CCL2 and neoplasm: For example, monocyte chemoattractant proteins, such as chemokine (C-C motif) ligand 2 (CCL2), secreted by many tumors mediate immunoinhibitory effects and facilitate tumor metastasis; blocking CCL2-CCR2 signalling by monoclonal antibodies has been shown to augment CD8+ T-cell-mediated responses elicited by immunotherapy and to inhibit metastatic seeding [34, 35].