Dysbiotic tumor microbiota associates with head and neck squamous cell carcinoma outcomes

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.

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.

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 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.

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.

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.

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.

Implications of oral dysbiosis and HPV infection in head and neck cancer: from molecular and cellular mechanisms to early diagnosis and therapy

Head and neck cancer (HNC) is the sixth most common type of cancer, with more than half a million new cases annually. This review focuses on the role of oral dysbiosis and HPV infection in HNCs, presenting the involved taxons, molecular effectors and pathways, as well as the HPV-associated particularities of genetic and epigenetic changes and of the tumor microenvironment occurred in different stages of tumor development. Oral dysbiosis is associated with the evolution of HNCs, through multiple mechanisms such as inflammation, genotoxins release, modulation of the innate and acquired immune response, carcinogens and anticarcinogens production, generation of oxidative stress, induction of mutations. Thus, novel microbiome-derived biomarkers and interventions could significantly contribute to achieving the desideratum of personalized management of oncologic patients, regarding both early diagnosis and treatment. The results reported by different studies are not always congruent regarding the variations in the abundance of different taxons in HNCs. However, there is a consistent reporting of a higher abundance of Gram-negative species such as Fusobacterium, Leptotrichia, Treponema, Porphyromonas gingivalis, Prevotella, Bacteroidetes, Haemophilus, Veillonella, Pseudomonas, Enterobacterales, which are probably responsible of chronic inflammation and modulation of tumor microenvironment. Candida albicans is the dominant fungi found in oral carcinoma being also associated with shorter survival rate. Specific microbial signatures (e.g., F. nucleatum, Bacteroidetes and Peptostreptococcus) have been associated with later stages and larger tumor, suggesting their potential to be used as biomarkers for tumor stratification and prognosis. On the other hand, increased abundance of Corynebacterium, Kingella, Abiotrophia is associated with a reduced risk of HNC. Microbiome could also provide biomarkers for differentiating between oropharyngeal and hypopharyngeal cancers as well as between HPV-positive and HPV-negative tumors. Ongoing clinical trials aim to validate non-invasive tests for microbiome-derived biomarkers detection in oral and throat cancers, especially within high-risk populations. Oro-pharyngeal dysbiosis could also impact the HNCs therapy and associated side-effects of radiotherapy, chemotherapy, and immunotherapy. HPV-positive tumors harbor fewer mutations, as well as different DNA methylation pattern and tumor microenvironment. Therefore, elucidation of the molecular mechanisms by which oral microbiota and HPV infection influence the HNC initiation and progression, screening for HPV infection and vaccination against HPV, adopting a good oral hygiene, and preventing oral dysbiosis are important tools for advancing in the battle with this public health global challenge.

Experimental Modeling of Host-Bacterial Interactions in Head and Neck Squamous Cell Carcinoma

The microscopic species colonizing the human body, collectively referred to as the microbiome, play a crucial role in the maintenance of tissue homeostasis, immunity, and the development of disease. There is evidence to suggest associations between alterations in the microbiome and the development of head and neck squamous cell carcinomas (HNSCC). The use of two-dimensional (2D) modeling systems has made significant strides in uncovering the role of microbes in carcinogenesis; however, direct mechanistic links remain in their infancy. Patient-derived three-dimensional (3D) HNSCC organoid and organotypic models have recently been described. Compared to 2D models, 3D organoid culture systems effectively capture the genetic and epigenetic features of parent tissue in a patient-specific manner and may offer a more nuanced understanding of the role of host-microbe responses in carcinogenesis. This review provides a topical literature review assessing the current state of the field investigating the role of the microbiome in HNSCC; including in vivo and in vitro modeling methods that may be used to characterize microbiome-epithelial interactions.

Association between gut microbial change and acute gastrointestinal toxicity in patients with prostate cancer receiving definitive radiation therapy

BACKGROUND

This prospective study investigated the association between gut microbial changes and acute gastrointestinal toxicities in prostate cancer patients receiving definitive radiation therapy (RT).

METHODS

Seventy-nine fecal samples were analyzed. Stool samples were collected at the following timepoints: pre-RT (prRT), 2 weeks after the start of RT (RT-2w), 5 weeks after the start of RT (RT-5w), 1 month after completion of RT (poRT-1 m), and 3 months after completion of RT (poRT-3 m). We computed the microbial community polarization index (MCPI) as an indicator of RT-induced dysbiosis.

