Thisreview describes the roles of CXCL12 and CXCR4 in normal tissue functions andin cancer, and suggests that the regulation of CXCR4 expression by PPARγ mayemerge to be a unique avenue by which a key receptor involved in cancer cellmetastasis can be suppressed in a way that will assist with disease therapy. The gene discussed is CXCR4; the disease is cancer.