Association of Oral Microbiome With Risk for Incident Head and Neck Squamous Cell Cancer

Altered Bacteria Abundance Is Associated With Outcomes in Head and Neck Squamous Cell Carcinoma

OBJECTIVE

To determine if microbiome differences exist in head and neck squamous cell carcinoma (HNSCC) based on high-risk pathologic features, smoking, and outcomes using The Cancer Microbiome Atlas (TCMA).

STUDY DESIGN

Database study.

SETTING

Database review.

METHODS

TCMA is a publicly available database containing curated, decontaminated microbial profiles for tumors from 1772 patients. The data were limited to microbiome profiles, survival, and clinicopathologic features for HNSCC patients. Phyloseq objects were created, low-read samples were removed, and differential abundance analysis (DAA) using Analysis of Compositions of Microbiomes with Bias Correction 2 (ANCOM-BC2) was performed. Statistical analysis was done in R (v4.3.1).

RESULTS

One hundred fifty-six patients with HNSCC were included from TCMA with a mean age of 59 (std 13, min 19, and max 90), 72% male (n = 113), and 91% white (n = 140). Primary sites encompassed oral cavity (n = 106, 68%), oropharynx (n = 26, 17%), and larynx/hypopharynx (n = 24, 15%). For all HNSCC in TCMA, rates of lymphovascular invasion were 17% (n = 26), perineural invasion, 34% (n = 53), and microscopic or gross extranodal extension (ENE), 19% (n = 30). DAA revealed significant changes in bacterial genera based on high-risk pathologic features, smoking status, vital status, and disease-specific survival (DSS). Genera observed with ANCOM-BC2 include Scardovia, Alloscardovia, Lactobacillus, and Corynebacterium genera for vital status and DSS.

CONCLUSION

Changes in the relative abundance of select intratumoral bacterial genera are associated with adverse pathologic features, DSS, and vital status in HNSCC. Shifts in the microbiome need further investigation to determine if they can provide any mechanistic insight or predictive role.

From Teeth to Body: The Complex Role of Streptococcus mutans in Systemic Diseases

Streptococcus mutans, the principal pathogen associated with dental caries, impacts individuals across all age groups and geographic regions. Beyond its role in compromising oral health, a growing body of research has established a link between S. mutans and various systemic diseases, including immunoglobulin A nephropathy (IgAN), nonalcoholic steatohepatitis (NASH), infective endocarditis (IE), ulcerative colitis (UC), cerebral hemorrhage, and tumors. The pathogenic mechanisms associated with S. mutans frequently involve collagen-binding proteins (CBPs) and protein antigens (PA) present on the bacterial surface. These components facilitate intricate interactions with the host immune system, thereby potentially contributing to various pathological processes. Specifically, CBP is implicated in the deposition of IgA and complement component C3, which exhibits characteristics reminiscent of IgAN-like lesions through animal models, recent clinical studies suggest a potential involvement of S. mutans in IgAN. In addition, CBP binds to complement component C1q, effectively inhibiting the classical activation pathway of the complement system. In addition, CBP promotes the induction of host cells to produce interferon-gamma (IFN-γ). Furthermore, CBP leads to direct inhibitory effects on platelets and the activation of matrix metalloproteinase-9 (MMP-9) at sites of vascular injury. Moreover, PA enhances the ability of S. mutans to invade hepatic tissue. Through utilization of its PAc, S. mutans excessively produces kynurenine (KYNA), which promotes the development and progression of oral squamous cell carcinoma (OSCC). This article synthesizes the latest advancements in understanding the mechanisms of intricate interactions between S. mutans and various systemic conditions in humans, expanding our perspective beyond the traditional focus on dental caries.

Complex of intratumoral mycobiome and bacteriome predicts the recurrence of laryngeal squamous cell carcinoma

Dysbiosis of intratumoral fungal and bacterial communities is associated with poor prognosis in various cancers. However, the mycobiome characteristics in laryngeal squamous cell carcinoma (LSCC) and its correlation with recurrence have not yet been investigated. The mycobiome in 80 LSCC samples was characterized using internal transcribed spacer sequencing, encompassing both tumor tissues and their matched para-cancerous tissues. The intratumoral bacteriome was further identified using 16S rRNA sequencing. These two microbial communities were analyzed using bioinformatics and statistical methods to determine its potential correlation with LSCC recurrence. The fungal alpha diversity in tumors was higher compared with that in para-cancerous tissues (P < 0.001). A significant difference in the overall fungal community patterns between tumor tissues and para-cancerous tissues was observed based on Bray-Curtis dissimilarity (P < 0.001). The presence of Alloprevotella, Porphyromonas, Candida, and Fusarium in tumors exhibited a correlation with alcohol consumption. The relative abundance of Penicillium, Exophiala, and Aspergillus in the mycobiome, as well as that of Alloprevotella, Porphyromonas, and Peptostreptococcus in the bacteriome significantly increased the risk of LSCC recurrence (P < 0.05). These six microorganisms can combine to form a microbial complex, which may independently contribute to recurrence risk in patients with LSCC when enriched within the tumor (hazard ratio = 6.844, P < 0.01). Intratumoral fungi and bacteria can be valuable indicators for assessing recurrence in patients with LSCC, indicating their potential as valuable targets for therapeutic intervention.

IMPORTANCE

Our results revealed that dysbiosis of intratumoral microbiota, including increased fungal community diversity and overgrowth of several fungal or bacterial organisms, is substantially linked to the recurrence of LSCC. Drinking habits might alter the laryngeal microbiota to influence the recurrence of LSCC. We also explored a method to potentially predict the recurrence of LSCC from a novel perspective. These findings could offer insights into the etiology of LSCC and pave way to prevent and treat LSCC.

Evaluating the radiosensitivity of the oral microbiome to predict radiation-induced mucositis in head and neck cancer patients: A prospective trial

Background

Predicting the occurrence and/or severity of oral mucositis (OM) before commencing radiotherapy (RT) remains very difficult. The aim of this prospective trial was to investigate whether the ex-vivo radiation sensitivity of oral keratinocytes from head and neck (H&N) cancer patients correlates with severe OM.

Methods

Oral microbiopsies of healthy gingival mucosa were collected from 63H&N cancer patients undergoing (chemo)RT, of which 58 samples were useable. Keratinocytes from these microbiopsies underwent ex-vivo proliferation, irradiation, and subsequently the cell spreading assay. Tubes with the cell suspension were placed within the irradiation chamber of a 137Cs Gammacell 40 Exactor (Best Theratronics, Canada) and exposed to 0, 2, 4, 6, or 8 Gy at a dose rate of 0.63 Gy min-1. Cell suspension was then immediately pipetted into custom-made polydimethylsiloxane (PDMS) rings.The effect of demographic and clinical parameters on the cell spreading assay were also analyzed. Systematic clinical recording of OM was conducted twice a week by a specially trained examiner.

Results

Most patients had node-positive disease and cancer of the oropharynx or oral cavity. The vast majority of patients received adjuvant RT and concurrent chemotherapy. Overall, 34 (58.6 %) participants developed grade 3 OM after a median dose of 32 Gy. No patient experienced a grade ≥ 4 event. There was a correlation between the cell spreading assay area and grade 3 OM (p < 0.05), equivalent to approximately 0.5 Gy dose. Demographic and clinical parameters had no significant impact on the cell spreading assay (p > 0.05 for all).

Conclusions

It is necessary to establish reliable predictors of severe OM before treatment in H&N cancer to allow early management of treatment-related sequelae. This prospective trial illustrates that the intrinsic ex-vivo radiosensitivity of oral keratinocytes could be correlated with RT-induced OM in patients with H&N cancer. This novel predictor requires validation in larger prospective cohorts.

Examining the healthy human microbiome concept

Human microbiomes are essential to health throughout the lifespan and are increasingly recognized and studied for their roles in metabolic, immunological and neurological processes. Although the full complexity of these microbial communities is not fully understood, their clinical and industrial exploitation is well advanced and expanding, needing greater oversight guided by a consensus from the research community. One of the most controversial issues in microbiome research is the definition of a 'healthy' human microbiome. This concept is complicated by the microbial variability over different spatial and temporal scales along with the challenge of applying a unified definition to the spectrum of healthy microbiome configurations. In this Perspective, we examine the progress made and the key gaps that remain to be addressed to fully harness the benefits of the human microbiome. We propose a road map to expand our knowledge of the microbiome-health relationship, incorporating epidemiological approaches informed by the unique ecological characteristics of these communities.

