Genetic polymorphisms in host innate immune sensor genes and the risk of nasopharyngeal carcinoma in North Africa

Toll-Like receptor 3 genetic polymorphism in dengue encephalitis

CONTEXT

Dengue is one of the important vector-borne viral diseases affecting humans with diverse manifestations. Toll-like receptors (TLR) are pattern recognition receptors and play an important role in innate immunity against microbes. TLR3 plays a critical role in controlling the innate immune response mediated by flaviviruses such as dengue.

AIM

We attempted to study the susceptibility of single nucleotide polymorphism of the TLR3 gene in dengue encephalitis (DE) patients and determine the association in terms of genotype, allele, and haplotype distribution along with the clinical outcome.

SETTINGS AND DESIGN

It was a case-controlled observational study in a tertiary care hospital.

METHODS AND MATERIAL

We investigated the single nucleotide polymorphism in the TLR3 Leu412Phe gene using real-time polymerase chain reaction in 29 cases of DE and compared them with equal number of age- and sex-matched dengue patients without neurological features.

STATISTICAL ANALYSIS USED

The genotype and allele frequencies were compared using a two-sided Chi-square or Fisher's exact test.

RESULTS

The findings revealed that the genotypic distribution of TLR3 Leu412Phe polymorphism for the mutant genotype Phe/Phe (TT) demonstrated increased association of DE (31.03% vs 6.8%, P 0.019, odds ratio 6.075, 95% confidence interval 1.181-31.245). However, the number of heterozygous (H) genotype (Leu/Phe-CT) and mutant Phe allele (T) did not show any statistically significant association. TLR3 gene polymorphism did not show any correlation with mortality outcome at 1 month.

CONCLUSION

The presence of mutant TLR3 Leu412Phe polymorphism may confer the propensity to have DE in patients with dengue infection in the Indian population. TLR3 polymorphism did not affect mortality outcome at 1 month.

Colorectal cancer-specific IFNβ delivery overcomes dysfunctional dsRNA-mediated type I interferon signaling to increase the abscopal effect of radiotherapy

BACKGROUND

Cancer-intrinsic type I interferon (IFN-I) production triggered by radiotherapy (RT) is mainly dependent on cytosolic double-stranded DNA (dsDNA)-mediated cGAS/STING signaling and increases cancer immunogenicity and enhances the antitumor immune response to increase therapeutic efficacy. However, cGAS/STING deficiency in colorectal cancer (CRC) may suppress the RT-induced antitumor immunity. Therefore, we aimed to evaluate the importance of the dsRNA-mediated antitumor immune response induced by RT in patients with CRC.

METHODS

Cytosolic dsRNA level and its sensors were evaluated via cell-based assays (co-culture assay, confocal microscopy, pharmacological inhibition and immunofluorescent staining) and in vivo experiments. Biopsies and surgical tissues from patients with CRC who received preoperative chemoradiotherapy (neoCRT) were collected for multiplex cytokine assays, immunohistochemical analysis and SNP genotyping. We also generated a cancer-specific adenovirus-associated virus (AAV)-IFNβ1 construct to evaluate its therapeutic efficacy in combination with RT, and the immune profiles were analyzed by flow cytometry and RNA-seq.

RESULTS

Our studies revealed that RT stimulates the autonomous release of dsRNA from cancer cells to activate TLR3-mediated IFN-I signatures to facilitate antitumor immune responses. Patients harboring a dysfunctional TLR3 variant had reduced serum levels of IFN-I-related cytokines and intratumoral CD8+ immune cells and shorter disease-free survival following neoCRT treatment. The engineered cancer-targeted construct AAV-IFNβ1 significantly improved the response to RT, leading to systematic eradication of distant tumors and prolonged survival in defective TLR3 preclinical models.

CONCLUSION

Our results support that increasing cancer-intrinsic IFNβ1 expression is an immunotherapeutic strategy that enhances the RT-induced antitumor immune response in locally patients with advanced CRC with dysfunctional TLR3.

