Evaluation of the detection of Toll-like receptors (TLRs) in cancer development and progression in patients with colorectal cancer

<div><p>Background</p><p>Toll-like receptors (TLRs) play essential role in innate and acquired immunity, are expressed in various cell types, and are associated with altered susceptibility to many diseases, and cancers. The aim of this study was to investigate <i>TLR2</i> (-196 to-174<i>del</i>), <i>TLR4</i> (Asp299Gly and Thr399Ile) and <i>TLR9</i> (T1237C and T1486C) gene polymorphisms at risk of colorectal cancer (CRC) development and progression.</p><p>Methods</p><p>Peripheral blood was obtained from 397 patients with adjuvant (stage II/III, n = 202) and metastatic (n = 195) CRC. Moreover, blood samples from 50 healthy volunteers and 40 patients with adenomatous polyps were also included as control groups. DNA from patients and controls was analyzed using PCR and PCR-RFLP for genotyping functional polymorphism within <i>TLR2</i>, <i>TLR4</i> and <i>TLR9</i> genotypes.</p><p>Results</p><p><i>TLR2–</i>196 to-174<i>del</i>/<i>del</i> genotype was detected in 76.6% of the patients and was significantly higher that the controls groups (<i>p</i><0.001). <i>TLR4</i> Asp299Gly, <i>TLR4</i> Thr399Ile, <i>TLR9 T1237C</i> and <i>T1486C</i> homozygous genotypes were detected in 70.5%, 70.5%, 61.5% and 61.5% of the patients respectively, and were also significantly higher than that in the control groups (<i>p</i><0.001). All polymorphisms detected were also significantly associated with the metastatic disease (<i>p</i><0.001) leading to shorter overall survival (<i>p</i><0.001); whereas, <i>TLR4</i> Asp299Gly and Thr399Ile polymorphisms were significantly associated with <i>KRAS</i> mutations.</p><p>Conclusions</p><p>The detection of higher frequencies of the <i>TLR2</i>, <i>TLR4</i> and/or <i>TLR9</i> polymorphisms in CRC patients compared with the control groups highlight the role of these polymorphism in CRC development and cancer progression.</p></div

Representative agarose gels showing PCR-RFLP analysis of different single nucleotide polymorphisms of the a) TLR2–196 to 174 del, b) TLR4 Asp299Gly, c) TLR4 Thr399Ile, d) TLR9 T1276C and e)TLR4 T1486C, respectively.

<p>Representative agarose gels showing PCR-RFLP analysis of different single nucleotide polymorphisms of the a) TLR2–196 to 174 del, b) TLR4 Asp299Gly, c) TLR4 Thr399Ile, d) TLR9 T1276C and e)TLR4 T1486C, respectively.</p

Patients’ demographics and tumor’s characteristics.

<p>Patients’ demographics and tumor’s characteristics.</p

Overall survival according to the detection of a) TLR2–196 to -174 del, b) TLR4 Asp299Gly (A/G), c) TLR4 Thr399Ile (T/C), d) TLR9 T1276C and e) TLR4 T1486C, respectively.

<p>Overall survival according to the detection of a) TLR2–196 to -174 del, b) TLR4 Asp299Gly (A/G), c) TLR4 Thr399Ile (T/C), d) TLR9 T1276C and e) TLR4 T1486C, respectively.</p

Association of TLR2, TLR4 and TLR9 variants and patients’ disease stage.

<p>Association of TLR2, TLR4 and TLR9 variants and patients’ disease stage.</p