Abstract
BACKGROUND: Toll-like receptors (TLRs) have garnered an extraordinary amount of interest in cancer research due to their role in tumor progression. By activating the production of several biological factors, TLRs induce type I interferons and other cytokines, which 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, 4, and 9 in prostate cancer. METHODS: The expression levels of TLR3, TLR4, and TLR9 were analyzed on tumors from 133 patients with prostate cancer. The analyses were performed by immunohistochemistry on tissue arrays and real time-PCR. RESULTS: Cancerous cells showed high expression levels of TLRs compared with controls. Samples of carcinomas with recurrence exhibited a significant increase in the mRNA levels of TLR3, TLR4, and TLR9. In addition, the tumors that showed high TLR3 or TLR9 expression levels were significantly associated with higher probability of biochemical recurrence. CONCLUSION: TLR expression is associated with prostate cancer with recurrence and the role of TLR receptors in the biology of malignancy merits study. Therapeutic strategies to boost or block TLRs may be of interest.