Microbiota in the Throat and Risk Factors for Laryngeal Carcinoma

Metagenomic shotgun sequencing reveals the enrichment of Salmonella and Mycobacterium in larynx due to prolonged ethanol exposure

The exposure of ethanol increases the risk of head and neck inflammation and tumor progression. However, limited studies have investigated the composition and functionality of laryngeal microbiota under ethanol exposure. We established an ethanol-exposed mouse model to investigate the changes in composition and function of laryngeal microbiota using Metagenomic shotgun sequencing. In the middle and late stages of the experiment, the laryngeal microbiota of mice exposed to ethanol exhibited obvious distinguished from that of the control group on principal-coordinate analysis (PCoA) plots. Among the highly abundant species, Salmonella enterica and Mycobacterium marinum were likely to be most impacted. Our findings indicated that the exposure to ethanol significantly increased their abundance in larynxes in mice of the same age, which has been confirmed through FISH experiments. Among the species-related functions and genes, metabolism is most severely affected by ethanol. The difference was most obvious in the second month of the experiment, which may be alleviated later because the animal established tolerance. Notable enrichments concerning energy, amino acid, and carbohydrate metabolic pathways occurred during the second month under ethanol exposure. Finally, based on the correlation between species and functional variations, a network was established to investigate relationships among microbiota, functional pathways, and related genes affected by ethanol. Our data first demonstrated the continuous changes of abundance, function and their interrelationship of laryngeal microbiota under ethanol exposure by Metagenomic shotgun sequencing.

Importance

Ethanol may participate in the inflammation and tumor progression by affecting the composition of the laryngeal microbiota. Here, we applied the metagenomic shotgun sequencing instead of 16 S rRNA sequencing method to identify the laryngeal microbiota under ethanol exposure. Salmonella enterica and Mycobacterium marinum are two dominant species that may play a role in the reconstruction of the laryngeal microenvironment, as their local abundance increases following exposure to ethanol. The metabolic function is most evidently impacted, and several potential metabolic pathways could be associated with alterations in microbiota composition. These findings could help us better understand the impact of prolonged ethanol exposure on the microbial composition and functionality in the larynx.

Assessing the oral microbiome of head and neck cancer patients before and during radiotherapy

OBJECTIVE

To characterize the oral microbiome of patients with head and neck squamous cell carcinoma (HNSCC) before and during radiotherapy (RT), compared to healthy individuals. Evaluating the impact of oral microbiome in the clinical outcomes one year following the end of RT.

METHODS

Oral samples were collected from HNSCC patients who underwent RT using the following regimens: no dose received (T0), dose 12-16 Gy (T1), dose 30-36 Gy (T2) and dose ≥ 60 Gy (T3). Samples from healthy individuals were also collected only once as a control group. Regions V1-V2 of the 16S rRNA were sequenced by Illumina and analyzed using Mothur.

RESULTS

49 patients with HNSCC and 25 healthy individuals were included. At T0, HNSCC patients showed a lower abundance of Firmicutes and Streptococcus (p = 0.011, p = 0.002) and a higher abundance of Bacteroidetes (p = 0.005) compared to healthy individuals. During RT, Fusobacterium (p = 0.017) and Porphyromonas (p = 0.0008) decreased, while Streptococcus increased at T1 (p = 0.001). By T3, the differences in Firmicutes, Bacteroidetes, and Streptococcus between the control and HNSCC groups were no longer significant (p > 0.3). Patients with higher initial abundances of Porphyromonas (p = 0.012) and Fusobacterium (p = 0.017) had poorer outcomes, including recurrence, metastasis, and death. In contrast, disease-free patients had a higher abundance of Streptococcus (p = 0.004).

CONCLUSION

Oral microbiome dysbiosis was found in HNSCC patients. By the end of RT, the main initial differences in phylum and genus abundance observed at T0 between the control and HNSCC groups were no longer present. Higher abundances of Fusobacterium and Porphyromonas were associated with poor outcomes.

Interaction of microbiota, mucosal malignancies, and immunotherapy-Mechanistic insights

The microbiome has emerged as a crucial modulator of host-immune interactions and clearly impacts tumor development and therapy efficacy. The microbiome is a double-edged sword in cancer development and therapy as both pro-tumorigenic and anti-tumorigenic bacterial taxa have been identified. The staggering number of association-based studies in various tumor types has led to an enormous amount of data that makes it difficult to identify bacteria that promote tumor development or modulate therapy efficacy from bystander bacteria. Here we aim to comprehensively summarize the current knowledge of microbiome-host immunity interactions and cancer therapy in various mucosal tissues to find commonalities and thus identify potential functionally relevant bacterial taxa. Moreover, we also review recent studies identifying specific bacteria and mechanisms through which the microbiome modulates cancer development and therapy efficacy.

BugSigDB captures patterns of differential abundance across a broad range of host-associated microbial signatures

The literature of human and other host-associated microbiome studies is expanding rapidly, but systematic comparisons among published results of host-associated microbiome signatures of differential abundance remain difficult. We present BugSigDB, a community-editable database of manually curated microbial signatures from published differential abundance studies accompanied by information on study geography, health outcomes, host body site and experimental, epidemiological and statistical methods using controlled vocabulary. The initial release of the database contains >2,500 manually curated signatures from >600 published studies on three host species, enabling high-throughput analysis of signature similarity, taxon enrichment, co-occurrence and coexclusion and consensus signatures. These data allow assessment of microbiome differential abundance within and across experimental conditions, environments or body sites. Database-wide analysis reveals experimental conditions with the highest level of consistency in signatures reported by independent studies and identifies commonalities among disease-associated signatures, including frequent introgression of oral pathobionts into the gut.

Cancer invasion and anaerobic bacteria: new insights into mechanisms

There is growing evidence that altered microbiota abundance of a range of specific anaerobic bacteria are associated with cancer, including Peptoniphilus spp., Porphyromonas spp., Fusobacterium spp., Fenollaria spp., Prevotella spp., Sneathia spp., Veillonella spp. and Anaerococcus spp. linked to multiple cancer types. In this review we explore these pathogenic associations. The mechanisms by which bacteria are known or predicted to interact with human cells are reviewed and we present an overview of the interlinked mechanisms and hypotheses of how multiple intracellular anaerobic bacterial pathogens may act together to cause host cell and tissue microenvironment changes associated with carcinogenesis and cancer cell invasion. These include combined effects on changes in cell signalling, DNA damage, cellular metabolism and immune evasion. Strategies for early detection and eradication of anaerobic cancer-associated bacterial pathogens that may prevent cancer progression are proposed.

Identification of consensus head and neck cancer-associated microbiota signatures: a systematic review and meta-analysis of 16S rRNA and The Cancer Microbiome Atlas datasets

Introduction. Multiple reports have attempted to describe the tumour microbiota in head and neck cancer (HNSC).Gap statement. However, these have failed to produce a consistent microbiota signature, which may undermine understanding the importance of bacterial-mediated effects in HNSC.Aim. The aim of this study is to consolidate these datasets and identify a consensus microbiota signature in HNSC.Methodology. We analysed 12 published HNSC 16S rRNA microbial datasets collected from cancer, cancer-adjacent and non-cancer tissues to generate a consensus microbiota signature. These signatures were then validated using The Cancer Microbiome Atlas (TCMA) database and correlated with the tumour microenvironment phenotypes and patient's clinical outcome.Results. We identified a consensus microbial signature at the genus level to differentiate between HNSC sample types, with cancer and cancer-adjacent tissues sharing more similarity than non-cancer tissues. Univariate analysis on 16S rRNA datasets identified significant differences in the abundance of 34 bacterial genera among the tissue types. Paired cancer and cancer-adjacent tissue analyses in 16S rRNA and TCMA datasets identified increased abundance in Fusobacterium in cancer tissues and decreased abundance of Atopobium, Rothia and Actinomyces in cancer-adjacent tissues. Furthermore, these bacteria were associated with different tumour microenvironment phenotypes. Notably, high Fusobacterium signature was associated with high neutrophil (r=0.37, P<0.0001), angiogenesis (r=0.38, P<0.0001) and granulocyte signatures (r=0.38, P<0.0001) and better overall patient survival [continuous: HR 0.8482, 95 % confidence interval (CI) 0.7758-0.9273, P=0.0003].Conclusion. Our meta-analysis demonstrates a consensus microbiota signature for HNSC, highlighting its potential importance in this disease.

