CCL4 and neoplasm: Tumour‐associated macrophages (TAMs) differentiate from monocyte precursors circulating in blood (Fig. 1B) and are recruited to tumour sites by several pro‐inflammatory molecules such as chemokines (C‐C motif chemokine ligand) CCL2, CCL3, CCL4, CCL5, and also VEGF, transforming growth factor‐β (TGF‐β) and colony‐stimulating factors (GM‐CSF and M‐CSF) 60.