Expression and significance of hypoxemia-inducible factor-1alpha in osteosarcoma of the jaws. The objective of this study was to examine the expression of hypoxia-inducible factor-1alpha (HIF-1alpha) in osteosarcoma of the jaw (OSJ) and its relationships with tumoral angiogenesis and clinicopathologic characteristics.Streptavidin peroxidase immunohistochemical staining was used to detect the expression of HIF-1alpha and CD34 in paraffin-embedded samples from 25 patients. There were 14 male and 11 female patients, ages ranged from 3 to 63 years.HIF-1alpha was overexpressed in OSJ. HIF-1alpha expression was correlated with tumoral microvascular density, as well as with the size, pathologic grade, and clinical stage of OSJ. Expression of HIF-1alpha was also correlated with clinicopathologic characteristics, such as primary occurrence or recurrence of the tumor, but not with metastasis.HIF-1alpha was significantly correlated with the size, pathologic grade, clinical stage, and primary occurrence or recurrence of the OSJ. HIF-1alpha appeared to promote tumoral angiogenesis in OSJ and may be an important target in antitumoral therapy.