Polymorphisms in toll-like receptor 3 and 4 genes as prognostic and outcome biomarkers in melanoma patients

Melanoma is one of the most aggressive tumors, and in the setting of rising incidence and mortality, there is an urgent need to identify new prognostic markers. Toll-like receptors (TLRs), are aberrantly expressed in numerous cancers, including melanoma. TLR signaling provides a microenvironment that is involved in antitumor immune response, chronic inflammation, cancer cell proliferation and evasion of immune destruction. In the present study, we investigated whether single nucleotide polymorphisms (SNPs) in TLR3 and TLR4 genes are associated with clinicopathologic features, progression and survival of melanoma patients. The study was conducted on 120 melanoma patients. DNA extracted from peripheral blood was genotyped for TLR3 polymorphisms rs5743312 and rs3775291 (L412F) and TLR4 polymorphisms rs4986790 (D299G) and rs4986791 (T399I), by TaqMan Real-Time PCR Assays. Kaplan-Meier survival curves were compared by the log-rank test. TLR3 polymorphism L412F was associated with a higher mitotic index (P = 0.035). TLR4 D299G and T399I polymorphisms were associated with indicators of melanoma severity, nodal metastases (P = 0.005 and P = 0.007, respectively) and advanced stage III (P = 0.005 and P = 0.004, respectively). Cox regression analysis showed that the presence of tumor-infiltrating lymphocytes (TILs) predicted better overall survival (HR = 0.318; P = 0.004). TLR4 T399I polymorphism was significantly associated with worse survival, P = 0.025. The overall survival rates were significantly lower for patients carrying variant allele T of TLR4 T399I SNP (TC and TT genotypes combined) (P = 0.008, log-rank test), compared to wild-type genotype CC. Our findings indicate that TLR4 polymorphisms T399I (rs4986791) and D299G (rs4986790) could be potential prognostic and survival markers for melanoma patients.

A review of methods for detecting single-nucleotide polymorphisms in the Toll-like receptor gene family

The Toll-like receptors play an essential role in immunity through targeting the pathogen-associated molecular patterns. Nucleotide variations in TLR genes, especially single-nucleotide polymorphisms, have been shown to alter host immune susceptibility to several infections and diseases. Since TLR genes' polymorphisms can be a promising biomarker, ongoing investigations aim to develop, optimize and validate SNP detection methods. This review discusses various TLR SNP detection methods, either used extensively or occasionally, but having a vast potential in high-throughput settings. Methods such as PCR-restriction fragment length polymorphism, TaqMan^® assay, direct sequencing and matrix-assisted laser desorption ionization - time of flight mass spectroscopy MS are frequently used methods whereas Illumina GoldenGate^® assay, reverse hybridization technology, PCR-confronting two-pair primers, KBiosciences KASPar^® SNP assay, SNP stream^®, PCR-fluorescence hybridization and SNaPshot^® are powerful but sporadically used methods. We suggest that, for individual laboratories, the detection method of choice depends on a combination of factors such as throughput volume, reproducibility, feasibility and cost-effectiveness.

Germline Genetic Variants of Viral Entry and Innate Immunity May Influence Susceptibility to SARS-CoV-2 Infection: Toward a Polygenic Risk Score for Risk Stratification

The ongoing COVID-19 pandemic caused by the novel coronavirus, SARS-CoV-2 has affected all aspects of human society with a special focus on healthcare. Although older patients with preexisting chronic illnesses are more prone to develop severe complications, younger, healthy individuals might also exhibit serious manifestations. Previous studies directed to detect genetic susceptibility factors for earlier epidemics have provided evidence of certain protective variations. Following SARS-CoV-2 exposure, viral entry into cells followed by recognition and response by the innate immunity are key determinants of COVID-19 development. In the present review our aim was to conduct a thorough review of the literature on the role of single nucleotide polymorphisms (SNPs) as key agents affecting the viral entry of SARS-CoV-2 and innate immunity. Several SNPs within the scope of our approach were found to alter susceptibility to various bacterial and viral infections. Additionally, a multitude of studies confirmed genetic associations between the analyzed genes and autoimmune diseases, underlining the versatile immune consequences of these variants. Based on confirmed associations it is highly plausible that the SNPs affecting viral entry and innate immunity might confer altered susceptibility to SARS-CoV-2 infection and its complex clinical consequences. Anticipating several COVID-19 genomic susceptibility loci based on the ongoing genome wide association studies, our review also proposes that a well-established polygenic risk score would be able to clinically leverage the acquired knowledge.

