Other chemokine ligands important during the metastatic process include the CXCR3 ligand CXCL10 (in melanoma and colorectal cancer) (148, 149), the CXCR4 ligand CXCL12 (in multiple types of cancer) (150, 151) and CCL1 (in melanoma) (152). This evidence concerns the gene CXCL12 and cancer.