TITLE:
Toll-Like Receptors as Biomarkers of Gastric Carcinogenesis: Implications for Diagnosis, Prognosis and Treatment
AUTHORS:
Pedro Pimentel-Nunes, João Bruno Soares, Mário Dinis-Ribeiro
KEYWORDS:
Toll-Like Receptors; Gastric Cancer; TOLLIP; Carcinogenesis; Helicobacter pylori
JOURNAL NAME:
Journal of Cancer Therapy,
Vol.4 No.5,
July
9,
2013
ABSTRACT: Toll-like receptors (TLR) are essential for Helicobacter pylori (Hp) recognition and subsequent innate and adaptive immunity responses. TLR2 appears to be the receptor responsible for most of the immunologic reaction against Hp infection. However, TLR4, TLR9 and eventually TLR5 may also have a synergic effect with TLR2 against Hp. It has been shown that gastric Hp infection increases TLR expression in the gastric mucosa. Moreover, recent studies have shown that human gastric carcinogenesis is associated not only with increased expression of TLR but also with decreased expression of their inhibitors such as Toll-Interacting Protein (TOLLIP) and peroxisome proliferator-activated receptor (PPAR)-g. Indeed, gastric dysplasia and adenocarcinoma are associated with high expression levels of TLR and low levels of TOLLIP and PPAR-g, suggesting increased activation of these receptors throughout human gastric carcinogenesis. In this article we discuss how these novels findings could be used not only for the diagnosis and prognosis of gastric lesions associated with Hp infection but also for their treatment. Specifically, we discuss the potential use of TLR agonists in addition to antibiotics to improve eradication rates of Hp and of TLR antagonists to slow the progression of gastric preneoplastic lesions. We also discuss the potential value of TLR signalling blockers and quantification of tumoral TLR expression, respectively, in the treatment and prognosis of gastric cancer. In conclusion, TLRs can be an important link between Hp and the sequence of gastric carcinogenesis and they can be used as biomarkers of gastric carcinogenesis. In this article, future lines of investigation related with these novel scientific findings are proposed and discussed.