Virus-associated human cancers in Moroccan population: From epidemiology to prospective research

Eight human viruses have been classified by the International Agency for Research on Cancer as carcinogenic or probably carcinogenic for humans. Infection with high risk human papillomaviruses, hepatitis B and C viruses, Epstein-Barr virus (EBV), human T-Cell Lymphotropic Virus Type 1 (HTLV-1), Human herpesvirus 8 (HHV-8), Merkel cell polyomavirus and human immunodeficiency virus-1 (HIV1) alone or in combination with other agents are the main etiologic factors of many cancers. This review highlights some aspects of virus-associated human cancers, potentially responsible for >14,000 malignancies per year in Morocco. Given that not all individuals infected with these viruses develop cancer, somatic alterations, genetic predisposition, and lifestyle or environmental factors obviously play potentializing roles modulating viral activity. These viral, host genetic signatures and lifestyle interactions may represent a reservoir of biomarkers for early detection, prevention of cancer and rationale-based therapy.

Evaluation of variants in IL6R, TLR3, and DC-SIGN genes associated with dengue in sampled Colombian population

INTRODUCTION

Host genetics is recognized as an influential factor for the development of dengue disease.

OBJECTIVE

This study evaluated the association of dengue with the polymorphisms rs8192284 for gene IL6R, rs3775290 for TLR3, and rs7248637 for DC-SIGN.

MATERIALS AND METHODS

Of the 292 surveyed subjects, 191 were confirmed for dengue fever and the remaining 101 were included as controls. The genotypes were resolved using polymerase chain reaction and restriction fragment length polymorphism (PCRRFLP). In an attempt to determine the risk (Odds Ratio) of suffering dengue fever, data were analyzed using chi-square for alleles and logistic regression for both genotypes and allelic combinations. Confidence intervals were set to 95% for all tests regardless of the adjustment by either self-identification or ancestry.

RESULTS

For Afro-Colombians, the allele rs8192284 C offered protection against dengue [OR=0.425,(0.204-0.887), p=0.020]. The alleles rs7248637 A and rs3775290 A posed, respectively, an increased risk of dengue for Afro-Colombians [OR=2.389, (1.170-4.879), p=0.015] and Mestizos [OR=2.329, (1.283-4.226), p=0.005]. The reproducibility for rs8192284 C/C [OR=2.45, (1.05-5.76), p=0.013] remained after adjustment by Amerindian ancestry [OR=2.52, (1.04-6.09), p=0.013]. The reproducibility for rs3775290 A/A [OR=2.48, (1.09-5.65), p=0.033] remained after adjustment by European [OR=2.34, (1.02-5.35), p=0.048], Amerindian [OR=2.49, (1.09-5.66), p=0.035], and African ancestry [OR=2.37, (1.04-5.41), p=0.046]. Finally, the association of dengue fever with the allelic combination CAG [OR=2.07, (1.06-4.05), p=0.033] remained after adjustment by Amerindian ancestry [OR=2.16, (1.09-4.28), p=0.028].

CONCLUSIONS

Polymorphisms rs8192284 for IL6R, rs3775290 for TLR3, and rs7248637 for DC-SIGN were associated with the susceptibility to suffer dengue fever in the sampled Colombian population.

Correlation of variable repeat number in the neck regions of DC-SIGN and DC-SIGNR with susceptibility to nasopharyngeal carcinoma in a Chinese population

Objective

To evaluate the potential association of variations in the number of tandem repeats in the dendritic cell-specific intercellular adhesion molecule-3 grabbing nonintegrin (DC-SIGN) and dendritic cell-specific intercellular adhesion molecule-3 grabbing nonintegrin-related (DC-SIGNR) neck region with susceptibility to nasopharyngeal carcinoma (NPC).

Methods

Variations in the number of repeats in the genotypes and alleles in the neck region of DC-SIGN/DC-SIGNR were analyzed in 477 unrelated NPC patients and 561 cancer-free controls.

Results

Genotypes and alleles in the DC-SIGN neck region did not differ significantly between NPC patients and controls, but the 9-repeat genotype in the DC-SIGNR neck region was significantly more frequent among patients (OR 1.339, 95% CI 1.018–1.760, P=0.037). The association between this genotype and NPC remained significant after adjusting for sex, age, smoking history, and presence of immunoglobulin against Epstein–Barr virus viral capsid antigen (OR 1.625, 95% CI 1.134–2.329, P=0.0082).

