Association between HPV-related cervical neoplasia (CIN) grades and Toll-like receptor (TLR) 2 and 4 gene polymorphisms

Background: The purpose of this study was to determine the association of i) Human papilloma virus (HPV) types 16, 31 and 51 and ii) Single nucleotide polymorphisms (SNPs) in TLR2 (Arg753Gln) and TLR4 (Asp299Gly ; Thr399Ile) with various stages of CIN progression in HPV-positive women in north-east Croatia. Methods: During a four-year period, 98 HPV-positive women (77 with high-grade disease (CIN2/3) and 21 without CIN) were genotyped using the Linear Array HPV Genotyping assay (Roche Diagnostics). Furthermore, their TLR 2 and 4 SNPs were determined using real-time Polymerase Chain Reaction ; 43 HPV negative healthy women of similar ethnicity were included as controls. Results: This study showed that women with CIN2/3 had a higher prevalence of HPVs 16 and 31 (21.4% vs 12.5% and 8% vs 6.3%, respectively) but lower prevalence of HPV 51 (5.4% vs 12.5%) than HPV-positive women without CIN. Multiple HPV infections were detected more often in women with CIN2/3 than in HPV-positive women without CIN (p<0.02) and in HPV-positive women who did not use any contraceptive during the past year. Similarly, active tobacco smoking significantly associated with HPV-related CIN2/3 when compared to women without CIN (p<0.001). The analysis of TLR4 genotype showed that homozygous SNPs in Asp299 (Gly/Gly) and Thr399 (Ile/Ile) occurred more often in HPV-positive women with CIN2/3 and without CIN than in healthy controls (p<0.03 and p<0.02, respectively). To the contrary, TLR4 heterozygous variants Asp299Gly and Thr399Ile were less often in women with CIN2/3 than in healthy controls (p<0.002). Conclusion: To sum up, our results indicated that: i) HPV 16 and HPV 31, the most oncogenic HPVs, correlate with cervical dysplasia, ii) TLR4 homozygous gene polymorphisms in Asp299 (Gly/Gly) and Thr399 (Ile/Ile) correlate with more severe CIN grade and cervical cancer susceptibility. Further follow-up study will be helpful in understanding how TLR4 polymorphisms and immunological mechanisms might influence the susceptibility to HPV infection and neoplasia progression, two critical steps in HPV-induced carcinogenesis.