EPO and hepatocellular carcinoma: HCC cells induce the proliferation of vessel endothelial cell via two approaches: one was secreting some cytokines such as VEGF-family, FGF-family, angiopoietin-2, EGF, CSFs, angiogenin, CXC chemokines with ELR motif, insulin-like growth factor- (IGF-) 1, erythropoietin, and interleukin- (IL-) 8.