ELR+ CXCLs, including CXCL1-3, CXCL5-8, and CXCL17, bind to CXC chemokine receptor 2 (CXCR2) to promote endothelial cell survival and tumor angiogenesis, whereas most ELR− CXCLs, including CXCL4, CXCL9-11, and CXCL16, bind to CXCR3 to inhibit endothelial cell proliferation and angiogenesis [6]. This evidence concerns the gene CXCR2 and neoplasm.