High toll-like receptor (TLR) 9 expression is associated with better prognosis in surgically treated pancreatic cancer patients

Associations Between Serum Soluble Toll-like Receptors 4 and 9 and Breast Cancer in Egyptian Patients

BACKGROUND

Toll-like receptors (TLRs) play an important role in regulation of immune cells and are vital in tumorigenesis due to its crucial role in inflammatory microenvironment regulation, as they promote the synthesis and release of inflammatory cytokines and chemokines. Toll-like receptors 4 and TLRs 9 were found to be highly expressed in breast cancer. The aim of this study is to investigate the soluble toll-like receptors 4 and 9 (sTLR4 and sTLR9) as potential biomarkers for diagnosis and prognosis of breast cancer and their association with the clinicopathological parameters of breast cancer.

PATIENTS AND METHOD

In this retrospective case-control study, 186 female subjects were recruited and divided into three groups, Group I: 62 healthy control, Group II: 62 subjects diagnosed with non-metastatic breast cancer, and Group III: 62 subjects diagnosed with metastatic breast cancer. Enzyme-linked immunosorbent assay (ELISA) technique was used to quantify the levels of sTLR4 and sTLR9 in serum.

RESULTS

Both non-metastatic and metastatic groups showed significant higher levels of both serum sTLR4 and sTLR9 expression compared to healthy controls. Only sTLR9 was significantly increased among metastatic patients compared to non-metastatic group. Serum levels of sTLR9 and sTLR4 were still significantly associated with breast cancer in a multiple logistic regression model (P = <.001). ROC curves showed that both sTLR4 and sTLR9 can be a significant parameter to discriminate between normal females and breast cancer patients.

CONCLUSION

Soluble toll-like receptors 4 and sTLR9 are over-expressed in patients with metastatic and non-metastatic BC than in benign cases. The expression levels of sTLR4 and TLR9 have clinical interest as indicators of tumor aggressiveness suggested to be prognostic biomarkers. Toll-like receptors may represent therapeutic targets in breast cancer.

The expression and prognostic value of toll-like receptors (TLRs) in pancreatic cancer patients treated with neoadjuvant therapy

OBJECTIVES

Toll-like receptors (TLRs) play a pivotal role in the immune system and carcinogenesis. There is no research on TLR expression and association with survival among preoperatively treated pancreatic cancer patients. We studied the expression intensity and prognostic value of TLRs in pancreatic cancer patients treated with neoadjuvant therapy (NAT) and compared the results to patients undergoing upfront surgery (US).

METHOD

Between 2000 and 2015, 71 borderline resectable patients were treated with NAT and surgery and 145 resectable patients underwent upfront surgery at Helsinki University Hospital, Finland. We immunostained TLRs 1-5, 7, and 9 on sections of tissue-microarray. We classified TLR expression as 0 (negative), 1 (mild), 2 (moderate), or 3 (strong) and divided into high (2-3) and low (0-1) expression for statistical purposes.

RESULTS

Among TLRs 1, 3, and 9 (TLR1 81% vs 70%, p = 0.008; TLR3 92% vs 68%, p = 0.001; TLR9 cytoplasmic 83% vs 42%, p<0.001; TLR9 membranous 53% vs 25%, p = 0.002) NAT patients exhibited a higher immunopositivity score more frequently than patients undergoing upfront surgery. Among NAT patients, a high expression of TLR1 [Hazards ratio (HR) 0.48, p<0.05] associated with a longer postoperative survival, whereas among US patients, high expression of TLR5 (HR 0.64, p<0.05), TLR7 (HR 0.59, p<0.01, and both TLR7 and TLR9 (HR 0.5, p<0.01) predicted a favorable postoperative outcome in separate analysis adjusted for background variables.

CONCLUSIONS

We found higher immunopositive intensities among TLRs 1, 3, and 9 in NAT patients. A high TLR1 expression associated with a longer survival among NAT patients, however, among US patients, high expression intensity of TLR5 and TLR7 predicted a favorable postoperative outcome in the adjusted analysis.

