Single-nucleotide Polymorphisms in Genes Encoding Toll-like Receptor -2, -3, -4, and -9 in a Case–Control Study with Bladder Cancer Susceptibility in a North Indian Population

Abstract

Impairment of the immune system may contribute to the risk for having cancer as Toll-like receptors are important for innate immunity. We examined the association between candidate disease-susceptibility polymorphisms in the single nucleotide polymorphism (SNPs) like TLR2 (-196 to-174del), TLR3 (C1377T), TLR4 (Thr399Ile) and TLR9 (G2848A) genes in patients with bladder cancer in a North Indian population. SNPs were comprised of TLR2 (-196 to -174 Del), TLR3(C1377T), TLR4 (Thr399Ile) and TLR9 (G2848A) genes. Allelic and genotypic frequencies of these TLRs SNP from histopathologically confirmed patients of bladder cancer (n = 200) and unrelated healthy controls of similar ethnicity (n = 200) were genotyped by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis. In TLR2 I/D gene polymorphism, the combination of ID+DD showed a significant 3-fold increased risk (p = 0.001). TLR2 with heterozygous genotype ID showed a 3-fold risk and combination of heterozygous and variant genotype (ID+DD) also showed a 5-fold risk with tumor stage/grade of patients with bladder cancer. The other genotypes of TLR3, 4 and 9 did not exhibit any significant association with bladder cancer risk. Our results suggested the involvement of TLR2 (-196 to-174 del) in bladder cancer susceptibility; however, TLR3, 4 and 9 genes were not associated with risk of bladder cancer, implicating that polymorphisms in these tested TLRs genes are not likely to be associated with increased risk for developing bladder cancer. Functional studies in ethnically diverse populations may provide a more comprehensive involvement of innate immunity in identifying the disease-associated variants for the etiology of bladder cancer.