Since the discovery of the CXCR4 chemokine receptor as one of the two principal co-receptors for HIV-1 entry in 1996 [10], CXCR4 has been a target of intensive biological, pharmaceutical and clinical research of its roles in not only HIV-1 infection but a growing number of pathologies and medical applications. The gene discussed is CXCR4; the disease is HIV-1 infection.