Intra-tumoral bacteria in head and neck cancer: holistic integrative insight

Intra-tumoral bacteria are pivotal in the initiation and progression of head and neck squamous cell carcinoma (HNSCC), exerting a significant influence on tumor cell biology, immune responses, and the tumor microenvironment (TME). Different types and distribution of bacteria threaten the balance of metabolism and the immune environment of tumor cells. Taking advantage of this disrupted homeostasis, intra-tumoral bacteria stimulate the secretion of metabolites or influence specific immune cell types to produce inflammatory or chemokines, thereby influencing the anti-tumor immune response while regulating the level of inflammation and immunosuppression within the TME. Some intra-tumoral bacteria are used as diagnostic and prognostic markers in clinical practice. Based on the unique characteristics of bacteria, the use of engineered bacteria and outer membrane vesicles for drug delivery and biological intervention is a promising new therapeutic strategy. The presence of intra-tumoral bacteria also makes chemoradiotherapy tolerable, resulting in a poor treatment effect. However, due to the immune-related complexity of intra-tumoral bacteria, there may be unexpected effects in immunotherapy. In this review the patterns of intra-tumoral bacteria involvement in HNSCC are discussed, elucidating the dual roles, while exploring the relevance to anti-tumor immune responses in the clinical context and the prospects and limitations of the use of bacteria in targeted therapy.

Systematic analyses uncover robust salivary microbial signatures and host-microbiome perturbations in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a prevalent malignancy in the oral-maxillofacial region with a poor prognosis. Oral microbiomes play a potential role in the pathogenesis of this disease. However, findings from individual studies have been inconsistent, and a comprehensive understanding of OSCC-associated microbiome dysbiosis remains elusive. Here, we conducted a large-scale meta-analysis by integrating 11 publicly available data sets comprising salivary microbiome profiles of OSCC patients and healthy controls. After correcting for batch effects, we observed significantly elevated alpha diversity and distinct beta-diversity patterns in the OSCC salivary microbiome compared to healthy controls. Leveraging random effects models, we identified robust microbial signatures associated with OSCC across data sets, including enrichment of taxa such as Streptococcus, Lactobacillus, Prevotella, Bulleidia moorei, and Haemophilus in OSCC samples. The machine learning models constructed from these microbial markers accurately predicted OSCC status, highlighting their potential as non-invasive diagnostic biomarkers. Intriguingly, our analyses revealed that the age- and gender-associated signatures in normal saliva microbiome were disrupted in the OSCC, suggesting perturbations in the intricate host-microbe interactions. Collectively, our findings uncovered complex alterations in the oral microbiome in OSCC, providing novel insights into disease etiology and paving the way for microbiome-based diagnostic and therapeutic strategies. Given that the salivary microbiome can reflect the overall health status of the host and that saliva sampling is a safe, non-invasive approach, it may be worthwhile to conduct broader screening of the salivary microbiome in high-risk OSCC populations as implications for early detection.

IMPORTANCE

The oral cavity hosts a diverse microbial community that plays a crucial role in systemic and oral health. Accumulated research has investigated significant differences in the saliva microbiota associated with oral cancer, suggesting that microbiome dysbiosis may contribute to the pathogenesis of oral squamous cell carcinoma (OSCC). However, the specific microbial alterations linked to OSCC remain controversial. This meta-analysis reveals robust salivary microbiome alterations. Machine learning models using differential operational taxonomic units accurately predicted OSCC status, highlighting the potential of the salivary microbiome as a non-invasive diagnostic biomarker. Interestingly, age- and gender-associated signatures in the normal salivary microbiome were disrupted in OSCC, suggesting perturbations in host-microbe interactions.

Structural and functional changes in the oral microbiome of patients with craniofacial microsomia

Craniofacial microsomia (CFM) is the second most common congenital craniofacial deformity, presenting diverse clinical manifestations and treatments that may influence oral bacteria dysbiosis (OBD). However, research linking CFM to OBD is limited. Saliva samples were collected from 20 patients with CFM and 24 controls. We compared oral microflora and gene function using 16 S ribosomal RNA sequencing and metagenomics. We also evaluated the correlation between CFM clinical phenotypes and microbiota community structure. Patients with CFM demonstrated greater richness and evenness in their oral microflora. The dominant genera included several pathogenic species, such as Actinomyces, Fusobacterium, and Prevotella. Notably, the severity of CFM correlated positively with the abundance of Neisseria and Porphyromonas. Upregulated pathways were primarily linked to biotin and amino acid metabolism, such as Tryptophan metabolism and Lysine degradation, and further underscored the need for focused oral health interventions in this population. This study is the first to indicate that CFM patients exhibit unique oral bacterial dysbiosis, marked by a higher presence of opportunistic pathogens and increased pathways related to oral and systemic health. These findings highlight the importance of monitoring oral health in patients with CFM.

Dysbiosis of Oral Microbiome: A Key Player in Oral Carcinogenesis? A Critical Review

The oral cavity is known to harbor hundreds of microorganisms, belonging to various genera, constituting a peculiar flora called the oral microbiome. The change in the relative distribution of the constituents of this microbial flora, due to any reason, leads to oral dysbiosis. For centuries, oral dysbiosis has been linked to the etiopathogenesis of several medical illnesses, both locally and systemically-. However, aided by the recent advent of bio-technological capabilities, several reports have re-emerged that link oral dysbiosis to oral carcinogenesis, and numerous studies are currently exploring their association and plausible mechanisms. Some of the proposed mechanisms of oral dysbiosis-induced carcinogenesis (ODIC) include-a bacteria-induced chronic inflammatory state leading to direct cellular damage, inflammatory-cytokine-mediated promotion of cellular proliferation and invasion, release of bacterial products that are carcinogenic, and suppression of local immunity by alteration of the tumor microenvironment. However, the actual interactions between these cellular mechanisms and their role in carcinogenesis are not yet fully understood. This review provides a comprehensive overview of the various hypotheses and mechanisms implicated in the ODIC, along with the corresponding molecular aberrations. Apart from discussing the usual constituents of the oral microbiome profile, the review also summarizes the various dysbiosis profiles implicated in ODIC. The review also sheds light on the potential clinical implications of the research on oral microbiome in the prevention and management of oral cancer.

HPV Infection and Oral Microbiota: Interactions and Future Implications

Human papillomavirus (HPV) is a leading cause of mucosal cancers, including the increasing incidence of HPV-related head and neck cancers. The oral microbiota-a diverse community of bacteria, fungi, and viruses-play a critical role in oral and systemic health. Oral microbiota dysbiosis is increasingly linked to inflammation, immune suppression, and cancer progression. Recent studies have highlighted a complex interaction between HPV and oral microbiota, suggesting this interplay influences viral persistence, immune response and the tumor microenvironment. These interactions hold significant implications for disease progression, clinical outcomes, and therapeutic approaches. Furthermore, the oral microbiota has emerged as a promising biomarker for HPV detection and disease progress assessment. In addition, probiotic-based treatments are gaining attention as an innovative approach for preventing or treating HPV-related cancers by modulating the microbial environment. In this review, current research on the interaction between HPV and oral microbiota is provided, their clinical implications are explored, and the future potential for utilizing microbiota for diagnostic and therapeutic innovations in HPV-associated cancers is discussed.

Dysbiotic oral microbiota-derived kynurenine, induced by chronic restraint stress, promotes head and neck squamous cell carcinoma by enhancing CD8+ T cell exhaustion

BACKGROUND

Chronic restraint stress (CRS) is a tumour-promoting factor. However, the underlying mechanism is unknown.

OBJECTIVE

We aimed to investigate whether CRS promotes head and neck squamous cell carcinoma (HNSCC) by altering the oral microbiota and related metabolites and whether kynurenine (Kyn) promotes HNSCC by modulating CD8+ T cells.

DESIGN

4-nitroquinoline-1-oxide (4NQO)-treated mice were exposed to CRS. Germ-free mice treated with 4NQO received oral microbiota transplants from either CRS or control mouse donors. 16S rRNA gene sequencing and liquid chromatography-mass spectrometry were performed on mouse saliva, faecal and plasma samples to investigate alterations in their microbiota and metabolites. The effects of Kyn on HNSCC were studied using the 4NQO-induced HNSCC mouse model.

RESULTS

Mice subjected to CRS demonstrated a higher incidence of HNSCC and oral microbial dysbiosis than CRS-free control mice. Pseudomonas and Veillonella species were enriched while certain oral bacteria, including Corynebacterium and Staphylococcus species, were depleted with CRS exposure. Furthermore, CRS-altered oral microbiota promoted HNSCC formation, caused oral and gut barrier dysfunction, and induced a host metabolome shift with increased plasma Kyn in germ-free mice exposed to 4NQO treatment. Under stress conditions, we also found that Kyn activated aryl hydrocarbon receptor (AhR) nuclear translocation and deubiquitination in tumour-reactive CD8+ T cells, thereby promoting HNSCC tumourigenesis.

CONCLUSION

CRS-induced oral microbiota dysbiosis plays a protumourigenic role in HNSCC and can influence host metabolism. Mechanistically, under stress conditions, Kyn promotes CD8+ T cell exhaustion and HNSCC tumourigenesis through stabilising AhR by its deubiquitination.

