Association between Toll-like receptor 3 polymorphisms and cancer risk: a meta-analysis

Toll-like receptors (TLRs) are well known as molecular sensors of pathogen-associated molecular patterns. They control activation of the innate immune response and subsequently shape the adaptive immune response. Polymorphisms in TLR3 gene associated with cancer have been studied extensively. However, the results remain controversial. A literature search was performed among PubMed, Embase, Web of Science, Science Direct, Wanfang, and Chinese National Knowledge Infrastructure databases to identify eligible studies on the association between TLR3 polymorphisms and cancer risk. A total of 12 studies in 11 articles were included in the meta-analysis including 5,861 cases and 6,339 controls. Significant associations with cancer risk were observed for single nucleotide polymorphisms (SNPs) rs3775291 (allele model: odds ratio (OR) = 1.12, 95 % confidence interval (95 % CI) = 1.00-1.25, P = 0.04), rs3775290 (allele model: OR = 1.12, 95 % CI = 1.00-1.25, P = 0.04; dominant model: OR = 1.30, 95 % CI = 1.05-1.60, P = 0.01; homozygous comparison: OR = 1.68, 95 % CI = 1.06-2.68, P = 0.03; heterozygous comparison: OR = 1.25, 95 % CI = 1.01-1.55, P = 0.04), rs5743305 (allele model: OR = 1.07, 95 % CI = 1.01-1.15, P = 0.03; dominant model: OR = 1.11, 95 % CI = 1.01-1.22, P = 0.03), and rs5743312 (allele model: OR = 1.13, 95 % CI = 1.01-1.27, P = 0.03; recessive model: OR = 1.86, 95 % CI = 1.31-2.63, P < 0.01; homozygous comparison: OR = 1.88, 95 % CI = 1.33-2.67, P < 0.01), respectively. Meanwhile, we did not find any significant association with cancer risk for rs7657186 and rs7668666. In conclusion, this meta-analysis indicates a significant association of four TLR3 gene polymorphisms with cancer risk. However, because the study size was limited, further studies are essential to confirm our results.