PTGS2 and neoplasm: Lipoteichoic acid (LTA) in gut microbiota collaboratively with DCA can upregulate the expression of senescence-associated secretory phenotype (SASP) and COX-2 through TLR2 in hepatic stellate cells, while COX-2-mediated prostaglandin E2 (PGE2) inhibits anti-tumor immunity through prostaglandin EP4 receptors 61.