Fecal and oral microbiome analysis of snakes from China reveals a novel natural emerging disease reservoir

Introduction

The gastrointestinal tract and oral cavity of animal species harbor complex microbial communities, the composition of which is indicative of the behavior, co-evolution, diet, and immune system of the host.

Methods

This study investigated the microbial composition in snakes from varying altitudinal ranges by assessing the fecal and oral bacterial communities in Protobothrops mucrosquamatus, Elaphe dione, and Gloydius angusticeps from Sichuan Province, China, using metagenomic sequencing.

Results and discussion

It was revealed that Bacteroidetes, Proteobacteria, Firmicutes, and Fusobacteria were the core microbial phyla in fecal samples across all three species, while Proteobacteria, Bacteroidetes, Actinobacteria, and Firmicutes were the core microbial phyla in oral samples across all three species. Notably, the dominance of Armatimonadetes was documented for the first time in the feces of all three species. Comparative analysis of the microbiomes of the three species indicated distinct microbiological profiles between snakes living at low- and high-altitude regions. Furthermore, 12 to 17 and 22 to 31 bacterial pathogens were detected in the oral and fecal samples, respectively, suggesting that snakes may serve as a novel reservoir for emerging diseases. Overall, this study provides a comparative analysis of the fecal and oral microbiomes in three snake species. Future investigations are anticipated to further elucidate the influence of age, genetics, behavior, diet, environment, ecology, and evolution on the gut and oral microbial communities of snakes.

Effects of squamous cell carcinoma and smoking status on oropharyngeal and laryngeal microbial communities

BACKGROUND

Still, little is known about microbial dysbiosis in oropharyngeal and laryngeal tissue as risk factor for development of local squamous cell carcinoma. The site-specific microbiota at these regions in healthy and cancer tissue and their modulation by environmental factors need to be defined.

METHODS

The local microbiota of cancer tissue and healthy controls was profiled by 16S rRNA gene amplicon sequencing and statistical analysis using 111 oropharyngeal and 72 laryngeal intraoperative swabs.

RESULTS

Oropharynx and larynx harbor distinct microbial communities. Clear effects of both smoking and cancer were seen in the oropharynx whereas effects in the larynx were minor.

CONCLUSION

The distinct microbial communities at larynx and oropharynx partially explain why the effects of cancer and smoking were distinct at those sites. Thus, the use of microbiota supposed to mirror community changes in another target location should be avoided and more studies on the actual cancerous environment are necessary.

Case report: isolated prevotella intermedia causing intracranial infection detected using metagenomic next generation sequencing

BACKGROUND

Isolated Prevotella intermedia, a rare gram-negative, rod-shaped, anaerobic bacterium, is rarely detected in clinical practice. It has been associated with infections of the oral cavity and female genital tract, but has never been detected in cerebrospinal fluid (CSF) of patients in China. Accurate detection of causative pathogens is still an arduous task owing to the difficult conditions of anaerobic bacterial culture. Isolated Prevotella intermedia can be detected by metagenomic next generation sequencing (mNGS) of the CSF. Correct diagnosis and antibiotic treatment can help patients avoid life-threatening events.

CASE PRESENTATION

Herein, we describe the case of a 64-year-old Chinese woman who presented with typical features of meningoencephalitis. Routine CSF culture failed to identify the causative pathogen. Isolated Prevotella intermedia was detected by mNGS, and the patient was treated with antibacterial agents including ceftriaxone, vancomycin, moxifloxacin, meropenem, metronidazole, and linezolid. The patient underwent surgical treatment for abscess of left frontal parietal lobe, which was observed on magnetic resonance imaging (MRI) and was suspected to be caused by Prevotella intermedia. It was further confirmed that it was a secondary infection from the oral cavity, and the possible etiology might have been dental surgery. Treatment was rendered to the patient based on metagenomic test result, and her condition improved after two months.

CONCLUSIONS

This case highlights the role of mNGS in accurate diagnosis of patients with central nervous system infection. In particular, mNGS can be used to identify rare pathogens and confirm the diagnosis in patients with unknown etiology.

Oral-microbiome-derived signatures enable non-invasive diagnosis of laryngeal cancers

BACKGROUND

Recent studies have uncovered that the microbiota in patients with head and neck cancers is significantly altered and may drive cancer development. However, there is limited data to explore the unique microbiota of laryngeal squamous cell carcinoma (LSCC), and little is known regarding whether the oral microbiota can be utilized as an early diagnostic biomarker.

METHODS

Using 16S rRNA gene sequencing, we characterized the microbiome of oral rinse and tissue samples from 77 patients with LSCC and 76 control patients with vocal polyps, and then performed bioinformatic analyses to identify taxonomic groups associated with clinicopathologic features.

RESULTS

Multiple bacterial genera exhibited significant differences in relative abundance when stratifying by histologic and tissue type. By exploiting the distinct microbial abundance and identifying the tumor-associated microbiota taxa between patients of LSCC and vocal polyps, we developed a predictive classifier by using rinse microbiota as key features for the diagnosis of LSCC with 85.7% accuracy.

CONCLUSION

This is the first evidence of taxonomical features based on the oral rinse microbiome that could diagnose LSCC. Our results revealed the oral rinse microbiome is an understudied source of clinical variation and represents a potential non-evasive biomarker of LSCC.

Fusobacterium nucleatum-triggered purine metabolic reprogramming drives tumorigenesis in head and neck carcinoma

BACKGROUND

Fusobacterium nucleatum (F. nucleatum) is a vital pro-oncogenic bacterium. Our previous study revealed that a high abundance of F. nucleatum in head and neck squamous cell carcinoma (HNSCC) is correlated with poor patient prognosis. However, the impact of F. nucleatum on metabolic reprogramming and tumor progression in HNSCC awaits more exploration.

METHODS

Liquid chromatography‒mass spectrometry (LC‒MS) was applied to analyze the altered metabolites in a head and neck carcinoma cell line (AMC-HN-8) after coculture with F. nucleatum for 24 hrs and 48 hrs. Both univariate and multivariate analyses were used to screen for differential metabolites. Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathway enrichment analysis was further used to explore the metabolic changes.

RESULTS

We observed a significantly altered metabolic profile in AMC-HN-8 cells over time after coculture with F. nucleatum. Among the several enriched pathways, the purine metabolic pathway was the most significantly enriched (P = 0.0005), with downregulation of purine degradation. Furthermore, uric acid, the end product of purine metabolism, significantly reversed F. nucleatum-triggered tumor progression and altered the intracellular reactive oxygen species (ROS) level. Moreover, the negative correlation between the serum uric acid level and the abundance of F. nucleatum was verified in 113 HNSCC patients (P = 0.0412, R = - 0.1924).

CONCLUSIONS

Our study revealed obviously aberrant purine metabolism driven by F. nucleatum in HNSCC, which was closely related to tumor progression and patient prognosis. These findings indicate the possibility of targeting F. nucleatum-induced purine metabolism reprogramming in the future treatment of HNSCC.

Assessment of the In Vitro Cytotoxic Profile of Two Broad-Spectrum Antibiotics-Tetracycline and Ampicillin-On Pharyngeal Carcinoma Cells

Background and Objectives: In spite of the fact that antibiotics are considered to be the cornerstone of modern medicine, their use in the treatment of cancer remains controversial. In the present study, the main objective was to examine the effects of two antibiotics—tetracycline and ampicillin—on the viability, morphology, migration, and organization and structure of the nuclei and the actin fiber network of pharyngeal carcinoma cells—Detroit-562. Materials and Methods: In order to determine the viability of the cells, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method was applied after the cells were stimulated with five concentrations of tetracycline and ampicillin (10, 25, 50, 75, and 100 μM) for 72 h. A scratch assay was used to assess the migration ability of the cells. For the visualization of the nuclei and actin fibers, 4,6-diamidino-2-phenylindole (Dapi) and Rhodamine-Phalloidin were used. Results: There are different effects of tetracycline and ampicillin. Thus, tetracycline: (i) exhibited a concentration-dependent cytotoxic effect, decreasing cell viability to approximately 46%; (ii) inhibits cellular migration up to 16% compared to 60% for control cells; and (iii) induces changes in cell morphology as well as apoptotic changes in the nucleus and F-actin fibers. In contrast, in the case of ampicillin, an increase in viability up to 113% was observed at 10 μM, while a decrease in viability up to approximately 94% was observed at the highest concentration tested (100 μM). Conclusions: The results indicated a different effect regarding the impact on pharyngeal carcinoma cells. Thus, tetracycline has a concentration-dependent cytotoxic effect, while in the case of ampicillin a slight stimulation of cell viability was observed.

