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. Author manuscript; available in PMC: 2008 Dec 1.
Published in final edited form as: Gastroenterology. 2007 Sep 14;133(6):1869–1881. doi: 10.1053/j.gastro.2007.09.008

Figure 6. Model of TLR4-mediated colon carcinogenesis.

Figure 6

TLR4 expression is increased in chronic intestinal inflammation. TLR4 signaling in response to LPS induces Cox-2 expression and PGE2 production. PGE2 through its receptors (EP) can act in a paracrine or autocrine fashion on colonocytes to stimulate the expression and release of amphiregulin, an EGFR ligand. EGFR signaling is associated with increased proliferation of colonocytes. Likewise, TLR4 expression in tumor-associated macrophages may also respond to LPS by inducing Cox-2 and PGE2, which may then act on the epithelium to stimulate proliferation of colonocytes.