Programmable DNA Hydrogels with Zinc Oxide Nanoparticles and Cisplatin for Diagnosis and Treatment of Oral Squamous Cell Carcinoma

This study explores the potential of DNA hydrogels as a novel approach for diagnosing and treating Oral Squamous Cell Carcinoma (OSCC). In the experiment, DNA hydrogels are synthesized and loaded with Zinc Oxide Nanoparticles (ZnO NPs) and Cisplatin. In vitro experiments evaluated drug delivery efficacy and the effect on cancer cell viability. In vivo, studies used mice models to assess the therapeutic potential and antimicrobial activity of the DNA hydrogels. Results demonstrate that DNA hydrogels significantly improve the delivery of Cisplatin to cancer cells, potentially allowing for lower drug doses and reduced side effects. The combination of Cisplatin and ZnO NPs show the most potent antibacterial effect against bacterial strains associated with OSCC. Analysis indicates that ZnO NPs within the hydrogels improve the efficacy of contrast agents, facilitating earlier and more accurate tumor diagnosis. The findings highlight that DNA hydrogels loaded with therapeutic agents can enhance drug delivery and reduce side effects, while ZnO NPs improve tumor diagnosis. DNA hydrogels may represent a promising patient-centric approach for more effective OSCC treatment.

The role of the microbiome in head and neck squamous cell cancers

The human microbiome has garnered tremendous interest in the field of oncology, and microbiota studies in head and neck oncology has also flourished. Given the increasing incidence and mortality of HNSCC, as well as the suboptimal outcomes of available treatments, there is an urgent need for innovative approaches involving the microbiome. This review evaluates the intricate relationship between the microbiome and HNSCC, highlighting the potential of the microbiome as a marker for cancer detection, its role in malignancy, and its impact on the efficacy of conventional treatments like chemotherapy and radiotherapy. The review also explores the effects of treatment modalities on the microbiome and discusses the potential of microbiome alterations to predict and influence treatment toxicities such as mucositis and xerostomia. Further research is warranted to characterize the microbiome-HNSCC association, which holds promise for advancing early diagnosis, enhancing prognostic accuracy, and personalizing treatment strategies to improve patient outcomes. The exploration of the microbiome in clinical trials indicates a burgeoning subject of microbiome-focused therapies, heralding a new frontier in most cancer care.

Carcinogenetic mechanisms employed by the oral microbiome: A narrative review

Cancers of the oral cavity, lip, salivary gland, and oropharynx cause substantial global disease burden. While tobacco-use and alcohol use are highly associated with oral cancers, the rising incidence of disease in patients who do not use tobacco or alcohol points to additional carcinogenic risk factors. Chronic inflammation, disruption of the oral microbiome, and dysbiosis are becoming more widely implicated in the pathogenesis of oral cancer. Several studies have identified specific bacterial species enriched in patients with oral cancer, including Porphyromonas gingivalis and Fusobacterium nucleatum. In this narrative review, we describe potential carcinogenic mechanisms exhibited by these species and other microbes in the development of oral cancer.

Host-microbe computational proteomic landscape in oral cancer revealed key functional and metabolic pathways between Fusobacterium nucleatum and cancer progression

Oral squamous cell carcinoma (OSCC) is the most common manifestation of oral cancer. It has been proposed that periodontal pathogens contribute to OSCC progression, mainly by their virulence factors. However, the main periodontal pathogen and its mechanism to modulate OSCC cells remains not fully understood. In this study we investigate the main host-pathogen pathways in OSCC by computational proteomics and the mechanism behind cancer progression by the oral microbiome. The main host-pathogen pathways were analyzed in the secretome of biopsies from patients with OSCC and healthy controls by mass spectrometry. Then, functional assays were performed to evaluate the host-pathogen pathways highlighted in oral cancer. Host proteins associated with LPS response, cell migration/adhesion, and metabolism of amino acids were significantly upregulated in the human cancer proteome, whereas the complement cascade was downregulated in malignant samples. Then, the microbiome analysis revealed large number and variety of peptides from Fusobacterium nucleatum (F. nucleatum) in OSCC samples, from which several enzymes from the L-glutamate degradation pathway were found, indicating that L-glutamate from cancer cells is used as an energy source, and catabolized into butyrate by the bacteria. In fact, we observed that F. nucleatum modulates the cystine/glutamate antiporter in an OSCC cell line by increasing SLC7A11 expression, promoting L-glutamate efflux and favoring bacterial infection. Finally, our results showed that F. nucleatum and its metabolic derivates promote tumor spheroids growth, spheroids-derived cell detachment, epithelial-mesenchymal transition and Galectin-9 upregulation. Altogether, F. nucleatum promotes pro-tumoral mechanism in oral cancer.

Preclinical in vitro models of HNSCC and their role in drug discovery - an emphasis on the cancer microenvironment and microbiota

INTRODUCTION

Head and neck squamous cell carcinoma (HNSCC) is the seventh most common cancer worldwide. Treatment options and patient outcomes have not improved significantly over the past decades, increasing the need for better preclinical models. Holistic approaches that include an intact and functional immune compartment along with the patient's individual tumor microbiome will help improve the predictive value of novel drug efficacy.

AREAS COVERED

In this review, we describe the challenges of modeling the complex and heterogeneous tumor landscape in HNSCC and the importance of sophisticated patient-specific 3D in vitro models to pave the way for clinical trials with novel immunomodulatory drugs. We also discuss the impact of the tumor microbiome and the potential implications for prospective drug screening and validation trials.

EXPERT OPINION

The repertoire of well-characterized preclinical 3D in vitro models continues to grow. With the increasing attention to the complex cellular, immunological, molecular, and spatio-temporal characteristics of tumors, well-designed proof-of-concept studies to test novel drug efficacy are on the verge of providing valuable, practice-changing insights for clinical trials. Bringing together expertise and improving collaboration between clinicians, academics, and regulatory agencies will facilitate the translation of preclinical findings into clinically meaningful outcomes.

The Oral Microbiome and Cancer

There is growing evidence suggesting a strong association between members of the oral microbiota and various types of cancer, including oral cancer, colorectal cancer, esophageal squamous cell carcinoma, and pancreatic cancer. Periodontal diseases closely associated with pathogenic bacteria in the oral cavity have been shown to be correlated with the occurrence and development of cancers. Among the periodontal disease-associated bacteria in the oral cavity, two prominent oral pathogens, Porphyromonas gingivalis and Fusobacterium nucleatum, have been found to promote tumor cell proliferation, invasion, and migration, as well as to inhibit immune cell function, thereby facilitating tumor progression. The presence of other oral pathogenic bacteria, such as Treponema denticola, Tannerella forsythia, Parvimonas micra, and Aggregatibacter actinomycetemcomitans, has also been found to be associated with cancer worsening. Oral commensal bacteria play a crucial role in maintaining the normal oral homeostasis. However, the relationship between oral commensal bacteria and the occurrence and development of cancers remains controversial. Some studies suggest an increase in oral commensal bacteria during tumor development, while others suggest an association of certain commensal bacteria with lower tumor risk. The microbiota can significantly alter responses and toxicity to various forms of cancer treatment through interactions with the human body, thereby influencing disease progression. In this chapter, we provide a concise overview of current understanding of the role of the oral microbiota in cancer.

Natural Antimicrobial Peptides and Their Synthetic Analogues for Effective Oral Microflora Control and Oral Infection Treatment-The Role of Ceragenins in the Development of New Therapeutic Methods

Oral diseases, both acute and chronic, of infectious or non-infectious etiology, represent some of the most serious medical problems in dentistry. Data from the literature increasingly indicate that changes in the oral microbiome, and therefore, the overgrowing of pathological microflora, lead to a variety of oral-localized medical conditions such as caries, gingivitis, and periodontitis. In recent years, compelling research has been devoted to the use of natural antimicrobial peptides as therapeutic agents in the possible treatment of oral diseases. This review focuses on the potential of ceragenins (CSAs), which are lipid analogs of natural antimicrobial peptides, as molecules for the development of new methods for the prevention and treatment of oral diseases. Studies to date indicate that ceragenins, with their spectrum of multidirectional biological activities, including antimicrobial, tissue regeneration-stimulating, anti-inflammatory, and immunomodulatory properties, are strong candidates for further development of oral formulations. However, many of the beneficial properties of ceragenins require confirmation in experimental conditions reproducing the oral environment to fully determine their application potential. Their transition to practical use also requires more advanced testing of these molecules in clinical trials, which have only been conducted in limited numbers to date.

The mouth of America: the oral microbiome profile of the US population

Importance

The oral microbiome is increasingly recognized to play key roles in human health and disease; yet, population-representative characterizations are lacking.

Objective

Characterize the composition, diversity, and correlates of the oral microbiome among US adults.

Design

Cross-sectional population-representative survey.

Setting

The National Health and Nutrition Examination Survey (NHANES, 2009-2012), a stratified multistage probability sample of the US population.

Participants

NHANES participants aged 18-69 years (n=8,237, representing 202,314,000 individuals).

Exposures

Demographic, socioeconomic, behavioral, anthropometric, metabolic, and clinical characteristics.

