CXCL12 signals through CXCR4 and CXCR7 receptors upregulated on cancer cells [17], and activates multiple molecular pathways such as the mitogen-activated protein kinase (MAPK), inositol 1,4,5-triphosphate (IP3), and phosphoinositide 3-kinase (PI3K) [18]. This evidence concerns the gene CXCR4 and cancer.