Polymorphisms and haplotypes in TLR9 and MYD88 are associated with the development of Hodgkin's lymphoma: a candidate-gene association study

Association between TLR 2 (rs3804099), TLR4 (rs4986790), and TLR 9 (rs187084) polymorphism and leukemia risk: a systematic review and meta-analysis

Toll-like receptors (TLRs) are crucial components of innate immunity. A specific form of genetic variation in TLR genes may increase the chance of developing leukemia. The present investigation conducted a comprehensive meta-analysis to examine the correlation between three TLR polymorphisms, namely TLR2 (rs3804099), TLR4 (rs4986790), and TLR9 (rs187084), within the leukemia risk group. An in-depth literature search was performed using Web of Science, PubMed, and Google Scholar to identify noteworthy research published in these scientific databases from 2012 to 2024. Research articles were evaluated according to rigorous inclusion criteria, and data was compiled for meta-analysis using Microsoft Excel (Ver. 2013), MedCalc (Ver. 19.3), and RevMan software (Ver. 5.3). Finally, 11 qualified studies were selected for the ongoing investigation, encompassing a combined total of 1315 leukemia cases and 1340 controls. Using a dominant genotype model, the meta-analysis found that the TLR2 (rs3804099) and TLR9 (rs187084) polymorphisms were strongly linked to higher risk of leukemia, with ORs of 2.042 (95% CI: 1.35-3.08, p = 0.001) and 1.38 (95% CI: 1.14-1.67, p = 0.001) respectively. Notably, the TLR4 (rs4986790) polymorphism did not exhibited any substantial correlation with the incidence of leukemia. The results indicate that variations in TLR2 and TLR9 genes could be considered a novel genetic biomarker for the leukemia development, highlighting their potential use in risk assessment and targeted therapies. This emphasizes the possibility of using these variations in evaluating risk and developing targeted remedies. However, greater research capacities are required to research into the fundamental mechanisms and authenticate these trends in other populations.

Pathogenetic Mechanisms Linking Sarcoidosis to Lymphoma

Sarcoidosis and lymphoma share immunopathological characteristics that suggest a complex, interconnected relationship. This article examines the multi-faceted mechanisms linking sarcoidosis to lymphoma, a phenomenon called sarcoidosis-lymphoma syndrome (SLS). SLS is hard to diagnose, requiring distinct criteria and imaging to differentiate overlapping features and histological differences. The co-occurrence of these diseases may be explained by genetic predispositions, immune dysregulation, and environmental factors that enhance malignancy risk. In active sarcoidosis, chronic inflammation and granuloma formation induce the production of cytokines that can contribute to lymphoma development. The role of macrophage polarization is also discussed. Immunosuppressive treatment prescribed in sarcoidosis patients, particularly corticosteroids and biological agents, may increase the susceptibility to lymphoproliferative malignancies. These common mechanisms emphasize the need for vigilant monitoring of lymphoma in patients with sarcoidosis, as this granulomatous disease can mimic and promote the development of lymphoma.

Revealing of TLR-9 gene polymorphisms by qPCR HRM technique and their influence on TLR-9 serum level in acute myeloid leukemia patients: Case-control study

Acute myeloid leukemia (AML) is one of the most common and fatal malignancies that affect adults, which can quickly become aggressive if left untreated, and leukemia cells invade the bone marrow. TLR-9 is an innate immune cell receptor sensitive to various PAMPs and encoded by the TLR-9 gene. As is often known, genetic polymorphisms in any gene can help the development of the disease, and these three polymorphisms, rs187084, rs5743836, and rs352140 of TLR-9, have been studied in many different cancer disorders. Therefore, this study aimed to discover the multiple forms of a TLR-9 gene in a sample of Iraqi AML patients. A total of 120 participants in a case-control study were enrolled in the current study. Using CBC, some hematological parameters were evaluated, and the serum level of TLR-9 was assessed using the ELISA technique. DNA was extracted directly from blood, and a high-resolution melting (HRM) analysis was then carried out. The results revealed a significant difference in some blood parameters among patients and healthy control, while WBC and lymphocytes were without an evident difference between the two groups of the current investigation. The serum concentration of TLR-9 showed an elevated level in patients (P value < 0.01). Nonetheless, this increase was not affected by the genotype patterns of polymorphisms. According to the P-value, there was a significant difference in wild genotypes of the three polymorphisms (rs187084, rs5743836, and rs352140). At the same time, the odds ratio revealed the association with the disease as a protective factor. In contrast, there was a significant difference in the heterozygous and mutant genotypes of TLR-9 polymorphisms, though the odds ratio confirmed the association with the AML as a risk factor. The results of rs352140 were compatible with H.W.E since there were no significant differences between the observed and expected values for either patients or healthy controls. In contrast, the result of rs5743836 was not consistent with the HWE. Furthermore, although it corresponds with the healthy one, the finding of rs187084 conflicted with H.W.E. in the patient group. In conclusion, High serum levels of TLR-9 in patients could act as biomarkers for AML. The TLR-9 gene polymorphisms (rs187084, rs5743836, and rs352140) have been linked to an increased risk of AML and may impact the disease progression in the Iraqi population.

Association of TLR9-1237T>C; rs5743836 polymorphism with increased risk of Hodgkin’s lymphoma: A case-control study

Mature B-cell neoplasms are typically divided into Hodgkin and Non-Hodgkin Lymphomas. Hodgkin Lymphoma is characterized by the neoplastic Reed-Sternberg cells, usually harbored in an inflammatory background, with a frequent clinical presentation of mediastinal lymphadenopathy. Many studies link between autoimmunity and lymphomagenesis, a large proportion of these studies evidently trace the pathogenesis back to the misdirected detection of self-derived nucleic acids by Toll-Like Receptors (TLRs), especially those of the intracellular type. In this study, we analyzed the relationship between a selected SNP in TLR9 (TLR9-1237T>C; rs5743836) and the risk and overall survival of HL patients in a Jordanian Arab population. A total of 374 subjects; 136 cases of Hodgkin lymphoma and 238 matched healthy controls were incorporated in this study. Genomic DNA was extracted from formalin-fixed paraffin-embedded tissues. Genotyping of the genetic polymorphisms was conducted using a sequencing protocol. The results show a statistically significant higher distribution of the rs5743836 (TLR9-1237T>C) allele among the case population, with a p-value of 0.031 (<0.05). This distribution proved significant when studied in the codominant (only significant in the T/C genotype, p-value = 0.030), dominant (p-value = 0.025), and overdominant (p-value = 0.035) models. None of the models showed any statistically significant difference in survival associated with the rs5743836 (TLR9-1237T>C) SNP.

TLR4 896A/G and TLR9 1174G/A polymorphisms are associated with the risk of infectious mononucleosis

Toll-like receptors (TLRs) recognize pathogen-associated molecular patterns and activate innate and adaptive immune responses. Single nucleotide polymorphisms (SNPs) within the TLR genes may influence host–pathogen interactions and can have an impact on the progression of infectious diseases. The present study aimed to investigate the genotype distribution of TLR2 (2029C/T, rs121917864; 2258G/A, rs5743708), TLR4 (896A/G, rs4986790), and TLR9 (− 1237T/C, rs5743836; − 1486T/C, rs187084; 1174G/A, rs352139; and 2848C/T, rs352140) polymorphisms in 149 children and adolescents with infectious mononucleosis (IM) and 140 healthy individuals. The potential association of TLR SNPs with the clinical manifestations of EBV infection was also studied. The presence of TLR2, TLR4, and TLR9 SNPs was identified by polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP). EBV DNA loads were detected by quantitative real-time PCR assay. The TLR4 896 GG and the TLR9 1174 GA genotypes were associated with an increased risk of EBV-related IM in examined patients (p = 0.014 and p = 0.001, respectively). The heterozygous genotype of the TLR4 896A/G SNP was associated with an increased risk of elevated liver enzyme levels and leukocytosis (p < 0.05). Our preliminary study revealed that the TLR4 896A/G and the TLR9 1174G/A polymorphisms seem to be related to the course of acute EBV infection in children and adolescents.

