The Ccl5ΔPE/ΔPE group exhibited a significant reduction in the number of metastatic lesions compared with the control Ccl5+/+ and Ccl5ΔDE/ΔDE groups, indicating that antimetastatic cancer immunity is enhanced by reduced homeostatic Ccl5 expression in host cells in the B16-F10 melanoma lung metastasis model. This evidence concerns the gene CCL5 and melanoma.