Like macrophages, following stimulation by tumor-derived cytokines including IL-1β, IFN-β, TGF-β, IL-8, and prostaglandin E2 (PGE2), TANs acquire the potential to be polarized to either the antitumor N1 (mainly IFN-β induced) or protumor N2 (mainly TGF-β induced) phenotype (Figure 3). This evidence concerns the gene CXCL8 and neoplasm.