Previous studies have shown that a remarkable increase in Th2 cytokines (anti-inflammatory cytokines: IL-4, IL-5, IL-6, and IL-10), and simultaneous decrease of Th1 cytokines (pro-inflammatory cytokines: TNF-α, IFN-γ, and IL-2) are often present as a hallmark feature of the tumor microenvironment, including tumors such as hepatocellular carcinoma, non-small-cell lung carcinoma, and other types of cancer (40–44). Here, IL2 is linked to cancer.