CXCR2 and neoplasm: CXCR2 ligands can increase the count of MDSCs [7,8,58,123,124] and Treg cells [112,115] in the tumor microenvironment, cells which are responsible for tumor immune evasion [67,68] and can indirectly contribute to reducing the infiltration by DCs and other cytotoxic cells, such as NK cells and CD8+ T cells.