Production of carcinogenic acetaldehyde byCandida albicansfrom patients with potentially malignant oral mucosal disorders

Probiotics and prebiotics: new treatment strategies for oral potentially malignant disorders and gastrointestinal precancerous lesions

Oral potentially malignant disorders (OPMDs) and gastrointestinal precancerous lesions (GPLs) are major public health concerns because of their potential to progress to cancer. Probiotics, prebiotics, and engineered probiotics can positively influence the prevention and management of OPMDs and GPLs. This review aims to comprehensively review the application status of probiotics, prebiotics and engineered probiotics in OPMDs and GPLs, explore their potential mechanisms of action, and anticipate their future clinical use.

The Role of Oral Yeasts in the Development and Progression of Oral Squamous Cell Carcinoma: A Scoping Review

The role of oral yeasts in oral squamous cell carcinoma (OSCC) has gained attention due to evidence linking fungal dysbiosis to carcinogenesis. While Candida albicans has been the primary focus, emerging studies highlight the importance of non-Candida species yeast genera. This scoping review synthesises the evidence on the role of oral yeasts, including Candida spp. and non-Candida species, in the development and progression of OSCC. A PRISMA-ScR-guided search was conducted in Medline, Embase, EBM Reviews, and CINAHL. Observational and experimental studies involving humans with OSCC, oral potentially malignant disorders (OPMDs), or oral epithelial dysplasia (OED) were included. This review analysed 75 studies. Research on oral yeast in OSCC has progressed since the 1970s, with advancements in identification techniques-from conventional culture methods to metagenomic sequencing and multi-omics approaches-alongside improved animal and cellular models of OSCC. These methodological advancements have identified notable distinctions in the oral mycobiome between carcinomatous and healthy states. Clinical findings reinforce the hypothesis that oral yeasts, particularly Candida spp., actively contribute to the dysplasia-carcinoma sequence. Emerging evidence suggests that oral yeasts may significantly modulate events contributing to OSCC progression. However, further mechanistic studies and robust clinical evidence are essential to establish causality and clarify their role in OSCC.

Mycobiome: an underexplored kingdom in cancer

SUMMARYThe human microbiome, including bacteria, fungi, archaea, and viruses, is intimately linked to both health and disease. The relationship between bacteria and disease has received much attention and intensive investigation, while that of the fungal microbiome, also known as mycobiome, has lagged far behind bacteria. There is growing evidence showing mycobiome dysbiosis in cancer patients, and certain cancer-specific fungi may contribute to cancer progression by interacting with both host and bacteria. It was also demonstrated that the role of fungi-derived products in cancer should also not be underestimated. Therefore, investigating how fungal pathogenesis contributes to the onset and spread of cancer would yield crucial information for cancer diagnosis, prevention, and anti-cancer therapy.

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.

E-Cigarette effects on oral health: A molecular perspective

Electronic cigarettes (e-cigarettes) have emerged as a potential alternative to traditional smoking and may aid in tobacco harm reduction and smoking cessation. E-cigarette use has notably increased, especially among young non-tobacco users, raising concerns due to the unknown long-term health effects. The oral cavity is the first and one of the most crucial anatomical sites for the deposition of e-cigarette aerosols. E-cigarette aerosols contain nicotine, flavors, volatile organic compounds, heavy metals, carcinogens, and other hazardous substances. These aerosols impact the oral cavity, disrupting host-microbial interactions and triggering gingivitis and systemic diseases. Furthermore, oral inflammation and periodontitis can be caused by proinflammatory cytokines induced by e-cigarette aerosols. The toxic components of e-cigarette aerosols increase the cellular reactive oxygen species (ROS) levels, reduce antioxidant capacity, increase DNA damage, and disrupt repair processes, which may further contribute to harmful effects on oral epithelum, leading to inflammatory and pre-malignant oral epithelial lesions. In this review, we analyze the toxicological properties of compounds in e-cigarette aerosols, exploring their cytotoxic, genotoxic, and inflammatory effects on oral health and delving into the underlying molecular mechanisms. Further research is essential to understand the impact of e-cigarettes on oral health and make informed regulatory decisions based on reliable scientific evidence.

The mycobiome in human cancer: analytical challenges, molecular mechanisms, and therapeutic implications

The polymorphic microbiome is considered a new hallmark of cancer. Advances in High-Throughput Sequencing have fostered rapid developments in microbiome research. The interaction between cancer cells, immune cells, and microbiota is defined as the immuno-oncology microbiome (IOM) axis. Fungal microbes (the mycobiome), although representing only ∼ 0.1-1% of the microbiome, are a critical immunologically active component of the tumor microbiome. Accumulating evidence suggests a possible involvement of commensal and pathogenic fungi in cancer initiation, progression, and treatment responsiveness. The tumor-associated mycobiome mainly consists of the gut mycobiome, the oral mycobiome, and the intratumoral mycobiome. However, the role of fungi in cancer remains poorly understood, and the diversity and complexity of analytical methods make it challenging to access this field. This review aims to elucidate the causal and complicit roles of mycobiome in cancer development and progression while highlighting the issues that need to be addressed in executing such research. We systematically summarize the advantages and limitations of current fungal detection and analysis methods. We enumerate and integrate these recent findings into our current understanding of the tumor mycobiome, accompanied by the prospect of novel and exhilarating clinical implications.

Esophageal Candida Infection and Esophageal Cancer Risk in Patients With Achalasia

Importance

Patients with achalasia face a higher risk of developing esophageal cancer (EC), but the surveillance strategies for these patients remain controversial due to the long disease duration and the lack of identified risk factors.

Objective

To investigate the prevalence of esophageal Candida infection among patients with achalasia and to assess the association of Candida infection with EC risk within this population.

Design, Setting, and Participants

This retrospective cohort study included patients with achalasia diagnosed at or referred for treatment and monitoring to the Erasmus University Medical Center in Rotterdam, the Netherlands, between January 1, 1980, and May 31, 2024. Data analysis was conducted from August 1 to October 31, 2024.

Exposure

Esophageal Candida infection.

Main Outcomes and Measures

The primary outcomes were the prevalence of esophageal Candida infection and its association with EC development among patients with achalasia. Associations were estimated using time-dependent Cox proportional hazards regression models with esophageal Candida infection as a time-varying covariate, adjusting for age at diagnosis and sex.

