CTLA4 and neoplasm: Significantly, the effect of anti-CTLA-4 depends on antibody-dependent cytotoxic activity (ADCC) to deplete CTLA-4-expressing Treg cells in the TME, and its deletion will abolish the anti-tumor effect of anti-CTLA-4 (Bulliard et al., 2013; Selby et al., 2013).