Oral microbiota in oropharyngeal cancers: Friend or foe?

Oral microbiome is a complex population of micro-organisms, which by cross-talking with the local immune system, plays a major role in the immune homeostasis of the oral cavity, further contributing in the physiology of the gastro-intestinal microbiota. Understanding their involvement in the onset and pathogenesis of oropharyngeal cancers is paramount, despite very few reports deal with the fundamental role exerted by oral microbiota disorders, such as dysbiosis and impairment in the oral microbiome composition as causative factors in the development of oropharyngeal tumors. Current research, via metabolomic or meta-transcriptomic analyses, is wondering how this complex microbial population regulates the immune homeostasis in oral and pharyngeal mucosa and whether changes in bacterial composition may give insights on the role of oral microbiome in the development of oropharyngeal tumors, so to prevent their occurrence.

Diet and Health in Otolaryngology

Diet is essential to health and can modulate inflammatory markers, the microbiota, and epigenetic outcomes. Proper nutrition is also key to good postsurgical outcomes. Diet is challenging to study, resulting in a relative dearth of influential studies. There is substantial evidence regarding the benefits of a whole food plant-predominant diet on health and longevity, in general, but limited evidence regarding otolaryngologic disorders. Diet may be associated with the risk of head and neck cancer, hearing loss, laryngopharyngeal reflux, and sinonasal symptoms. Evidence, however, is heterogenous and often insufficient for treatment recommendations. Many opportunities exist for future research and expansion..

Fusobacterium nucleatum impairs DNA mismatch repair and stability in patients with squamous cell carcinoma of the head and neck

BACKGROUND

Dysbiosis of the laryngeal microbiota has been demonstrated to the development of head and neck squamous cell carcinoma (HNSCC), but the association of Fusobacterium and Fusobacterium nucleatum (F. nucleatum) with DNA mismatch repair (MMR) and microsatellite instability (MSI) has not been investigated.

METHODS

The abundance of Fusobacterium and F. nucleatum, the status of deficient MMR (dMMR) and MSI, and MMR-related gene expression were analyzed in 171 HNSCC tissues, 61 paired para-tumor tissues, and 60 vocal cord polyp tissues. The molecular mechanism of F. nucleatum and MMR-related gene expression were investigated in two human HNSCC cell lines (Tu 686 and FD-LSC-1).

RESULTS

Our results demonstrated that a high Fusobacterium abundance was detected in the HNSCC tissues and was exaggerated in the recurrent patients. We further found that a high Fusobacterium abundance was detected in the HNSCC tissues with dMMR and MSI. The Fusobacterium abundance was negatively correlated with the expression of MLH1, MSH2, and MSH6 in the HNSCC tissues. The Fusobacterium abundance was closely associated with the F. nucleatum abundance in the HNSCC tissues. F. nucleatum increased miR-205-5p expression to suppress MLH1, MSH2, and MSH6 expression via the TLR4- and MYD88-dependent innate immune signaling pathway, resulting in dMMR, DNA damage, and cell proliferation in HNSCC.

CONCLUSIONS

F. nucleatum impacts HNSCC epigenetic changes in tissues with dMMR to promote DNA damage and cell proliferation by suppressing MMR-related gene expression via the TLR4/MYD88/miR-205-5p signaling pathway, which is valuable in the development of efficient strategies for HNSCC prevention and treatment.

LAY SUMMARY

This study clearly indicates that Fusobacterium induced head and neck squamous cell carcinoma (HNSCC) aggressiveness to affect poor prognosis in HNSCC patients by epigenetic alteration of DNA mismatch repair (MMR) and microsatellite instability. Moreover, the research has shown that Fusobacterium nucleatum ( F. nucleatum ) impacts HNSCC epigenetic changes in tissues with deficient MMR to promote DNA damage and cell proliferation by suppressing MMRrelated gene expression via the TLR4/MYD88/miR-205-5p signaling pathway.

Pathogen detection and characterization from throat swabs using unbiased metatranscriptomic analyses

OBJECTIVES

Infectious diseases are common but are not easily or readily diagnosed with current methodologies. This problem is further exacerbated by the constant presence of mutated, emerging, and novel pathogens. One of the most common sites of infection by many pathogens is the human throat. However, there is no universal diagnostic test that can distinguish these pathogens. Metatranscriptomic (MT) analysis of the throat represents an important and novel development in infectious disease detection and characterization, because it is able to identify all pathogens using a fully unbiased approach.

METHODS

To test the utility of an MT approach to pathogen detection, throat samples were collected from participants before, during, and after an acute sickness.

RESULTS

Clear sickness-associated shifts in pathogenic microorganisms were detected in the patients. Important insights into microbial functions and antimicrobial resistance genes were obtained.

CONCLUSION

MT analysis of the throat represents an effective method for the unbiased identification and characterization of pathogens. Because MT data include all microorganisms in the sample, this approach should not only allow the identification of pathogens, but provide an understanding of the effects of the resident throat microbiome in the context of human health and disease.

Characterization of the bacterial microbiota in different gut and oral compartments of splendid japalure (Japalura sensu lato)

Background

Gut and oral microbes form complex communities and play key roles in co-evolution with their hosts. However, little is understood about the bacterial community in lizards.

Results

In this study, we investigated the gut and oral bacterial communities in Japalura sensu lato from Sichuan Province, China, using 16S rRNA gene sequencing. Results showed that Bacteroidota (36.5%) and Firmicutes (32.8%) were the main phyla in the gut, while Proteobacteria, Bacteroidota, Firmicutes, and Actinobacteriota were the dominant phyla in the oral cavity. 16 S rRNA sequencing analysis of fecal samples showed that: (1) Bacteroidota was the most abundant in Japalura sensu lato, which was different from the bacterial community of insectivorous animals; (2) Bacteroidota, Firmicutes, Actinobacteriota, Fusobacteriota, and Cyanobacteria were the most abundant phylum in Japalura sensu lato. (3) Proteobacteria was the dominant phylum in Japalura sensu lato and other domestic insectivorous lizards (Shinisaurus crocodilurus, Phrynocephalus vlangalii, and Takydromus septentrionalis); (4) Comparing with the bacterial community of Shinisaurus crocodilurus, Phrynocephalus vlangalii, Takydromus septentrionalis, Liolaemus parvus, L. ruibali, and Phymaturus williamsi, Desulfobacterota was uniquely present in the gut of Japalura sensu lato. 16 S rRNA sequencing of oral samples showed that Chloroflexi and Deinococcota phyla were enriched in the oral cavity, which may have a significant influence on living in extreme environments.

Conclusions

Thus, based on 16 S rRNA sequencing analysis of the community composition of the gut and oral microbiomes, this study firstly represents a foundation for understanding the gut and oral microbial ecology of Japalura sensu lato, and constitutes a detail account of the diversity of the microbiota inhabiting the gut and oral cavity of Japalura sensu lato. Further researches will continue to reveal how gut and oral microbial communities may be impacting the ecology and evolution of lizards.

Supplementary information

The online version contains supplementary material available at 10.1186/s12917-022-03300-w.

