Abstract
Chronic hepatitis C virus (HCV) infection is a major risk factor for hepatocellular carcinoma (HCC). HCV proteins core and NS3 can bind to toll‐like receptor 2 (TLR2) and trigger inflammatory responses. Polymorphisms in the TLR2 gene predispose to various forms of malignancy but have not been studied in HCV‐associated HCC. Here, we investigated whether single nucleotide polymorphisms (SNPs), rs4696480, rs5743708, rs5743704 and the ‐196 to ‐174 del/ins polymorphism of the TLR2 gene affect the risk for HCC in chronic hepatitis C. The study involved 189 and 192 HCV genotype 1 infected patients with and without HCC, respectively, as well as 347 healthy controls. TLR2 alleles were determined by hybridization probe assays and allele‐specific short fragment polymerase chain reaction on a LightCycler system. All TLR2 polymorphisms matched the Hardy–Weinberg equilibrium in each study group. Although TLR2 SNPs showed no effect, the frequency of the TLR2 ‐196 to ‐174 del allele was significantly higher in patients with HCV‐associated HCC (22.5%) than in HCV‐infected patients without HCC (15.6%, p = 0.016) and healthy controls (15.3%, p = 0.003). HCV‐infected carriers of a TLR2 ‐196 to ‐174 del allele had significantly higher HCV viral loads than TLR2 ‐196 to ‐174 ins/ins homozygous patients (p = 0.031). Finally, in carriers of the TLR2 ‐196 to ‐174 del allele, stimulation of monocytes resulted in significantly lower TLR2 expression levels and interleukin‐8 (IL‐8) induction than in individuals with the TLR2 ‐196 to ‐174 ins/ins genotype (p < 0.05). Our data suggest the TLR2 ‐196 to ‐174 del allele to affect HCV viral loads and to increase the risk for HCC in HCV genotype1‐infected patients.