Apoptosis and genes involved in oral cancer - a comprehensive review

Oral cancers needs relentless research due to high mortality and morbidity associated with it. Despite of the comparable ease in accessibility to these sites, more than 2/3^rd cases are diagnosed in advanced stages. Molecular/genetic studies augment clinical assessment, classification and prediction of malignant potential of oral lesions, thereby reducing its incidence and increasing the scope for early diagnosis and treatment of oral cancers. Herein we aim to review the role of apoptosis and genes associated with it in oral cancer development in order to aid in early diagnosis, prediction of malignant potential and evaluation of possible treatment targets in oral cancer. An internet-based search was done with key words apoptosis, genes, mutations, targets and analysis to extract 72 articles after considering inclusion and exclusion criteria. The knowledge of genetics and genomics of oral cancer is of utmost need in order to stop the rising prevalence of oral cancer. Translational approach and interventions at the early stage of oral cancer, targeted destruction of cancerous cells by silencing or promoting involved genes should be the ideal intervention.

CD markers polymorphisms as prognostic biomarkers in hematological malignancies

The clusters of differentiation (CD) are surface molecules used for immunophenotyping of cells. The expression of CD markers is widely used to classify hematological malignancies, including leukemia and lymphoma. Single nucleotide polymorphisms (SNPs) are crucial genetic changes that can be associated with abnormal expression and function of CD markers. In this paper, we assess the prognostic effect of CD markers’ SNPs in hematological malignancies. Materials and methods and relevant literature was identified by a PubMed search (2001-2019) of English language papers using the following terms: ‘polymorphism’, ‘CD marker’, ‘leukemia’, ‘lymphoma’, ‘prognosis’, ‘CD marker’, and ‘polymorphism’. Many studies have demonstrated the effects of CD markers’ polymorphisms on risk of hematological malignancies. Also, SNPs of CD markers can be related with clinicopathological features, invasiveness, and response to therapy of these disorders. Considering the importance of SNPs in the expressions of CD markers, these genetic changes could be used as potential prognostic biomarkers in hematological malignancies. It is hoped that the evaluation of SNPs in CD markers will enable early diagnosis, prognosis, and detection of response to treatment. However, better understanding of SNPs in CD markers that are involved in hematological malignancies requires further studies on different populations of the worldwide.

Combination of genetic polymorphisms in TLR influence cytokine profile in HCV patients treated with DAAs in the State of Amazonas

Hepatitis C is a public health problem and affects approximately 3% of the world's population. HCV infections have a wide spectrum of clinical manifestations, and several single nucleotide polymorphisms (SNPs) in the genes of the toll-like receptors are cited to influence the clinical outcomes. A cross-sectional study was conducted in the Amazonas State, Brazil in which SNPs in TLR4 and TLR9 genes were genotyped by PCR-RFLP in 151 HCV chronic liver disease patients and 206 healthy donors. The circulating cytokines IL-6, TNF, IL-10, IL-2, IFN-γ, IL-4 and IL-17A were measured by cytometric bead array (CBA) which revealed that the combined genotypes of TLR9 -1237T/T and -1486C/T seem to influence the cytokine profile under lipopolysaccharide (LPS) stimulation of the Th17 profile, especially among patients with advanced chronic liver disease when treated with DAAs.

Functional Polymorphisms and Gene Expression of TLR9 Gene as Protective Factors for Nasopharyngeal Carcinoma Severity and Progression

Nasopharyngeal carcinoma (NPC) is a disease that is closely associated with EBV infection. Toll-like receptor 9 is an important factor mediating the interaction between EBV and the host immune response. Any genetic (single nucleotide polymorphisms, SNPs) or expression variation in TLR9 gene may modify the ability of the receptor to respond correctly to viral infection as in NPC. This study is aimed at evaluating the effect of TLR9 functional polymorphisms (TLR9-1486 T/C and TLR9-1237 T/C) and TLR9 mRNA expression in NPC severity and progression at diagnosis and after treatment. This study included 322 patients with NPC. RFLP-PCR and real-time PCR were used to assess, respectively, the genotypes and the mRNA expression of TLR9 gene. The genotyping analysis showed that the presence of mutated allele -1237C (TLR9-1237 TC+CC) was associated with large tumor size (p = 0.017; OR (CI 95%) = 1.888 (1.11-3.19)) at diagnosis. After treatment, the -1237C allele was associated with a better chance of complete remission (p = 0.031, OR (CI 95%) = 0.486 (0.25-0.95)), a lower risk of distant metastasis (p = 0.028, OR (CI 95%) = 0.435 (0.18-1.02)), and a lower risk of death by NPC (p = 0.003, OR (CI 95%) = 0.20 (0.06-0.67)). Kaplan-Meier analysis showed that patients with -1237CC and -1237TC genotypes had a better overall survival (OVS) (p < 0.01) and distant metastasis-free survival (DMFS) (p < 0.05). A multivariate analysis revealed that TLR9-1237 T/C polymorphism was an independent prognostic factor in OVS (p = 0.02; HR = 0.244) and DMFS (p = 0.048; HR = 0.388). The transcriptomic analysis showed that the mRNA expression was reduced in patients with larger tumor size (T4) (p = 0.013) and advanced clinical stage (SIII-SIV) (p = 0.037). The TLR9 mRNA expression was inversely correlated with tumor size (p = 0.014; r = −0.314) at diagnosis. Our results indicated for the first time that the functional -1237 T/C polymorphism and mRNA expression of TLR9 gene may be considered as protective factors for NPC severity and progression.

Pharmacological modulation of nucleic acid sensors - therapeutic potential and persisting obstacles

Nucleic acid sensors, primarily TLR and RLR family members, as well as cGAS-STING signalling, play a critical role in the preservation of cellular and organismal homeostasis. Accordingly, deregulated nucleic acid sensing contributes to the origin of a diverse range of disorders, including infectious diseases, as well as cardiovascular, autoimmune and neoplastic conditions. Accumulating evidence indicates that normalizing aberrant nucleic acid sensing can mediate robust therapeutic effects. However, targeting nucleic acid sensors with pharmacological agents, such as STING agonists, presents multiple obstacles, including drug-, target-, disease- and host-related issues. Here, we discuss preclinical and clinical data supporting the potential of this therapeutic paradigm and highlight key limitations and possible strategies to overcome them.

Toll-like receptor 6 expression, sequence variants, and their association with colorectal cancer risk

This is the first study to examine the potential correlation of the rs3796508 and rs5743810 SNPs of the TLR6 gene in patients with colorectal cancer (CRC) in a subset of the Saudi population. TLR6 gene expression was studied by real-time PCR assaysin 10 matching normal and cancer colon tissues. TLR6 expression at the protein level was determined by immunohistochemistry. A case-control search was conductedon 115 case patients and 102 controls. All samples were genotyped with the TaqMan assay for the TLR6 gene. Odds ratios and 95% confidence interval were computed from logistic regression models after adjusting for age, sex, and tumor localization. Our findings showed a decrease in TLR6 expression (p <0.001) in colon cancer tissues when compared to normal colon tissues. Global analysis revealed no significant association between the TLR6 rs3796508 and rs5743810 and CRC in this population. However, the Val/Met genotype of rs3796508 had a significantly higher frequency in the control group than in the cases for the male group (OR= 0.095, and p= 0.03385) or the volunteers aged more than 57 years OR= 0.152; and p= 0.04069, respectively). Two non-synonymous single nucleotide polymorphisms (SNP; S249P and V327M) were common in a few patients and were predicted as damaging by SIFT and Polyphen and were further analyzed for their protein stability and function using advanced bioinformatics tools. The results suggest that TLR6 rs3796508 has a crucial role as a protective factor against colorectal cancer in the older Saudi male population.