Prevotella species as oral residents and infectious agents with potential impact on systemic conditions

Oral Prevotella are known as anaerobic commensals on oral mucosae and in dental plaques from early life onwards, including pigmented P. melaninogenica, P. nigrescens, and P. pallens and non-pigmented Prevotella species. Many Prevotella species contribute to oral inflammatory processes, being frequent findings in dysbiotic biofilms of periodontal diseases (P. intermedia, P. nigrescens), cariotic lesions (P. denticola, Alloprevotella (formerly Prevotella) tannerae), endodontic infections (P. baroniae, P. oris, P. multisaccharivorax), and other clinically relevant oral conditions. Over the years, several novel species have been recovered from the oral cavity without knowledge of their clinical relevance. Within this wide genus, virulence properties and other characteristics like biofilm formation seemingly vary in a species- and strain-dependent manner, as shown for the P. intermedia group organisms (P. aurantiaca, P. intermedia, P. nigrescens, and P. pallens). Oral Prevotella species are identified in various non-oral infections and chronic pathological conditions. Here, we have updated the knowledge of the genus Prevotella and the role of Prevotella species as residents and infectious agents of the oral cavity, as well as their detection in non-oral infections, but also gathered information on their potential link to cancers of the head and neck, and other systemic disorders.

Diagnostic and Therapeutic Uses of the Microbiome in the Field of Oncology

Cancer is a leading cause of death worldwide and it can affect almost every part of the human body. Effective screening and early diagnosis of cancers is extremely difficult due to the multifactorial etiology of the disease and delayed presentation of the patients. The available treatments are usually not specific to the affected organ system, leading to intolerable systemic side effects and early withdrawal from therapies. In vivo and in vitro studies have revealed an association of specific microbiome signatures with individual cancers. The cancer-related human microbiome has also been shown to affect the response of tissues to chemotherapy, immunotherapy, and radiation. This is an excellent opportunity for us to design specific screening markers using the microbiome to prevent cancers and diagnose them early. We can also develop precise treatments that can target cancer-affected specific organ systems and probably use a lesser dose of chemotherapy or radiation for the same effect. This prevents adverse effects and early cessation of treatments. However, we need further studies to exactly clarify and characterize these associations. In this review article, we focus on the association of the microbiome with individual cancers and highlight its future role in cancer screenings, diagnosis, prognosis, and treatments.

Distinct microbiota dysbiosis in patients with laryngopharynx reflux disease compared to healthy controls

OBJECTIVE

To compare the differences in the laryngopharynx microbiome between patients with laryngopharyngeal reflux disease (LPRD) and healthy people and further explore the influence of related risk factors pharyngeal microbiome.

METHODS

This was a case-control study. Patients with a reflux symptom index (RSI) score > 13 or reflux finding score (RFS) score > 7 were diagnosed with suspected LPRD at the Department of Otolaryngology-Head and Neck Surgery of The 900th Hospital of Joint Logistic Support Force. Patients were assessed using a related risk factors questionnaire survey and examined by electronic naso-laryngoscopy. Simultaneously, laryngopharynx secretions were collected from the patients. The patients received at least eight weeks of proton pump inhibitor therapy, and those who responded were enrolled in the final experimental group. In parallel, laryngopharynx secretions were collected from healthy volunteers as the control group, and the laryngopharynx microbiota were analyzed using second-generation high-throughput sequencing.

RESULTS

A total of 23 cases each in the experimental and control group were included in this study. The experimental group microbiota were composed of Streptococcus, Prevotella, Haemophilus, Neisseria, Actinobacillus, Fusobacterium, and Porphyromonas. There was no significant difference in microbial alpha and beta-diversity analysis between the two groups. However, some advantageous bacterium groups were significantly different. The abundance of Prevotella in the experimental group was significantly higher than that of the control group (U = 117, P < 0.05), while the abundance of Fusobacterium (U = 140, P = 0.006) and Porphyromonas (U = 120, P = 0.002) was significantly lower than the control group. Smoking was positively correlated with Pectin (r = 0.46, P = 0.037), Lactobacillus (r = 0.48, P = 0.027), and Clostridium (r = 0.46, P = 0.037), while alcohol was negatively correlated with Streptococcus (r = - 0.5539, P = 0.0092).

CONCLUSION

The dominant microflora in the laryngopharynx of LPRD patients was significantly different from that of healthy people, suggesting that the change of laryngopharynx microflora may play an important role in the pathogenesis of LPRD. Smoking, drinking, eating habits, and age correlated with different genus levels of the laryngopharynx microbiota.

Mapping bacterial diversity and metabolic functionality of the human respiratory tract microbiome

Background

The Human Respiratory Tract (HRT) is colonized by various microbial taxa, known as HRT microbiota, in a manner that is indicative of mutualistic interaction between such microorganisms and their host.

Aim

To investigate the microbial composition of the HRT and its possible correlation with the different compartments of the respiratory tract.

Methods

In the current study, we performed an in-depth meta-analysis of 849 HRT samples from public shotgun metagenomic datasets obtained through several distinct collection methods.

Results

The statistical robustness provided by this meta-analysis allowed the identification of 13 possible HRT-specific Community State Types (CSTs), which appear to be specific to each anatomical region of the respiratory tract. Furthermore, functional characterization of the metagenomic datasets revealed specific microbial metabolic features correlating with the different compartments of the respiratory tract.

Conclusion

The meta-analysis here performed suggested that the variable presence of certain bacterial species seems to be linked to a location-related abundance gradient in the HRT and seems to be characterized by a specific microbial metabolic capability.

A positive feed-forward loop between Fusobacterium nucleatum and ethanol metabolism reprogramming drives laryngeal cancer progression and metastasis

Alcohol consumption, which affects the structure and composition of the laryngeal microbiota, is one of the most important risk factors for laryngeal squamous cell cancer (LSCC). Our results demonstrated that high enrichment of Fusobacterium nucleatum (F. nucleatum) in LSCC was associated with poor prognosis. F. nucleatum increased miR-155-5p and miR-205-5p expression to suppress alcohol dehydrogenase 1B (ADH1B) and transforming growth factor β receptor 2 (TGFBR2) expression by activating innate immune signaling, resulting in ethanol metabolism reprogramming to allow F. nucleatum accumulation and PI3K/AKT signaling pathway activation to promote epithelial-mesenchymal transition, further exacerbating the uncontrolled progression and metastasis of LSCC. Therefore, the positive feed-forward loop between F. nucleatum and ethanol metabolism reprogramming promotes cell proliferation, migration, and invasion to affect LSCC patient prognosis. The amount of F. nucleatum is a potential prognostic biomarker, which yields valuable insight into clinical management that may improve the oncologic outcome of patients with LSCC.

Defining the microbiome of the head and neck: A contemporary review

OBJECTIVE

The purpose of this paper is to define the microbiome of the head and neck by characterizing and distinguishing the commensal bacteria from pathogenic species.

STUDY DESIGN

Literature review.

METHODS

Pubmed and Google scholar databases were queried for relevant articles. Keywords such as "middle ear microbiome", "outer ear microbiome", "sinonasal microbiome", "tonsil microbiome", and "laryngeal microbiome" were utilized separately to identify articles pertaining to each topic of study. All applicable abstracts were chosen for initial review and relevant abstracts were then selected for review of the full texts. Articles that did not study the human microbiome, those not written primarily in English, those that were not readily available for full review, and case reports were excluded from the study.

RESULTS

Limited studies that investigate the microbial environments of isolated anatomic subsites in the head and neck exist, however the comprehensive microbiome of the head and neck has yet to be completely defined. Based on this review, various studies of the ears, larynx, tonsils and sinus microbiomes exist and yield valuable information, however they are limited in scope and anatomic subsite. In this literature review, these studies are compiled in order to create a comprehensive text inclusive of the known microbial elements of the major anatomic subsites of the head and neck, namely the tonsils, larynx, sinus, outer ear and middle ear.

CONCLUSIONS

The significance of the human microbiome in identifying and preventing disease has been established in various physiologic systems, however there is limited research on the microbiome of the head and neck. Understanding the microbiome of the head and neck can help differentiate disease-prone patients from normal patients and guide treatment regimens and antibiotic usage, to aid in resistance control and limit adverse effects of antibiotic overuse. Understanding the elements that lead to dysbiosis can help treat and even prevent common conditions as tonsillitis and rhinosinusitis. In this review, we provide a comprehensive review to serve as an initial background for future studies to define the head and neck microbiome distinguished by all relevant subsites.

Bacteriophage manipulation of the microbiome associated with tumour microenvironments-can this improve cancer therapeutic response?