Results

This study included 234 patients with achalasia (median [IQR] age at diagnosis, 45 [32-63] years; 117 [50%] male), with a median follow-up time of 13 (4-22) years. Esophageal Candida infection was identified in 29 patients (12%), while EC was observed in 24 patients (10%). Esophageal cancer risk analysis was performed for 207 patients with 2 or more consecutive endoscopy follow-up visits (median [IQR] age at diagnosis, 43 [32-60] years; 104 [50%] male). The median (IQR) follow-up time for this subgroup was 16 (9-26) years. Among these patients, esophageal Candida infection was independently associated with an increased risk of EC (adjusted hazard ratio [AHR], 8.24 [95% CI, 2.97-22.89]). Additionally, age at diagnosis (AHR, 1.06 [95% CI, 1.03-1.10]) and male sex (AHR, 3.34 [95% CI, 1.08-10.36]) were independently associated with EC risk.

Conclusions and Relevance

This retrospective cohort study found that prior esophageal Candida infection, older age at diagnosis, and male sex were associated with increased risk of EC among patients with achalasia. These findings provide an important rationale for optimizing the monitoring of patients with achalasia.

Candida albicans Induces Oral Microbial Dysbiosis and Promotes Oral Diseases

Candida albicans are ubiquitous fungal organisms that colonize the oral cavity of healthy individuals without causing disease. C. albicans is an opportunistic microorganism with several virulent factors that influence the inflammatory process and allow it to invade tissues, evade host defense mechanisms, and release toxins, facilitating proliferation and degradation. At present, increasing emphasis is placed on polymicrobial interactions between C. albicans and various bacterial pathogens. Such interaction is mutually beneficial for both parties: it is competitive and antagonistic. Their complex interaction and colonization in the oral cavity serve as the basis for several oral diseases. The dispersion of C. albicans in saliva and the systemic circulation is noted in association with other bacterial populations, suggesting their virulence in causing disease. Hence, it is necessary to understand fungal-bacterial interactions for early detection and the development of novel therapeutic strategies to treat oral diseases. In this paper, we review the mutualistic interaction of C. albicans in oral biofilm formation and polymicrobial interactions in oral diseases. In addition, C. albicans virulence in causing biofilm-related oral diseases and its presence in saliva are discussed.

Clinical and mycological analysis of colonization by Candida spp. in oral leukoplakia and oral lichen planus

OBJECTIVE

This study aims to analyze the prevalence of Candida spp. colonization in oral leukoplakia and oral lichen planus lesions, verify the influence of systemic and local factors, besides identify and determine the in vitro antifungal susceptibility profile of Candida species.

MATERIALS AND METHODS

Samples were collected by swabbing from oral lesions and healthy mucosa and cultured on Sabouraud Dextrose and CHROMagar® Candida plates. Species identification was confirmed with MALDI-TOF MS analysis.

RESULTS

Candida spp. was found in 36.8% of cases of oral leukoplakia and 18.2% of cases of oral lichen planus. Candida albicans was the only species found in oral lichen planus lesions (n = 2, 100%) and the most prevalent in oral leukoplakia (n = 5, 76.4%). Among the non-albicans Candida species found in oral leukoplakia were C. parapsilosis (n = 2, 25.5%) and C. tropicalis (n = 1, 14.1%). Candida isolates were susceptible to all antifungals tested.

CONCLUSION

C. albicans was the most commonly found species in the studied lesions. No correlation was found between systemic and local factors with positive cases of oral lichen planus. However, smoking and alcohol consumption may be associated with positive cases of oral leukoplakia, especially the non-homogeneous clinical form. In addition, there is a possible predisposition to associated Candida colonization in cases of epithelial dysplasia found in oral leukoplakia. The antifungal medications tested showed excellent efficacy against isolates.

Clinical and Biological Perspectives on Noncanonical Esophageal Squamous Cell Carcinoma in Rare Subtypes

Esophageal squamous cell carcinoma (ESCC) remains the most common malignancy of the esophagus worldwide. Environmental and lifestyle exposures such as alcohol and tobacco have been well defined in the pathogenesis of ESCC, acting in concert with cell intrinsic epigenomic, genomic and transcriptomic changes. However, a variety of nonenvironmental etiologies including Fanconi anemia, lichen planus, chronic mucocutaneous candidiasis, esophageal epidermoid metaplasia, epidermolysis bullosa, tylosis, esophageal atresia, and achalasia receive minimal attention despite a high risk of ESCC in these diseases. The goal of this review was to promote clinical recognition and suggest a diagnostic framework for earlier detection of ESCC in patients with these rare diseases. In all the discussed conditions, a change in symptoms should trigger a prompt endoscopic evaluation, and endoscopic surveillance programs with advanced imaging techniques and chromoendoscopy should be considered. Moreover, we leverage the convergence of these diseases on ESCC to identify common mechanisms underlying malignant transformation including aberrant proliferation, mucosal barrier dysfunction, increased inflammation, and genome instability. In this study, we summarize the clinical presentation, pathologic findings, potential screening strategies, and common mechanisms of malignant transformation associated with these rare diseases that drive ESCC.

"Nutrient-fungi-host" tripartite interaction in cancer progression

The human microbiome exhibits a profound connection with the cancer development, progression, and therapeutic response, with particular emphasis on its components of the mycobiome, which are still in the early stages of research. In this review, we comprehensively summarize cancer-related symbiotic and pathogenic fungal genera. The intricate mechanisms through which fungi impact cancer as an integral member of both gut and tissue-resident microbiomes are further discussed. In addition, we shed light on the pivotal physiological roles of various nutrients, including cholesterol, carbohydrates, proteins and minerals, in facilitating the growth, reproduction, and invasive pathogenesis of the fungi. While our exploration of the interplay between nutrients and cancer, mediated by the mycobiome, is ongoing, the current findings have yet to yield conclusive results. Thus, delving into the relationship between nutrients and fungal pathogenesis in cancer development and progression would provide valuable insights into anticancer therapy and foster precision nutrition and individualized treatments that target fungi from bench to bedside.

Risk of Esophageal Cancer in Achalasia: A Matched Cohort Study Using the Nationwide Veterans Affairs Achalasia Cohort

INTRODUCTION

Achalasia is a postulated risk factor of esophageal cancer (EC); however, EC-associated risk in achalasia is understudied. We aimed to evaluate EC risk among individuals within the nationwide Veterans Affairs Achalasia Cohort.

METHODS

We conducted a matched cohort study among US veterans aged 18 years or older from 1999 to 2019. Individuals with achalasia were age matched and sex matched 1:4 to individuals without achalasia. Follow-up continued from study entry until diagnosis with incident/fatal EC (primary outcome), death from non-EC-related causes, or end of the study follow-up (December 31, 2019). Association between achalasia and EC risk was examined using Cox regression models.

