Specific isotypes of anti-CTLA-4 (aCTLA-4) mAbs [immunoglobulin G2a (IgG2a)] mediate the depletion of tumor-resident Tregs (trTregs) via antibody-dependent cellular cytotoxicity, although other isotypes (IgG1) do not (4–6). This evidence concerns the gene CTLA4 and neoplasm.