Other studies investigated the expression of orphan receptors as well as known chemokine receptors and chemokine ligands in melanoma metastases, leading to the identification of several molecules differentially expressed in metastatic melanoma, such as GPR18, GPR34, GPR119, GPR160, GPR183, P2RY10, CCR5, CXCR4, CXCR6, CCL4, CCL5, CCL14/15, CXCL8, CXCL9, CXCL14, and XCL1/2 [5]. This evidence concerns the gene CCL4 and melanoma.