CCL2 and neoplasm: Of note, many cytokines which activate the tumour microenvironment, including platelet-derived growth factor, B polypeptide (PDGFB), interleukin-6 (IL6), chemokine (C–C motif) ligand 2 (CCL2), and leukaemia inhibitory factor (LIF) were included as targets of TGF-β (Fig. 5d).