CCR4 and melanoma: CXCL10 is primarily induced by IFN-γ in monocytes, endothelial cells and fibroblasts.5 Its cognate receptor, CXCR3, is expressed by activated T cells and NK cells6,7 but may also be expressed by melanoma cells.8,9 CCR4 interacts with CCL2, CCL4 and CCL5, while CCR5 interacts with CCL4 and CCL5.