CXCL12 and metastatic melanoma: Among the CXCL chemokines, CXCL-12/SDF-1 was previously associated with the rejection of metastatic melanoma during IL-2 therapy [31] and together with CXCL-9 through -11 chemokines in association with the rejection of basal cell carcinomas (BCCs) treated with TLR7 agonists [32].