RESULTS

We included 9,315 individuals in the analytic cohort (median age 55 years; 92% male): 1,863 with achalasia matched to 7,452 without achalasia. During a median 5.5 years of follow-up, 17 EC occurred (3 esophageal adenocarcinoma, 12 squamous cell carcinoma, and 2 unknown type) among individuals with achalasia, compared with 15 EC (11 esophageal adenocarcinoma, 1 squamous cell carcinoma, and 3 unknown type) among those without achalasia. EC incidence for those with achalasia was 1.4 per 1,000 person-years, and the median time from achalasia diagnosis to EC development was 3.0 years (Q1-Q3: 1.3-9.1). Individuals with achalasia had higher cumulative EC incidence at 5, 10, and 15 years of follow-up compared with individuals without achalasia, and EC risk was 5-fold higher (hazard ratio 4.6, 95% confidence interval: 2.3-9.2).

DISCUSSION

Based on substantial EC risk, individuals with achalasia may benefit from a high index of suspicion and endoscopic surveillance for EC.

Quinalizarin as a potential antifungal drug for the treatment of Candida albicans fungal infection in cancer patients

This study aims to analyze the antifungal properties of quinalizarin, a plant-derived compound with proven anticancer effects. Quinalizarin exhibited antifungal activity against opportunistic pathogenic Candida species and Geotrichum capitatum. The treatment with this anthraquinone reduced hyphal growth, inhibited biofilm formation, and damaged mature Candida albicans biofilms. Real-time RT-PCR revealed that quinalizarin downregulated the expression of hyphae-related and biofilm-specific genes. The flow cytometry method used in the study showed that both apoptosis and necrosis were the physiological mechanisms of quinalizarin-induced C. albicans cell death, depending on the dose of the antifungal agent. A further study revealed an increase in the levels of intracellular reactive oxygen species and alterations in mitochondrial membrane potential after treatment with quinalizarin. Finally, quinalizarin was found to have low toxicity in a hemolytic test using human erythrocytes. In conclusion, we have identified quinalizarin as a potential antifungal compound.IMPORTANCEThis article is a study to determine the antifungal activity of quinalizarin (1,2,5,8-tetrahydroxyanthraquinone). Quinalizarin has potential antitumor properties and is effective in different types of tumor cells. The aim of the present study was to prove that quinalizarin can be used simultaneously in the treatment of cancer and in the treatment of intercurrent fungal infections. Quinalizarin was identified as a novel antifungal compound with low toxicity. These results may contribute to the development of a new drug with dual activity in the treatment of cancer-associated candidiasis.

Oral Potentially Malignant Disorders and Candida in Oral Tongue Squamous Cell Carcinoma Patients

This retrospective study addressed the role of oral potentially malignant disorders and the presence of intraepithelial Candida hyphae in the carcinogenesis of the oral tongue squamous cell carcinoma and its association with smoking, alcohol consumption, and oral inflammatory burden. The medical records of 183 subjects diagnosed with oral tongue squamous cell carcinoma at the Helsinki University Hospital were investigated. Preceding oral lichen planus, lichenoid reaction, and leukoplakia diagnosis were recorded. Further, the data on Candida hyphae in histological samples as an indicator of oral candidiasis, oral inflammatory burden, smoking, and alcohol consumption were recorded and analyzed. The histopathological diagnosis of oral lichen planus/lichenoid reaction (p < 0.001) and the presence of Candida hyphae (p = 0.005) were associated significantly with female gender. Oral lichen planus/lichenoid reaction patients were less often smokers than patients without these lesions. Candida hyphae were more often recorded in patients without alcohol use (p = 0.012). Oral lichen planus/lichenoid reaction and Candida hyphae in histological samples were associated with female gender and lower levels of typical risk factors, such as alcohol use and smoking, in oral tongue squamous cell carcinoma patients. Therefore, these patients should be well monitored despite a potential lack of the classical risk factors of oral carcinoma.

Gut fungal mycobiome: A significant factor of tumor occurrence and development

A variety of bacteria, viruses, fungi, protists, archaea and protozoa coexists within the mammalian gastrointestinal (GI) tract such as that fungi are detectable in all intestinal and colon segments in almost all healthy adults. Although fungi can cause infectious diseases, they are also related to gut and systemic homeostasis. Importantly, through transformation of different forms such as from yeast to hyphae, interaction among gut microbiota such as fungal and bacterial interaction, host factors such as immune and host derived factors, and fungus genetic and epigenetic factors, fungi can be transformed from commensal into pathogenic lifestyles. Recent studies have shown that fungi play a significant role in the occurrence and development of tumors such as colorectal cancer. Indeed, evidences have shown that multiple species of different fungi exist in different tumors. Studies have also demonstrated that fungi are related to the occurrence and development of tumors, and also survival of patients. Here we summarize recent advances in the transformation of fungi from commensal into pathogenic lifestyles, and the effects of gut pathogenic fungi on the occurrence and development of tumors such as colorectal and pancreatic cancers.

A preliminary study of the salivary microbiota of young male subjects before, during, and after acute high-altitude exposure

Background

The microbial community structure in saliva differs at different altitudes. However, the impact of acute high-altitude exposure on the oral microbiota is unclear. This study explored the impact of acute high-altitude exposure on the salivary microbiome to establish a foundation for the future prevention of oral diseases. Methods. Unstimulated whole saliva samples were collected from 12 male subjects at the following three time points: one day before entering high altitude (an altitude of 350 m, pre-altitude group), seven days after arrival at high altitude (an altitude of 4,500 m, altitude group) and seven days after returning to low altitude (an altitude of 350 m, post-altitude group). Thus, a total of 36 saliva samples were obtained. 16S rRNA V3-V4 region amplicon sequencing was used to analyze the diversity and structure of the salivary microbial communities, and a network analysis was employed to investigate the relationships among salivary microorganisms. The function of these microorganisms was predicted with a Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) analysis.

Results

In total, there were 756 operational taxonomic units (OTUs) identified, with 541, 613, and 615 OTUs identified in the pre-altitude, altitude, and post-altitude groups, respectively. Acute high-altitude exposure decreased the diversity of the salivary microbiome. Prior to acute high-altitude exposure, the microbiome mainly consisted of Proteobacteria, Firmicutes, Bacteroidetes, Fusobacteria, and Actinobacteria. After altitude exposure, the relative abundance of Streptococcus and Veillonella increased, and the relative abundance of Prevotella, Porphyromonas, and Alloprevotella decreased. The relationship among the salivary microorganisms was also affected by acute high-altitude exposure. The relative abundance of carbohydrate metabolism gene functions was upregulated, while the relative abundance of coenzyme and vitamin metabolism gene functions was downregulated.

Conclusion

Rapid high-altitude exposure decreased the biodiversity of the salivary microbiome, changing the community structure, symbiotic relationships among species, and abundance of functional genes. This suggests that the stress of acute high-altitude exposure influenced the stability of the salivary microbiome.

