IL18 and melanoma: Imanaka et al. [27] discovered that after daily oral administration of β-sitosterol for 7 days, the number of metastatic colonies in the lungs of B16BL6 melanoma cells was prominently less than that of the control group, which might be the result of enhanced immune surveillance activity evidenced by the increase of NK cells and immune response cytokines such as IL-12 and IL-18.