CXCR4 and atherosclerosis: Also researchers reported that stromal cell-derived factor 1 (stromal cell-derived factor-1, SDF-1) was upregulated upon platelet activation; SDF-1 and its receptor CXCR4 (CXC chemokine receptor 4) composed SDF-1/CXCR4 axis which is related to the formation of atherosclerosis; expression of SDF-1 is enhanced on platelet surface in atherosclerosis plaques [6–8].