shHif-2α severely curtailed the expression of Hif-2αtranscript and protein (Figure 4) to nearly undetectable levels in Hu-glioma cells under hypoxia, while not significantly affecting Hif-1αConsistent with the hypothesis that Klf5 acts downstream of Hif-2α, knockdown of Hif-2αin Hu-glioma cells resulted in ≈70% reduced expression of Klf5 (Figure 4). This evidence concerns the gene EPAS1 and central nervous system cancer.