Tilsotolimod: an investigational synthetic toll-like receptor 9 (TLR9) agonist for the treatment of refractory solid tumors and melanoma

INTRODUCTION

Cancer immunotherapy has seen tremendous strides in the past 15 years, with the introduction of several novel immunotherapeutic agents. Nevertheless, as clinical practice has shown, significant challenges remain with a considerable number of patients responding sub-optimally to available therapeutic options. Research has demonstrated the important immunoregulatory role of the tumor microenvironment (TME), with the potential to either hinder or promote an effective anti-tumor immune response. As such, scientific efforts have focused on investigating novel candidate immunomodulatory agents with the potential to alter the TME toward a more immunopotentiating composition.

AREAS COVERED

Herein, we discuss the novel investigational toll-like receptor 9 agonist tilsotolimod currently undergoing phase II and III clinical trials for advanced refractory cancer, highlighting its mode of action, efficacy, tolerability, and potential future applications in the treatment of cancer. To this effect, we conducted an exhaustive Web of Science and PubMed search to evaluate available research on tilsotolimod as of August 2021.

EXPERT OPINION

With encouraging early clinical results demonstrating extensive TME immunomodulation and abscopal effects on distant tumor lesions, tilsotolimod has emerged as a potential candidate immunomodulatory agent with the possibility to augment currently available immunotherapy and provide novel avenues of treatment for patients with advanced refectory cancer.

The Role of Toll-like Receptors (TLRs) Mediated Inflammation in Pancreatic Cancer Pathophysiology

Pancreatic cancer (PC) is one of the most lethal forms of cancer, characterized by its aggressiveness and metastatic potential. Despite significant improvements in PC treatment and management, the complexity of the molecular pathways underlying its development has severely limited the available therapeutic opportunities. Toll-like receptors (TLRs) play a pivotal role in inflammation and immune response, as they are involved in pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs). Activation of TLRs initiates a signaling cascade, which in turn, leads to the transcription of several genes involved in inflammation and anti-microbial defense. TLRs are also deregulated in several cancers and can be used as prognostic markers and potential targets for cancer-targeted therapy. In this review we discuss the current knowledge about the role of TLRs in PC progression, focusing on the available TLRs-targeting compounds and their possible use in PC therapy.

TLR2 activation promotes tumour growth and associates with patient survival and chemotherapy response in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) has an extremely poor prognosis, and is plagued by a paucity of targeted treatment options and tumour resistance to chemotherapeutics. The causal link between chronic inflammation and PDAC suggests that molecular regulators of the immune system promote disease pathogenesis and/or therapeutic resistance, yet their identity is unclear. Here, we couple endoscopic ultrasound-guided fine-needle aspiration, which captures tumour biopsies from all stages, with whole transcriptome profiling of PDAC patient primary tumours to reveal enrichment of the innate immune Toll-like receptor 2 (TLR2) molecular pathway. Augmented TLR2 expression associated with a 4-gene "TLR2 activation" signature, and was prognostic for survival and predictive for gemcitabine-based chemoresistance. Furthermore, antibody-mediated anti-TLR2 therapy suppressed the growth of human PDAC tumour xenografts, independent of a functional immune system. Our results support TLR2-based therapeutic targeting for precision medicine in PDAC, with further clinical utility that TLR2 activation is prognostic and predictive for chemoresponsiveness.

