In a previous clinical study, increased expression of specific cardiac markers (Nkx2-5, gata-4, and mef2c) in PBMNCs, and increased number of CD34+/CXCR4+ and CD34+/CD117+ stem cells in PB were observed in ST-elevated MI patients compared to patients with stable angina and healthy Controls[51]. Here, CXCR4 is linked to angina pectoris.