SDF-1 exerts effects through its cognate receptor CXC chemokine receptor (CXCR4), which is the only physiological receptor for SDF-1 and is known to play roles in chemotaxis [11,12], haematopoiesis [13,14], vasculogenesis [15-17] and tumour spread and metastasis [6,18,19]. The gene discussed is CXCL12; the disease is neoplasm.