CD4 and cancer: Specifically, the pro-inflammatory chemokine CXCL12 and its receptor CXCR4 and CXCR7 was shown to play a major role in cancer progression [80]; however, this chemokine also induces CD4+ T cell activation and regulates the trafficking of inflammatory cells (neutrophils, leukocytes, B-lymphocytes) and apoptosis to sites of inflammation [81, 82].