Microsatelite GT Polymorphism in the Toll-like Receptor 2 is Associated with Colorectal Cancer

Factors underlying genetic predisposition for development of sporadic colorectal cancer are largely unknown. The fact that this cancer is more common in patients suffering from inflammatory bowel disease raises the question of the relationship between chronic inflammation and cancer. Toll-like receptors 2 (TLR2) and 4 (TLR4) are critical in initiating innate immune response and inflammation toward various bacteria commonly found in the intestine. Recent evidence about the association of polymorphisms in these genes with ulcerative colitis and Crohn's disease, as well as other inflammatory conditions, was the basis for our investigation of their role in sporadic colorectal cancer. We assessed genotype and allele frequencies of TLR2 GT microsatelite polymorphism, TLR2 Arg753Gln, TLR4 Asp299Gly and TLR4 Thr399Ile polymorphisms in 89 colorectal cancer patients and 88 age- and sex-matched controls. The frequency of TLR2 GT microsatelite alleles with 20 and 21 GT repeats was decreased (p = 0.0044 and p = 0.001, respectively), while the frequency of the allele with 31 GT repeats was increased (p = 0.0147) in patients. The mutant allele Asp299Gly of TLR4 gene was slightly more frequent in colorectal cancer patients (p = 0.0269). In conclusion, we report an association of microsatelite GT polymorphisms of TLR2 gene and Asp299Gly polymorphism of the TLR4 gene with sporadic colorectal cancer among Croatians.