rHuEPO may have a close relationship to tumor cell metastasis to the peripheral blood through the formulation of new blood vessels and may prompt tumor stromal cells to secret cytokines that promote tumor cell migration and invasion, as implied by Ribatti et al. Human EA.hy926 endothelial cells express an EPO receptor that binds to JAK2 and induces its transient activation after rHuEPO exposure. This evidence concerns the gene JAK2 and neoplasm.