The Impact of Alcohol Consumption and Oral Microbiota on Upper Aerodigestive Tract Carcinomas: A Pilot Study

Alcohol consumption is associated with oxidative stress and an increased risk of carcinoma of the upper aero-digestive tract (UADT). Recently, it has been found that some microorganisms in the human oral cavity may locally metabolize ethanol, forming acetaldehyde, a carcinogenic metabolite of alcohol. In a cohort of patients first visited for UADT cancers, we estimated their alcohol consumption by measuring Ethyl Glucuronide/EtG (a long-lasting metabolite of ethanol) in the hair and carbohydrate-deficient transferrin/CDT (short-term index of alcohol intake) in the serum. Moreover, we analyzed, by culture-based methods, the presence of Neisseria subflava, Streptococcus mitis, Candida albicans, and glabrata (microorganisms generating acetaldehyde) in the oral cavity. According to the EtG values, we correlated drinking alcohol with endogenous oxidative stress and the investigated microorganism's presence. We found that 55% of heavy drinkers presented microorganisms generating acetaldehyde locally. Moreover, we found that the presence of oral acetaldehyde-producing bacteria correlates with increased oxidative stress compared to patients without such bacteria. As for the study of alcohol dehydrogenase gene polymorphisms (the enzyme that transforms alcohol to acetaldehyde), we found that only the "CGTCGTCCC" haplotype was more frequent in the general population than in carcinoma patients. This pilot study suggests the importance of estimating alcohol consumption (EtG), the presence of bacteria producing acetaldehyde, and oxidative stress as risk factors for the onset of oral carcinomas.

Fungi and cancer

The microbiome may impact cancer development, progression and treatment responsiveness, but its fungal components remain insufficiently studied in this context. In this review, we highlight accumulating evidence suggesting a possible involvement of commensal and pathogenic fungi in modulation of cancer-related processes. We discuss the mechanisms by which fungi can influence tumour biology, locally by activity exerted within the tumour microenvironment, or remotely through secretion of bioactive metabolites, modulation of host immunity and communications with neighbouring bacterial commensals. We examine prospects of utilising fungi-related molecular signatures in cancer diagnosis, patient stratification and assessment of treatment responsiveness, while highlighting challenges and limitations faced in performing such research. In all, we demonstrate that fungi likely constitute important members of mucosal and tumour-residing microbiomes. Exploration of fungal inter-kingdom interactions with the bacterial microbiome and the host and decoding of their causal impacts on tumour biology may enable their harnessing into cancer diagnosis and treatment.

Is Candida albicans a contributor to cancer? A critical review based on the current evidence

The association between Candida albicans (C. albicans) and cancer has been noticed for decades. Whether C. albicans infection is a complication of cancer status or as a contributor to cancer development remains to be discussed. This review systematically summarized the up-to-date knowledge about associations between C. albicans and various types of cancer, and discussed the role of C. albicans in cancer development. Most of the current clinical and animal evidence support the relationship between C. albicans and oral cancer development. However, there is insufficient evidence to demonstrate the role of C. albicans in other types of cancer. Moreover, this review explored the underlying mechanisms for C. albicans promoting cancer. It was hypothesized that C. albicans may promote cancer progression by producing carcinogenic metabolites, inducing chronic inflammation, remodeling immune microenvironment, activating pro-cancer signals, and synergizing with bacteria.

Association of oral candidiasis with oral lichen planus in patients using corticosteroid therapy - Meta-analysis

Oral lichen planus (OLP) is a chronic inflammatory disease that commonly affects the skin and mucous membranes. There is a difference of opinion among clinicians about whether OLP has been associated with oral candidiasis. Nonetheless, in OLP patients, the oral candidiasis prevalence rate ranges from 7.7 to 16.6%, as established through biopsy findings, whereas 37-50% of the prevalence rate has been noticed in culture findings. Oral candidiasis has been linked to several local and systemic factors, including salivary gland dysfunction, dental prostheses, topical or inhaled corticosteroids, smoking, and the use of systemic medications. The aim was to highlight the association of Candida in patients diagnosed with OLP, correlate the use of steroid therapy, and enumerate the factors of using steroid therapy as implicated causes for oral candidiasis. A search was made using search engines such as PubMed, Scopus, Cochrane Database of Systematic Reviews, Science Citation Index, NIH Public Access, and Clarivate Analytics (Figure 1). The keywords using the research option for this field were "Oral Candidiasis" AND "Oral Lichen planus" or "Candidiasis" AND "Corticosteroids" or "Topical Corticosteroids" AND Oral Lichen planus or "Inhalation Corticosteroids" AND "Candidiasis" or "Oral Lichen planus" AND "Corticosteroids." The database search was made for the duration of 1991 to -2021 (Table 1). Additional articles were obtained regarding the literature on OLP and oral candidiasis and were considered background material. The incidence of oral candidiasis and associated lichen planus following steroid therapy enlisted by various authors has been addressed. According to the results of this study, there is a positive correlation between the presence of oral candidiasis in the OLP's patients treated with corticosteroids. Finally, this meta-analysis concluded that there is a positive correlation between the presence of Candida species in OLP and steroid medication.

Metaproteomic Analysis of an Oral Squamous Cell Carcinoma Dataset Suggests Diagnostic Potential of the Mycobiome

Oral squamous cell carcinoma (OSCC) is the most common head and neck malignancy, with an estimated 5-year survival rate of only 40-50%, largely due to late detection and diagnosis. Emerging evidence suggests that the human microbiome may be implicated in OSCC, with oral microbiome studies putatively identifying relevant bacterial species. As the impact of other microbial organisms, such as fungi and viruses, has largely been neglected, a bioinformatic approach utilizing the Trans-Proteomic Pipeline (TPP) and the R statistical programming language was implemented here to investigate not only bacteria, but also viruses and fungi in the context of a publicly available, OSCC, mass spectrometry (MS) dataset. Overall viral, bacterial, and fungal composition was inferred in control and OSCC patient tissue from protein data, with a range of proteins observed to be differentially enriched between healthy and OSCC conditions, of which the fungal protein profile presented as the best potential discriminator of OSCC within the analysed dataset. While the current project sheds new light on the fungal and viral spheres of the oral microbiome in cancer in silico, further research will be required to validate these findings in an experimental setting.

Role of Candida albicans in Oral Carcinogenesis

Oral carcinogenesis is also dependent on the balance of the oral microbiota. Candida albicans is a member oral microbiota that acts as an opportunistic pathogen along with changes in the epithelium that can predispose to premalignancy and/or malignancy. This systematic review uses the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines to analyze the role of Candida albicans in the process of oral carcinogenesis. Eleven articles qualified inclusion criteria, matched keywords, and provided adequate information about the carcinogenesis parameters of Candida albicans in oral cancer. Candida albicans in oral carcinogenesis can be seen as significant virulent factors for patients with oral squamous cell carcinoma (OSCC) or potentially malignant disorder (OPMD) with normal adjacent mucosa. Candida albicans have a role in the process of oral carcinogenesis concerning morphological phenotype changes in cell structure and genotype and contribute to the formation of carcinogenic substances that can affect cell development towards malignancy.

