Extensive hypoxia in intracranial gliomas derived from transformed human astrocytes overexpressing integrin 3. Normal human astrocytes expressing E6/E7, hTERT, mutant H-Ras, and integrin 3 were intracra-nially injected into immunodeficient mice and allowed to form tumors. Following pimonidazol perfusion, the extent of tumor hypoxia was exam-ined by immunohistochemical detection of hypoxia-mediated pimonidazol adducts (green fluorescence). 3 overexpressing tumors showed signif-cantly more hypoxia than tumors derived from cells not overexpressing integrin 3. Increased hypoxia was coupled with decreased vessel diame-ter, loss of endothelial cell-associated pericytes, and growth suppression, suggesting that rather than promoting glioma growth, 3 and V-3 integrin complexes, in the appropriate genetic context, have the potential to alter glioma vasculature formation and suppress gliomagenesis. For details, see the article by Kanamori et al.. on page 2751 of this issue.