Elevated HIF-1α in glioma cells have been shown to cause an increase in the expression of VEGF and CXC chemokine ligand (Jain et al., 2007) both of which promote angiogenesis through different mechanisms, eventually leading to the formation of the malformed vessels, thus leading to a vicious cycle that promotes GB tumor growth and aggressiveness (Würth et al., 2014). This evidence concerns the gene HIF1A and glioma.