RESULTS

Patients experiencing toxicity had lower alpha diversity, especially at RT-2w (p = 0.037) and RT-5w (p = 0.003). Compared to patients without toxicity, the MCPI in those experiencing toxicities was significantly elevated (p = 0.019). In terms of predicted metabolic pathways, we found linearly decreasing pathways, including carbon fixation pathways in prokaryotes (p = 0.035) and the bacterial secretion system (p = 0.005), in patients who experienced toxicities.

CONCLUSIONS

We showed RT-induced dysbiosis among patients who experienced toxicities. Reduced diversity and elevated RT-related MCPI could be helpfully used for developing individualized RT approaches.

The emerging role of oral microbiota in oral cancer initiation, progression and stemness

Oral squamous cell carcinoma (OSCC) is the most prevalent malignancy among the Head and Neck cancer. OSCCs are highly inflammatory, immune-suppressive, and aggressive tumors. Recent sequencing based studies demonstrated the involvement of different oral microbiota in oral cavity diseases leading OSCC carcinogenesis, initiation and progression. Researches showed that oral microbiota can activate different inflammatory pathways and cancer stem cells (CSCs) associated stemness pathways for tumor progression. We speculate that CSCs and their niche cells may interact with the microbiotas to promote tumor progression and stemness. Certain oral microbiotas are reported to be involved in dysbiosis, pre-cancerous lesions, and OSCC development. Identification of these specific microbiota including Human papillomavirus (HPV), Porphyromonas gingivalis (PG), and Fusobacterium nucleatum (FN) provides us with a new opportunity to study the bacteria/stem cell, as well as bacteria/OSCC cells interaction that promote OSCC initiation, progression and stemness. Importantly, these evidences enabled us to develop in-vitro and in-vivo models to study microbiota interaction with stem cell niche defense as well as CSC niche defense. Thus in this review, the role of oral microbiota in OSCC has been explored with a special focus on how oral microbiota induces OSCC initiation and stemness by modulating the oral mucosal stem cell and CSC niche defense.

Systematic review on oral microbial dysbiosis and its clinical associations with head and neck squamous cell carcinoma

OBJECTIVES

The relationship between head and neck squamous cell carcinoma (HNSCC) and the oral microbiome has been drawn in various studies. Microbial diversities, microbiome profiles, metagenomic analysis, and host-pathogen interactions were collected from these studies to highlight similarities and account for inconsistencies. We also evaluate the possible clinical applications of the microbiome regarding screening and diagnosis of HNSCC.

METHODS

Systematic analysis of studies regarding HNSCC and the microbiome was done according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement guidelines. Articles were retrieved from four databases (PubMed, ScienceDirect, CUHK Full-Text Journals, and Cochrane database) and were screened using predefined criteria.

RESULTS

Twenty studies were chosen after screening for full-text review. α-diversity comparison was inconsistent whereas β-diversity between HNSCC and normal samples showed distinct clustering. Microbial dysbiosis characterized by change in the relative abundances of several bacterial species were also seen in HNSCC patients. At a phylum level, inconsistencies were seen between studies using HNSCC tumor tissue samples and saliva samples. At a genus level, Fusobacterium, Peptostreptococcus, Alloprevotella, Capnocytophaga, Catonella, and Prevotella were differentially enriched in HNSCC while Streptococcus, Actinomyces Veillonella, and Rothia were differentially depleted. Co-occurrence network analysis revealed a positive correlation of HNSCC with periodontal pathogens and a negative correlation with commensal bacteria. Metagenomic analysis of microbiota revealed a differential enrichment of pro-inflammatory genomic pathways which was consistent across various studies. Microbial dysbiosis was applied in clinical use as a tool for HNSCC screening. Random-forest analysis was adopted to differentiate between tumor and normal tissue, at 95.7% and 70.0% accuracies respectively in two studies. Microbial dysbiosis index was also used to predict prognosis.

CONCLUSIONS

Oral microbial dysbiosis could be a promising tool for HNSCC screening and diagnosis. However, more research should be conducted pertaining to clinical applications to improve diagnostic accuracy and explore other clinical uses.

