CCL4 and cancer: moM1 can be recruited to the tumor microenvironment where they can be transformed into tumor-associated macrophages (TAMs) that facilitate tumorigenesis by suppression of CD8+ T-cell function, recruitment of regulatory T (Treg) cells, angiogenesis, tumor cell intravasation, and metastasis [76], while moM3 display an anti-tumoral role, by directly engulfing cancer cells and by releasing CCL3, CCL4 and CCL5 chemokines, which in turn induce recruitment and activation of cytotoxic natural killer (NK) cells [52].