We show that in both HC and MM patients NK cell cytotoxic activity performed against standard sensitive erythromyeloid K562 tumor target cell line after treatment with 10 ng/ml of IL-12 alone or in combination with IL-18 (100 ng/ml) is high significantly (p < 0.01, Wilcoxon signed rank test) enhanced, while after treatment with IL-18 alone is significantly (p < 0.05, Wilcoxon signed rank test) augmented only in HC compared to the results in CM. The gene discussed is IL18; the disease is neoplasm.