Pancreatic Cancer and Immunotherapy: A Clinical Overview

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease with high mortality. The vast majority of patients present with unresectable, advanced stage disease, for whom standard of care chemo(radio)therapy may improve survival by several months. Immunotherapy has led to a fundamental shift in the treatment of several advanced cancers. However, its efficacy in PDAC in terms of clinical benefit is limited, possibly owing to the immunosuppressive, inaccessible tumor microenvironment. Still, various immunotherapies have demonstrated the capacity to initiate local and systemic immune responses, suggesting an immune potentiating effect. In this review, we address PDAC's immunosuppressive tumor microenvironment and immune evasion methods and discuss a wide range of immunotherapies, including immunomodulators (i.e., immune checkpoint inhibitors, immune stimulatory agonists, cytokines and adjuvants), oncolytic viruses, adoptive cell therapies (i.e., T cells and natural killer cells) and cancer vaccines. We provide a general introduction to their working mechanism as well as evidence of their clinical efficacy and immune potentiating abilities in PDAC. The key to successful implementation of immunotherapy in this disease may rely on exploitation of synergistic effects between treatment combinations. Accordingly, future treatment approaches should aim to incorporate diverse and novel immunotherapeutic strategies coupled with cytotoxic drugs and/or local ablative treatment, targeting a wide array of tumor-induced immune escape mechanisms.

Digital Gene Expression Analysis of Epithelioid and Sarcomatoid Mesothelioma Reveals Differences in Immunogenicity

Malignant pleural mesothelioma (MPM) is an aggressive malignancy associated with asbestos exposure. Median survival ranges from 14 to 20 months after initial diagnosis. As of November 2020, the FDA approved a combination of immune checkpoint inhibitors after promising intermediate results. Nonetheless, responses remain unsatisfying. Adequate patient stratification to improve response rates is still lacking. This retrospective study analyzed formalin fixed paraffin embedded specimens from a cohort of 22 MPM. Twelve of those samples showed sarcomatoid, ten epithelioid differentiation. Complete follow-up, including radiological assessment of response by modRECIST and time to death, was available with reported deaths of all patients. RNA of all samples was isolated and subjected to digital gene expression pattern analysis. Our study revealed a notable difference between epithelioid and sarcomatoid mesothelioma, showing differential gene expression for 304/698 expressed genes. Whereas antigen processing and presentation to resident cytotoxic T cells as well as phagocytosis is highly affected in sarcomatoid mesothelioma, cell-cell interaction via cytokines seems to be of greater importance in epithelioid cases. Our work reveals the specific role of the immune system within the different histologic subtypes of MPM, providing a more detailed background of their immunogenic potential. This is of great interest regarding therapeutic strategies including immunotherapy in mesothelioma.

Tumor-Associated Macrophages in Pancreatic Ductal Adenocarcinoma: Origin, Polarization, Function, and Reprogramming

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy. PDAC is only cured by surgical resection in its early stage, but there remains a relatively high possibility of recurrence. The development of PDAC is closely associated with the tumor microenvironment. Tumor-associated macrophages (TAMs) are one of the most abundant immune cell populations in the pancreatic tumor stroma. TAMs are inclined to M2 deviation in the tumor microenvironment, which promotes and supports tumor behaviors, including tumorigenesis, immune escape, metastasis, and chemotherapeutic resistance. Herein, we comprehensively reviewed the latest researches on the origin, polarization, functions, and reprogramming of TAMs in PDAC.

Toll-like receptors (TLRs): An old family of immune receptors with a new face in cancer pathogenesis

In the dark path of tumorigenesis, the more carefully the cancer biology is studied, the more brilliant answers could be given to the countless questions about its orchestrating derivers. The identification of the correlation between Toll-like receptors (TLRs) and different processes involved in carcinogenesis was one of the single points of blinding light highlighting the interconnection between the immune system and cancer. TLRs are a wide family of single-pass membrane-spanning receptors that have developed through the evolution to recognize the structurally conserved molecules derived from microorganisms or damaged cells. But this is not everything about these receptors as they could orchestrate several downstream signalling pathways leading to the formation or suppression of cancer cells. The present review is tempted to provide a concise schematic about the biology and the characters of TLRs and also summarize the major findings of the regulatory role of TLRs and their associated signalling in the pathogenesis of human cancers.