Main outcomes

Oral microbiome, characterized through 16S rRNA sequencing. Microbiome metrics were alpha diversity (number of observed Amplicon Sequence Variants [ASV], Faith's Phylogenetic diversity, Shannon-Weiner Index, and Simpson Index); beta diversity (unweighted UniFrac, weighted UniFrac, and Bray-Curtis dissimilarity); and prevalence and relative abundance at taxonomic levels (phylum through genus). Analyses accounted for the NHANES complex sample design.

Results

Among US adults aged 18-69 years, the oral microbiome encompassed 37 bacterial phyla, 99 classes, 212 orders, 446 families, and 1,219 genera. Five phyla-Firmicutes, Actinobacteria, Bacteroidetes, Proteobacteria, and Fusobacteria and six genera-Veillonella, Streptococcus, Prevotella7, Rothia, Actinomyces, and Gemella, were present in nearly all US adults (weighted-prevalence >99%). These genera also were the most abundant, accounting for 65.7% of abundance. Observed ASVs showed a quadratic pattern with age (peak at 30 years), was similar by sex, significantly lower among non-Hispanic White individuals, and increased with higher body mass index (BMI) categories, alcohol use, and periodontal disease severity. All covariates together accounted for a modest proportion of oral microbiome variability, as measured by beta diversity (unweighted UniFrac=8.7%, weighted UniFrac=7.2%, and Bray-Curtis=6.3%). By contrast, relative abundance of a few genera explained a high percentage of variability in beta diversity (weighted UniFrac: Aggregatibacter=22.4%, Lactococcus=21.6%, Haemophilus=18.4%). Prevalence and relative abundance of numerous genera were significantly associated (Bonferroni-corrected Wald-p<0.0002) with age, race and ethnicity, smoking, BMI categories, alcohol use, and periodontal disease severity.

Conclusions

We provide a contemporary reference standard for the oral microbiome of the US adult population. Our results indicate that a few genera were universally present in US adults and a different set of genera explained a high percentage of oral microbiome diversity across the population.

A molecular viewpoint of the intricate relationships among HNSCC, HPV infections, and the oral microbiota dysbiosis

HPV infection and the type of host microbiota play a role in the formation of HNCs. In contrast to other forms of OSCC, where the relationship between HPV and the cancer is less obvious, HPV-HNSCC is a particular type of oropharyngeal cancer. HPV has infected a stratified squamous epithelium, which includes the throat, mouth, anogenital tract, respiratory tract, and skin on the hands and feet. HPV DNA was found in high amounts in the saliva and gargle samples of patients with HPV-related HNSCC. It has been discovered that the specificity of oral mRNA (HPV) and HPV DNA identification varies from 23 % to 82 % in the identification of OPSCCs. The higher rate of HPV transmission through vaginal-oral compared to penile-oral sexual activity may be the reason for the difference in HPV-positive HNSCC patients between males and females. The researchers postulate that HPV-inactive tumours signify an advanced stage of HPV-positive HNSCC, which explains why there are racial disparities in gene expression that correspond to different disease progressions in Black and White patients. The increase of CD8+ T cells in the cancer microenvironment, linked to P16 activation, extends life expectancy in OSCC. tumour markers methylation caused by HPV and suggested using them as possible HNC biomarkers. Fusobacterium levels are much higher in patients with OSCC, while Actinobacteria phylum and Firmicutes are significantly lower. It also serves as a biomarker for notable variations found in Firmicutes, Actinobacteria, Fusobacteriales, Fusobacteriia, Fusobacterium, and Fusobacteriaceae. Therefore, based on this we evidence, we could investigate the role of oral microbiota as a maker for the HPV associated HNSCC.

The interplay between microbiome and host factors in pathogenesis and therapy of head and neck cancer

Heterogeneous cancers that lack strong driver mutations with high penetrance, such as head and neck squamous cell carcinoma (HNSCC), present unique challenges to understanding their aetiology due to the complex interactions between genetics and environmental factors. The interplay between lifestyle factors (such as poor oral hygiene, smoking, or alcohol consumption), the oral and gut microbiome, and host genetics appears particularly important in the context of HNSCC. The complex interplay between the gut microbiota and cancer treatment outcomes has also received increasing attention in recent years. This review article describes the bidirectional communication between the host and the oral/gut microbiome, focusing on microbiome-derived metabolites and their impact on systemic immune responses and the modulation of the tumour microenvironment. In addition, we review the role of host lifestyle factors in shaping the composition of the oral/gut microbiota and its impact on cancer progression and therapy. Overall, this review highlights the rationality of considering the oral/gut microbiota as a critical determinant of cancer therapy outcomes and points to therapeutic opportunities offered by targeting the oral/gut microbiota in the management of HNSCC.

Spontaneous regression of head and neck squamous cell carcinoma: a systematic review and meta-analysis of case reports

OBJECTIVE

A systematic review of case reports in spontaneous regression of head and neck squamous cell carcinoma (SCC) was carried out to investigate the pattern and characteristics of this phenomenon.

METHODS

A systematic search of case studies of spontaneously regressed head and neck SCC was carried out in Ovid Embase, Ovid Medline and Pubmed. Methodological quality was assessed by ascertainment of diagnosis and overall details of reports. Outcomes included patient demographics, head and neck SCC characteristics and clinical course of disease.

RESULTS

A total of 8 cases were included and 50 per cent (n = 4) of the reported cases were SCC of the vocal folds. All cases received a surgical biopsy and three cases had possible febrile episodes preceding regression. The mean length of time to regression was 4.3 months.

DISCUSSION

Spontaneous regression in head and neck SCC is likely to be under-reported. A better understanding of how the host immune system can instigate an antitumour response will shed light on the development of novel treatments.

Current status and prospect of gut and oral microbiome in pancreatic cancer: Clinical and translational perspectives

Pancreatic cancer is a highly lethal malignancy, and its diagnosis and treatment continue to pose significant challenges. Despite advancements in surgical and comprehensive treatment methods, the five-year survival rate remains below 12 %. With the rapid development of microbiome science, the gut and oral microbiota, which are readily accessible and can be sampled non-invasively, have emerged as a novel area of interest in pancreatic cancer research. Dysbiosis in these microbial communities can induce persistent inflammatory responses and affect the host's immune system, promoting cancer development and impacting the efficacy of treatments like chemotherapy and immunotherapy. This review provides an up-to-date overview of the roles of both gut and oral microbiota in the onset, progression, diagnosis, and treatment of pancreatic cancer. It analyzes the potential of utilizing these microbiomes as biomarkers and therapeutic targets from a clinical application perspective. Furthermore, it discusses future research directions aimed at harnessing these insights to advance the diagnosis and treatment strategies for pancreatic cancer. By focusing on the microbiome's role in clinical and translational medicine, this review offers insights into improving pancreatic cancer diagnosis and treatment outcomes.

Oral Microbiome and Subsequent Risk of Head and Neck Squamous Cell Cancer

Importance

The oral microbiota may be involved in development of head and neck squamous cell cancer (HNSCC), yet current evidence is largely limited to bacterial 16S amplicon sequencing or small retrospective case-control studies.

Objective

To test whether oral bacterial and fungal microbiomes are associated with subsequent risk of HNSCC development.

Design, Setting, and Participants

Prospective nested case-control study among participants providing oral samples in 3 epidemiological cohorts, the American Cancer Society Cancer Prevention Study II Nutrition Cohort, the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, and the Southern Community Cohort Study. Two hundred thirty-six patients who prospectively developed HNSCC were identified during a mean (SD) of 5.1 (3.6) years of follow-up. Control participants who remained HNSCC free were selected by 2:1 frequency matching on cohort, age, sex, race and ethnicity, and time since oral sample collection. Data analysis was conducted in 2023.

Exposures

Characterization of the oral bacterial microbiome using whole-genome shotgun sequencing and the oral fungal microbiome using internal transcribed spacer sequencing. Association of bacterial and fungal taxa with HNSCC was assessed by analysis of compositions of microbiomes with bias correction. Association with red and orange oral pathogen complexes was tested by logistic regression. A microbial risk score for HNSCC risk was calculated from risk-associated microbiota.

Main Outcomes and Measures

The primary outcome was HNSCC incidence.

Results

The study included 236 HNSCC case participants with a mean (SD) age of 60.9 (9.5) years and 24.6% women during a mean of 5.1 (3.6) years of follow-up, and 485 matched control participants. Overall microbiome diversity at baseline was not related to subsequent HNSCC risk; however 13 oral bacterial species were found to be differentially associated with development of HNSCC. The species included the newly identified Prevotella salivae, Streptococcus sanguinis, and Leptotrichia species, as well as several species belonging to beta and gamma Proteobacteria. The red/orange periodontal pathogen complex was moderately associated with HNSCC risk (odds ratio, 1.06 per 1 SD; 95% CI, 1.00-1.12). A 1-SD increase in microbial risk score (created based on 22 bacteria) was associated with a 50% increase in HNSCC risk (multivariate odds ratio, 1.50; 95% CI, 1.21-1.85). No fungal taxa associated with HNSCC risk were identified.

