Toll-like receptor 2 gene polymorphisms and cancer susceptibility: a meta-analysis.

To date, epidemiological studies have assessed the association between Toll-like receptor 2 (TLR2) gene polymorphisms and cancer risk. However, the results of these studies remain controversial. We aimed to examine the associations between three SNPs (Delta22, rs3804099 and rs3804100) of TLR2 gene and cancer risk by conducting a meta-analysis of case-control studies. A total of eight studies eligible for TLR2 Delta22 polymorphism (2,061 cancer cases and 3,490 controls), six studies for rs3804099 polymorphism (1,681 cases and 1,996 controls), and five studies for rs3804100 polymorphism (3,131 cases and 2,969 controls) were included in this meta-analysis. Our results suggested that Delta22 represented a risk factor on cancers (del-allele versus ins-allele, OR=1.35, 95% CI: 1.05-1.72; del/del versus ins/ins, OR=1.91, 95% CI: 1.03-3.56; del/del + del/ins versus ins/ins, OR=1.33, 95% CI: 1.02-1.73; del/del versus del/ins + ins/ins, OR=1.79, 95% CI: 1.02-3.13), especially in Caucasian population and among population-based studies. For TLR2 rs3804099 polymorphism, we found a decreased cancer risk associated with CC/CT genotype only in Asians compared with TT genotype. TLR2 rs3804100 polymorphism was significantly associated with an elevated cancer risk in overall analysis (CC versus CT, OR=1.70, 95% CI: 1.20-2.42; CC versus CT/TT, OR=1.61, 95% CI: 1.15-2.25). In a stratified analysis, a statistically significant correlation was also observed in non-Caucasian population and population-based studies. In conclusion, the Delta22 and rs3804100 polymorphisms in TLR2 are risk factors for cancer susceptibility while the TLR2 rs3804099 dominant genotype is a protective factor, especially in Asians. Further large and well-designed studies are needed to confirm these conclusions.