Antimicrobial Effect of Extracellular Vesicles Derived From Human Oral Mucosal Epithelial Cells on Candida albicans

Candida albicans (C. albicans) is a commensal microorganism that colonizes the mucosal surfaces of healthy individuals. Changes in the host or environment can lead to overgrowth of C. albicans and infection of the host. Extracellular vesicles (EVs) are released by almost all cell types and play an increasingly recognized role in fighting microbial infection. The aim of the present study was to assess whether EVs derived from human oral mucosal epithelial (Leuk-1) cells can suppress the growth and invasion of C. albicans. The in vitro efficacy of Leuk-1-EVs against C. albicans was assessed by optical microscopy, laser scanning confocal microscopy, scanning electron microscopy, and transmission electron microscopy. The germ tube formation rate, the percentage of hyphae and the microcolony optical density were also used to analyze the growth of C. albicans in a coculture model with Leuk-1 cells and EVs or after inhibition of the secretion of EVs. A mouse model of oral candidiasis was established and submucosal injection of Leuk-1-EVs in the tongue was performed. Macroscopic observation, H&E staining, PAS staining, and scanning electron microscopy were used to assess antifungal effects of Leuk-1-EVs in vivo. The in vitro results showed that the growth of C. albicans was inhibited and that the morphology and ultrastructure were changed following Leuk-1-EVs treatment. The in vivo results exhibited that white lesions of the tongue, C. albicans infection, and oral mucosal inflammation of the infected mice were significantly alleviated after Leuk-1-EVs treatment. We thus reveal an antifungal capability of EVs derived from oral epithelial cells against C. albicans that is mediated by direct damage effects and potential synergy between EVs and human oral mucosal epithelial cells. This finding offers an intriguing, previously overlooked method of antifungal defense against C. albicans.

Alcohol and Head and Neck Cancer: Updates on the Role of Oxidative Stress, Genetic, Epigenetics, Oral Microbiota, Antioxidants, and Alkylating Agents

Head and neck cancer (HNC) concerns more than 890,000 patients worldwide annually and is associated with the advanced stage at presentation and heavy outcomes. Alcohol drinking, together with tobacco smoking, and human papillomavirus infection are the main recognized risk factors. The tumorigenesis of HNC represents an intricate sequential process that implicates a gradual acquisition of genetic and epigenetics alterations targeting crucial pathways regulating cell growth, motility, and stromal interactions. Tumor microenvironment and growth factors also play a major role in HNC. Alcohol toxicity is caused both directly by ethanol and indirectly by its metabolic products, with the involvement of the oral microbiota and oxidative stress; alcohol might enhance the exposure of epithelial cells to carcinogens, causing epigenetic modifications, DNA damage, and inaccurate DNA repair with the formation of DNA adducts. Long-term markers of alcohol consumption, especially those detected in the hair, may provide crucial information on the real alcohol drinking of HNC patients. Strategies for prevention could include food supplements as polyphenols, and alkylating drugs as therapy that play a key role in HNC management. Indeed, polyphenols throughout their antioxidant and anti-inflammatory actions may counteract or limit the toxic effect of alcohol whereas alkylating agents inhibiting cancer cells' growth could reduce the carcinogenic damage induced by alcohol. Despite the established association between alcohol and HNC, a concerning pattern of alcohol consumption in survivors of HNC has been shown. It is of primary importance to increase the awareness of cancer risks associated with alcohol consumption, both in oncologic patients and the general population, to provide advice for reducing HNC prevalence and complications.

Human Gut Microbiota in Health and Selected Cancers

The majority of the epithelial surfaces of our body, and the digestive tract, respiratory and urogenital systems, are colonized by a vast number of bacteria, archaea, fungi, protozoans, and viruses. These microbiota, particularly those of the intestines, play an important, beneficial role in digestion, metabolism, and the synthesis of vitamins. Their metabolites stimulate cytokine production by the human host, which are used against potential pathogens. The composition of the microbiota is influenced by several internal and external factors, including diet, age, disease, and lifestyle. Such changes, called dysbiosis, may be involved in the development of various conditions, such as metabolic diseases, including metabolic syndrome, type 2 diabetes mellitus, Hashimoto's thyroidis and Graves' disease; they can also play a role in nervous system disturbances, such as multiple sclerosis, Alzheimer's disease, Parkinson's disease, and depression. An association has also been found between gut microbiota dysbiosis and cancer. Our health is closely associated with the state of our microbiota, and their homeostasis. The aim of this review is to describe the associations between human gut microbiota and cancer, and examine the potential role of gut microbiota in anticancer therapy.

Overview of Candida albicans and Human Papillomavirus (HPV) Infection Agents and their Biomolecular Mechanisms in Promoting Oral Cancer in Pediatric Patients

Oral carcinoma represents one of the most common malignancies worldwide. Oral squamous cell carcinomas (OSCCs) account over 90% of all oral malignant tumors and are characterized by high mortality in the advanced stages. Early diagnosis is often a challenge for its ambiguous appearance in early stages. Mucosal infection by the human papillomavirus (HPV) is responsible for a growing number of malignancies, particularly cervical cancer and oropharyngeal carcinomas. In addition, Candida albicans (C. albicans), which is the principal fungi involved in the oral cancer development, may induce carcinogenesis through several mechanisms, mainly promoting inflammation. Medical knowledge and research on adolescent/pediatric patients' management and prevention are in continuous evolution. Besides, microbiota can play an important role in maintaining oral health and therefore all human health. The aim of this review is to evaluate epidemiological and pathophysiological characteristics of the several biochemical pathways involved during HPV and C. albicans infections in pediatric dentistry.

Exploring the Inflammatory Pathogenesis of Colorectal Cancer

Colorectal cancer is one of the most commonly diagnosed cancers worldwide. Traditionally, mechanisms of colorectal cancer formation have focused on genetic alterations including chromosomal damage and microsatellite instability. In recent years, there has been a growing body of evidence supporting the role of inflammation in colorectal cancer formation. Multiple cytokines, immune cells such T cells and macrophages, and other immune mediators have been identified in pathways leading to the initiation, growth, and metastasis of colorectal cancer. Outside the previously explored mechanisms and pathways leading to colorectal cancer, initiatives have been shifted to further study the role of inflammation in pathogenesis. Inflammatory pathways have also been linked to some traditional risk factors of colorectal cancer such as obesity, smoking and diabetes, as well as more novel associations such as the gut microbiome, the gut mycobiome and exosomes. In this review, we will explore the roles of obesity and diet, smoking, diabetes, the microbiome, the mycobiome and exosomes in colorectal cancer, with a specific focus on the underlying inflammatory and metabolic pathways involved. We will also investigate how the study of colon cancer from an inflammatory background not only creates a more holistic and inclusive understanding of this disease, but also creates unique opportunities for prevention, early diagnosis and therapy.

