In response to hypoxia, HIF-1 binds a conserved DNA consensus sequence known as the hypoxia-responsive element (HRE) on promoters of genes encoding molecules controlling tumor angiogenesis, such as endothelin-1 (ET-1), VEGF, and erythropoietin, in different tumor cells [6], [15], [16]. This evidence concerns the gene HIF1A and neoplasm.