High expression levels of TLR9 and PD-L1 indicates a poor prognosis in patients with angioimmunoblastic T-cell lymphoma: a retrospective study of 88 cases in a single center

Background: The role of TLR9 expressed by tumor cells in evading immune surveillance was confirmed. PD-L1 expression in tumor cells plays a key role in tumor immune escape, which is associated with poor prognosis. However, the clinical relevance of TLR9 and PD-L1 expression in angioimmunoblastic T-cell lymphoma (AITL) has not been evaluated.

Materials and methods: In this study, we identified differentially expressed genes in AITL samples by bioinformatic analysis, and we first examined TLR9 and PD-L1 expression by immunohistochemical staining in patients with AITL and compared these data with clinical features and survival time.

Results: It was found that the expression of PD-L1 and multiple TLRs was higher in AITL than normal T-cell samples, and TLR9 and PD-L1 expression displayed complex interactions by bioinformatic analysis. The rates of TLR9 and PD-L1 high expression were 69% and 50%, respectively. High expression of either TLR9 or PD-L1 indicated a poor survival rate for patients with AITL. Multivariate analysis further confirmed that high expression levels of TLR9 and PD-L1 were unfavorable prognostic factors for AITL. We further found inferior overall survival in AITL with clinical features of ECOG status ≥ 2, advanced-stage, elevated serum LDH levels, elevated serum β₂-MG levels, and high IPI score.

Conclusion: TLR9 and PD-L1 expression may be a novel predictor of prognosis for patients with AITL and may serve as potential therapeutic strategy.

TLR9 expression is associated with PD-L1 expression and indicates a poor prognosis in patients with peripheral T-cell lymphomas

Toll-like receptor9 (TLR9), a member of pattern recognition receptors, play an important role in tumor immunologic surveillance. However, the clinical impact of TLR9 and programmed cell death-ligand 1 (PD-L1) in peripheral T-cell lymphomas (PTCL) remains unclear. In this study, we examined the expression of TLR9 and PD-L1 by immunohistochemical staining in patients with PTCL, and evaluated the clinical significance between expression and clinicopathological features. We found that the rates of high expression of TLR9 and PD-L1 on tumor cells were 65.3% and 45.8% in PTCL, respectively. TLR9 expression was associated with PD-L1 expression in PTCL. Moreover, TLR9 expression was associated with gender, ECOG score, Ki-67 expression, while PD-L1 expression was associated with the number of extranodal involvement and platelet count. High expression of either TLR9 or PD-L1 indicated a poor survival rate for patients with PTCL. Multivariate analysis confirmed that high expression of TLR9 and PD-L1 were unfavorable prognostic factors for patients with PTCL. Thus, TLR9 and PD-L1 expression might be important on the point of prognostic markers in PTCL.

Exosomes and pancreatic diseases: status, challenges, and hopes

Pancreatic disease, including pathologies such as acute pancreatitis (AP), chronic pancreatitis (CP), and pancreatic cancer (PC), is a complicated and dangerous clinical condition involving the disruption of exocrine or endocrine function. PC has one of the highest mortality rates among cancers due to insufficient diagnosis in early stages. Furthermore, efficient treatment options for the disease etiologies of AP and CP are lacking. Thus, the identification of new therapeutic targets and reliable biomarkers is required. As essential couriers in intercellular communication, exosomes have recently been confirmed to play an important role in pancreatic disease, but the specific underlying mechanisms are unknown. Herein, we summarize the current knowledge of exosomes in pancreatic disease with respect to diagnosis, molecular mechanisms, and treatment, proposing new ideas for the study of pancreatic disease.

Toll-like receptor 1 predicts favorable prognosis in pancreatic cancer

Background

The link between inflammation and carcinogenesis is indisputable. In trying to understand key factors at play, cancer research has developed an interest in the toll-like receptors (TLRs), which have shown signs of having prognostic value in various adenocarcinomas. We began investigating the expression of toll-like receptors 1, 3, 5, 7, and 9 to evaluate their prognostic value of patients with pancreatic ductal adenocarcinoma (PDAC).