DNA methylation patterns of adult survivors of adolescent/young adult Hodgkin lymphoma compared to their unaffected monozygotic twin

DNA methylation (DNAm) silences gene expression and may play a role in immune dysregulation that is characteristic of adolescent/young adult Hodgkin lymphoma (AYAHL). We used the Infinium HumanMethylation27 BeadChip to quantify DNAm in blood (N = 9 pairs, mean age 57.4 y) or saliva (N = 36 pairs, mean age 50.0 y) from long-term AYAHL survivors and their unaffected co-twins. Epigenetic aging (DNAm age) was calculated using previously described methods and compared between survivors and co-twins using paired t-tests and analyses were stratified by sample type, histology, sex, age at sample collection and time since diagnosis. Differences in blood DNAm age were observed between survivors and unaffected co-twins (64.1 vs. 61.3 years, respectively, p = .04), especially in females (p = .01); no differences in saliva DNAm age were observed. Survivors and co-twins had 74 (in blood DNA) and 6 (in saliva DNA) differentially methylated loci. Our results suggest persistent epigenetic aging in AYAHL survivors long after HL cure.

Association of Toll-like receptor 3 and Toll-like receptor 9 single-nucleotide polymorphisms with hepatitis C virus persistence among Egyptians

Toll-like receptors (TLRs) give the innate immune system a considerable specificity for a large range of pathogens. TLR3 detects dsRNA of viruses while TLR9 recognizes bacterial and viral unmethylated CpG motifs. This study examined whether there is a potential association between single-nucleotide polymorphisms (SNPs) in the TLR3.rs3775290 (c.1377C/T), TLR9.rs5743836 (-1237T→C) and TLR9.rs352140 (G2848A) genes and HCV infection among Egyptian patients and healthcare workers (HCWs). We enrolled 546 subjects (409 HCWs and 137 patients) divided into four groups: group 1 included 265 seronegative, aviremic subjects; group 2 included 25 seronegative, viremic subjects; group 3 included 87 subjects with spontaneously resolved HCV infection; and group 4 included 169 chronic HCV patients. All subjects were genotyped for TLR3.rs3775290, TLR9.rs5743836 and TLR9.rs352140 SNPs by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis. TLR3.rs3775290 "CC" genotype was associated with chronic HCV infection, where there was a significantly greater frequency of this genotype among chronic patients when compared to subjects with spontaneously resolved infection (63.9% vs. 51.9%; p = 0.033; OR = 1.639 and 95% CI = 0.94-2.84). However, this SNP did not correlate with the HCV RNA load among the chronic subjects (p > 0.05). There was no significant difference in TLR9.rs5743836 and TLR9.rs352140 genotype distribution between groups (p > 0.05). Lack of association between the three SNPs was found, as the three SNPs are located on two different chromosomes. In conclusion, the TLR3.rs3775290 "CC" genotype was associated with HCV chronicity, while the TLR9 gene may not play a major role in HCV infection.

Lack of Associations between TLR9 and MYD88 Gene Polymorphisms and Risk of Chronic Lymphocytic Leukemia

Background:

Genetic factors like single nucleotide polymorphisms (SNPs) may play an important role in the etiology of chronic lymphocytic leukemia (CLL). Mutations in Toll like receptor 9 (TLR9) and myeloid differentiation primary response 88 (MYD88) genes may lead to an abnormal immune response that may cause greater cell proliferation and thus alter an individual’s susceptibility to haematological malignancies including CLL.

Objective:

This work was designed to study any association of the TLR9 (rs2066807C/G and rs187084T/C) and MYD88 (L265P) single nucleotide polymorphism (SNPs) with risk of CLL in Egyptians.

Materials and methods:

One hundred patients with CLL and 100 healthy controls from the Egyptian population were genotyped by the polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP) method.

Results:

With TLR9 rs2066807C/G the CC genotype was more frequent in both control and patient groups while for TLR9 rs187084T/C the TT genotype was most common. There were no significant associations with CLL risk. With MYD88 (L265P) only the TT genotype was detected.

Conclusion:

Our preliminary data suggest that polymorphisms in the TLR9 and MYD88 genes may not contribute to CLL susceptibility. To the best of our knowledge, this study is the first dealing with TLR9 and MYD88 gene polymorphisms in CLL patients. Further studies with larger sample size should be conducted to validate these results in the Egyptian population.

A Polymorphism Located Near PMAIP1/Noxa Gene Influences Susceptibility to Hodgkin Lymphoma Development in South India

Background:

Single nucleotide polymorphisms (SNPs) in DNA repair and Toll-like receptor (TLR) genes have been reported to be associated with Hodgkin Lymphoma (HL) risk. Since such associations may be ethnicity dependent, polymorphisms in TLR4 rs1554973, Xeroderma pigmentosum C (XPC) rs2228000, rs2228001 and a variant near PMAIP1/Noxa gene rs8093763 were here investigated with regard to HL susceptibility in a south Indian population. Normative frequencies of SNPs were established and compared with data for 1000 genome populations.

Methods:

We conducted a case control study consisting of 200 healthy volunteers and 101 cases with HL. DNA samples were genotyped using real-time PCR. Linkage disequilibrium (LD) analysis between rs2228000 and rs2228001 was performed using HaploView (version 4.2).

Results:

Among the studied variants, we observed that a variant rs8093763 located near PMAIP1/Noxa gene was associated with HL risk (OR=1.72 and 95% CI=1.004-2.93). The major allele frequencies of XPC (rs2228000 and rs2228001), TLR4 (rs1554973) and PMAIP1/NOXA (rs8093763) variants were 79%, 66%, 67% and 59% respectively. The studied frequencies were significantly different from 1000 genome populations.

Conclusion:

The results suggest that a variant rs8093763 located near the PMAIP1/Noxa gene may modify risk of HL. We found variation in distribution of polymorphic frequencies between the study population and 1000 genome populations. The results may help identify individual risk of development of HL in our south Indian population.

Proliferation through activation: hemophagocytic lymphohistiocytosis in hematologic malignancy

Hemophagocytic lymphohistiocytosis (HLH) is a syndrome of cytokine-driven immune activation. Cardinal features include fever, hemophagocytosis, hepatosplenomegaly, lymphocytic infiltration, and hypercytokinemia that result in multisystem organ dysfunction and failure. Familial HLH is genetically driven, whereas secondary HLH (SHL) is caused by drugs, autoimmune disease, infection, or cancer. SHL is associated with worse outcomes, with a median overall survival typically of less than 1 year. This reflects difficulty in both diagnostic accuracy and in establishing reliable treatments, especially in cases of malignancy-induced SHL, which have significantly worse outcomes. Malignancy-induced HLH is seen almost exclusively with hematologic malignancies, constituting 97% of cases in the literature over the past 2 years. In these situations, the native immune response driven by CD8 T cells produces an overabundance of T helper 1 cytokines, notably interferon-γ, tumor necrosis factor-α, and interleukin-6, which establish a positive feedback loop of inflammation, enhancing replication of hematologic malignancies while leaving the host immune system in disarray. In this paper, we present 2 case studies of secondary HLH driven by HM, followed by a review of the literature discussing the cytokines driving HLH, diagnostic criteria, and current treatments used or undergoing investigation.

