TNF and hepatitis A virus infection: Although overexpression of IL-1β has been found to be associated with an increased risk of human gastric cancer (60–62), and although upregulation of cytokines have been found in gerbil gastric mucosae infected with H. pylori (Cxcl2, IL-1β, Nos2 and TNF) and in human hepatitis and ulcerative colitis (TGF-β, IL-10, TNFα, IL-1β, Nos2) (56,63,64), the mechanism by which cytokine signaling is able to produce epigenetic changes is not yet fully understood.