that incorporate the Fcer1-encoded subunits, Simpson et al showed that tumor rejection and Treg depletion requires engagement of activating FcγRIV,17 suggesting an obligatory interaction between the Fc portion of anti-CTLA-4 mAb and FcR on either neutrophils or macrophages. This evidence concerns the gene CTLA4 and neoplasm.