In vivo studies have demonstrated that the expression of the chemokine receptors CCR7, CCR10, CXCR3, and CXCR4 correlates with melanoma lymph node metastasis,27 which is regarded as an indication of tumour aggressiveness and is negatively associated with survival.29As such, it is generally assumed that chemokines predominantly favour tumour development in various ways (Figure 1). This evidence concerns the gene CXCR4 and melanoma.