Higher Number of EBI3 Cells in Mucosal Chronic Hyperplastic Candidiasis May Serve to Regulate IL-17-Producing Cells

Previous research into the inflammatory cell infiltrate of chronic hyperplastic candidosis (CHC) determined that the immune response is primarily composed of T cells, the majority of which are T helper (CD4⁺) cells. This present investigation used immunohistochemistry to further delineate the inflammatory cell infiltrate in CHC. Cells profiled were those expressing IL-17A cytokine, EBI3 and IL-12A subunits of the IL-35 cytokine, and FoxP3⁺ cells. Squamous cell papilloma (with Candida infection) and oral lichen planus tissues served as comparative controls to understand the local immune responses to Candida infection. The results demonstrated that Candida-induced inflammation and immune regulation co-exist in the oral mucosa of CHC and that high prevalence of cells expressing the EBI3 cytokine subunit may play an important role in this regulation. This balance between inflammation and immune tolerance toward invading Candida in the oral mucosa may be critical in determining progress of infection.

Candida albicans and Oral Carcinogenesis. A Brief Review

Current medical knowledge and research on patients’ management are still evolving, and several protocols on minimizing risk of infection by Candida spp. among the population have developed. The aim of this work is to review the epidemiological and biomolecular characteristics and the various histopathological carcinogenesis hypothesis mechanisms that can occur during Candida albicans infections. Current evidence from the literature on the role of C. albicans during potentially malignant oral disorders and oral cancer has been sought. Thus, these biomolecular processes can give or contribute to benign lesions, also in precancerous or cancerous situations. Alongside this, the physiological microorganism oral flora (microbiota) can play a crucial role in maintaining oral health during those infections and therefore avoid carcinogenesis.

Malignant transformation of oral lichen planus: a retrospective study of 565 Japanese patients

Background

Oral lichen planus (OLP) is a chronic inflammatory oral mucosa disease that is recognized as an oral potentially malignant disorder. However, the potentially malignant nature of OLP remains unclear.

Methods

We designed this study to examine the demographic and clinical characteristics of patients with OLP and evaluate the associated malignant transformation rate. A total of 565 patients with a clinical and histopathological diagnosis of OLP who presented at our department between 2001 and 2017 were retrospectively studied. Patients who had clinical and histopathological features of oral lichenoid lesions (OLLs) classified as oral lichenoid contact lesions, oral lichenoid drug reactions and oral lichenoid lesions of graft-versus-host disease were excluded.

Results

The study population included 123 men and 442 women aged 21–93 years (mean ± standard deviation, 60.5 ± 11.8). The 565 patients were followed up for a duration of 55.9 ± 45.3 months, during which 4 (0.7%) patients developed squamous cell carcinoma (SCC). In three of these 4 patients who developed SCC, the clinical type of OLP was the red type.

Conclusions

Our results suggested that OLP was associated with a low risk of malignant transformation. We recommend regular follow-up for OLP patients and clear differentiation of oral epithelial dysplasia and OLLs to enable early detection of malignant transformation. Further investigation of the clinical risk factors associated with malignant transformation is necessary.

Bifacial biological effects of ethanol: acetaldehyde production by oral Streptococcus species and the antibacterial effects of ethanol against these bacteria

Background:Many previous studies have focused on the acetaldehyde produced from ethanol by oral bacteria as a risk factor for oral cancer. Most of these studies involved low ethanol concentrations (ca. 10 mM), but oral bacteria are exposed to a wide range of ethanol concentrations (100–10,000 mM) when alcoholic beverages are consumed. In contrast, ethanol is widely used at high concentrations (> 5,000 mM) as an antiseptic/disinfectant, suggesting that ethanol has bifacial biological effects; i.e. it acts as both a metabolic substrate for bacterial acetaldehyde production and an antimicrobial agent.

Materials and methods:We examined the acetaldehyde production from ethanol by oral streptococci and the effects of ethanol exposure on the growth and viability of these bacteria at a wide range of ethanol concentrations (10–10,000 mM).

Results:Acetaldehyde production was the highest at an ethanol concentration of 2,000 mM (2.1–48-fold higher than that seen at an ethanol concentration of 10 mM). Bacterial growth was inhibited by > 1,000 mM of ethanol, and the bacteria did not seem viable in the presence of > 5,000 mM of ethanol, although they still produced acetaldehyde.

Conclusion:Ethanol has bifacial biological effects, and the concentration ranges of these effects overlap.

Human papillomavirus, Epstein-Barr virus, and Candida albicans co-infection in oral leukoplakia with different degrees of dysplasia

OBJECTIVES

To identify human papillomavirus (HPV), Epstein-Barr virus (EBV), and Candida albicans in oral leukoplakia with different degrees of dysplasia.

MATERIALS AND METHODS

An observational, cross-sectional, descriptive study was performed using 30 formalin-fixed and paraffin-embedded tissues from patients with clinical suspicion of leukoplakia and confirmed diagnosis of oral dysplasia. Histological analyses were performed by two pathologists (interobserver) and dysplasias were classified as mild, moderate, or severe. Conventional PCR was used to detect HPV and EBV viruses and C. albicans. To determine the association between each microorganism with different degrees of dysplasia a Chi-square test was employed.

RESULTS

The tongue was the most common site for leukoplakias (71.4%) in females with a mean age of 50 years (ranging between 30 to 50 years old; 57.1%). EBV was the most frequently detected (73.3%), followed by HPV (43.3%), mainly of type 16 (40%), and C. albicans (23.3%). Significant differences were observed between degrees of dysplasia and HPV presence (p = 0.005). In lesions positive for HPV, EBV, and C. albicans the most frequent histological changes were hyperkeratosis, irregular interpapillary ridges, and loss of basal stratum cell polarity.

CONCLUSION

Co-infection with human papillomavirus, Epstein Barr virus, and Candida albicans in oral leukoplakia could be associated with dysplastic changes.

Therapeutic implications of candida phenotypes, virulence factors and antifungal sensitivity in Oral leukoplakia

Objectives

To determine the association of Candida phenotypes, virulence factors, antifungal sensitivity and clinical response to Fluconazole in Oral leukoplakia (OL).