Conclusion

These results suggest that genotypes/alleles in the DC-SIGN neck region are not associated with NPC susceptibility, whereas the 9-repeat variant in the neck region of DC-SIGNR may increase the risk of NPC.

Enhancing the immune stimulatory effects of cetuximab therapy through TLR3 signalling in Epstein-Barr virus (EBV) positive nasopharyngeal carcinoma

Cetuximab immunotherapy targeting the epidermal growth factor receptor (EGFR) has been used to treat nasopharyngeal cancer (NPC) with some success. Therefore, combining an immune adjuvant to boost the immune microenvironment may improve its clinical efficacy. Herein, we investigate the immune-stimulatory effects of Poly-ICLC (a TLR3 agonist) in enhancing cetuximab-based immunotherapy and correlate these responses with FcɣRIIIa (V158F) or TLR3 single nucleotide polymorphisms (SNPs- L412F and C829T) expressed on immune effector cells. We observed high levels of TLR3 mRNA in NPC cells; and both TLR3 and EGFR expression were unaffected by Poly-ICLC treatment. Cetuximab plus Poly-ICLC significantly enhanced NK-mediated ADCC through up-regulation of CD107a and Granzyme B expression. This effect was independent of FcɣRIIIa-V158F and TLR3-L412F or TLR3-C829T polymorphisms expressed on NK cells. Additionally, IFN-ɣ expression and secretion were doubled following cetuximab plus poly-ICLC treatment; compared to either treatment alone. This effect was independent of TLR3 polymorphisms. Consequentially, adaptive immune responses were also seen with increased DC maturation (CD83), co-stimulatory molecules expression (CD80 and CD86) and increased frequency of EGFR-specific CD8 + T cells following Poly-ICLC treatment. The percentage of CD80+ CD83+ and CD83+ CD86+ DC was highest in the Poly-ICLC plus cetuximab group, compared to either treatment alone. These results demonstrate the effectiveness of Poly-ICLC in enhancing both cetuximab-mediated innate and adaptive anti-tumor immunity against NPC, which is independent of FcɣRIIIa-158, TLR3-L412F or TLR3-C829T polymorphisms. Additionally, Poly-ICLC does not downregulate EGFR expression on NPC cells and hence, will not dampen cetuximab anti-tumor activity.

SOCS1 and pattern recognition receptors: TLR9 and RIG-I; novel haplotype associations in Egyptian fibrotic/cirrhotic patients with HCV genotype 4

In this paper we explore the role of suppressor of cytokine signaling 1 (SOCS1) (rs243327), the regulator of toll-like receptor-9 (TLR9) (rs352140), retinoic acid inducible gene-I (RIG-I) (rs669260), and cluster of differentiation 152 (CD152) (rs231776) in fibrotic/cirrhotic patients. Single nucleotide polymorphisms (SNPs) within these genes as well as haplotype analyses were performed on a cohort of 120 Egyptian fibrotic patients. Fibrosis had progressed from HCV genotype 4 infections. Using RT-PCR, SNPs were evaluated in the DNA collected from each patient using TaqMan® genotyping assays. A regression model was used to evaluate allelic and haplotypic associations with a fibrosis/cirrhotic scale. The necroinflammatory A score was adjusted for non-genetic covariates. The genotype distributions for SOCS1 (rs243327) and TLR-9 (rs352140) differed significantly between the F1-F3 and F3-F4 groups. On the other hand, the genotype distributions for RIG-I (rs669260) and CD152 (rs231776) genes did not significantly differ. The allele frequency was calculated using Hardy-Weinberg Equilibrium (HWE) for the SOCS1 (rs243327), RIG-I (rs669260), and CD152 (rs231776) genes. These calculated frequency values indicated the need to compare them to another population for that locus. However, TLR9 (rs352140) did not show similar results. The A allele in SOCS1, TLR9, and RIG-I SNPs was an adverse prognostic factor for liver fibrosis and liver activity. Haplotype analysis revealed a significant association between SOCS1 and TLR9 in fibrotic/cirrhotic patients. This indicated the presence of the A allele in either gene, which is considered a risk factor for the progression of liver disease to cirrhosis. SOCS1 rs243327, TLR9 rs352140, and RIG-I rs669260 polymorphisms might affect liver pathophysiology and the cirrhotic outcome following genotype 4 HCV infection. Therefore, performing this specific SNP testing may be of value for the stratification of the population at risk.