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.

The -938C>A Polymorphism in MYD88 Is Associated with Susceptibility to Tuberculosis: A Pilot Study

Introduction. Tuberculosis (TB) is a major disease worldwide, caused by Mycobacterium tuberculosis (MTB) infection. The Toll-Like Receptor (TLR) pathway plays a crucial role in the recognition of MTB. Aim. The present study aimed to investigate the involvement of myeloid differentiation primary response protein 88 (MYD88) gene polymorphisms in TB. Materials and Methods. A total of 103 TB cases and 92 control subjects were genotyped for the MYD88 -938C>A (rs4988453) and 1944C>G (rs4988457) polymorphisms. Results. The MYD88 -938CA and -938AA genotypes were associated with an increased risk for tuberculosis with odds ratio (OR) of 5.71 (95% confidence intervals [CIs] 2.89–11.28, p = 0.01). Conclusions. The MYD88 -938C>A genetic polymorphism is associated with increased susceptibility to TB and may serve as a marker to screen individuals who are at risk.

Association between TLR-9 polymorphisms and colon cancer susceptibility in Saudi Arabian female patients

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.

TLR9 -1486T/C and 2848C/T SNPs Are Associated with Human Cytomegalovirus Infection in Infants

Toll-like receptor 9 (TLR9) recognizes non-methylated viral CpG-containing DNA and serves as a pattern recognition receptor that signals the presence of human cytomegalovirus (HCMV). Here, we present the genotype distribution of single-nucleotide polymorphisms (SNPs) of the TLR9 gene in infants and the relationship between TLR9 polymorphisms and HCMV infection. Four polymorphisms (-1237T/C, rs5743836; -1486T/C, rs187084; 1174G/A, rs352139; and 2848C/T, rs352140) in the TLR9 gene were genotyped in 72 infants with symptomatic HCMV infection and 70 healthy individuals. SNP genotyping was performed by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Digested fragments were separated and identified by capillary electrophoresis. The HCMV DNA copy number was measured by a quantitative real-time PCR assay. We found an increased frequency of heterozygous genotypes TLR9 -1486T/C and 2848C/T in infants with HCMV infection compared with uninfected cases. Heterozygous variants of these two SNPs increased the risk of HCMV disease in children (P = 0.044 and P = 0.029, respectively). In infants with a mutation present in at least one allele of -1486T/C and 2848C/T SNPs, a trend towards increased risk of cytomegaly was confirmed after Bonferroni's correction for multiple testing (Pc = 0.063). The rs352139 GG genotype showed a significantly reduced relative risk for HCMV infection (Pc = 0.006). In contrast, the -1237T/C SNP was not related to viral infection. We found no evidence for linkage disequilibrium with the four examined TLR9 SNPs. The findings suggest that the TLR9 -1486T/C and 2848C/T polymorphisms could be a genetic risk factor for the development of HCMV disease.

Associations between TLR9 polymorphisms and cancer risk: evidence from an updated meta-analysis of 25,685 subjects

A meta-analysis incorporating 34 case-control studies from 19 articles involving 12,197 cases and 13,488 controls was conducted to assess the effects of three genetic variants of Toll-like receptor 9 (TLR9): rs187084, rs352140, and rs5743836. Studies on associations between TLR9 polymorphisms and cancer risk were systematically searched in electronic databases. The reported odds ratios (OR) and 95% confidence intervals (CI) were pooled to assess the strength of any associations. The results showed that the rs187084 polymorphism was significantly associated with an increased risk of cancer (CC vs TC+TT: OR=1.14, 95% CI=1.02-1.28), specifically cervical cancer (C vs T: OR=1.19, 95% CI=1.05-1.34; TC vs TT: OR=1.32, 95% CI=1.10-1.58; CC vs TT: OR=1.31, 95% CI= 1.03-1.68; CC+TC vs TT: OR=1.32, 95% CI=1.11-1.56), and that this association was significantly positive in Caucasians (CC vs. TC+TT: OR=1.18, 95% CI=1.01-1.38). The rs352140 polymorphism had a protective effect on breast cancer (GA vs GG: OR=0.77, 95% CI=0.66-0.89), whereas the rs5743836 polymorphism was likely protective for digestive system cancers (CC+TC vs TT: OR=0.81, 95% CI=0.66-0.98). In conclusion, our results suggest that the rs187084 polymorphism may be associated with an elevated cancer risk, whereas polymorphisms of rs352140 and rs5743836 may play protective roles in the development of breast and digestive system cancers, respectively. From the results of this meta-analysis further large-scale case-control studies are warranted to verify associations between TLR9 polymorphisms and cancer.

Association between toll-like receptors 9 (TLR9) gene polymorphism and risk of pulmonary tuberculosis: meta-analysis

BACKGROUND

Previous studies indicated that the single nucleotide polymorphisms (SNPs) in TLR9 gene might be associated with Tuberculosis (TB) risk. However, the results are inconsistent and inconclusive.

METHODS

1745 articles from four databases were involved in our study. A meta-analysis on the associations between the seven polymorphisms and TB risk was carried out by comparison using different genetic models.

RESULTS

In this systematic review 8 studies from seven English articles were analyzed. Our results showed that rs352139 is significantly associated with TB risk (AA vs. AG, OR 0.77, 95% CI 0.65-0.92, P = 0.004). In the ethnic subgroup analysis, Indonesians with AA genotype had a decreased susceptibility while Mexicans with GG allele had an increased risk.

CONCLUSIONS

The meta-analysis indicated that rs352139 polymorphism might be associated with decreased TB risk in Indonesians whereas increased risk in Mexicans. Whether the observed association was due to causal effect needs to be further studied.

Inhibition of IRAK1/4 sensitizes T cell acute lymphoblastic leukemia to chemotherapies

Signaling via the MyD88/IRAK pathway in T cells is indispensable for cell survival; however, it is not known whether this pathway functions in the progression of T acute lymphoblastic leukemia (T-ALL). Here, we determined that compared with thymic and peripheral T cells, T-ALL cells from patients have elevated levels of IRAK1 and IRAK4 mRNA as well as increased total and phosphorylated protein. Targeted inhibition of IRAK1 and IRAK4, either with shRNA or with a pharmacological IRAK1/4 inhibitor, dramatically impeded proliferation of T-ALL cells isolated from patients and T-ALL cells in a murine leukemia model; however, IRAK1/4 inhibition had little effect on cell death. We screened several hundred FDA-approved compounds and identified a set of drugs that had enhanced cytotoxic activity when combined with IRAK inhibition. Administration of an IRAK1/4 inhibitor or IRAK knockdown in combination with either ABT-737 or vincristine markedly reduced leukemia burden in mice and prolonged survival. IRAK1/4 signaling activated the E3 ubiquitin ligase TRAF6, increasing K63-linked ubiquitination and enhancing stability of the antiapoptotic protein MCL1; therefore, IRAK inhibition reduced MCL1 stability and sensitized T-ALL to combination therapy. These studies demonstrate that IRAK1/4 signaling promotes T-ALL progression through stabilization of MCL1 and suggest that impeding this pathway has potential as a therapeutic strategy to enhance chemotherapeutic efficacy.

