Clinical Significance of Toll- like Receptor 3, 4, and 9 in Gastric Cancer

Toll-like receptors (TLRs) have raised an extraordinary interest in cancer research due to their role in tumor progression. By activating the production of several biological factors, TLRs drive an inflammatory response and activate the adaptive immune system. The aim of this study was to investigate the expression and clinical relevance of TLR3, TLR4, and TLR9 in gastric cancer. For this purpose, an immunohistochemical study on cancer specimens from 106 patients with gastric cancer was performed using tissue arrays and specific antibodies against TLR3, TLR4, and TLR9. The results indicate that gastric carcinomas samples show high expression of TLR3, TLR4, and TLR9 by cancer cells. The expression of TLR3 by cancer cells was significantly associated with a poor overall survival in patients with resectable tumors. Moreover, in patients with resectable tumors and lymph node invasion, a high TLR3 expression defines a population with even worse prognosis. Therefore, TLR3 may have clinical interest as indicator of tumor aggressiveness and as a prognostic indicator in gastric cancer.