Toll-like receptor 2 -196 to 174del polymorphism influences the susceptibility of Japanese people to gastric cancer

Toll like receptors (TLR) play important roles in the signaling of many pathogen-related molecules and endogenous proteins associated with immune activation. The -196 to -174del polymorphism affects the TLR2 gene and alters its promoter activity. We investigated the influence of the TLR2-196 to -174del polymorphism on the occurrence of non-cardiac gastric cancer (NCGC) in a Japanese population. The study was carried out with 289 patients with NCGC, 309 non-cancer patients with abdominal discomfort and 146 healthy controls. The -196 to -174del TLR2 polymorphism was investigated using the allele-specific polymerase chain reaction method in all of the subjects. The -196 to -174del/del genotype of TLR2 showed a significantly higher frequency in NCGC patients than in healthy controls (adjusted odds ratio [OR] = 6.06; 95% confidence interval [CI] = 1.86-19.72). Similarly, the frequency of the -196 to -174del/del genotype was significantly higher among NCGC patients than in non-cancer patients (adjusted OR = 2.02; 95% CI = 1.22-3.34). The same genotype was associated with an increased risk of both intestinal (OR = 2.00, 95% CI = 1.12-3.60) and diffuse-type (OR = 2.05; 95% CI = 1.11-3.79) histopathology. There were no significant associations between TLR2 genotypes and tumor stage and anatomical location. Our data suggest that the -196 to -174del/del genotype of TLR2 may increase the risk of gastric cancer in the Japanese population.