In addition, HIF-1α may control the expression of vascular endothelial growth factor (VEGF) and erythropoietin (EPO) genes, resulting in the promotion of tumor angiogenesis, as both stimulate endothelial cell proliferation and migration, and EPO alone promotes an increase in the proliferation and growth of various human neoplasias. This evidence concerns the gene HIF1A and neoplasm.