Since hypoxia leads to the activation of the transcription factor hypoxia-inducible factor (HIF)-1 via stabilization of its α-subunit, the aforementioned results are supported by a number of studies which have indicated a widespread expression of HIF-1α (11–15) and its target genes glucose transporter (GLUT)-1 (16) and carbonic anhydrase (CA) IX (16,17), in malignant astrocytomas. This evidence concerns the gene HIF1A and astrocytoma (excluding glioblastoma).