en Infectious Disease Infectious Disease Original Research Original Research <span style="font-size:13pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="text-autospace:none"><span new="" roman="" style="font-family:" times=""><span style="font-style:italic"><b><span style="font-size:9.0pt"><span style="font-style:normal">Background: </span></span></b><span style="font-size:9.0pt"><span style="font-style:normal">Colorectal cancer (CRC) represents 9% of all malignancies globally. TLR4 gene defenses against </span></span><span style="font-size:9.0pt">Helicobacter pylori</span><span style="font-size:9.0pt"><span style="font-style:normal"> infection (HPI), so its mutations are a risk factor for CRC. As there is a correlation between (HPI) and gastric cancer, we investigated whether there is an association between CagA virulence factor in HPI and D299G polymorphism of TLR4 gene with developing CRC among Iranians. </span></span></span></span></span></span></span></span><br> <span style="font-size:13pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="text-autospace:none"><span new="" roman="" style="font-family:" times=""><span style="font-style:italic"><span style="font-size:9.0pt"><span style="font-style:normal">&nbsp;&nbsp; <b>Methods:</b> This retrospective study included 85 biopsies of confirmed colorectal lesions out of 230 subjects, which were divided into two age groups. Single nucleotide polymorphism (SNP) D299G in the TLR4 gene was assessed using Tetra-primer ARMS-PCR. The expression of TLR4 and the CagA virulence factor in </span></span><span style="font-size:9.0pt">H.pylori</span><span style="font-size:9.0pt"><span style="font-style:normal"> was assessed using real-time PCR (RT-PCR). </span></span></span></span></span></span></span></span><br> <span style="font-size:13pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="text-autospace:none"><span new="" roman="" style="font-family:" times=""><span style="font-style:italic"><span style="font-size:9.0pt"><span style="font-style:normal">&nbsp;&nbsp; <b>Results:</b> Chi-squared test showed genotype frequencies of GG were 79% and 62%in patients 51> and 51<years, a="" allele="" and="" association="" between="" caga="" gg="" high="" logistic="" of="" positive="" presence="" regression="" respectively.="" showed="" the=""></years,></span><span style="font-size:9.0pt">p</span><span style="font-size:9.0pt"><span style="font-style:normal">=0.002). The odd ratio was predicted as 4.80 using the Hardy-Weinberg equilibrium assumption. Iranians with CagA and high GG of D299G were four times more likely to develop CRC than their peers with AA allele. </span></span></span></span></span></span></span></span><br> <span style="font-size:13pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="text-autospace:none"><span new="" roman="" style="font-family:" times=""><span style="font-style:italic"><span style="font-size:9.0pt"><span style="font-style:normal">&nbsp;&nbsp; <b>Conclusion:</b> </span></span><span style="font-size:9.0pt">H. pylori</span><span style="font-size:9.0pt"><span style="font-style:normal">-positive CagA has a higher ability to escape from the immune response. D299G polymorphism of TLR4 gene full of GG allele is an influential risk factor in developing CRC. Hence finding </span></span><span style="font-size:9.0pt">H. pylori</span><span style="font-size:9.0pt"><span style="font-style:normal">-positive CagA should be noticed as a marker of the TLR4 gene full of GG allele in screening plans. </span></span></span></span></span></span></span></span><br> <span style="font-size:13pt"><span style="text-justify:kashida"><span style="text-kashida:0%"><span style="text-autospace:none"><span new="" roman="" style="font-family:" times=""><span style="font-style:italic"><span style="font-size:9.0pt"><span style="font-style:normal"></span></span></span></span></span></span></span></span></span> H.pylori, Virulence Factor CagA, Toll-like Receptor4, Colorectal Cancer 720 725 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-7128-1&slc_lang=en&sid=1 Sama Malallah Ghayemia samaqayemi@gmail.com 200319475328460072665 200319475328460072665 No Department of Cellular and Molecular Biology, Faculty of Advanced ‎Science and Technology, Tehran Medical Sciences, Islamic Azad ‎University, Tehran, Iran Nahid Aboutaleb dr.nabotaleb@gmail.com 200319475328460072666 200319475328460072666 No Physiology Research Center, & Department of Physiology, School of Medicine, Iran University of ‎Medical Sciences, Tehran, Iran Ghazal Yousefi Ghazalyousefi94@gmail.com 200319475328460072667 200319475328460072667 No Department of Veterinary Medicine, Science and Research Branch, ‎Islamic Azad University, Tehran, Iran Neda Mousavi-Niri neda.mousaviniri@gmail.com 200319475328460072668 200319475328460072668 No Department of Biotechnology, Faculty of Advanced Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran Maryam Naseroleslami m.naseroleslami@iautmu.ac.ir 200319475328460072669 200319475328460072669 Yes Department of Cellular and Molecular Biology, Faculty of Advanced ‎Science and Technology, Tehran Medical Sciences, Islamic Azad ‎University, Tehran, Iran