Conclusions and Relevance

This case-control study yielded compelling evidence that oral bacteria are a risk factor for HNSCC development. The identified bacteria and bacterial complexes hold promise, along with other risk factors, to identify high-risk individuals for personalized prevention of HNSCC.

Exploring the gut microbiome and head and neck cancer interplay

The gut microbiome, a complex community of microorganisms residing in the gastrointestinal tract, plays a crucial role in maintaining human health and influencing disease outcomes. Recent advancements in sequencing technologies have revealed the intricate relationship between gut microbiota and various health conditions. This review explores the impact of gut microbiome dysbiosis on immune function, chronic inflammation, and cancer progression. Dysbiosis, characterized by an imbalance in microbial populations, can lead to immune dysfunction, creating a pro-inflammatory environment conducive to tumorigenesis. Gut microbiome metabolites, such as short-chain fatty acids and bile acids, also play a significant role in modulating these processes. The interplay between these factors contributes to the development and progression of HNC. Furthermore, this review highlights the potential of therapeutic interventions targeting the gut microbiome, including probiotics, prebiotics, and dietary modifications, to restore microbial balance and mitigate cancer risk. Understanding the mechanisms by which the gut microbiome influences HNC can provide valuable insights into novel preventive and therapeutic strategies. Future research should focus on elucidating the specific microbial taxa and metabolites involved in HNC, as well as the impact of lifestyle factors such as diet, alcohol consumption, and oral hygiene on the gut microbiome. By leveraging the growing knowledge of the gut microbiome, it may be possible to develop personalized approaches to cancer prevention and treatment, ultimately improving patient outcomes.

Fusobacterium in oral bacterial flora relates with asymptomatic brain lesions

Background

Specific bacterial species in the oral cavity contribute to cerebral hemorrhage and microbleeds. The relationship between oral bacterial flora and asymptomatic brain lesions (ABL) remains unclear. This study aimed to investigate this relationship in a healthy Japanese cohort.

Methods

This cross-sectional study included participants who underwent health examinations at our Brain Dock facility between October 2020 and March 2021. The oral microbiomes of participants with and without ABL were compared using magnetic resonance imaging. To extensively assess the oral bacterial flora, the differences in genes and species compositions between the ABL and noBL (without brain lesions) groups were statistically evaluated via extensive analysis using 16S rRNA gene-based cloning.

Results

Among 143 patients, 48.3 % had ABL. In the univariate analyses, Fusobacterium and Leptotrichia were associated with ABL (P = 0.017 and P < 0.001, respectively). In the adjusted models, Fusobacterium was associated with ABL (P = 0.006). In an intergroup comparison of seven Fusobacterium species, F. nucleatum, F. naviforme, and F. canifelinum were associated with ABL (P < 0.001, P = 0.002, P < 0.001).

Conclusions

The elevation of Fusobacterium in the ABL indicates the importance of the microbiome in the oral cavity as a factor in inducing cerebral small-vessel disease in healthy individuals, whose preventive approach might have an impact on therapeutic applications.

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.

Six months of different exercise type in sedentary primary schoolchildren: impact on physical fitness and saliva microbiota composition

Introduction

Lifestyle influences microbiota composition. We previously reported a healthier microbiota composition in saliva from active schoolchildren compared to sedentary. In the present study, we evaluated the effects of 6 months of different exercise types on physical fitness and saliva microbiota composition in 8-11-years-old sedentary schoolchildren.

Methods

Sixty-four sedentary children from five primary schools in Turin, Italy, were divided into three groups: one continued normal curricular activity while two underwent different exercise protocols for 6 months. The Structured Exercise (Sa) group did 2 h per week of muscle activation, strength and coordination exercises supervised by a kinesiologist. The Daily Mile (Dm) group did 1 h per week of Sa plus 15 min of walking/running outdoors four times a week, supervised by a class teacher; control group (Ct) did 2 h a week of curricular exercise supervised by a class teacher. Physical fitness was evaluated before and after the intervention. Saliva samples were collected post-intervention in all participants and analyzed using PCR amplification of 16S rRNA bacterial genes. The Amplicon Sequence Variants were filtered, decontaminated, and phylogenetically classified using DADA2 software. Differential abundance analysis of microbiome taxa and pathway data was conducted using the LEfSe algorithm and PICRUSt.

Results

The Sa group showed better performances in lower limb power and sprint performance while both the Sa and Dm groups improved in endurance and balance at the end of the intervention; only balance resulted slightly improved in the Ct group. Among the genera differently enriched in saliva after the training intervention, we found that the Prevotella, the Dubosiella and the Family XIII AD3011 group were the most abundant in the Sa group; differently, the Neisseria and the Abiotrophia in Ct group. Four species showed significant the Prevotella melaninogenica and the Prevotella nanceiensis were more abundant in the Sa, conversely, Gemella sanguinis was enriched in Dm and Abiotrophia defectiva in Ct saliva group.

Conclusion

We demonstrated that Sa and Dm, not curricular exercise, improve the physical fitness components in sedentary schoolchildren correlated to health and promote an enrichment in saliva microbiota species associated to a healthier profile.

Analysis of Risk Factors with Assessment of the Impact of the Microbiome on the Risk of Squamous Cell Carcinoma of the Larynx

Introduction: Head and neck squamous cell carcinoma (HNSCC) ranks sixth among cancers in the world, and the 5-year survival rate ranges from 25% to 60%. The risk factors for HNSCC are primarily smoking, alcohol consumption and human papillomavirus (HPV). Data indicate that 15-20% of cancers are caused by infectious agents, 20-30% by smoking and 30-35% by unhealthy lifestyles, diet, lack of physical activity and obesity. Dysbiosis is a microbiome imbalance, which promotes oncogenesis by intensifying inflammatory processes and affecting the host's metabolism. Profiling the microbiome in various types of cancer is currently the subject of research and analysis. However, there is still little information on the correlation of the microbiome with HNSCC and its impact on oncogenesis, the course of the disease and its treatment. Objective: The aim of the study was to prospectively assess risk factors with assessment of the impact of the microbiome on the risk of squamous cell carcinoma of the larynx. The study included a group of 44 patients diagnosed with squamous cell carcinoma of the larynx and 30 patients from the control group. Results: In the control group, bacteria of the normal microbiome dominated-the genus Streptococcus, Gemella, Neisseria and Kingella. In the group of patients with laryngeal cancer, Prevotella, Clostridiales and Stomatobaculum were found significantly more often. Porphyromonas, Fusobacterium, Lactobacillus, Actinobacteria, Actinomyces and Shaalia odontolytica were also found at a higher percentage in the study group. Analyzing the phylum, Firmicutes dominated in the control group; there were statistically significantly more of them than in patients from the study group. Bacteroides and Bacillota were found significantly more often in patients with laryngeal cancer. Conclusions: The importance of the microbiome in oncology has been confirmed in many studies. Independent risk factors for laryngeal cancer were primarily a lower number of Firmicutes in the microbiome, but also an increased leukocyte level above 6.52 × 103/mm and a decreased total protein level below 6.9 g/dL. Prevotella, Clostridiales, Stomatobaculum, Porphyromonas, Fusobacterium, Lactobacillus, Actinobacteria, Actinomyces and Shaalia were considered to be the bacteria contributing to the development of laryngeal cancer. Streptococcus, Gemella, Neisserie and Kingella were considered to be protective bacteria. Moreover, the study confirmed the significant impact of smoking, alcohol consumption and poor oral hygiene on the development of laryngeal cancer. The microbiome, its identification and manipulation may constitute a breakthrough discovery for improving the diagnosis and oncological therapy of laryngeal cancer, and also of the entire group of HNSCC. Profiling the microbiome may allow for personalized therapy related to its modification. Assessing the microbiome of patients diagnosed with cancer may provide an opportunity to predict treatment response and effectiveness.

Insulin-like growth factor 1 receptor expression correlates with programmed death ligand 1 expression and poor survival in non-small cell lung cancer

The insulin-like growth factor 1 receptor (IGF1R) has been associated with growth and metastasis in various cancers. However, its role in postoperative recurrence and prognosis in lung cancer lacks clear consensus. Therefore, this study aimed to investigate the potential relationship between IGF1R and postoperative recurrence as well as long-term survival in a large cohort. Additionally, we assessed the relationship between IGF1R and programmed death ligand 1 (PD-L1) expression. Our study encompassed 782 patients with non-small cell lung cancer (NSCLC). Immunostaining of surgical specimens was performed to evaluate IGF1R and PD-L1 expression. Among the patients, 279 (35.8%) showed positive IGF1R expression, with significantly worse relapse-free survival (RFS) and overall survival (OS). Notably, no significant differences in RFS and OS were observed between IGF1R-positive and -negative groups in stages 2 and 3. However, in the early stages (0-1), the positive group displayed significantly worse RFS and OS. In addition, PD-L1 expression was detected in 100 (12.8%) patients, with a significant predominance in the IGF1R-positive. IGF1R may serve as a prognostic indicator and a guide for perioperative treatment strategies in early-stage lung cancer. In conclusion, our findings underscore an association between IGF1R expression and poor survival and PD-L1 expression in NSCLC.