Association of Single-Nucleotide Polymorphisms in DC-SIGN with Nasopharyngeal Carcinoma Susceptibility

The aim of this study was to explore potential relationships of four single-nucleotide polymorphisms (SNPs) in the gene encoding dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin (DC-SIGN) with risk of nasopharyngeal carcinoma (NPC). The DC-SIGN SNPs rs7252229, rs4804803, rs2287886, and rs735240 were genotyped in 477 unrelated NPC patients and 561 cancer-free controls. At rs7252229, risk of NPC was significantly lower in individuals with GC (odds ratio [OR] 0.076, 95% confidence interval [CI] 0.008-0.690), GG (OR 0.056, 95%CI 0.006-0.487), or GC + GG (OR 0.059, 95%CI 0.007-0.515) than in individuals with the CC genotype, after adjusting for age, gender, smoking history, and EBV-VCA-IgA status. At rs4804803, risk of NPC was significantly higher in individuals with the genotype GG than in those with the genotype AA (adjusted OR 9.038, 95%CI 1.708-47.822). At rs735240, risk of NPC did not change significantly with genotypes AG, GG, or AG + GG after adjusting for age, gender, and smoking history. However, when data were also adjusted for EBV-VCA-IgA status, three genotypes emerged as associated with significantly higher risk of NPC than the AA genotype: AG (OR 2.976, 95%CI 1.123-7.888), GG (OR 3.314, 95%CI 1.274-8.622), or GG + AG (OR 3.191, 95%CI 1.237-8.230). Our results suggest that DC-SIGN SNPs rs7252229, rs4804803, and rs735240 may influence NPC risk in the Chinese population. The mechanisms mediating this risk require a further study.

Association of DDX58 177 C > T polymorphism with decreased risk of Epstein-Barr virus-related nodular sclerosis classical Hodgkin lymphoma

Classical Hodgkin lymphoma (cHL) is frequently related to Epstein-Barr virus (EBV) infection. Its malignant capacity is attributed to disruption of an EBV-host balance influenced by environmental and genetic drivers. EBV structures activate Type I interferon (IFN) pathway of the innate immunity, therefore, genetic polymorphisms could influence this response. We explored the impact of four single nucleotide polymorphisms (SNPs) on EBV-associated cHL susceptibility. Toll-like receptors 9 (TLR9_rs5743836), and 3 (TLR3_rs3775291), Interleukin-28B (IL28B_rs12979860), and DEAD-box polypeptide 58 (DDX58_rs10813831) were genotyped in 73 EBV-positive and 106 EBV-negative cHL patients and 396 controls. Only DDX58_rs10813831 T-allele was decreased among EBV-positive cHL compared to controls. A stratified analysis in EBV-positive cHL showed that the reduced rate was associated with younger age and nodular sclerosis. In conclusion, DDX58_rs10813831 T-allele may be associated with a reduced risk of nodular sclerosis EBV-related cHL, which suggests a role for RIG-I (retinoic acid-inducible gene I), encoded by DDX58, in these cases.

[History of resaerch on Epstein-Barr virus--target cells of infection, and disease]

Half a century has passed since Epstein-Barr virus (EBV) particles were isolated from the cultured lymphoblasts of Burkitt lymphoma. During the period, molecular biology, hematology/immunology, and transplantation medicine made amazing progress, that clarified the mode of infection and pathophysiology of the virus in human diseases. Research strategies on the relationship between EBV and human have expanded to the epidemiology, structures and functions of both genomes, regulatory genes including microRNA, and the nature of epigenetics. Although no animal models of EBV infection long hampered the completion of in vivo experiments, humanized mice have broken through a barrier of in vitro study on EBV-infected cell lines. Our understanding of the life cycle of EBV has continued to deepen about the infection via the CD21 receptor expressed on B cells, the latency, reactivation/reinfection, and transformation, and also the dynamics of T-cell immune response and the intracellular immunosurveillance beyond acquired and innate immunity. On the other hand, the disease entity of life-threatening lymphoproliferative disease of EBV-infected T cells or NK cells is on controversial. The other parts of this special issue include the recent topics of the basic and clinical researches of EBV as the oncogenic virus. Then, we herewith overview the research history of EBV with special reference to the infected cells and host immune responses in EBV-associated diseases.

