CXCL12 and myocardial infarction: Furthermore, the expression of SDF1 is upregulated following irradiation and hypoxia, and SDF1 can induce the recruitment of endothelial progenitor cells in a regeneration model for myocardial infarction (Ceradini et al. 2004).Thus, it is of interest to investigate the mechanism underlying stem cell recruitment to injured tissues by evaluating the level of SDF1 or the frequency of CXCR4-positive cells in various samples.