The CXCL12/CXCR4 axis is important for activating a plethora of phenomena, including chemotaxis, invasion, tumorigenicity and angiogenesis and proliferation in cancer, particularly in the process of organ-selective metastasis (6,8,9), demonstrating that tumor cells expressing a high level of CXCR4 exhibit metastasis to target tissues (lung, liver and bone). The gene discussed is CXCL12; the disease is cancer.