TLR3 gene polymorphisms in cancer: a systematic review and meta-analysis

INTRODUCTION

Recent studies examining the association of Toll-like receptor 3 (TLR3) gene polymorphisms with the risk of developing various types of cancer have reported conflicting results. Clarifying this association could advance our knowledge of the influence of TLR3 single nucleotide polymorphisms (SNPs) on cancer risk.

METHODS

We systematically reviewed studies that focused on a collection of 12 SNPs located in the TLR3 gene and the details by which these SNPs influenced cancer risk. Additionally, 14 case-control studies comprising a total of 7997 cases of cancer and 8699 controls were included in a meta-analysis of 4 highly studied SNPs (rs3775290, rs3775291, rs3775292, and rs5743312).

RESULTS

The variant TLR3 genotype rs5743312 (C9948T, intron 3, C>T) was significantly associated with an increased cancer risk as compared with the wild-type allele (odds ratio [OR]=1.11, 95% confidence interval [CI]=1.00-1.24, P=0.047). No such association was observed with other TLR3 SNPs. In the stratified analysis, the rs3775290 (C13766T, C>T) variant genotype was found to be significantly associated with an increased cancer risk in Asian populations. Additionally, the rs3775291 (G13909A, G>A) variant genotype was significantly associated with an increased cancer risk in Asians, subgroup with hospital-based controls, and subgroup with a small sample size.

CONCLUSION

After data integration, our findings suggest that the TLR3 rs5743312 polymorphism may contribute to an increased cancer risk.

The immunological, environmental, and phylogenetic perpetrators of metastatic leishmaniasis

Cutaneous leishmaniases have persisted for centuries as chronically disfiguring parasitic infections affecting millions of people across the subtropics. Symptoms range from the more prevalent single, self-healing cutaneous lesion to a persistent, metastatic disease, where ulcerations and granulomatous nodules can affect multiple secondary sites of the skin and delicate facial mucosa, even sometimes diffusing throughout the cutaneous system as a papular rash. The basis for such diverse pathologies is multifactorial, ranging from parasite phylogeny to host immunocompetence and various environmental factors. Although complex, these pathologies often prey on weaknesses in the innate immune system and its pattern recognition receptors. This review explores the observed and potential associations among the multifactorial perpetrators of infectious metastasis and components of the innate immune system.

Association between Toll-like receptor 3 polymorphisms and cancer risk: a meta-analysis

Toll-like receptors (TLRs) are well known as molecular sensors of pathogen-associated molecular patterns. They control activation of the innate immune response and subsequently shape the adaptive immune response. Polymorphisms in TLR3 gene associated with cancer have been studied extensively. However, the results remain controversial. A literature search was performed among PubMed, Embase, Web of Science, Science Direct, Wanfang, and Chinese National Knowledge Infrastructure databases to identify eligible studies on the association between TLR3 polymorphisms and cancer risk. A total of 12 studies in 11 articles were included in the meta-analysis including 5,861 cases and 6,339 controls. Significant associations with cancer risk were observed for single nucleotide polymorphisms (SNPs) rs3775291 (allele model: odds ratio (OR) = 1.12, 95 % confidence interval (95 % CI) = 1.00-1.25, P = 0.04), rs3775290 (allele model: OR = 1.12, 95 % CI = 1.00-1.25, P = 0.04; dominant model: OR = 1.30, 95 % CI = 1.05-1.60, P = 0.01; homozygous comparison: OR = 1.68, 95 % CI = 1.06-2.68, P = 0.03; heterozygous comparison: OR = 1.25, 95 % CI = 1.01-1.55, P = 0.04), rs5743305 (allele model: OR = 1.07, 95 % CI = 1.01-1.15, P = 0.03; dominant model: OR = 1.11, 95 % CI = 1.01-1.22, P = 0.03), and rs5743312 (allele model: OR = 1.13, 95 % CI = 1.01-1.27, P = 0.03; recessive model: OR = 1.86, 95 % CI = 1.31-2.63, P < 0.01; homozygous comparison: OR = 1.88, 95 % CI = 1.33-2.67, P < 0.01), respectively. Meanwhile, we did not find any significant association with cancer risk for rs7657186 and rs7668666. In conclusion, this meta-analysis indicates a significant association of four TLR3 gene polymorphisms with cancer risk. However, because the study size was limited, further studies are essential to confirm our results.