Methods

Sterile swabs were obtained from oral lesions in immunocompetent subjects [30 Homogenous (HOL), 31 Non- Homogenous (NHOL] and normal buccal mucosa in 30 age and sex-matched healthy controls (C). Candida phenotypes, virulence factors (Secreted Aspartyl Proteinase (SAP), Phospholipase (PL), Biofilm formation (BF) and antifungal sensitivity were determined. Clinical features (Size, Erythema, thickness, oral burning sensation (VAS scores) before and after Fluconazole therapy in OL were recorded by two calibrated observers.

Results

Candida was associated with OL (p ​< ​0.01). Candida albicans was the most common phenotype sensitive to Fluconazole. SAP, PL and BF activity was significantly high in NHOL. Strong positive correlation was seen between SAP, and PL activity and pre-treatment VAS scores in NHOL. There was significant reduction in VAS scores, size of lesion [HOL (p ​< ​0.001) NHOL (p ​< ​0.05)], erythematous areas (67.8%) in NHOL and thickness of lesions (42.6%) in both types OL after Fluconazole therapy with substantial inter-observer agreement. Non albicans candida (NAC) species had similar virulence profiles but resistant to Fluconazole and showed minimal clinical improvement.

Conclusions

Virulence activity of Candida in OL increases severity of lesions. Fluconazole is effective against virulent Candida albicans, causes clinical improvement and down-staging from high -risk NHOL to low-risk HOL which can reduce risk of malignant transformation. Detection of highly virulent NAC infection and antifungal sensitivity is recommended in OL recalcitrant to Fluconazole therapy.

Candida albicans disorder is associated with gastric carcinogenesis

Background: Bacterial infection is associated with gastric carcinogenesis. However, the relationship between nonbacterial components and gastric cancer (GC) has not been fully explored. We aimed to characterize the fungal microbiome in GC. Methods: We performed ITS rDNA gene analysis in cancer lesions and adjacent noncancerous tissues of 45 GC cases from Shenyang, China. Obtaining the OTUs and combining effective grouping, we carried out species identifications, alpha and beta diversity analyses, and FUNGuild functional annotation. Moreover, differences were compared and tested between groups to better investigate the composition and ecology of fungi associated with GC and find fungal indicators. Results: We observed significant gastric fungal imbalance in GC. Principal component analysis revealed separate clusters for the GC and control groups, and Venn diagram analysis indicated that the GC group showed a lower OTU abundance than the control. At the genus level, the abundances of 15 fungal biomarkers distinguished the GC group from the control, of which Candida (p = 0.000246) and Alternaria (p = 0.00341) were enriched in GC, while Saitozyma (p = 0.002324) and Thermomyces (p = 0.009158) were decreased. Combining the results of Welch's t test and Wilcoxon rank sum test, Candida albicans (C. albicans) was significantly elevated in GC. The species richness Krona pie chart further revealed that C. albicans occupied 22% and classified GC from the control with an area under the receiver operating curve (AUC) of 0.743. Random forest analysis also confirmed that C. albicans could serve as a biomarker with a certain degree of accuracy. Moreover, compared with that of the control, the alpha diversity index was significantly reduced in the GC group. The Jaccard distance index and the Bray abundance index of the PCoA clarified separate clusters between the GC and control groups at the species level (p = 0.00051). Adonis (PERMANOVA) analysis and ANOVA showed that there were significant differences in fungal structure among groups (p = 0.001). Finally, FUNGuild functional classification predicted that saprotrophs were the most abundant taxa in the GC group. Conclusions: This study revealed GC-associated mycobiome imbalance characterized by an altered fungal composition and ecology and demonstrated that C. albicans can be a fungal biomarker for GC. With the significant increase of C. albicans in GC, the abundance of Fusicolla acetilerea, Arcopilus aureus, Fusicolla aquaeductuum were increased, while Candida glabrata, Aspergillus montevidensis, Saitozyma podzolica and Penicillium arenicola were obviously decreased. In addition, C. albicans may mediate GC by reducing the diversity and richness of fungi in the stomach, contributing to the pathogenesis of GC.

Candida albicans and candidalysin in inflammatory disorders and cancer

As our understanding of mycology progresses, the impact of fungal microbes on human health has become increasingly evident. Candida albicans is a common commensal fungus that gives rise to local and systemic infections, particularly in immunocompromised patients where it can result in mortality. However, C. albicans has also been quietly linked with a variety of inflammatory disorders, to which it has traditionally been considered incidental; recent studies may now provide new aspects of these relationships for further consideration. This review provides a novel perspective on the impact of C. albicans and its peptide toxin, candidalysin, on human health, exploring their contributions to pathology within a variety of diseases.

Gut mycobiome: A promising target for colorectal cancer

The human gut is mainly habited by a staggering amount and abundance of bacteria as well as fungi. Gut dysbiosis is believed as a pivotal factor in colorectal cancer (CRC) development. Lately increasing evidence from animal or clinical studies suggested that fungal disturbance also contributed to CRC development. This review summarized the current status of fungal dysbiosis in CRC and highlighted the potential tumorigenic mechanisms of fungi. Then the fungal markers and some therapeutic strategies for CRC were discussed. It would provide a better understanding of the correlation of mycobiota and CRC, and modulating fungal community would be a promising target against CRC.

Microbial neoformation of volatiles: implications for the estimation of post-mortem interval in decomposed human remains in an indoor setting

The objective of this study was to determine if a relationship between microbial neoformation of volatiles and the post-mortem interval (PMI) exists, and if the volatiles could be used as a tool to improve the precision of PMI estimation in decomposed human remains found in an indoor setting. Chromatograms from alcohol analysis (femoral vein blood) of 412 cases were retrospectively assessed for the presence of ethanol, N-propanol, 1-butanol, and acetaldehyde. The most common finding was acetaldehyde (83% of the cases), followed by ethanol (37%), N-propanol (21%), and 1-butanol (4%). A direct link between the volatiles and the PMI or the degree of decomposition was not observed. However, the decomposition had progressed faster in cases with microbial neoformation than in cases without signs of neoformation. Microbial neoformation may therefore act as an indicator of the decomposition rate within the early decomposition to bloating stages. This may be used in PMI estimation based on the total body score (TBS) and accumulated degree days (ADD) model, to potentially improve the model's precision.

The interplay of the oral microbiome and alcohol consumption in oral squamous cell carcinomas

Oral cancer (OC) is among the top twenty occurring cancers in the world, with a mortality rate of 50%. A shift to a functionally inflammatory or a 'disease state' oral microbiome composition has been observed amongst patients with premalignant disorders and OC, with evidence suggesting alcohol could be exacerbating the inflammatory influence of the oral microorganisms. Alcohol dehydrogenase (ADH, EC 1.1.1.1) converts alcohol into a known carcinogenic metabolite, acetaldehyde and while ADH levels in oral mucosa are low, several oral commensal species possess ADH and could produce genotoxic levels of acetaldehyde. With a direct association between oral microbiome status, alcohol and poor oral health status combining to induce chronic inflammation with increased acetaldehyde levels - this leads to a tumour promoting environment. This new disease state increases the production of reactive oxygen species (ROS), while impairing anti-oxidant systems thus activating the redox signalling required for the promotion and survival of tumours. This review aims to highlight the evidence linking these processes in the progression of oral cancer.

