It is well known that activated HIF-1 plays a crucial role in the adaptive responses of tumor cells to changes in oxygen partial pressure through activation of transcription of over 100 downstream genes, including the genes encoding VEGF, transforming growth factor-β (TGF-β), and erythropoietin (EPO) that are involved in angiogenesis and cell proliferation [25]. This evidence concerns the gene EPO and neoplasm.