Seventy-five years of impactful environmental and occupational health research at the Nelson Institute of Environmental Medicine at New York University

Founded in 1947 as the Institute of Industrial Medicine, the Nelson Institute and Department of Environmental Medicine at New York University (NYU) Grossman School of Medicine (NYUGSOM) was supported by a National Institute of Environmental Health Science (NIEHS) Center Grant for over 56 years. Nelson Institute researchers generated 75 years of impactful research in environmental and occupational health, radiation effects, toxicology, and cancer. Environmental health research is continuing at NYUGSOM in its departments of medicine and population health. The objective of this historical commentary is to highlight the major achievements of the Nelson Institute and the department in the context of its history at facilities in Sterling Forest, Tuxedo, NY and Manhattan, NY. Aspects of our discussion include leadership, physical facilities, and research in many areas, including air pollution, health effects of environmental radiation exposures, inhalation toxicology methodology, carcinogenesis by chemicals, metals, and hormones, cancer chemoprevention, human microbiome, ecotoxicology, epidemiology, biostatistics, and community health concerns. The research of the institute and department benefited from unique facilities, strong leadership focused on team-based science, and outstanding investigators, students, and staff. A major lasting contribution has been the training of hundreds of graduate students and postdoctoral fellows, many of whom have been and are training the next generation of environmental and occupational health researchers at various institutions.

Is Short-Read 16S rRNA Sequencing of Oral Microbiome Sampling a Suitable Diagnostic Tool for Head and Neck Cancer?

The oral microbiome, studied by sampling the saliva or by oral rinse, has been long thought to have diagnostic capacity for head and neck cancers (HNC). However, previous reports on the HNC oral microbiome provide inconsistent results. The aim of this study is to consolidate these datasets and determine the oral microbial composition between HNC patients to healthy and premalignant individuals. We analyzed 16 published head and neck cancer (HNC) short-read 16S rRNA sequencing datasets, specifically targeting the V3V4, V4 and V4V5 regions. These datasets included saliva and oral rinse samples from donors with HNC, as well as from healthy and premalignant donors. Differences in diversities and microbial abundance were determined. HNC saliva displayed lower alpha diversity than healthy donors. In contrast, the opposite trend was observed for oral rinse samples. Beta diversity scores were largely similar across different patient types. Similar oral phyla were detected for all samples, but proportions were largely dependent on sample type (i.e., saliva or oral rinse) and primer set utilized for 16S rRNA sequencing. Neisseria, Leptotrichia and Megasphaera were elevated in healthy saliva, while Mycoplasma was elevated in HNC saliva. Oral rinse and saliva displayed similar enrichment for Fusobacterium, while Veillonella, Alloprevotella, and Campylobacter showed conflicting results. The sparse partial least squares discriminant analysis model performed effectively in discriminating HNC from healthy or premalignant patients using V3V4 saliva (AUC = 0.888) and V3V4 oral rinse (AUC = 0.928), while poor discriminative capacity was observed for V4 saliva (AUC = 0.688). In conclusion, our meta-analysis highlighted the limitations of 16S rRNA sequencing, particularly due to variations across study batches, primer sets (i.e., V3V4, V4), and sample types. Hence, caution should be exercised when interpreting 16S rRNA sequencing results across studies, especially when different primer sets and sample types are used.

Association of Oral Microbiome With Oral Human Papillomavirus Infection: A Population Study of the National Health and Nutrition Examination Survey, 2009-2012

BACKGROUND

Oral human papillomavirus (HPV) infection and the oral microbiome are associated with oropharyngeal cancer. However, population-based data on the association of oral microbiome with oral HPV infection are limited.

METHOD

A cross-sectional analysis of 5496 20-59-year-old participants in the 2009-2012 National Health and Nutrition Examination Survey was performed. Associations with oral HPV infection were assessed using multivariable logistic regression for oral microbiome α-diversity (within-sample diversity), and using principal coordinate analysis and permutational multivariate analysis of variance for β-diversity (between-sample heterogeneity).

RESULTS

Overall, for α-diversity, a lower number of observed amplicon sequence variants (adjusted odds ratio [aOR] = 0.996; 95% confidence interval [CI] = .992-.999) and reduced Faith's phylogenetic diversity (aOR = 0.95; 95% CI = .90-.99) were associated with high-risk oral HPV infection. β-diversity showed differentiation of oral microbiome community by high-risk oral HPV infection as measured by Bray-Curtis dissimilarity (R2 = 0.054%; P = .029) and unweighted UniFrac distance (R2 = 0.046%; P = .045). There were differential associations when stratified by sex.

CONCLUSIONS

Both oral microbiome α-diversity and β-diversity were marginally associated with oral HPV infection. Longitudinal studies are needed to characterize the role of the microbiome in the natural history of oral HPV infection.

Defining intra-tumoral and systemic immune biomarkers for locally advanced head-and-neck cancer - detailed protocol of a prospective, observatory multicenter trial (ImmunBioKHT) and first results of the immunophenotyping of the patients' peripheral blood

The approval and effectiveness of immune checkpoint inhibitors in head-and-neck squamous cell carcinoma (HNSCC) highlights the role of the immune system in this tumor entity. HNSCCs not only interacts with the immune system in the tumor tissue, but also induce systemic effects that may be additionally influenced by further factors such as the microbiome. Nonetheless, reliable immunological biomarkers that predict treatment response and outcome in HNSCC patients are lacking. The currently available biomarkers are mainly limited to analyses from tumor biopsies, while biomarkers from liquid biopsies, such as peripheral blood are not well-established. Thus, the here presented trial aims to identify interactions of intra-tumoral and systemic immune responses and to define prognostic immune signatures. Consequently, not only samples from the tumor tissue, but also from peripheral blood and the microbiome will be studied/are being evaluated and correlated with the clinical outcome. In this prospective, multi-center trial, 1000 HNSCC patients and 100 patients in the control cohort with non-tumor head-and-neck surgery will be enrolled. The local immune status from of the tumor and the microbiome will be sampled before treatment. In addition, the systemic immune status from peripheral blood will be analyzed before and after surgery and after the adjuvant and definitive radio-chemotherapy (RCT). Clinical baseline characteristics and outcome will additionally be collected. Data mining and modelling approaches will finally be applied to identify interactions of local and systemic immune parameters and to define prognostic immune signatures based on the evaluated immune markers. Approval from the institutional review board of the Friedrich-Alexander-Universität Erlangen-Nürnberg was granted in December 2021 (application number 21-440-B). By now, 150 patients have been enrolled in the intervention cohort. The results will be disseminated to the scientific audience and the general public via presentations at conferences and publication in peer-reviewed journals.

Cancer and the Microbiome of the Human Body

Cancer remains a public health concern worldwide, with its incidence increasing worldwide and expected to continue growing during the next decades. The microbiome has emerged as a central factor in human health and disease, demonstrating an intricate relationship between the microbiome and cancer. Although some microbiomes present within local tissues have been shown to restrict cancer development, mainly by interacting with cancer cells or the host immune system, some microorganisms are harmful to human health and risk factors for cancer development. This review summarizes the recent evidence concerning the microbiome and some of the most common cancer types (i.e., lung, head and neck, breast, gastric, colorectal, prostate, and cervix cancers), providing a general overview of future clinical approaches and perspectives.

Oral microbiota and gastric cancer: recent highlights and knowledge gaps

Gastric cancer is one of the most common malignant tumors worldwide and has a high mortality rate. However, tests for the early screening and diagnosis of gastric cancer are limited and invasive. Certain oral microorganisms are over-expressed in gastric cancer, but there is heterogeneity among different studies. Notably, each oral ecological niche harbors specific microorganisms. Among them, tongue coating, saliva, and dental plaque are important and unique ecological niches in the oral cavity. The colonization environment in different oral niches may be a source of heterogeneity. In this paper, we systematically discuss the latest developments in the field of the oral microbiota and gastric cancer and elucidate the enrichment of microorganisms in the oral ecological niches of the tongue coatings, saliva, and dental plaque in gastric cancer patients. The various potential mechanisms by which the oral microbiota induces gastric cancer (activation of an excessive inflammatory response; promotion of proliferation, migration, invasion, and metastasis; and secretion of carcinogens, leading to imbalance in gastric microbial communities) are explored. In this paper, we also highlight the applications of the rapeutics targeting the oral microbiota in gastric cancer and suggests future research directions related to the relationship between the oral microbiota and gastric cancer.

