Coupling of stromal cell derived factor 1 (SDF-1; CXCL12) with its receptor CXCR4, which was previously identified as a major coreceptor for the entry of T-tropic HIV [1], [2], [3], [4], plays critical roles in inflammation [5], as well as cancer metastasis [6]. The gene discussed is CXCR4; the disease is cancer.