Evaluation of neonatal Toll-like receptors 3 (c.1377C/T) and 9 (G2848A) gene polymorphisms in HBV intrauterine transmission susceptibility

To investigate whether single nucleotide polymorphisms (SNPs) in Toll-like receptors (TLRs) 3 and 9 affect the susceptibility of hepatitis B virus (HBV) intrauterine transmission, we genotyped 399 neonates for TLR3 (c.1377C/T) [rs3775290] and TLR9 (G2848A) [rs352140] using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). A femoral venous blood sample was obtained from these subjects. Hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) were measured using chemiluminescence immunoassay kits and hepatitis B virus DNA (HBV DNA) levels were determined by fluorescence quantitative PCR assay. Our results showed that when adjusting for maternal HBeAg, maternal HBV DNA and mode of delivery, allele 'T' for SNP c.1377C/T was significantly associated with HBV intrauterine transmission susceptibility [adjusted OR (aOR) 0.55, 95% confidence interval (CI) 0.34-0.91, P = 0.020] and the TT genotype decreased the risk of HBV intrauterine transmission (aOR 0.28, 95% CI 0.09-0.91, P = 0.033). Allele 'A' for SNP G2848A was significantly associated with HBV intrauterine transmission susceptibility (aOR 0.62, 95% CI 0.39-1.00, P = 0.048) and the GA genotype protected neonates from HBV intrauterine transmission (aOR 0.45, 95% CI 0.22-0.93, P = 0.031). The TLR3 (c.1377C/T) and TLR9 (G2848A) polymorphisms may be relevant for HBV intrauterine transmission susceptibility, although the reduction in risk to HBV intrauterine transmission is modest and the biological mechanism of the observed association merits further investigation.

Toll-like receptors in the pathogenesis of human B cell malignancies

Toll-like receptors (TLRs) are important players in B-cell activation, maturation and memory and may be involved in the pathogenesis of B-cell lymphomas. Accumulating studies show differential expression in this heterogeneous group of cancers. Stimulation with TLR specific ligands, or agonists of their ligands, leads to aberrant responses in the malignant B-cells. According to current data, TLRs can be implicated in malignant transformation, tumor progression and immune evasion processes. Most of the studies focused on multiple myeloma and chronic lymphocytic leukemia, but in the last decade the putative role of TLRs in other types of B-cell lymphomas has gained much interest. The aim of this review is to discuss recent findings on the role of TLRs in normal B cell functioning and their role in the pathogenesis of B-cell malignancies.

Trial Watch: Toll-like receptor agonists in oncological indications

Toll-like receptors (TLRs) are an evolutionarily conserved group of enzymatically inactive, single membrane-spanning proteins that recognize a wide panel of exogenous and endogenous danger signals. Besides constituting a crucial component of the innate immune response to bacterial and viral pathogens, TLRs appear to play a major role in anticancer immunosurveillance. In line with this notion, several natural and synthetic TLR ligands have been intensively investigated for their ability to boost tumor-targeting immune responses elicited by a variety of immunotherapeutic and chemotherapeutic interventions. Three of these agents are currently approved by the US Food and Drug Administration (FDA) or equivalent regulatory agencies for use in cancer patients: the so-called bacillus Calmette-Guérin, monophosphoryl lipid A, and imiquimod. However, the number of clinical trials testing the therapeutic potential of both FDA-approved and experimental TLR agonists in cancer patients is stably decreasing, suggesting that drug developers and oncologists are refocusing their interest on alternative immunostimulatory agents. Here, we summarize recent findings on the use of TLR agonists in cancer patients and discuss how the clinical evaluation of FDA-approved and experimental TLR ligands has evolved since the publication of our first Trial Watch dealing with this topic.

The genetics of innate immunity sensors and human disease

Since their discovery, innate immunity microbial sensors have been increasingly studied and shown to play a critical role in innate responses to microbes in several experimental in vitro, ex vivo, and animal models. However, their role in the human response to infection in natural conditions has just started to be deciphered, by means of clinical studies of primary immunodeficiencies and epidemiological genetic studies. Here, we summarize the major findings concerning the genetic diversity of the various families of microbial sensors in humans, and of other molecules involved in the signaling pathways they trigger. Specifically, we review the genetic associations, revealed by both clinical and epidemiological genetics studies, of microbial sensors from five different families: Toll-like receptors, C-type lectin receptors, NOD-like receptors, RIG-I-like receptors, and cytosolic DNA sensors. In particular, we consider the relationships between variation at the genes encoding these molecules and susceptibility to and the severity of infectious diseases and other clinical conditions associated with immune dysfunction, including autoimmunity, inflammation, allergy, and cancer. Despite the fact that the genetic links between innate immunity sensors and human disorders remain still limited, human genetics studies are increasingly improving our understanding of the genuine functions of microbial sensors and downstream signaling molecules in the natural setting.

The TLR9 gene polymorphisms and the risk of cancer: evidence from a meta-analysis

Background

Growing studies have revealed the association between polymorphisms in the Toll-like receptor 9 (TLR9) and susceptibility to cancer, however, the results remained inconsistent.

Methodology/Principal Findings

To assess the effect of three selected SNPs (rs352140, rs5743836 and rs187084) in TLR9 on cancer, we performed a meta-analysis based on 11 case-control studies, including a total of 6,585 cancer cases and 7,506 controls. Summary odds ratios (OR) and corresponding 95% confidence intervals (CIs) for polymorphisms in TLR9 and cancer risk were estimated. Our meta-analysis indicated that rs352140 was associated with an increased cancer risk, especially in Caucasian. However, no significantly increased cancer risk was detected to be associated with rs187084 and rs5743836 either the overall or subgroup estimation.

Conclusions

These meta-analysis results indicate that polymorphisms in TLR9 may play a role in cancer development.

Trial Watch: Toll-like receptor agonists for cancer therapy

Toll-like receptors (TLRs) have long been known for their ability to initiate innate immune responses upon exposure to conserved microbial components such as lipopolysaccharide (LPS) and double-stranded RNA. More recently, this family of pattern recognition receptors has been attributed a critical role in the elicitation of anticancer immune responses, raising interest in the development of immunochemotherapeutic regimens based on natural or synthetic TLR agonists. In spite of such an intense wave of preclinical and clinical investigation, only three TLR agonists are currently licensed by FDA for use in cancer patients: bacillus Calmette-Guérin (BCG), an attenuated strain of Mycobacterium bovis that operates as a mixed TLR2/TLR4 agonist; monophosphoryl lipid A (MPL), a derivative of Salmonella minnesota that functions as a potent agonist of TLR4; and imiquimod, a synthetic imidazoquinoline that activates TLR7. One year ago, in the August and September issues of OncoImmunology, we described the main biological features of TLRs and discussed the progress of clinical studies evaluating the safety and therapeutic potential of TLR agonists in cancer patients. Here, we summarize the latest developments in this exciting area of research, focusing on preclinical studies that have been published during the last 13 mo and clinical trials launched in the same period to investigate the antineoplastic activity of TLR agonists.

Toll-like receptors and human disease: lessons from single nucleotide polymorphisms

Toll-like receptors (TLRs), a large group of proteins which recognize various pathogen-associated molecular patterns, are critical for the normal function of the innate immune system. Following their discovery many single nucleotide polymorphisms within TLRs and components of their signaling machinery have been discovered and subsequently implicated in a wide range of human diseases including atherosclerosis, sepsis, asthma, and immunodeficiency. This review discusses the effect of genetic variation on TLR function and how they may precipitate disease.