Some cancer treatment failures have been attributed to the tumour microbiota, with implications that microbiota manipulation may improve treatment efficacy. While antibiotics have been used to control bacterial growth, their dysbiotic effects on the microbiome, failure to penetrate biofilms and decreased efficacy due to increasing antimicrobial resistance by bacteria, suggest alternatives are needed. Bacteriophages may provide a precise means for targeting oncobacteria whose relative abundance is increased in tumour tissue microbiomes. Fusobacterium, Streptococcus, Peptostreptococcus, Prevotella, Parvimonas, and Treponema species are prevalent in tumour tissue microbiomes of some cancers. They may promote cancer growth by dampening immunity, stimulating release of proinflammatory cytokines, and directly interacting with cancer cells to stimulate proliferation. Lytic bacteriophages against some of these oncobacteria have been isolated and characterised. The search continues for others. The possibility exists for their testing as adjuncts to complement existing therapies. In this review, we highlight the role of oncobacteria, specifically those whose relative abundance in the intra-tumour microbiome is increased, and discuss the potential for bacteriophages against these micro-organisms to augment existing cancer therapies. The capacity for bacteriophages to modulate immunity and kill specific bacteria makes them suitable candidates to manipulate the tumour microbiome and negate the effects of these oncobacteria.

Commensal microbiota in the digestive tract: a review of its roles in carcinogenesis and radiotherapy

The human microflora is a complex ecosystem composed of diverse microorganisms mainly distributed in the epidermal and mucosal habitats of the entire body, including the mouth, lung, intestines, skin, and vagina. These microbial communities are involved in many essential functions, such as metabolism, immunity, host nutrition, and diseases. Recent studies have focused on the microbiota associated with cancers, particularly the oral and intestinal microbiota. Radiotherapy, the most effective cytotoxic modality available for solid tumors, contributes to the treatment of cancer patients. Mounting evidence supports that the microbiota plays pivotal roles in the efficacy and prognosis of tumor radiotherapy. Here, we review current research on the microbiota and cancer development, and describe knowledge gaps in the study of radiotherapy and the microbiota. Better understanding of the effects of the microbiome in tumorigenesis and radiotherapy will shed light on future novel prevention and treatment strategies based on modulating the microbiome in cancer patients.

Alterations of bacterial communities of vocal cord mucous membrane increases the risk for glottic laryngeal squamous cell carcinoma

Bacteria are among the important factors that play a role in the balance of human health, and their relationship with some tumors has been well established. However, the association between bacteria colonizing the vocal cords and glottic laryngeal squamous cell carcinoma (GLSCC) remains unclear. Here, we investigated whether bacterial communities of the vocal cord mucous membrane play a role in the development of GLSCC. We collected tumor tissue and normal adjacent tissue (NAT) samples from 19 GLSCC patients, and the bacterial communities were compared with control samples (control) from 21 vocal cord polyps using 16S rRNA high-throughput pyrosequencing. We detected 41 phyla, 93 classes, 188 orders, 373 families, and 829 genera in the vocal cord mucous membrane. A comparison of the bacterial communities in the NAT samples showed higher α‐diversity than in the tumor samples. In the tumor samples, seven groups of bacteria, i.e., the phylum Fusobacteria, the class Fusobacteriia, the order Fusobacteriales, the family Fusobacteriaceae, and the genera Fusobacterium, Alloprevotella, and Prevotella, were significantly enriched, as revealed by linear discriminant analysis coupled with effect size measurements (LEfSe). However, bacteria from the phylum Firmicutes were most significantly enriched in the vocal cord polyp tissues. These findings suggest alterations in the bacterial community structure of the vocal cord mucous membrane of GLSCC patients and that seven groups of bacteria are related to GLSCC, indicating that imbalances in bacterial communities increase the risk for the development of GLSCC.

High-throughput sequencing profile of laryngeal cancers: analysis of co-expression and competing endogenous RNA networks of circular RNAs, long non-coding RNAs, and messenger RNAs

Background

Circular RNAs (circRNAs) and long non-coding RNAs (lncRNAs) have been recently identified as new classes of non-coding RNAs which participate in carcinogenesis and tumor progression. However, the functions of these non-coding RNAs and gene expression patterns are largely unknown.

Methods

We carried out high-throughput sequencing to analyze the differential expression of RNAs in 5 coupled laryngeal cancer (LC) and corresponding adjacent noncancerous tissues. Bioinformatics analyses were performed to predict the functions of these non-coding RNAs via co-expression, competing endogenous RNA networks and pathway enrichment analysis. The differential expression of the selected RNAs were confirmed using RT-qPCR. The CCK8, EDU, Transwell, and wound healing assays were conducted to validate the biological functions of SNHG29 in LC. Western blot assay was performed to identify the effects of SNHG29 having on the epithelial to mesenchymal transition process. Kaplan-Meier analysis was used to investigate whether the expression level of SNHG29 correlated with survival in LC patients. One-way ANOVA was used to analyze the correlation between the expression of SNHG29 and clinicopathological parameters of the included patients.

Results

Compared to normal laryngeal tissues, 31,763 non-coding RNAs were upregulated and 11,557 non-coding RNAs were downregulated in cancer tissues. SNHG29 expression was low in the LC cell lines and tissues predicting a better clinical prognosis. SNHG29 was also found to inhibit the proliferation, migration, and invasion ability of LC, exerting a suppressive role in the epithelial to mesenchymal transition process as well. SNHG29 downregulation was significantly correlated with differentiation (P=0.026), T-stage (P=0.041), lymphatic metastasis (P=0.044), and clinical stage (P=0.037). We found that the biological functions of differentially expressed transcripts included cell adhesion, biological adhesion, and migration and invasion related to adherens junction pathways.

Conclusions

Our study was the first to describe the non-coding RNA profile of LC, and suggested that dysregulated non-coding RNAs could be involved in LC tumorigenesis. SNHG29 was demonstrated to play crucial roles in inhibiting the pathogenesis and progression of LC. Our findings provide a new approach for further analyses of pathogenetic mechanisms, the detection of novel transcripts, and the identification of valuable biomarkers for this tumor.

The Microbiome and Its Implications in Cancer Immunotherapy

Cancer is responsible for ~18 million deaths globally each year, representing a major cause of death. Several types of therapy strategies such as radiotherapy, chemotherapy and more recently immunotherapy, have been implemented in treating various types of cancer. Microbes have recently been found to be both directly and indirectly involved in cancer progression and regulation, and studies have provided novel and clear insights into the microbiome-mediated emergence of cancers. Scientists around the globe are striving hard to identify and characterize these microbes and the underlying mechanisms by which they promote or suppress various kinds of cancer. Microbes may influence immunotherapy by blocking various cell cycle checkpoints and the production of certain metabolites. Hence, there is an urgent need to better understand the role of these microbes in the promotion and suppression of cancer. The identification of microbes may help in the development of future diagnostic tools to cure cancers possibly associated with the microbiome. This review mainly focuses on various microbes and their association with different types of cancer, responses to immunotherapeutic modulation, physiological responses, and prebiotic and postbiotic effects.

Throat Microbial Community Structure and Functional Changes in Postsurgery Laryngeal Carcinoma Patients

The microbial community structure in the throat and its shift after laryngectomy in laryngeal squamous cell carcinoma (LSCC) patients were investigated. Thirty swab samples taken prior to laryngectomy (SLC), 18 samples 1 week after laryngectomy (SLCA1w), and 30 samples 24 weeks after laryngectomy (SLCA24w) from 30 LSCC patients were examined. Microbial diversity was profiled through sequencing the V3-V4 variable region of the 16S rRNA gene. Quantitative real-time PCR (qPCR) was used to validate the 16S rRNA sequence data for the V3-V4 region. The community structure and function of throat microbiota were assessed by PICRUSt (phylogenetic investigation of communities by reconstruction of unobserved states) analysis. Both alpha and beta diversity results showed significant differences in the throat microbiota of LSCC patients before and after laryngectomy (P < 0.05). The drinking index of the SLC group was positively associated with the genus abundance of Prevotella (P < 0.05). The SLCA1w group had lower abundances of Fusobacterium, Leptotrichia, Lachnoanaerobaculum, and Veillonella than the SLC group (P < 0.05). The SLCA24w group had higher abundances of Streptococcus and Leptotrichia as well as lower abundances of Fusobacterium and Alloprevotella than the SLC group (P < 0.05). The throat microbiomes of the SLC group could be implicated in human cancer signaling pathways, as evidenced by PICRUSt analysis (P < 0.05). Our study clarifies alterations in throat microbial community structure and function in LSCC patients during the perioperative period and postoperative recovery period.IMPORTANCE Laryngeal squamous cell carcinoma greatly impacts patients' lives, and noninvasive means of prognostic assessment are valuable in determining the effectiveness of laryngectomy. We set out to study the microbial structure changes in the throat before and after laryngectomy and found the gene functions of several throat bacteria to be associated with human cancer signaling pathways. Our findings may offer insights into the disease management of patients with laryngeal squamous cell carcinoma. We hope to provide a means of using molecular mechanisms to improve the prognosis of laryngeal cancer treatment and to facilitate relevant research.