Methods

We collected tumor biopsies from 154 stage I-III PDAC patients surgically treated at Helsinki University Hospital between 2002 and 2011, excluding patients undergoing neoadjuvant therapy. We used tissue microarray slides and immunohistochemistry to assess expression of TLRs 1, 3, 5, 7, and 9 in PDAC tissue. Immunopositivity scores and clinicopathological characteristics were subjected to Fisher’s exact test or the linear-by-linear association test. For the survival analysis, we applied the Kaplan-Meier method and log-rank test, and the Cox regression proportional hazard model served for univariate and multivariate analyses.

Results

Strong TLR1 expression was observable in 60 (39%), strong TLR3 in 48 (31%), strong TLR5 in 58 (38%), strong TLR7 in 14 (9%), and strong TLR9 in 22 (14%) patients. The multivariate analysis showed strong TLR1 expression to associate with better survival than moderate, low, or negative expression (HR = 0.68; 95% CI 0.47–0.99; p = 0.044). Additionally, those few patients with tumors negative for TLR1, TLR3, TLR7, or TLR9 fared poorly (HR = 2.41; 95% CI 1.31–4.43; p = 0.005; n = 13).

Conclusion

Strong TLR1 expression suggested better prognosis in PDAC patients, whereas negative expression of TLR1, TLR3, TLR7, or TLR9 was a sign of poor prognosis.

Significance and Role of Pattern Recognition Receptors in Malignancy

Pattern recognition receptors (PRRs) are members of innate immunity, playing pivotal role in several immunological reactions. They are known to act as a bridge between innate and adaptive immunity. They are expressed on several normal cell types but have been shown with increasing frequency on/in tumor cells. Significance of this phenomenon is largely unknown, but it has been shown by several authors that they, predominantly Toll-like receptors (TLRs), act in the interest of tumor, by promotion of its growth and spreading. Preparation of artificial of TLRs ligands (agonists) paved the way to use them as a therapeutic agents for cancer, so far in a limited scale. Agonists may be combined with conventional anti-cancer modalities with apparently promising results. PRRs recognizing nucleic acids such as RIG-1 like receptors (sensing RNA) and STING (sensing DNA) constitute a novel promising approach for cancer immunotherapy.

Extracellular Histones Activate Plasma Membrane Toll-Like Receptor 9 to Trigger Calcium Oscillations in Rat Pancreatic Acinar Tumor Cell AR4-2J

In acute pancreatitis, histones are released by infiltrating neutrophils, but how histones modulate pancreatic acinar cell function has not been investigated. We have examined histone modulation of rat pancreatic acini and pancreatic acinar tumor cell AR4-2J by calcium imaging. Histones were found to have no effect on calcium in pancreatic acini but blocked calcium oscillations induced by cholecystokinin or acetylcholine. Both mixed (Hx) and individual (H1, H2A, H2B, H3, H4) histones induced calcium oscillations in AR4-2J. RT-PCR and Western blot verified the expression of histone-targeted Toll-like receptor (TLR) 2, 4 and 9. Immunocytochemistry identified TLR2/TLR4 on apical plasma membrane and TLR9 in zymogen granule regions in pancreatic acini. TLR2 was found on neighboring and TLR9 on peripheral plasma membranes, but TLR4 was in the nucleus in AR4-2J clusters. Neither TLR2 agonist zymosan-A nor TLR4 agonist lipopolysaccharide had any effect on calcium, but TLR9 agonist ODN1826 induced calcium oscillations; TLR9 antagonist ODN2088 blocked H4-induced calcium oscillations in AR4-2J, which also disappeared after treatment of AR4-2J with glucocorticoid dexamethasone, with concurrent TLR9 migration from plasma membrane to cell interiors. TLR9 down regulation with siRNA suppressed H4-induced calcium oscillations. These data together suggest that extracellular histones activate plasma membrane TLR9 to trigger calcium oscillations in AR4-2J cells.

