EPO and neoplasm: In lung metastases, AN-to-tumor signals consisted of RESISTIN, IL-7 and EDA; tumor-to-AN signals consisted of CCL, RLN and AVP. In liver metastases, AN-outgoing ligands included complement genes (C4A) (Fig. 4c), EPO and CHEMERIN, and tumor-outgoing ligands included only GH. Moreover, splenic metastases featured both AN-to-tumor (ANGPT2) and tumor-to-AN (GH1 and AVP) axes.