On the one hand, M2 macrophages residing in the TME manifest “iron-donor” phenotype with high expression of ferroportin, and can act as one important iron source to promote cancer cell proliferation in iron-dependent manner62.Moreover, LCN2 derived from the TAM enhances cancer cells uptake of iron in TF-TFR1-independent manner and stimulate cancer cell growth34. Here, SLC40A1 is linked to cancer.