Oral microbiome and its relationship with oral cancer

ABSTRACT

As the initial point for digestion, the balance of oral microorganisms plays an important role in maintaining local and systemic health. Oral dysbiosis, or an imbalance in the oral microbial community, may lead to the onset of various diseases. The presence or abnormal increase of microbes in the oral cavity has attracted significant attention due to its complicated relationship with oral cancer. Oral cancer can remodel microbial profiles by creating a more beneficial microenvironment for its progression. On the other hand, altered microbial profiles can promote tumorigenesis by evoking a complex inflammatory response and affecting host immunity. This review analyzes the oncogenic potential of oral microbiome alterations as a driver and biomarker. Additionally, a potentially therapeutic strategy via the reversal of the oral microbiome dysbiosis in oral cancers has been discussed.

A Mendelian randomization analysis reveals the multifaceted role of the skin microbiota in liver cancer

Background

Hepatocellular carcinoma (HCC, or hepatic cancer, HC) and cholangiocarcinoma (CCA, or hepatic bile duct cancer, HBDC) are two major types of primary liver cancer (PLC). Previous studies have suggested that microbiota can either act as risk factors or preventive factors in PLC. However, no study has reported the relationship between skin microbiota and PLC. Therefore, we conducted a two-sample Mendelian randomization (MR) study to assess the causality between skin microbiota and PLC.

Methods

Data from the genome-wide association study (GWAS) on skin microbiota were collected. The GWAS summary data of GCST90018803 (HBDC) and GCST90018858 (HC) were utilized in the discovery and verification phases, respectively. The inverse variance weighted (IVW) method was utilized as the principal method in our MR study. The MR-Egger intercept test, Cochran's Q-test, MR-Pleiotropy RESidual Sum and Outlier (MR-PRESSO), and leave-one-out analysis were conducted to identify the heterogeneity and pleiotropy.

Results

The results showed that Veillonella (unc.) plays a protective role in HBDC, while the family Neisseriaceae has a positive association with HBDC risk. The class Betaproteobacteria, Veillonella (unc.), and the phylum Bacillota (Firmicutes) play a protective role in HC. Staphylococcus epidermidis, Corynebacterium (unc.), the family Neisseriaceae, and Pasteurellaceae sp. were associated with an increased risk of HC.

Conclusion

This study provided new evidence regarding the association between skin microbiota and PLC, suggesting that skin microbiota plays a role in PLC progression. Skin microbiota could be a novel and effective way for PLC diagnosis and treatment.

Oral microbiota distinguishes patients with osteosarcoma from healthy controls

Objective

The human microbiota plays a key role in cancer diagnosis, pathogenesis, and treatment. However, osteosarcoma-associated oral microbiota alterations have not yet been unraveled. The aim of this study was to explore the characteristics of oral microbiota in osteosarcoma patients compared to healthy controls, and to identify potential microbiota as a diagnostic tool for osteosarcoma.

Methods

The oral microbiota was analyzed in osteosarcoma patients (n = 45) and matched healthy controls (n = 90) using 16S rRNA MiSeq sequencing technology.

Results

The microbial richness and diversity of the tongue coat were increased in osteosarcoma patients as estimated by the abundance-based coverage estimator indices, the Chao, and observed operational taxonomy units (OTUs). Principal component analysis delineated that the oral microbial community was significant differences between osteosarcoma patients and healthy controls. 14 genera including Rothia, Halomonas, Rhodococcus, and Granulicatella were remarkably reduced, whereas Alloprevotella, Prevotella, Selenomonas, and Campylobacter were enriched in osteosarcoma. Eventually, the optimal four OTUs were identified to construct a microbial classifier by the random forest model via a fivefold cross-validation, which achieved an area under the curve of 99.44% in the training group (30 osteosarcoma patients versus 60 healthy controls) and 87.33% in the test group (15 osteosarcoma patients versus 30 healthy controls), respectively. Notably, oral microbial markers validated strong diagnostic potential distinguishing osteosarcoma patients from healthy controls.

Conclusion

This study comprehensively characterizes the oral microbiota in osteosarcoma and reveals the potential efficacy of oral microbiota-targeted biomarkers as a noninvasive biological diagnostic tool for osteosarcoma.

Novel pretreatment nomograms based on pan-immune-inflammation value for predicting clinical outcome in patients with head and neck squamous cell carcinoma

Background

The prognostic value of an effective biomarker, pan-immune-inflammation value (PIV), for head and neck squamous cell carcinoma (HNSCC) patients after radical surgery or chemoradiotherapy has not been well explored. This study aimed to construct and validate nomograms based on PIV to predict survival outcomes of HNSCC patients.

Methods

A total of 161 HNSCC patients who underwent radical surgery were enrolled retrospectively for development cohort. The cutoff of PIV was determined using the maximally selected rank statistics method. Multivariable Cox regression and least absolute shrinkage and selection operator (LASSO) regression analyses were performed to develop two nomograms (Model A and Model B) that predict disease-free survival (DFS). The concordance index, receiver operating characteristic curves, calibration curves, and decision curve analysis were used to evaluate the nomograms. A cohort composed of 50 patients who received radiotherapy or chemoradiotherapy (RT/CRT) alone was applied for generality testing of PIV and nomograms.

Results

Patients with higher PIV (≥123.3) experienced a worse DFS (HR, 5.01; 95% CI, 3.25-7.72; p<0.0001) and overall survival (OS) (HR, 5.23; 95% CI, 3.34-8.18; p<0.0001) compared to patients with lower PIV (<123.3) in the development cohort. Predictors of Model A included age, TNM stage, neutrophil-to-lymphocyte ratio (NLR), and PIV, and that of Model B included TNM stage, lymphocyte-to-monocyte ratio (LMR), and PIV. In comparison with TNM stage alone, the two nomograms demonstrated good calibration and discrimination and showed satisfactory clinical utility in internal validation. The generality testing results showed that higher PIV was also associated with worse survival outcomes in the RT/CRT cohort and the possibility that the two nomograms may have a universal applicability for patients with different treatments.

Conclusions

The nomograms based on PIV, a simple but useful indicator, can provide prognosis prediction of individual HNSCC patients after radical surgery and may be broadly applicated for patients after RT/CRT alone.

The intratumor microbiome varies by geographical location and anatomical site in head and neck squamous cell carcinoma

Head and Neck Squamous Cell Carcinoma (HNSCC) is a highly heterogeneous cancer that is characterized by distinct phenotypes based on anatomical site and etiological agents. Recently, the intratumor microbiome has been implicated in cancer pathogenesis and progression. Although it is well established that the gut microbiome varies with geographical location and is highly influenced by factors such as diet, environment, and genetics, the intratumor microbiome is not very well characterized. In this review, we aim to characterize the HNSCC intratumor microbiome by geographical location and anatomical site. We conducted a review of primary literature from PubMed and assessed studies based on relevancy and recency. To the best of our knowledge, we are the first to comprehensively examine the tumor microenvironment of HNSCC with respect to these two primary factors on a large scale. Our results suggest that there are unique bacterial and fungal biomarkers for HNSCC for each of the following geographical locations: North America, Asia, Europe, Australia, and Africa. We also identified a panel of microbial biomarkers that are unique to two primary HNSCC anatomic sites, as well as microbial biomarkers associated with various etiological agents of HNSCC. Future study of these microbes may improve HNSCC diagnostic and therapeutic modalities by accounting for differences based on geographic regions and anatomical sites.

Oral microbiome sequencing revealed the enrichment of Fusobacterium sp., Porphyromonas sp., Campylobacter sp., and Neisseria sp. on the oral malignant fibroma surface of giant panda

Introduction

Microbial community composition is closely associated with host disease onset and progression, underscoring the importance of understanding host-microbiota dynamics in various health contexts.

Methods

In this study, we utilized full-length 16S rRNA gene sequencing to conduct species-level identification of the microorganisms in the oral cavity of a giant panda (Ailuropoda melanoleuca) with oral malignant fibroma.

Results

We observed a significant difference between the microbial community of the tumor side and non-tumor side of the oral cavity of the giant panda, with the latter exhibiting higher microbial diversity. The tumor side was dominated by specific microorganisms, such as Fusobacterium simiae, Porphyromonas sp. feline oral taxon 110, Campylobacter sp. feline oral taxon 100, and Neisseria sp. feline oral taxon 078, that have been reported to be associated with tumorigenic processes and periodontal diseases in other organisms. According to the linear discriminant analysis effect size analysis, more than 9 distinct biomarkers were obtained between the tumor side and non-tumor side samples. Furthermore, the Kyoto Encyclopedia of Genes and Genomes analysis revealed that the oral microbiota of the giant panda was significantly associated with genetic information processing and metabolism, particularly cofactor and vitamin, amino acid, and carbohydrate metabolism. Furthermore, a significant bacterial invasion of epithelial cells was predicted in the tumor side.

Discussion

This study provides crucial insights into the association between oral microbiota and oral tumors in giant pandas and offers potential biomarkers that may guide future health assessments and preventive strategies for captive and aging giant pandas.

