For instance, in the breast tumor region lacking blood vessels, tumor cells may release cytokines such as vascular endothelial growth factor (VEGF), IL-8, and TGF-β to attract macrophages due to hypoxia, thus enabling them to play a role in promoting angiogenesis in tumor tissue (Kuroda and Jamiyan 2021). This evidence concerns the gene CXCL8 and neoplasm.