Polymorphisms and haplotypes in MyD88 are associated with the development of sarcoidosis: a candidate-gene association study

Sarcoidosis is considered as a disorder of protracted immune response to an as yet unidentified causative agent that leads to granuloma formation. Material from M. tuberculosis and P. acne has been repeatedly detected in the sarcoidosis lesions, implying the involvement of the Toll-like receptor2 (TLR2) gene that responds to these intracellular pathogens. Since TLR2 association studies have produced controversial results, we sought to investigate whether the downstream signalling molecule MyD88 could be linked to disease susceptibility. We analyzed a total of 93 cases with sarcoidosis and of 89 controls for the most common MyD88 SNPs: -938C>A (rs4988453) and 1944C>G (rs4988457). There is evidence that the genotype distributions of both variants are associated with the development of sarcoidosis (p = 0.038 for -938C>A and p = 0.026 for 1944C>G). In particular, -938A and 1944G carriers were associated with risk of sarcoidosis [OR = 2.48 (1.23-5.02) and OR = 0.33 (0.14-0.76)], respectively, indicating dominance of the mutant alleles; however, the adjustment of the effect size for age and sex diminished the significance. The haplotype analysis showed association for the -938A/1944G haplotype (p < 0.001). Since genetic association studies have linked MyD88 to Hodgkin's lymphoma it is tempting to speculate that MyD88 may contribute to the granuloma formation that characterizes sarcoidosis.

Single-nucleotide polymorphisms in genes encoding toll-like receptor -2, -3, -4, and -9 in a case-control study with bladder cancer susceptibility in a North Indian population

BACKGROUND AND AIMS

Impairment of the immune system may contribute to the risk for having cancer as Toll-like receptors are important for innate immunity. We examined the association between candidate disease-susceptibility polymorphisms in the single nucleotide polymorphism (SNPs) like TLR2 (-196 to-174del), TLR3 (C1377T), TLR4 (Thr399Ile) and TLR9 (G2848A) genes in patients with bladder cancer in a North Indian population.

METHODS

SNPs were comprised of TLR2 (-196 to -174 Del), TLR3(C1377T), TLR4 (Thr399Ile) and TLR9 (G2848A) genes. Allelic and genotypic frequencies of these TLRs SNP from histopathologically confirmed patients of bladder cancer (n = 200) and unrelated healthy controls of similar ethnicity (n = 200) were genotyped by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis.

RESULTS

In TLR2 I/D gene polymorphism, the combination of ID+DD showed a significant 3-fold increased risk (p = 0.001). TLR2 with heterozygous genotype ID showed a 3-fold risk and combination of heterozygous and variant genotype (ID+DD) also showed a 5-fold risk with tumor stage/grade of patients with bladder cancer. The other genotypes of TLR3, 4 and 9 did not exhibit any significant association with bladder cancer risk.

CONCLUSIONS

Our results suggested the involvement of TLR2 (-196 to-174 del) in bladder cancer susceptibility; however, TLR3, 4 and 9 genes were not associated with risk of bladder cancer, implicating that polymorphisms in these tested TLRs genes are not likely to be associated with increased risk for developing bladder cancer. Functional studies in ethnically diverse populations may provide a more comprehensive involvement of innate immunity in identifying the disease-associated variants for the etiology of bladder cancer.

Involvement of Toll-like Receptor 9 polymorphism in cervical cancer development

The role played by the polymorphism located in Toll-like Receptor 9 (TLR9) as a risk factor of cervical cancer remains elusive. Therefore, we studied the association of the TLR9 −1486 T/C (rs187084) and C2848T (rs352140) polymorphisms with cervical cancer. The TLR9 −1486 T/C and C2848T polymorphism was genotyped in 426 patients and 460 unrelated healthy females from the Polish population. Logistic regression analysis adjusting for age, pregnancy, oral contraceptive use, tobacco smoking, and menopausal status showed that both the TLR9 −1486 T/C and C2848T polymorphisms could be a genetic risk factor for cervical cancer. For the TLR9 −1486 T/C polymorphism, the adjusted OR for patients with the C/T genotype versus T/T genotype was 1.371 (95 % CI 1.021–1.842, p = 0.0361), the adjusted OR for the C/C genotype vs the T/T genotype was 1.300 (95 % CI 1.016–1.507, p = 0.0096), and the adjusted OR for the C/T or C/C genotype vs the T/T genotype was 1.448 (95 % CI 1.099–1.908, p = 0.0083). For the C2848T polymorphism, the adjusted OR for patients with the C/T genotype vs C/C genotype was 1.443 (95 % CI 1.019–2.043, p = 0.0380), the adjusted OR for the T/T genotype vs the C/C genotype was 1.237 (95 % CI 1.016–1.507, p = 0.0328), and the adjusted OR for the T/C or T/T genotype vs the C/C genotype was 1.345 (95 % CI 0.976–1.855, p = 0.0700). Our studies suggest that the TLR9 −1486 T/C and C2848T polymorphisms may be a genetic risk factor for cervical cancer.

Exogenous or endogenous Toll-like receptor ligands: which is the MVP in tumorigenesis?

Toll-like receptors (TLRs) are a class of pattern recognition receptors sensing microbial components and triggering an immune response against pathogens. In addition to their role in anti-infection immunity, increasing evidence indicates that engagement of TLRs can promote cancer cell survival and proliferation, induce tumor immune evasion, and enhance tumor metastasis and chemoresistance. Recent studies have demonstrated that endogenous molecules or damage-associated molecular patterns released from damaged/necrotic tissues are capable of activating TLRs and that the endogenous ligands-mediated TLR signaling is implicated in the tumor development and affects the therapeutic efficacy of tumors. Since both exogenous and endogenous TLR ligands can initiate TLR signaling, which is the most valuable player in tumor development becomes an interesting question. Here, we summarize the effect of TLR signaling on the development and progression of tumors, and discuss the role of exogenous and endogenous TLR ligands in the tumorigenesis.

Association of Toll-like receptor (TLR) 2, 3 and 9 genes polymorphism with prostate cancer risk in North Indian population

Prostate cancer (PCa) is the most common cancer among men. It has been suggested that toll like receptors (TLRs) may contribute to PCa pathogenesis by stimulating prostate epithelial cell proliferation in response to infectious stimuli. We performed case control study to analyze the genetic variants of TLR2, 3 and 9 gene polymorphisms with PCa risk in a North Indian population. For this study we genotyped age matched, unrelated 195 PCa patients and 250 healthy controls of similar ethnicity in a case-control study. They were genotyped for TLR2 (-196 to -174 Del), TLR3 (c.1377C/T) [rs3775290] and TLR9 (G2848A) [rs352140] gene polymorphisms using polymerase chain reaction and restriction fragment length polymorphism method. Variant allele Del (D) carriers i.e. (ID + DD) of TLR2 (-196 to -174 Del) SNP, demonstrated 1.57 fold increased risk (p = 0.040; OR = 1.57, 95% CI = 1.02-2.24) as compared to Ins (I) allele, suggesting a dominant effect model involved in the risk of this polymorphism in PCa. However, variants of TLR3 and 9 gene polymorphisms were not associated with PCa risk. Our results suggested the low penetrance variant of TLR2 (-196 to -174 Del) to be at increased PCa risk in North Indian population. Functional studies in ethnically diverse populations may provide a more comprehensive involvement of innate immunity in identifying the disease-associated variants for PCa etiology.