Percutaneous transhepatic cholangial drainage or antibiotic therapy worsens response to immunotherapy in advanced cholangiocarcinoma

BACKGROUND

Bile duct obstruction is a common issue for patients with advanced cholangiocarcinoma (CCA). Percutaneous transhepatic cholangial drainage (PTCD) is often required to relieve the obstruction. However, PTCD may alter the intestinal microbiota, which can affect the efficacy of immunotherapy. Antibiotics (ATB) can also have significant immunomodulatory effects by perturbing the gut microbiota. Therefore, this study aimed to investigate whether PTCD or ATB therapy is associated with overall survival (OS) or progression-free survival (PFS) in patients with advanced CCA receiving first-line chemotherapy plus immune checkpoint blockade (ICB) in clinical practice. We also explored whether the gut microbiota changes after receiving PTCD.

METHODS

We conducted a single-center retrospective analysis of PTCD and ATB therapy in patients with advanced CCA. PTCD was performed before ICB initiation, and ATB was administered within 1 month before and 6 weeks after ICB initiation. Our primary outcomes were PFS and OS. Moreover, we used 16s rRNA sequencing to analyze fecal and bile samples obtained from patients who underwent PTCD.

RESULTS

In total, 107 patients with CCA were included. Among patients who did not undergo PTCD, ICB plus chemotherapy significantly improved OS vs. chemotherapy alone (hazard ratio [HR] 0.21, 95% confidence interval [CI] 0.09-0.45, p < 0.0001). PFS was also significantly improved in patients who received ICB plus chemotherapy compared with chemotherapy alone (HR 0.36, 95% CI 0.16-0.80, p = 0.0024). However, ICB plus chemotherapy did not improve survival compared with chemotherapy alone among patients who received PTCD. Overall changes in the fecal microbiota of patients after PTCD involved significant reductions in which Escherichia - Shigella.

CONCLUSIONS

The use of ATB or PTCD in patients with CCA receiving ICB was associated with worse OS compared with chemotherapy alone, and PTCD affects the gut microbiota. Escherichia - Shigella was significantly reduced in feces of patients after PTCD.

Hydrogen-Rich Water Ameliorates Metabolic Disorder via Modifying Gut Microbiota in Impaired Fasting Glucose Patients: A Randomized Controlled Study

OBJECTIVE

Molecular hydrogen (H₂) exhibits antioxidant, anti-inflammatory and anti-apoptotic effects, and has shown benefits in glucose and lipid metabolism in certain animal metabolic disorder models. However, the potential benefits of H₂ treatment in individuals with impaired fasting glucose (IFG) has seldom been studied. This randomized controlled study (RCT) aims to investigate the effects of hydrogen-rich water (HRW) on IFG subjects and explore the underlying mechanism involved.

METHODS

Seventy-three patients with IFG were enrolled in a randomized, double-blind, placebo-controlled clinical study. These patients were assigned to receive either 1000 mL per day of HRW or placebo pure water (no H₂ infusion) for a duration of eight weeks. Metabolic parameters and fecal gut microbiota were assessed at baseline (week 0) and at week 8. A combined analysis of metabolomics and intestinal microbiota was conducted to investigate the correlation between the effect of H₂ on the metabolisms and the diversity of intestinal flora in the IGF patients.

RESULTS

Both pure water and HRW demonstrated a significant reduction in fasting blood glucose in IFG patients, with a significant difference between pure water and HRW after eight weeks. Among IFG patients with abnormal pre-experimental fatty liver, 62.5% (10/16) in the HRW group and 31.6% (6/19) in the pure water group achieved remission. Furthermore, 16S RNA analysis revealed HRW-modified gut microbiota dysbiosis in the fecal samples of IGF patients. Through Pearson correlation analysis, the differential gut microbiota obtained by 16S analysis was found to be highly correlated with nine metabolites.

CONCLUSION

H₂ slightly improved metabolic abnormalities and gut microbiota dysbiosis, providing a novel target and theoretical basis for the prevention and treatment of blood glucose regulation in patients with IFG.

The Microbiome's Influence on Head and Neck Cancers

PURPOSE OF REVIEW

Head and neck tumors (HNC) rank sixth among cancers worldwide. Due to their late diagnosis and poor prognosis, they are a clinical challenge. However, recent years have seen a dynamic development of science on the microbiome. The aim of the study is to discuss the role of the microbiome in HNC, the impact of the microbiome on oncogenesis, the course of the disease, as well as on treatment, and its toxicity.

