[Tumor hypoxia: the role of HIF]

Solid tumors usually occur and progress in a hypoxic environment, suggesting that tumor cells are resistant to apoptosis and are associated to an increased angiogenesis, which makes them more aggressive, with invasive capacity and resistant to treatment. The genetic and biological mechanisms underlying this phenomenon are still unclear, but many studies suggest a role of HIF in this process. Under hypoxic conditions, the alpha subunit is not destroyed, and will activate transcription of a set of genes contributing to tumor aggressiveness. Its expression is associated to an increased metastatic potential that has been shown in both animal studies and human tumors. Tumor hypoxia has emerged as a key factor in tumor progression and is associated to a poor prognosis, particularly in kidney and prostate tumors. The purpose of this study was to review the significance of hypoxia in carcinogenesis and tumor progression by reviewing the current knowledge on the subject and the mechanisms of action and activation of HIF-1a Tumor hypoxia has emerged as a key factor in tumor progression and is associated to a poor prognosis, particularly in kidney and prostate tumors. The purpose of this study was to review the significance of hypoxia in carcinogenesis and tumor progression by reviewing the current knowledge on the subject and the mechanisms of action and activation of HIF-1a.