The C allele of rs5743836 polymorphism in the human TLR9 promoter links IL-6 and TLR9 up-regulation and confers increased B-cell proliferation

In humans, allelic variants in Toll-like receptors (TLRs) associate with several pathologies. However, the underlying cellular and molecular mechanisms of this association remain largely unknown. Analysis of the human TLR9 promoter revealed that the C allele of the rs5743836 polymorphism generates several regulatory sites, including an IL-6-responding element. Here, we show that, in mononuclear cells carrying the TC genotype of rs5743836, IL-6 up-regulates TLR9 expression, leading to exacerbated cellular responses to CpG, including IL-6 production and B-cell proliferation. Our study uncovers a role for the rs5743836 polymorphism in B-cell biology with implications on TLR9-mediated diseases and on the therapeutic usage of TLR9 agonists/antagonists.

A genome-wide meta-analysis of nodular sclerosing Hodgkin lymphoma identifies risk loci at 6p21.32

Nodular sclerosing Hodgkin lymphoma (NSHL) is a distinct, highly heritable Hodgkin lymphoma subtype. We undertook a genome-wide meta-analysis of 393 European-origin adolescent/young adult NSHL patients and 3315 controls using the Illumina Human610-Quad Beadchip and Affymetrix Genome-Wide Human SNP Array 6.0. We identified 3 single nucleotide polymorphisms (SNPs) on chromosome 6p21.32 that were significantly associated with NSHL risk: rs9268542 (P = 5.35 × 10(-10)), rs204999 (P = 1.44 × 10(-9)), and rs2858870 (P = 1.69 × 10(-8)). We also confirmed a previously reported association in the same region, rs6903608 (P = 3.52 × 10(-10)). rs204999 and rs2858870 were weakly correlated (r(2) = 0.257), and the remaining pairs of SNPs were not correlated (r(2) < 0.1). In an independent set of 113 NSHL cases and 214 controls, 2 SNPs were significantly associated with NSHL and a third showed a comparable odds ratio (OR). These SNPs are found on 2 haplotypes associated with NSHL risk (rs204999-rs9268528-rs9268542-rs6903608-rs2858870; AGGCT, OR = 1.7, P = 1.71 × 10(-6); GAATC, OR = 0.4, P = 1.16 × 10(-4)). All individuals with the GAATC haplotype also carried the HLA class II DRB1*0701 allele. In a separate analysis, the DRB1*0701 allele was associated with a decreased risk of NSHL (OR = 0.5, 95% confidence interval = 0.4, 0.7). These data support the importance of the HLA class II region in NSHL etiology.

Effects of Toll-like receptor signals in T-cell neoplasms

T-cell neoplasms have poor prognosis and few effective therapeutic options. Therefore, identification of factors in T-cell leukemia/lymphoma that are associated with cancer progression may represent novel therapeutic targets. Recent studies have highlighted a previously unappreciated role for the expression of Toll-like receptors (TLRs) on T cells and their effects on cell survival and proliferation. TLRs can bind exogenous molecules derived from pathogens as well as endogenous self-ligands released from damaged cells. Recent reports demonstrate that TLR engagement on primary mouse or human T cells enhances proliferation and/or cell survival. The mechanisms by which TLR stimulation on T cells influences these parameters and the different T-cell subsets that are affected by TLR stimulation are currently under investigation. Furthermore, neither the biological importance of stimulating TLRs on neoplastic T cells nor the prevalence of TLR expression in T-cell malignancies have yet to be characterized. Based on published reports and compelling preliminary data, we propose that the activation of the TLR-MyD88 signaling pathway in neoplastic T cells contributes to disease progression by reducing cell death and enhancing cell division. In this article, we present both theoretical arguments and experimental data in support of this hypothesis.

Toll Like Receptors Signaling Pathways as a Target for Therapeutic Interventions

This review summarizes the key role of Toll-Like Receptor (TLRs) molecules for igniting the immune system. Activated by a broad spectrum of pathogens, cytokines or other specific molecules, TLRs trigger innate immune responses. Published data demonstrate that the targeting and suppression of TLRs and TLR-related proteins with particular inhibitors may provide pivotal treatments for patients with cancer, asthma, sepsis, Crohn's disease and thrombosis. Many drugs that target cytokines act in the late phases of the activated pathways, after the final peptides, proteins or glycoproteins are formed in the cell environment. TLR activity occurs in the early activation of cellular pathways; consequently inhibiting them might be most beneficial in the treatment of human diseases.

The rs5743836 polymorphism in TLR9 confers a population-based increased risk of non-Hodgkin lymphoma

Non-Hodgkin lymphoma (NHL) has been associated with immunological defects, chronic inflammatory and autoimmune conditions. Given the link between immune dysfunction and NHL, genetic variants in toll-like receptors (TLRs) have been regarded as potential predictive factors of susceptibility to NHL. Adequate anti-tumoral responses are known to depend on TLR9 function, such that the use of its synthetic ligand is being targeted as a therapeutic strategy. We investigated the association between the functional rs5743836 polymorphism in the TLR9 promoter and risk for B-cell NHL and its major subtypes in three independent case-control association studies from Portugal (1160 controls, 797 patients), Italy (468 controls, 494 patients) and the US (972 controls, 868 patients). We found that the rs5743836 polymorphism was significantly overtransmitted in both Portuguese (odds ratio (OR), 1.85; P=7.3E-9) and Italian (OR, 1.84; P=6.0E-5) and not in the US cohort of NHL patients. Moreover, the increased transcriptional activity of TLR9 in mononuclear cells from patients harboring rs5743836 further supports a functional effect of this polymorphism on NHL susceptibility in a population-dependent manner.

Association of polymorphisms in TLR genes and in genes of the Toll-like receptor signaling pathway with cancer risk

Toll-like receptors (TLRs) constitute a family of receptors directly recognizing a wide spectrum of exogenous and endogenous ligands playing the key role in realization of innate and adaptive immune response, and participating in the processes of cell proliferation, survival, apoptosis, angiogenesis, tissue remodeling and repair. Polymorphisms in TLR genes may shift balance between pro- and anti-inflammatory cytokines, modulating the risk of infection, chronic inflammation and cancer. The short list of TLR polymorphisms perspective for oncogenomic investigations can include rs10008492, rs4833103, rs5743815, rs11466657, rs7696175 (TLR1-TLR6-TLR10 gene cluster); rs3804100, rs4696480, -196 - -174 del (Delta22), GT-microsatellite polymorphism (TLR2); 829A/C (TLR3); rs5743836, rs352140 (TLR9). The extended list can additionally include rs4833095 rs5743551, rs5743618 (TLR1); rs5743704, rs62323857, rs1219178642 (TLR2); rs5743305, rs3775291, rs121434431, rs5743316 (TLR3); rs5744168 (TLR5); rs179008 (TLR7); rs3764880, rs2407992 (TLR8); rs352139, rs187084, rs41308230, rs5743844 (TLR9); rs4129009 (TLR10). General reasons for discrepancies between studies are insufficiency of sample size, age/gender/BMI/ethnic/racial differences, differences in prevalence of infectious agent in case and control groups, differences in immune response caused by specific ligand, differences in stratification, methods of diagnostics of cancer or chronic inflammatory conditions, genotyping methods, and chance. Future well-designed studies on large samples should shed light on the significance of TLR polymorphisms for cancer prevention.

