Since CCR2+ monocytes are absent in the periphery of CCR2−/− mice (because they are retained in the bone marrow), we hypothesize that non-MDSC (Ly6C−) CCR2+ monocytes may suppress tumor growth in certain tumor models under basal conditions because these cells may directly attack tumor cells or present tumor antigens to T cells. Here, CCR2 is linked to neoplasm.