TLR-2 gene polymorphisms and susceptibility to cancer: evidence from meta-analysis.

The ability to respond properly to Toll-like receptor (TLR) ligands may be impaired by polymorphisms within the TLR family of genes, which results in an altered susceptibility to cancers. However, the results of epidemiological studies remained inconsistent. To assess the effect of four selected polymorphisms (rs5743708, -196 to -174 del polymorphism, rs3804099, and rs3804100) in TLR-2 on cancer, we conducted a meta-analysis, up to November 2012; 20 case-control studies were available. Summary odds ratios (OR) and corresponding 95% confidence intervals (CIs) for polymorphisms in TLR-2 and cancer risk were estimated. Our meta-analysis identified that elevated cancer risk was statistically associated with -196 to -174 del allele in -196 to -174 del polymorphism (OR=1.63, 95% CI=1.10-2.41 for allele comparison; OR=1.64, 95% CI=1.05-2.57 for dominant model; OR=2.26, 95% CI=1.24-4.12 for recessive model; OR=2.57, 95% CI=1.30-5.08 for DD vs. II and OR=1.53, 95% CI=1.01-2.32 for ID vs. II in codominant model); whereas rs3804099 in TLR-2 was associated with decreased cancer risk. Moreover, in terms of stratified analyses by cancer type for -196 to -174 del polymorphism, significantly elevated risk was observed to be associated with -196 to -174 del allele in "other cancers." These findings indicate that polymorphisms in TLR-2 may play a role, although modest, in cancer development.