Composition of gut and oropharynx bacterial communities in Rattus norvegicus and Suncus murinus in China

Background

Rattus norvegicus and Suncus murinus are important reservoirs of zoonotic bacterial diseases. An understanding of the composition of gut and oropharynx bacteria in these animals is important for monitoring and preventing such diseases. We therefore examined gut and oropharynx bacterial composition in these animals in China.

Results

Proteobacteria, Firmicutes and Bacteroidetes were the most abundant phyla in faecal and throat swab samples of both animals. However, the composition of the bacterial community differed significantly between sample types and animal species. Firmicutes exhibited the highest relative abundance in throat swab samples of R. norvegicus, followed by Proteobacteria and Bacteroidetes. In throat swab specimens of S. murinus, Proteobacteria was the predominant phylum, followed by Firmicutes and Bacteroidetes. Firmicutes showed the highest relative abundance in faecal specimens of R. norvegicus, followed by Bacteroidetes and Proteobacteria. Firmicutes and Proteobacteria had almost equal abundance in faecal specimens of S. murinus, with Bacteroidetes accounting for only 3.07%. The family Streptococcaceae was most common in throat swab samples of R. norvegicus, while Prevotellaceae was most common in its faecal samples. Pseudomonadaceae was the predominant family in throat swab samples of S. murinus, while Enterobacteriaceae was most common in faecal samples. We annotated 33.28% sequences from faecal samples of S. murinus as potential human pathogenic bacteria, approximately 3.06-fold those in R. norvegicus. Potential pathogenic bacteria annotated in throat swab samples of S. murinus were 1.35-fold those in R. norvegicus.

Conclusions

Bacterial composition of throat swabs and faecal samples from R. norvegicus differed from those of S. murinus. Both species carried various pathogenic bacteria, therefore both should be closely monitored in the future, especially for S. murinus.

Supplementary information

Supplementary information accompanies this paper at 10.1186/s12917-020-02619-6.

The promise and challenge of cancer microbiome research

Many microbial agents have been implicated as contributors to cancer genesis and development, and the search to identify and characterize new cancer-related organisms is ongoing. Modern developments in methodologies, especially culture-independent approaches, have accelerated and driven this research. Recent work has shed light on the multifaceted role that the community of organisms in and on the human body plays in cancer onset, development, detection, treatment, and outcome. Much remains to be discovered, however, as methodological variation and functional testing of statistical correlations need to be addressed for the field to advance.

Detection of Fusobacterium in oral and head and neck cancer samples: A systematic review and meta-analysis

AIMS

This systematic review aimed to analyse: a) the presence and the abundance of Fusobacterium; b) the Fusobacterium species most often found, and c) the most common methods used for their identification in oral/head and neck cancer samples.

DESIGN

A protocol was registered on PROSPERO database. This review was conducted following PRISMA guidelines. Literature search was performed on five electronic biomedical databases, namely Pubmed, Scopus, Web of Science, Embase, and Cochrane from their start dates to 30 August 2018. Two reviewers independently assessed the eligibility for inclusion; extracted the data; and evaluated the risk of bias.

RESULTS

From 118 unique abstract records, 88 full-text articles were assessed for eligibility. According to inclusion and exclusion criteria, 17 publications were included in this review. Meta-analysis showed an increased prevalence of 6 % (95 % CI, 3-9) of Fusobacterium in tumour lesions than in non-tumour lesions (Fusobacterium prevalence of 16 % in tumour lesions and of 10 % in non-tumour lesions), and a 2.93 higher chance of Fusobacterium being present in tumour lesions (95 % CI, 1.47-5.81). The most common detection methods were based on molecular evidence (64.70 %) (95 % CI, 37.7-84.7). F. nucleatum was the most prevalent species (47.06 %) (95 % CI, 23.5-72).

CONCLUSION

In conclusion, Fusobacterium is present and in higher abundance in oral/head and neck cancer samples when compared to non-cancer samples, suggesting that Fusobacterium may contribute to oral/head and neck cancer development.

Antagonistic effects of Streptococcus and Lactobacillus probiotics in pharyngeal biofilms

Direct antagonism towards pathogens including Streptococcus pyogenes is a proposed mechanism of pharyngeal probiosis but off-target effects on the symbiotic microbiota of the throat are possible and may be beneficial, harmful or neutral. We have assessed the bacteriological effects of two candidate Lactobacillus probiotics and the established pharyngeal probiotic Streptococcus salivarius K12. Antagonism towards S. pyogenes and potential off-target effects were determined using sessile monospecies biofilms and pharyngeal microcosms, respectively. The candidate probiotics were antagonistic towards S. pyogenes (rank order of increasing potency, Lactobacillus acidophilus < Lactobacillus plantarum < Streptococcus salivarius) in the absence of significant acidification or cell-cell contact. Streptococcus salivarius and L. plantarum caused significant reductions in viable counts of streptococci in pharyngeal microbiotas, whilst S. salivarius also caused reductions in staphylococci. In contrast, changes in pharyngeal eubacterial DNA profiles were limited overall. In summary, the three candidate probiotics suppressed axenic Streptococcus pyogenes biofilms by mechanisms that did not depend on cell-cell contact or acidification and did not markedly destabilize complex pharyngeal microbiotas derived from healthy individuals. SIGNIFICANCE AND IMPACT OF THE STUDY: Candidate probiotic bacteria deployed to prevent or treat bacterial pharyngitis will interact with the target bacteria such as Streptococcus pyogenes as well as with the microbiota of the throat, where off-target effects are possible. Three candidate probiotics Lactobacillus acidophilus, Lactobacillus plantarum and Streptococcus salivarius reduced viability within extant S. pyogenes biofilms through the elaboration of diffusible factors other than fermentation acids but did not markedly disrupt ex situ pharyngeal microcosms. This work demonstrates the application of in vitro pharyngeal models in the preclinical testing of the safety and efficacy of candidate pharyngeal probiotics.

Frequency of diseases presenting in ENT OPD at Ayub Teaching Hospital Abbottabad

Introduction: Patient presents with ear, nose and throat diseases in ENT OPD to otolaryngologist/ENT specialist. ENT diseases are serious public health problems because of their universal distribution the morbidities which they cause due to inherent physiological function that take place in head and neck region. Objectives of our study were to know frequency of ENT diseases in patients presenting at ENT OPD at Ayub Teaching Hospital Abbottabad. Methods: A cross sectional study was done in Ayub Teaching Hospital Abbottabad from December 2015. to August 2016. Patients presenting at ENT OPD of Ayub Teaching Hospital Abbottabad were selected for study. Data about their ENT problems and concerned information were collected from them through well structured questionnaire. Data after collection was entered and analysed using SPSS-16. Results: The minimum age is 1 and maximum age is 80 years. Out of total 250 patients, 129 (51.6%) were males and 121 (48.4%) were females, majority of patients 181 (72.4%) were from Abbottabad and majority of patients 165 (66.0%) were poor. The most common cases in ENT OPD were bilateral ear wax 15.2% followed by acute otitis media 13.2% and allergic rhinitis 13.2%. Conclusion: It is concluded from our research that most common problems of ENT disorders are bilateral ear wax, allergic rhinitis, acute otitis media, chronic supporative otitis media and deviated nasal septum. The most common causes are infection, poor hygiene and poor nutrition.

