In addition to suppressing T cell functions, MDSCs facilitate tumor progression through cell–cell contact with macrophages and inhibiting their IL-12 secretion [11], inhibiting NK cell-mediated cytotoxicity against tumors [12], and recruiting and inducing Foxp3+ T-regulatory (Treg) within the tumor microenvironment [13,14]. This evidence concerns the gene FOXP3 and neoplasm.