IL6 and hepatocellular carcinoma: Regarding this, arachidonic acid metabolism and the overproduction of prostaglandin E2 (PGE2) in HCC have been shown to suppress antitumor immunity via the Prostaglandin E 2 receptor 4 (EP4) receptor on immune cells, inhibiting IFNγ and TNF-α while promoting IL-10 and IL-6 production [166].