Toll-like receptors 2, 4 and 9 and hypoxia markers HIF-1alpha and CAIX in pancreatic intraepithelial neoplasia

Pancreatic cancer arises from precursor lesions called pancreatic intraepithelial neoplasia (PanIN) characterized by inflammatory microenvironment. In pancreatic cancer, strong innate immunity and hypoxia responses are typical. Occurrence and relationship of these responses in human PanINs is unknown. We have studied the expression of toll-like receptors (TLR) TLR2, TLR4 and TLR9, and hypoxia markers HIF-1alpha and Carbonic anhydrase IX (CAIX) in normal and inflamed pancreatic ducts, in PanINs and in cancers. The samples of 69 surgically resected pancreatic ductal adenocarcinoma patients were stained using immunohistochemistry. We found TLR2, TLR9, HIF-1alpha and CAIX to be prominently expressed in pancreatic intraepithelial neoplasia. Expression of TLR2 showed a linear increase from PanIN1 to PanIN3, while the highest TLR4 expression was detected in inflamed ducts, and TLR9 expression in PanIN1 lesions. Within the PanIN1-group, nuclear HIF-1alpha correlated with membranous and cytoplasmic TLR2 expression (ρ = 0.982 and 0.815; p < 0.001 and p = 0.025, respectively), and in the PanIN2-group nuclear HIF-1alpha correlated with nuclear TLR9 expression 0.636, p = 0.026). Our findings show that the expression of TLRs 2, 4 and 9, and hypoxia markers HIF-1alpha and CAIX is abnormal in pancreatic intraepithelial neoplasia suggesting that both the innate immunity activation and hypoxia response are involved in early pancreatic carcinogenesis. However, these processes might be independent.

Prognostic role of Toll-like receptors in cancer: a meta-analysis

Background

Recent studies have shown that Toll-like receptors (TLRs) may be associated with cancers. The aim of this meta-analysis is to summarize the predicting role of TLRs for survival in patients with a variety of carcinomas.

Materials and methods

Eligible studies were identified and assessed for quality through multiple search strategies. We collected data from studies investigating the relationship between the expression level of TLRs and survival in cancer patients. Studies were pooled and combined hazard ratios (HRs) of TLRs for survival were analyzed.

Results

A total of 24 studies, including 2,812 patients with various cancers, were identified for the meta-analysis. Importantly, this meta-analysis showed that higher expression levels of TLR4 or TLR7 in tumor tissues could predict poorer survival, with the pooled HR being 1.29 (95% CI: 1.17, 1.42) and 1.71 (95% CI: 1.38, 2.12), respectively. However, higher expression of TLR9 had no significant association with outcome as HR was 0.84 (95% CI: 0.62, 1.115). Heterogeneity existed in TLR4 and TLR9 studies (P-value <0.001) but not in TLR7 studies (P-value >0.05).

Conclusion

The expression level of TLR4 or TLR7 in cancerous tissue may have a prognosis value in patients with various cancers.

Prognostic value of platelet-to-lymphocyte ratio in pancreatic cancer: a comprehensive meta-analysis of 17 cohort studies

Background and aims

Several studies were conducted to explore the prognostic value of platelet-to-lymphocyte ratio (PLR) in pancreatic cancer and have reported contradictory results. This study aims to summarize the prognostic role of PLR in pancreatic cancer.

Materials and methods

Embase, PubMed and Cochrane Library were completely searched. The cohort studies focusing on the prognostic role of PLR in pancreatic cancer were eligible. The overall survival (OS) and progression-free survival (PFS) were analyzed.

Results

Fifteen papers containing 17 cohort studies with pancreatic cancer were identified. The results showed patients that with low PLR might have longer OS when compared to the patients with high PLR (hazard ratio=1.28, 95% CI=1.17–1.40, P<0.00001; I²=42%). Similar results were observed in the subgroup analyses of OS, which was based on the analysis model, ethnicity, sample size and cut-off value. Further analyses based on the adjusted potential confounders were conducted, including CA199, neutrophil-to-lymphocyte ratio, modified Glasgow Prognostic Score, albumin, C-reactive protein, Eastern Cooperative Oncology Group, stage, tumor size, nodal involvement, tumor differentiation, margin status, age and gender, which confirmed that low PLR was a protective factor in pancreatic cancer. In addition, low PLR was significantly associated with longer PFS when compared to high PLR in pancreatic cancer (hazard ratio=1.27, 95% CI=1.03–1.57, P=0.03; I²=33%).