Human pharyngeal microbiota in age-related macular degeneration

BACKGROUND

While the aetiology of age-related macular degeneration (AMD)-a major blinding disease-remains unknown, the disease is strongly associated with variants in the complement factor H (CFH) gene. CFH variants also confer susceptibility to invasive infection with several bacterial colonizers of the nasopharyngeal mucosa. This shared susceptibility locus implicates complement deregulation as a common disease mechanism, and suggests the possibility that microbial interactions with host complement may trigger AMD. In this study, we address this possibility by testing the hypothesis that AMD is associated with specific microbial colonization of the human nasopharynx.

RESULTS

High-throughput Illumina sequencing of the V3-V6 region of the microbial 16S ribosomal RNA gene was used to comprehensively and accurately describe the human pharyngeal microbiome, at genus level, in 245 AMD patients and 386 controls. Based on mean and differential microbial abundance analyses, we determined an overview of the pharyngeal microbiota, as well as candidate genera (Prevotella and Gemella) suggesting an association towards AMD health and disease conditions.

CONCLUSIONS

Utilizing an extensive study population from Singapore, our results provided an accurate description of the pharyngeal microbiota profiles in AMD health and disease conditions. Through identification of candidate genera that are different between conditions, we provide preliminary evidence for the existence of microbial triggers for AMD. Ethical approval for this study was obtained through the Singapore Health Clinical Institutional Review Board, reference numbers R799/63/2010 and 2010/585/A.

Proinflammatory diet is associated with increased risk of squamous cell head and neck cancer

Diets high in fruits and vegetables and low in red meat intake have been associated with decreased risk of head and neck cancer. Additionally, chronic inflammation pathways and their association with cancer have been widely described. We hypothesized a proinflammatory diet, as measured by the dietary inflammatory index (DII^® ), is associated with increased risk of head and neck cancer. We used the Carolina Head and Neck Cancer (CHANCE) study, a population-based case-control study of head and neck squamous cell carcinoma. Cases were recruited from a 46-county region in central North Carolina. Controls, frequency-matched on age, race, and sex were identified through the North Carolina Department of Motor Vehicle records. The DII score, adjusted for energy using the density approach (E-DII), was calculated from a food frequency questionnaire and split into four quartiles based on the distribution among controls. Adjusted odds ratios (ORs) were estimated with unconditional logistic regression. Cases had higher E-DII scores (i.e., a more proinflammatory diet) compared with controls (mean: -0.14 vs. -1.50; p value < 0.001). When compared with the lowest quartile, the OR for the highest quartile was 2.91 (95% confidence interval (CI): 2.16-3.95), followed by 1.93 (95% CI: 1.43-2.62) for the third quartile, and 1.37 (95% CI: 1.00-1.89) for the second quartile. Both alcohol and smoking had a significant additive interaction with E-DII (smoking relative excess risk due to interaction (RERI): 2.83; 95% CI: 1.36-4.30 and alcohol RERI: 1.75; 95% CI: 0.77-2.75). These results provide additional evidence for the association between proinflammatory diet and head and neck cancer.

Respiratory microbiota and lower respiratory tract disease

INTRODUCTION

The respiratory airways harbor a complex succession of ecological niches with distinct but related bacterial communities. Particular challenges of respiratory microbiome research have led to limited scientific output compared to other human microbiomes. Areas covered: In this review, we summarize the current state of knowledge of the bacterial respiratory microbiome, with a particular focus on associations between the respiratory microbiome and lower respiratory tract conditions. Expert commentary: There is growing evidence that the respiratory microbiome is associated with lower respiratory infectious diseases and related conditions. Most respiratory microbiome reports are metataxonomic cross-sectional or case-control studies with relatively small sample sizes. Large, prospective projects with metatranscriptomics or metabolomics approach are needed to unravel the effect of the respiratory microbiome on health-related conditions. Moreover, standardization in sampling, library preparation, sequencing techniques and data analysis should be encouraged.

[The Microbiome - The Unscheduled Parameter for Future Therapies]

The microbiome is defined as the total of cellular microorganisms of baczerial, viral or e. g., parasite origin living on the surface of a body. Within the anatomical areas of otorhinolaryngology, a significant divergence and variance can be demonstrated. For ear, nose, throat, larynx and cutis different interactions of microbiome and common factors like age, diet and live style factors (e. g., smoking) have been detected in recent years. Besides, new insights hint at a passible pathognomic role of the microbiome towards diseases in the ENT area. This review article resumes the present findings of this rapidly devloping scientific area.

TrkB promotes laryngeal cancer metastasis via activation PI3K/AKT pathway

OBJECTIVES

The aim of our study was to investigate the role of TrkB pathway in tumor occurrence and development for in order to provide theoretical basis to laryngeal cancer therapy.

MATERIALS AND METHODS

Biological characteristics of the cells were studied by migration tests and colony forming assay. Gene and protein expression analysis was performed by RT-PCR or western blot. in vivo experiments were conducted in syngeneic BALB/c mice.

RESULTS

Significant changes in protein and gene expression, including higher expression level of TrkB, were found in cells and laryngeal cancer specimens. we demonstrated that TrkB activates AKT via c-Src, leading to increased proliferation. Also, TrkB induced EMT via increased expression of EMT related transcription factors such as Twist-1 and Twist-2.

CONCLUSION

Our data indicate TrkB are overexpressed in laryngeal cancer, and TrkB signaling is involved in tumorigenicity of laryngeal cancer. These observations suggest that TrkB is a promising target for future intervention strategies to prevent tumor metastasis, EMT program in laryngeal cancer.What is already known about this subject?• Cancer of the larynx is one of the most common types of head and neck cancer.• The survival rate of advanced laryngeal cancer is only 30 to 40%.• The tropomyosin-related kinase B receptor (TrkB), together with TrkA and TrkC, are neurotrophin receptors regulating the proliferation and differentiation of neuronal cells.What are the new findings?• TrkB are overexpressed in laryngeal cancer.• TrkB signaling is involved in tumorigenicity of laryngeal cancer.• TrkB acts as a key regulator of the PI3K/AKT signal pathway-mediated tumor metastasis.How might these results change the focus of research or clinical practice?• These observations suggest that TrkB is a promising target for future intervention strategies to prevent tumor metastasis, EMT program in laryngeal cancer. Our study provides molecular insight into the tumor metastasis and has important implications in elucidating oncogenic processes.

A Microbiomic Analysis in African Americans with Colonic Lesions Reveals Streptococcus sp.VT162 as a Marker of Neoplastic Transformation

Increasing evidence suggests a role of the gut microbiota in colorectal carcinogenesis (CRC). To detect bacterial markers of colorectal cancer in African Americans a metabolomic analysis was performed on fecal water extracts. DNA from stool samples of adenoma and healthy subjects and from colon cancer and matched normal tissues was analyzed to determine the microbiota composition (using 16S rDNA) and genomic content (metagenomics). Metagenomic functions with discriminative power between healthy and neoplastic specimens were established. Quantitative Polymerase Chain Reaction (q-PCR) using primers and probes specific to Streptococcus sp. VT_162 were used to validate this bacterium association with neoplastic transformation in stool samples from two independent cohorts of African Americans and Chinese patients with colorectal lesions. The metabolomic analysis of adenomas revealed low amino acids content. The microbiota in both cancer vs. normal tissues and adenoma vs. normal stool samples were different at the 16S rRNA gene level. Cross-mapping of metagenomic data led to 9 markers with significant discriminative power between normal and diseased specimens. These markers identified with Streptococcus sp. VT_162. Q-PCR data showed a statistically significant presence of this bacterium in advanced adenoma and cancer samples in an independent cohort of CRC patients. We defined metagenomic functions from Streptococcus sp. VT_162 with discriminative power among cancers vs. matched normal and adenomas vs. healthy subjects’ stools. Streptococcus sp. VT_162 specific 16S rDNA was validated in an independent cohort. These findings might facilitate non-invasive screening for colorectal cancer.