A single nucleotide polymorphism in the 3'-untranslated region of MyD88 gene is associated with Buerger disease but not with Takayasu arteritis in Japanese

Buerger disease (BD) and Takayasu arteritis (TA) are rare vascular disorders. Although their etiology and pathogenesis have not been elucidated, several studies have suggested the involvement of innate immunity. Myeloid differentiation primary-response protein 88 (MyD88) is a key signaling adaptor for all Toll-like receptors, which have a central role in innate immunity. In the present study, we evaluated the association of MyD88 with BD and TA. We conducted case-control studies in Japanese populations composing of 131 BD cases, 90 TA cases and 270 healthy controls to be genotyped for a single nucleotide polymorphism rs7744 A>G in the 3'-untranslated region of MyD88 gene. The frequency of GG genotype was significantly lower in the BD patients than in the controls (6.9 vs 15.9%, P=0.011, odds ratio=0.39, 95% confidence interval; 0.19, 0.81), although there was no significant difference in the genotype frequencies between the TA patients and controls. It was suggested that MyD88 may confer resistance to BD in Japanese. Because this is the first report of the association between MyD88 and BD, replication studies in other cohorts are required.

Classical Hodgkin's lymphoma shows epigenetic features of abortive plasma cell differentiation

BACKGROUND

Epigenetic changes are involved in the extinction of the B-cell gene expression program of classical Hodgkin's lymphoma. However, little is known regarding epigenetic similarities between cells of classical Hodgkin's lymphoma and plasma cell myeloma, both of which share extinction of the gene expression program of mature B cells.

DESIGN AND METHODS

Global histone H3 acetylation patterns were determined in cell lines derived from classical Hodgkin's lymphoma, plasma cell myeloma and B-cell lymphoma by chromatin immunoprecipitation and subsequent hybridization onto promoter tiling arrays. H3K27 trimethylation was analyzed by chromatin immunoprecipitation and real-time DNA polymerase chain reaction for selected genes. Epigenetic modifications were compared to gene expression data.

RESULTS

Characteristic B-cell genes were hypoacetylated in classical Hodgkin's lymphoma and plasma cell myeloma cell lines as demonstrated by comparison of their histone H3 acetylation patterns to those of B-cell lines. However, the number of genes jointly hyperacetylated and expressed in classical Hodgkin' lymphoma and plasma cell myeloma cell lines, such as IRF4/MUM1 and RYBP, is limited. Moreover, H3K27 trimethylation for selected characteristic B-cell genes revealed that this additional epigenetic silencing is much more prevalent in classical Hodgkin's lymphoma than in plasma cell myeloma.

CONCLUSIONS

Our epigenetic data support the view that classical Hodgkin's lymphoma is characterized by abortive plasma cell differentiation with a down-regulation of characteristic B-cell genes but without activation of most genes typical of plasma cells.

Comprehensive genetic assessment of a functional TLR9 promoter polymorphism: no replicable association with asthma or asthma-related phenotypes

Background

Prior studies suggest a role for a variant (rs5743836) in the promoter of toll-like receptor 9 (TLR9) in asthma and other inflammatory diseases. We performed detailed genetic association studies of the functional variant rs5743836 with asthma susceptibility and asthma-related phenotypes in three independent cohorts.

Methods

rs5743836 was genotyped in two family-based cohorts of children with asthma and a case-control study of adult asthmatics. Association analyses were performed using chi square, family-based and population-based testing. A luciferase assay was performed to investigate whether rs5743836 genotype influences TLR9 promoter activity.

Results

Contrary to prior reports, rs5743836 was not associated with asthma in any of the three cohorts. Marginally significant associations were found with FEV₁ and FVC (p = 0.003 and p = 0.008, respectively) in one of the family-based cohorts, but these associations were not significant after correcting for multiple comparisons. Higher promoter activity of the CC genotype was demonstrated by luciferase assay, confirming the functional importance of this variant.

Conclusion

Although rs5743836 confers regulatory effects on TLR9 transcription, this variant does not appear to be an important asthma-susceptibility locus.

Evaluation of Toll-like receptors 3 (c.1377C/T) and 9 (G2848A) gene polymorphisms in cervical cancer susceptibility

Cervical cancer is emerging as a leading cause of morbidity and mortality in women worldwide. Toll-like Receptor (TLR) gene polymorphisms may contribute to subsequent inter-individual variability in cancer susceptibility. The present study aimed to identify the role of TLR 3 (c.1377C/T) [rs3775290] and TLR 9 (G2848A) [rs352140] gene polymorphisms in the risk of developing cervical cancer in North India. Peripheral blood samples were collected from 200 histopathologically confirmed cervical cancer patients from North India and 200 unrelated, cancer-free, age-matched healthy female controls of similar ethnicity. Genomic DNA was extracted using the salting-out method, and genotyped for TLR 3 and TLR 9 using polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP). Our data demonstrated a lack of association between TLR 3 (c.1377C/T) and TLR 9 (G2848A) gene polymorphisms and the risk of developing cervical cancer. TLR 3 CT + TT was marginally associated (P = 0.061; age-adjusted OR = 1.46; 95% CI = 0.98-2.16) with cervical cancer susceptibility. The AA genotype of TLR 9 showed borderline significance (P = 0.053) conferring a marginal increased risk (OR = 2.63, 95%CI = 0.99-7.01) for advanced cancer stages (III + IV). Further, TLR 3 and 9 polymorphisms did not have a significant role in modulation of risk due to tobacco usage in cervical cancer patients. Our study suggests only marginal role of TLR 3 and 9 gene polymorphisms in cervical cancer susceptibility in North India; however, future studies in ethnically diverse populations may provide a more comprehensive involvement of innate immunity in cervical cancer etiology in women worldwide.

Single nucleotide polymorphisms of pattern recognition receptors and chronic periodontitis

BACKGROUND AND OBJECTIVE

Periodontitis is a multifactorial disease influenced partly by genetics. Activation of pattern recognition receptors (PRRs) can lead to the up-regulation of inflammatory pathways, resulting in periodontal tissue destruction. Hence, functional polymorphisms located in PRRs can explain differences in host susceptibility to periodontitis. This study investigated single nucleotide polymorphisms of PRRs including toll-like receptor (TLR)2 (G2408A), TLR4 (A896G), TLR9 (T1486C), TLR9 (T1237C) and CD14 (C260T) in patients with chronic periodontitis and in periodontally healthy subjects.

METHODS

One-hundred and fourteen patients with chronic periodontitis and 77 periodontally healthy subjects were genotyped using TaqMan® allelic discrimination assays. Fisher's exact test and chi-square analyses were performed to compare genotype and allele frequencies.

RESULTS

The frequency of subjects with the CC genotype of CD14 (C260T) (24.6% in the chronic periodontitis group vs. 13% in the periodontally healthy group) and those expressing the T allele of CD14 (C260T) (CT and TT) (75.4% in the chronic periodontitis group vs. 87% in the periodontally healthy group) was statistically different among groups (p = 0.04). Homozygocity for the C allele of the CD14 (C260T) polymorphism (CC) was associated with a two--fold increased susceptibility to periodontitis (p = 0.04; odds ratio, 2.49; 95% confidence interval, 1.06-6.26). Individuals with the CC genotype of TLR9 (T1486C) (14.9% in the chronic periodontitis group vs. 28.6% in the periodontally healthy group) and those expressing the T allele of TLR9 (T1486C) (CT and TT) (85.1% in the chronic periodontitis group vs. 71.4% in the periodontally healthy group) were also significantly differently distributed between groups without adjustment (p = 0.03). Further analysis of nonsmokers revealed a significant difference in the distribution of genotypes between groups for TLR9 (T1486C; p = 0.017) and CD14 (C260T; p = 0.03), polymorphisms again without adjustment.

CONCLUSION

The CC genotype of CD14 (C260T) is related to susceptibility to chronic periodontitis in Caucasians. In addition, differences observed in the distribution of TLR9 (T1486C) genotypes between groups warrant further investigation.