Association between <em>TLR-9</em> polymorphisms and colon cancer susceptibility in Saudi Arabian female patients

Abstract

Objective: The authors aimed to explore the relationship between the expression/polymorphisms of TLR-9 and susceptibility to colon cancer development in the Saudi Arabian population. Methods: In total, blood samples from 115 patients with colon cancer and 102 participants without colon cancer were analyzed in this study. Three single-nucleotide polymorphisms (SNPs) were selected from the TLR-9 gene, including two sites within the TLR-9 gene’s promoter region (rs352144 and rs187084) and one site in a TLR-9 intron region (rs5743839). Odds ratios (ORs) and 95% confidence intervals (CIs) were computed from logistic regression models after adjusting for age, gender, and tumor localization. To investigate the differential expression of TLR-9 in colon cancer, TLR-9 expression was evaluated using quantitative real-time reverse transcription polymerase chain reaction on 40 matched normal and colon tissues. Results: The authors found that TLR-9 expression was decreased in colon cancer tissues as compared with that in normal tissues. Moreover, significant associations between the TLR-9 rs187084 SNP and colon cancer risk were observed in female patients only. In rs187084, the T allele had a significantly lower frequency (2.8 times) in female cancer patients than in controls (0.27 vs 0.41). The TLR-9 rs352139 and rs352144 SNPs were significantly associated with colon cancer development when the tumor was located in the rectal area. Conclusion: The findings support the hypothesis that TLR-9 has an anticancer role in colon cancer development. Furthermore, genetic variation may influence colon cancer development, and SNPs in TLR-9 could serve as biomarkers for decision making in the treatment of females with rectal cancer. Keywords: Innate, immunity, TLR polymorphisms, rs187084, rs352139, rs352144