Tumor-associated M2 macrophages and CD4+ CD25+FoxP3+ regulatory T-cells (Tregs) suppress anti-tumor immune responses through secretion of immunosuppressive cytokines IL-10 and TGFβ, and presentation of CTLA4 on T cells and PD-L1 on macrophages28–33. Here, CTLA4 is linked to neoplasm.