Birner and coworkers analyzed 44 primary and 16 recurrent oligodendroglial neoplasms with 1p deletion or imbalance status for hypoxia-inducible factor 1α (HIF1α), CA IX, and vascular endothelial growth factor (VEGF), and based on the expression of all molecules a hypoxia score was established [60]. Here, CA9 is linked to oligodendroglial tumor.