It is possible that IL-18 levels may have an impact on tumor regression/growth as administration of low dose IL-18 in murine melanoma model promoted metastasis due to suppressed mature NK cell number, while high doses of IL-18 that resulted in IL-18 serum levels > 1 ng/mL inhibited tumor growth without a decrease in mature NK cell number (95). The gene discussed is IL18; the disease is melanoma.