CCL2 and neoplasm: Hence, it has been reported that circulating monocytes subsets so-called classical inflammatory monocytes (moM1, CD14++/CD16-) and patrolling non-classical monocytes (moM3, CD14+/CD16++) exert opposite effects after their recruitment in tumor microenvironment via the chemokine (C-C motif) ligand 2 (CCL2), also referred to as monocyte chemoattractant protein 1 (MCP1) and small inducible cytokine A2, which is secreted by malignant cells.