RECENT FINDINGS

The microbiome's influence on oncogenesis, the course of the disease, and the effectiveness of oncological treatment have been confirmed in cancers of the colon, pancreas, lungs, and prostate. There is no solid literature on HNC. Many studies indicate disruption of the oral microbiome and periodontal disease as potential cancer risk factors. Disruption of the microbiome increases radiotherapy's toxicity, intensifying radiation reactions. The microbiome plays an important role in cancer. It is a new target in research into new therapies. It may also be a prognostic marker of cancer development. Changes in the composition of the microbiome modulate the effectiveness of oncological treatment. More research is needed on the microbiome and its effects on HNC.

Lower Genital Tract Microbiome in Early Pregnancy in the Eastern European Population

BACKGROUND

It is known that the features of the cervicovaginal microbiome can depend on ethnicity, which might be caused by genetic factors, as well as differences in diet and lifestyle. There is no research on the cervicovaginal microbiome of Eastern European women during early pregnancy.

METHODS

We evaluated the cervical and cervicovaginal microbiome of women with first-trimester pregnancy (n = 22), further delivered at term, using the 16S rRNA sequencing method.

RESULTS

The predominant bacterial species in both groups was Lactobacillus iners, followed by Prevotella copri, Ileibacterium valens, Gardnerella vaginalis and Muribaculum intestinale in the cervical samples, and Gardnerella vaginalis, Prevotella copri, Bifidobacterium longum, Ileibacterium valens and Muribaculum intestinale in the cervicovaginal samples. The cervical microbiome had higher alpha diversity; a higher abundance of Muribaculum intestinale, Aquabacterium parvum and Methyloversatilis universalis; and a lower abundance of Psychrobacillus psychrodurans.

CONCLUSIONS

The Lactobacillus iners-dominated microbiome (CST III) was the predominant type of cervical and cervicovaginal microbiome in early pregnancy in the majority of the women. The presence of soil and animal bacteria in the cervicovaginal microbiome can be explained by the rural origin of patients.

Multi-Omics Integration Reveals the Crucial Role of Fusobacterium in the Inflammatory Immune Microenvironment in Head and Neck Squamous Cell Carcinoma

The tumor microbiome is believed to have a profound impact on tumor progression owing to its local colonization in the tumor microenvironment (TME). Using the Cancer Microbiome Atlas (TCMA), a database of curated, decontaminated microbial profiles for 3,689 oropharyngeal, esophageal, gastrointestinal, and colorectal tissue samples from 1,772 patients, we conducted a comprehensive multi-omics analysis to reveal microbial signatures among various cancers and the potential mechanisms involved in tumor progression of head and neck squamous cell carcinoma (HNSC). We found that compared with other cancer types, the tumor-resident microbiome of HNSC accounted for the highest bacterial abundance and strongest association with host TME signatures. Fusobacterium was found to be enriched in HNSC tissues, which was associated with an increased inflammatory effect and inferior prognosis. Moreover, we revealed that the microbiota-associated inflammatory TME was attributed to the competing endogenouse RNA (ceRNA) network and chromatin accessibility. IMPORTANCE Studies on revealing the composition and potential mechanisms of the tumor microbiome are still at an initial stage. We uncovered the potential contribution of the tumor-resident microbiota on the immunosuppressive microenvironment in HNSC, which will provide a new perspective for tumor microbiome research and yield valuable insights into the clinical management of HNSC.

A Review of the Role of Oral Microbiome in the Development, Detection, and Management of Head and Neck Squamous Cell Cancers

The role of the microbiome in the development and propagation of head and neck squamous cell cancer (HNSCC) is largely unknown and the surrounding knowledge lags behind what has been discovered related to the microbiome and other malignancies. In this review, the authors performed a structured analysis of the available literature from several databases. The authors discuss the merits and detriments of several studies discussing the microbiome of the structures of the aerodigestive system throughout the development of HNSCC, the role of the microbiome in the development of malignancies (generally and in HNSCC) and clinical applications of the microbiome in HNSCC. Further studies will be needed to adequately describe the relationship between HNSCC and the microbiome, and to push this relationship into a space where it is clinically relevant outside of a research environment.