For example, hypoxia, a characteristic feature of the tumor microenvironment, can upregulate integrin αvβ3, vascular endothelial growth factor (VEGF), and its receptor tyrosine kinase, vascular endothelial growth factor receptor (VEGFR), via the release of hypoxia inducible factor 1 (HIF1), eventually enhancing angiogenesis (Casali et al., 2022). This evidence concerns the gene KDR and neoplasm.