The role of intratumoral microorganisms in the progression and immunotherapeutic efficacy of head and neck cancer

The effectiveness of cancer immunization is largely dependent on the tumor’s microenvironment, especially the tumor immune microenvironment. Emerging studies say microbes exist in tumor cells and immune cells, suggesting that these microbes can affect the state of the immune microenvironment of the tumor. Our comprehensive review navigates the intricate nexus between intratumoral microorganisms and their role in tumor biology and immune modulation. Beginning with an exploration of the historical acknowledgment of microorganisms within tumors, the article underscores the evolution of the tumor microenvironment (TME) and its subsequent implications. Using findings from recent studies, we delve into the unique bacterial compositions across different tumor types and their influence on tumor growth, DNA damage, and immune regulation. Furthermore, we illuminate the potential therapeutic implications of targeting these intratumoral microorganisms, emphasizing their multifaceted roles from drug delivery agents to immunotherapy enhancers. As advancements in next-generation sequencing (NGS) technology redefine our understanding of the tumor microbiome, the article underscores the importance of discerning their precise role in tumor progression and tailoring therapeutic interventions. The review culminates by emphasizing ongoing challenges and the pressing need for further research to harness the potential of intratumoral microorganisms in cancer care.

Insights into the oral microbiota in human systemic cancers

The oral cavity stands as one of the pivotal interfaces facilitating the intricate interaction between the human body and the external environment. The impact of diverse oral microorganisms on the emergence and progression of various systemic cancers, typified by oral cancer, has garnered increasing attention. The potential pathogenicity of oral bacteria, notably the anaerobic Porphyromonas gingivalis and Fusobacterium nucleatum, has been extensively studied and exhibits obvious correlation with different carcinoma types. Furthermore, oral fungi and viruses are closely linked to oropharyngeal carcinoma. Multiple potential mechanisms of oral microbiota-induced carcinogenesis have been investigated, including heightened inflammatory responses, suppression of the host immune system, influence on the tumor microenvironment, anti-apoptotic activity, and promotion of malignant transformation. The disturbance of microbial equilibrium and the migration of oral microbiota play a pivotal role in facilitating oncogenic functions. This review aims to comprehensively outline the pathogenic mechanisms by which oral microbiota participate in carcinogenesis. Additionally, this review delves into their potential applications in cancer prevention, screening, and treatment. It proves to be a valuable resource for researchers investigating the intricate connection between oral microbiota and systemic cancers.

Gut and local microbiota in patients with cancer: increasing evidence and potential clinical applications

In recent years, cancer research has highlighted the role of disrupted microbiota in carcinogenesis and cancer recurrence. However, microbiota may also interfere with drug metabolism, influencing the efficacy of cancer drugs, especially immunotherapy, and modulating the onset of adverse events. Intestinal micro-organisms can be altered by external factors, such as use of antibiotics, proton pump inhibitors treatment, lifestyle and the use of prebiotics or probiotics. The aim of our review is to provide a picture of the current evidence about preclinical and clinical data of the role of gut and local microbiota in malignancies and its potential clinical role in cancer treatments. Standardization of microbiota sequencing approaches and its modulating strategies within prospective clinical trials could be intriguing for two aims: first, to provide novel potential biomarkers both for early cancer detection and for therapeutic effectiveness; second, to propose personalized and "microbiota-tailored" treatment strategies.

Circulating microbiome DNA as biomarkers for early diagnosis and recurrence of lung cancer

Lung cancer mortality is exacerbated by late-stage diagnosis. Emerging evidence indicates the potential clinical significance of distinct microbial signatures as diagnostic and prognostic biomarkers across various cancers. However, circulating microbiome DNA (cmDNA) profiles are underexplored in lung cancer (LC). Here, whole-genome sequencing is performed on plasma of LC patients and healthy controls (HCs). Differentially enriched microbial species are identified between LC and HC. A diagnostic model is developed, which has a high sensitivity of 87.7% and achieves an AUC of 93.2% in the independent validation dataset. Crucially, this model demonstrates the capability to detect early-stage LC, achieving a sensitivity of 86.5% for stage I and 87.1% for tumors <1 cm. In addition, we construct a cmDNA model for recurrence, which precisely predicts LC recurrence after surgery. Overall, this study highlights the significant alterations of cmDNA profiles in LC, indicating its potential as biomarkers for early diagnosis and recurrence.

Translational research in head and neck cancer: Molecular and immunological updates

Head and neck squamous cell carcinoma (HNSCC) has a poor prognosis. Each year, approximately 880,000 patients are newly diagnosed with HNSCC worldwide, and 450,000 patients with HNSCC die. Risk factors for developing HNSCC have been identified, with cigarette smoking, alcohol consumption, and viral infections being the major factors. Owing to the prevalence of human papillomavirus infection, the number of HNSCC cases is increasing considerably. Surgery and chemoradiotherapy are the primary treatments for HNSCC. With advancements in tumor biology, patients are eligible for novel treatment modalities, namely targeted therapies, immunotherapy, and photoimmunotherapy. Because this area of research has rapidly progressed, clinicians should understand the basic biology of HNSCC to choose an appropriate therapy in the upcoming era of personalized medicine. This review summarized recent developments in tumor biology, focusing on epidemiology, genetic/epigenetic factors, the tumor microenvironment, microbiota, immunity, and photoimmunotherapy in HNSCC, as well as how these findings can be translated into clinical settings.

The Microbiome Modulates the Immune System to Influence Cancer Therapy

The gut microbiota composition can affect the tumor microenvironment and its interaction with the immune system, thereby having implications for treatment predictions. This article reviews the studies available to better understand how the gut microbiome helps the immune system fight cancer. To describe this fact, different mechanisms and approaches utilizing probiotics to improve advancements in cancer treatment will be discussed. Moreover, not only calorie intake but also the variety and quality of diet can influence cancer patients' immunotherapy treatment because dietary patterns can impair immunological activities either by stimulating or suppressing innate and adaptive immunity. Therefore, it is interesting and critical to understand gut microbiome composition as a biomarker to predict cancer immunotherapy outcomes and responses. Here, more emphasis will be given to the recent development in immunotherapies utilizing microbiota to improve cancer therapies, which is beneficial for cancer patients.

Cocaine use and head and neck cancer risk: A pooled analysis in the International Head and Neck Cancer Epidemiology Consortium

BACKGROUND

Cocaine is an illegal recreational drug used worldwide, yet little is known about whether cocaine inhalation (smoking/snorting) increases the risk of head and neck cancer (HNC).

METHODS

The analyses were conducted by pooling data from three case-control studies with 1639 cases and 2506 controls from the International Head and Neck Cancer Epidemiology Consortium. Epidemiologic data, including cocaine use histories, were obtained in face-to-face interviews. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were estimated using hierarchical logistic regression models.

RESULTS

Controlling for cumulative tobacco and alcohol use, we observed a weak positive association between cocaine use and HNC (ORever vs. never  = 1.35, 95% CI: 0.96, 1.90). In stratified analysis, while we did not detect associations among never tobacco or alcohol users due to the limited sample size, the association with cocaine use was observed among tobacco users and alcohol drinkers. ORs for ever and high cumulative use (>18 times) versus never use were 1.40 (95% CI: 0.98, 2.00) and 1.66 (95% CI: 1.03, 2.69) among tobacco users, and 1.34 (95% CI: 0.93, 1.92) and 1.59 (95% CI: 1.00, 2.51) among alcohol drinkers, respectively.

CONCLUSION

In this pooled analysis, we observed a weak positive association between cocaine inhalation and HNC risk. Our findings provide preliminary evidence of the potential carcinogenic effect of cocaine on HNC. Because of study limitations, including limited number of cocaine users, confounding, and heterogeneity across studies, future investigations will require larger studies with more detailed information on cocaine use history.

The salivary microbiota of patients with acute lower respiratory tract infection-A multicenter cohort study

The human microbiome contributes to health and disease, but the oral microbiota is understudied relative to the gut microbiota. The salivary microbiota is easily accessible, underexplored, and may provide insight into response to infections. We sought to determine the composition, association with clinical features, and heterogeneity of the salivary microbiota in patients with acute lower respiratory tract infection (LRTI). We conducted a multicenter prospective cohort study of 147 adults with acute LRTI presenting to the emergency department of seven hospitals in three states (Pennsylvania, Michigan, and Ohio) between May 2017 and November 2018. Salivary samples were collected in the emergency department, at days 2-5 if hospitalized, and at day 30, as well as fecal samples if patients were willing. We compared salivary microbiota profiles from patients to those of healthy adult volunteers by sequencing and analyzing bacterial 16-rRNA. Compared to healthy volunteers, the salivary microbiota of patients with LRTI was highly distinct and strongly enriched with intestinal anaerobes such as Bacteroidaceae, Ruminococcaceae, and Lachnospiraceae (e.g., mean 10% relative abundance of Bacteroides vs < 1% in healthy volunteers). Within the LRTI population, COPD exacerbation was associated with altered salivary microbiota composition compared to other LRTI conditions. The largest determinant of microbiota variation within the LRTI population was geography (city in which the hospital was located).