Microbiota dysbiosis in select human cancers: Evidence of association and causality

The human microbiota is a complex ecosystem of diverse microorganisms consisting of bacteria, viruses, and fungi residing predominantly in epidermal and mucosal habitats across the body, such as skin, oral cavity, lung, intestine and vagina. These symbiotic communities in health, or dysbiotic communities in disease, display tremendous interaction with the local environment and systemic responses, playing a critical role in the host's nutrition, immunity, metabolism and diseases including cancers. While the profiling of normal microbiota in healthy populations is useful and necessary, more recent studies have focused on the microbiota associated with disease, particularly cancers. In this paper, we review current evidence on the role of the human microbiota in four cancer types (colorectal cancer, head and neck cancer, pancreatic cancer, and lung cancer) proposed as affected by both the oral and gut microbiota, and provide a perspective on current gaps in the knowledge of the microbiota and cancer.

Alterations of microbiota structure in the larynx relevant to laryngeal carcinoma

The microbial communities that inhabit the laryngeal mucosa build stable microenvironments and have the potential to influence the health of the human throat. However, the associations between the microbiota structure and laryngeal carcinoma remain uncertain. Here, we explored this question by comparing the laryngeal microbiota structure in laryngeal cancer patients with that in control subjects with vocal cord polyps through high-throughput pyrosequencing. Overall, the genera Streptococcus, Fusobacterium, and Prevotella were prevalent bacterial populations in the laryngeal niche. Tumor tissue samples and normal tissues adjacent to the tumor sites (NATs) were collected from 31 laryngeal cancer patients, and the bacterial communities in laryngeal cancer patients were compared with control samples from 32 subjects. A comparison of the laryngeal communities in the tumor tissues and the NATs showed higher α-diversity in cancer patients than in control subjects, and the relative abundances of seven bacterial genera differed among the three groups of samples. Furthermore, the relative abundances of ten bacterial genera in laryngeal cancer patients differed substantially from those in control subjects. These findings indicate that the laryngeal microbiota profiles are altered in laryngeal cancer patients, suggesting that a disturbance of the microbiota structure might be relevant to laryngeal cancer.

Determination of nasal and oropharyngeal microbiomes in a multicenter population-based study - findings from Pretest 1 of the German National Cohort

We examined acceptability, preference and feasibility of collecting nasal and oropharyngeal swabs, followed by microbiome analysis, in a population-based study with 524 participants. Anterior nasal and oropharyngeal swabs were collected by certified personnel. In addition, participants self-collected nasal swabs at home four weeks later. Four swab types were compared regarding (1) participants' satisfaction and acceptance and (2) detection of microbial community structures based on deep sequencing of the 16 S rRNA gene V1-V2 variable regions. All swabbing methods were highly accepted. Microbial community structure analysis revealed 846 phylotypes, 46 of which were unique to oropharynx and 164 unique to nares. The calcium alginate tipped swab was found unsuitable for microbiome determinations. Among the remaining three swab types, there were no differences in oropharyngeal microbiomes detected and only marginal differences in nasal microbiomes. Microbial community structures did not differ between staff-collected and self-collected nasal swabs. These results suggest (1) that nasal and oropharyngeal swabbing are highly feasible methods for human population-based studies that include the characterization of microbial community structures in these important ecological niches, and (2) that self-collection of nasal swabs at home can be used to reduce cost and resources needed, particularly when serial measurements are to be taken.

Bacterial microbiome of the nose of healthy dogs and dogs with nasal disease

The role of bacterial communities in canine nasal disease has not been studied so far using next generation sequencing methods. Sequencing of bacterial 16S rRNA genes has revealed that the canine upper respiratory tract harbors a diverse microbial community; however, changes in the composition of nasal bacterial communities in dogs with nasal disease have not been described so far. Aim of the study was to characterize the nasal microbiome of healthy dogs and compare it to that of dogs with histologically confirmed nasal neoplasia and chronic rhinitis. Nasal swabs were collected from healthy dogs (n = 23), dogs with malignant nasal neoplasia (n = 16), and dogs with chronic rhinitis (n = 8). Bacterial DNA was extracted and sequencing of the bacterial 16S rRNA gene was performed. Data were analyzed using Quantitative Insights Into Microbial Ecology (QIIME). A total of 376 Operational Taxonomic Units out of 26 bacterial phyla were detected. In healthy dogs, Moraxella spp. was the most common species, followed by Phyllobacterium spp., Cardiobacteriaceae, and Staphylococcus spp. While Moraxella spp. were significantly decreased in diseased compared to healthy dogs (p = 0.005), Pasteurellaceae were significantly increased (p = 0.001). Analysis of similarities used on the unweighted UniFrac distance metric (p = 0.027) was significantly different when nasal microbial communities of healthy dogs were compared to those of dogs with nasal disease. The study showed that the canine nasal cavity is inhabited by a highly species-rich bacterial community, and suggests significant differences between the nasal microbiome of healthy dogs and dogs with nasal disease.

A comparison of sampling methods for examining the laryngeal microbiome

Shifts in healthy human microbial communities have now been linked to disease in numerous body sites. Noninvasive swabbing remains the sampling technique of choice in most locations; however, it is not well known if this method samples the entire community, or only those members that are easily removed from the surface. We sought to compare the communities found via swabbing and biopsied tissue in true vocal folds, a location that is difficult to sample without causing potential damage and impairment to tissue function. A secondary aim of this study was to determine if swab sampling of the false vocal folds could be used as proxy for true vocal folds. True and false vocal fold mucosal samples (swabbed and biopsied) were collected from six pigs and used for 454 pyrosequencing of the V3–V5 region of the 16S rRNA gene. Most of the alpha and beta measures of diversity were found to be significantly similar between swabbed and biopsied tissue samples. Similarly, the communities found in true and false vocal folds did not differ considerably. These results suggest that samples taken via swabs are sufficient to assess the community, and that samples taken from the false vocal folds may be used as proxies for the true vocal folds. Assessment of these techniques opens an avenue to less traumatic means to explore the role microbes play in the development of diseases of the vocal folds, and perhaps the rest of the respiratory tract.

Microbiomic differences in tumor and paired-normal tissue in head and neck squamous cell carcinomas

BACKGROUND

While the role of the gut microbiome in inflammation and colorectal cancers has received much recent attention, there are few data to support an association between the oral microbiome and head and neck squamous cell carcinomas. Prior investigations have been limited to comparisons of microbiota obtained from surface swabs of the oral cavity. This study aims to identify microbiomic differences in paired tumor and non-tumor tissue samples in a large group of 121 patients with head and neck squamous cell carcinomas and correlate these differences with clinical-pathologic features.

METHODS

Total DNA was extracted from paired normal and tumor resection specimens from 169 patients; 242 samples from 121 patients were included in the final analysis. Microbiomic content of each sample was determined using 16S rDNA amplicon sequencing. Bioinformatic analysis was performed using QIIME algorithms. F-testing on cluster strength, Wilcoxon signed-rank testing on differential relative abundances of paired tumor-normal samples, and Wilcoxon rank-sum testing on the association of T-stage with relative abundances were conducted in R.

RESULTS

We observed no significant difference in measures of alpha diversity between tumor and normal tissue (Shannon index: p = 0.13, phylogenetic diversity: p = 0.42). Similarly, although we observed statistically significantly differences in both weighted (p = 0.01) and unweighted (p = 0.04) Unifrac distances between tissue types, the tumor/normal grouping explained only a small proportion of the overall variation in the samples (weighted R2 = 0.01, unweighted R2 < 0.01). Notably, however, when comparing the relative abundances of individual taxa between matched pairs of tumor and normal tissue, we observed that Actinomyces and its parent taxa up to the phylum level were significantly depleted in tumor relative to normal tissue (q < 0.01), while Parvimonas was increased in tumor relative to normal tissue (q = 0.01). These differences were more pronounced among patients with more extensive disease as measured by higher T-stage.

CONCLUSIONS

Matched pairs analysis of individual tumor-normal pairs revealed significant differences in relative abundance of specific taxa, namely in the genus Actinomyces. These differences were more pronounced among patients with higher T-stage. Our observations suggest further experiments to interrogate potential novel mechanisms relevant to carcinogenesis associated with alterations of the oral microbiome that may have consequences for the human host.