These studies have shown that in the tumor microenvironment, CXCL12/CXCR4 may foster local tumor growth and that high CXCR4 expressing tumor cells have a greater invasive and metastatic potential that may be blocked by CXCR4 antagonism [36,37,38,39,40,41]. The gene discussed is CXCR4; the disease is neoplasm.