EPA (Eicosapentaenoic acid, molecular formula C20H30O2) belongs to ω-3 polyunsaturated fatty acid (ω-3 PUFA). EPA is one of the main constituent of fish oil. EPA decreases LPS-stimulated macrophage production of TNF-α, IL-1β, IL-6, and human B lymphocytes production of IL-10, TNF-α, IFN-γ. EPA can suppress cancer induced lipolysis, and enhanced the inhibitory effect of 5-Fu over cancer cell proliferation. However, cancer patients are always lack of EPA.