EDITORIAL Is HIF-1 a Valid Therapeutic Target?

Hypoxia, a reduction in the normal level of tissue oxygen tension, occurs during several pathophysiological processes in-cluding tumorigenesis. It may occur during the initial avascular phase or develop in established tumors as a result of new blood vessel formation which is ineffective and provides poor blood flow. Although hypoxia generates a situation unfavorable for cell growth, cancer cells may undergo a series of genetic and metabolic changes that allow them to survive and even prolif-erate. Tumor hypoxia plays a major role in the induction of the “angiogenic switch ” during tumor development. Targeting the critical steps in tumor angiogenesis, including hypoxia-induced pathways, has become a focus for many basic research scientists and clinical investigators. Hypoxia is associated with poor treat-ment outcome regardless of the modality, suggesting that it should be considered in the development of optimum treatmen