Attraction of NK cells is mediated by chemokines, such as CCL5 (or RANTES, binding CCR5), CCL19 and CCL21 (binding CCR7), CXCL10 (binding CXCR3) and CXCL12 (binding CXCR4) that are secreted by other immune cells or the tumor itself [30]. This evidence concerns the gene CCL5 and neoplasm.