The activation of NF-κB plays a critical role in cancer cell survival, especially melanoma cancer cells and in CCR5 expression. To evaluate whether the tumor inhibition was related with the inactivation of NF-κB in melanoma, the DNA binding activity of NF-κB was determined by electromobility shift assay (EMSA) in melanoma tissue. The constitutively activated DNA binding activity was reduced in the CCR5−/− mice tumor tissue (Figure 2A). Moreover, the translocation of p50 and p-p65 into the nucleus through the inhibition of phosphorylation of IκB was also prevented in the tumor tissues of CCR5−/− mice (Figure 2B). Immunofluorescence analysis also confirmed that the intensity of nuclear staining for p50 had decreased in the tumor tissues of CCR5−/− mice (Figure 2C).