Erythropoietin-producing hepatoma (Eph) receptor signalling consists of receptor tyrosine kinases that bind to membrane-anchored ligands, ephrins that influence cell behaviour attraction/repulsion, adhesion/de-adhesion in axon guidance, cell migration, angiogenesis and synaptic plasticity, and thus affect tumour growth, angiogenesis, and metastasis in cancer [43,44,45,46]. Here, EPO is linked to cancer.