Conclusion

In conclusion, it was found that high PLR is an unfavorable predictor of OS and PFS in patients with pancreatic cancer, and PLR is a promising prognostic biomarker for pancreatic cancer.

Toll-like receptor 5 and 7 expression may impact prognosis of HPV-positive oropharyngeal squamous cell carcinoma patients

A large subset of oropharyngeal squamous cell carcinomas (OPSCCs) is associated with HPV infection and has better outcome than non-viral-related tumors. Various malignancies also carry a role for TLRs, key activators of inflammation and innate immunity. We examined the expression of TLRs in OPSCC, and their association with HPV status and treatment outcome. TLR 5, 7, 9, and p16 were studied by immunohistochemistry and HPV status was detected with in situ hybridization in 202 tumors of consecutively treated OPSCC patients using tissue microarray method. The relations between TLR expression and HPV status, p16 expression, clinicopathological factors, and survival were analyzed. TLR 5, 7, and 9 expression patterns differed between HPV-positive and -negative tumors, and they were statistically significantly associated with history of smoking, heavy drinking, tumor site, grade, size (T), metastasis (N), and stage. Moreover, in HPV-positive tumors the expression of TLR 5 and 7 correlated with tumor recurrence. After adjustment, among HPV-positive OPSCC patients, high TLR 5 and low TLR 7 expression were associated with poor disease-specific survival. Our results indicate that TLR 5 and 7 may have a role in the prognostication of HPV-positive OPSCC, however, further studies are needed to clarify the comprehensive role of these TLRs in OPSCC.

Lower frequency of TLR9 variant associated with protection from breast cancer among African Americans

Introduction

Toll-like receptor 9 (TLR9) is an innate immune system DNA-receptor that regulates tumor invasion and immunity in vitro. Low tumor TLR9 expression has been associated with poor survival in Caucasian patients with triple negative breast cancer (TNBC). African American (AA) patients with TNBC have worse prognosis than Caucasians but whether this is due to differences in tumor biology remains controversial. We studied the prognostic significance of tumor Toll like receptor-9 (TLR9) protein expression among African American (AA) triple negative breast cancer (TNBC) patients. Germline TLR9 variants in European Americans (EAs) and AAs were investigated, to determine their contribution to AA breast cancer risk.

Methods

TLR9 expression was studied with immunohistochemistry in archival tumors. Exome Variant Server and The Cancer Genome Atlas were used to determine the genetic variation in the general EA and AA populations, and AA breast cancer cases. Minor allele frequencies (MAFs) were compared between EAs (n = 4300), AAs (n = 2203), and/or AA breast cancer cases (n = 131).

Results

Thirty-two TLR9 variants had a statistically significant MAF difference between general EAs and AAs. Twenty-one of them affect a CpG site. Rs352140, a variant previously associated with protection from breast cancer, is more common in EAs than AAs (p = 2.20E-16). EAs had more synonymous alleles, while AAs had more rare coding alleles. Similar analyses comparing AA breast cancer cases with AA controls did not reveal any variant class differences; however, three previously unreported TLR9 variants were associated with late onset breast cancer. Although not statistically significant, rs352140 was observed less frequently in AA cases compared to controls. Tumor TLR9 protein expression was not associated with prognosis.

Conclusions

Tumor TLR9 expression is not associated with prognosis in AA TNBC. Significant differences were detected in TLR9 variant MAFs between EAs and AAs. They may affect TLR9 expression and function. Rs352140, which may protect from breast cancer, is 1.6 X more common among EAs. These findings call for a detailed analysis of the contribution of TLR9 to breast cancer pathophysiology and health disparities.