[Research progress of Candida albicans on malignant transformation of oral mucosal diseases]

Oral cancer is the most common malignant tumor in the head and neck, and is one of the world's top ten malignancies. Microbial infection is an important risk factor of oral cancer. Candida albicans is the most popular opportunistic fungal pathogen. Epidemiological studies have shown that Candida albicans is closely tied to oral malignancy. Animal experimentation have also proven that infection of Candida albicans can promote the development of oral epithelial carcinogenesis. The current studies have revealed several mechanisms involved in this process, including destroying the epithelial barrier, producing carcinogenic substances (nitrosamines, acetaldehyde), inducing chronic inflammation, activating immune response, etc. However, current researches on mechanisms are still inadequate, and some hypotheses remain controversial. Here, we review the findings related to Candida albicans' effect on the malignant transformation of oral mucosa, hoping to provide reference for deep research and controlling oral cancer clinically.

Wine Consumption and Oral Cavity Cancer: Friend or Foe, Two Faces of Janus

The health benefits of moderate wine consumption have been extensively studied during the last few decades. Some studies have demonstrated protective associations between moderate drinking and several diseases including oral cavity cancer (OCC). However, due to the various adverse effects related to ethanol content, the recommendation of moderate wine consumption has been controversial. The polyphenolic components of wine contribute to its beneficial effects with different biological pathways, including antioxidant, lipid regulating and anti-inflammatory effects. On the other hand, in the oral cavity, ethanol is oxidized to form acetaldehyde, a metabolite with genotoxic properties. This review is a critical compilation of both the beneficial and the detrimental effects of wine consumption on OCC.

Acetaldehyde production by Rothia mucilaginosa isolates from patients with oral leukoplakia

Rothia mucilaginosa has been found at high abundance on oral leukoplakia (OLK). The ability of clinical isolates to produce acetaldehyde (ACH) from ethanol has not been investigated. The objective of the current study was to determine the capacity of R. mucilaginosa isolates recovered from OLK to generate ACH. Analysis of R. mucilaginosa genomes (n = 70) shows that this species does not normally encode acetaldehyde dehydrogenase (ALDH) required for detoxification of ACH. The predicted OLK metagenome also exhibited reduced ALDH coding capacity. We analysed ACH production in 8 isolates of R. mucilaginosa and showed that this species is capable of generating ACH in the presence of ethanol. The levels of ACH produced (mean = 53 µM) were comparable to those produced by Neisseria mucosa and Candida albicans in parallel assays. These levels were demonstrated to induce oxidative stress in cultured oral keratinocytes. This study shows that R. mucilaginosa can generate ACH from ethanol in vitro at levels which can induce oxidative stress. This organism likely contributes to oral ACH levels following alcohol consumption and the significance of the increased abundance of R. mucilaginosa in patients with potentially malignant disorders requires further investigation.

A pilot study: a possible implication of Candida as an etiologically endogenous pathogen for oral lichen planus

Background

The aim of this study was to investigate the prevalence and genotypic profiles of Candida albicans in patients with oral lichen planus (OLP).

Materials and methods

Positive rates and genotypic profiles of Candida albicans strains from OLP patients and healthy controls were analyzed. Random amplified polymorphic DNA and internal transcribed spacer of ribosome DNA polymerase chain reactions were used to sequence the DNA of these strains, and then their genetic similarity was measured using BLAST, UIV Band, and Vector NTI Suite Sequence Analyses Software.

Results

The prevalence of C. albicans strains detected from erosive-OLP, non-erosive OLP, and normal individuals was 18.87, 18.75, and 7.92%, respectively. Four different genotypes were revealed by the two methods. To be specific, type I was found only in the healthy subjects; type II a and II b were found in non-erosive OLP, and type III was identified in erosive OLP. Intragroup similarity coefficients, i.e. S_AB were 100%, and inter-groups similarity coefficients, i.e. S_AB were less than 30%.

Conclusions

The genotypic results of C. albicans in OLP revealed an endogenous rather than exogenous infection of C. albicans. In addition, a possible pathogenic role of C. albicans in OLP, with the etiologic sense contributing to a more proper recognition on the pathogenesis, development, and progression of OLP, as well as some strategies for its diagnosis and treatment were identified.

Pathogenetic Impact of Bacterial-Fungal Interactions

Polymicrobial infections are of paramount importance because of the potential severity of clinical manifestations, often associated with increased resistance to antimicrobial treatment. The intricate interplay with the host and the immune system, and the impact on microbiome imbalance, are of importance in this context. The equilibrium of microbiota in the human host is critical for preventing potential dysbiosis and the ensuing development of disease. Bacteria and fungi can communicate via signaling molecules, and produce metabolites and toxins capable of modulating the immune response or altering the efficacy of treatment. Most of the bacterial–fungal interactions described to date focus on the human fungal pathogen Candida albicans and different bacteria. In this review, we discuss more than twenty different bacterial–fungal interactions involving several clinically important human pathogens. The interactions, which can be synergistic or antagonistic, both in vitro and in vivo, are addressed with a focus on the quorum-sensing molecules produced, the response of the immune system, and the impact on clinical outcome.

Malignant development in patients with oral potentially malignant disorders detected through nationwide screening: Outcomes of 5-year follow-up at a single hospital

BACKGROUND

Although survival rate and quality of life are improved if patients with oral carcinoma can be detected early, however, such lesions are usually asymptomatic; therefore, it is hard to raise awareness. Screening has proved to be cost-effective for early detection.

METHODS

Sixty-two patients with oral carcinomas and 555 patients with oral potentially malignant disorders (OPMDs) who were detected through screening were examined the relationship between clinicopathological features and follow-up outcomes.

RESULTS

The 5-year cumulative cancer-free interval rate was 94.1%, and the annual malignant transformation rate was 1.16%. The rate of interval carcinoma development from Candida hyperplasia, oral submucous fibrosis, homogeneous leukoplakia, non-homogenous leukoplakia, and verrucous hyperplasia, was 13.6%, 5.7%, 4.6%, 12.1%, and 21.3%, respectively. Significant independent risk factors for interval carcinoma development were heavy betel quid chewing, verrucous hyperplasia, and surgery refusal.

CONCLUSIONS

Well-designed risk assessment, treatment, and surveillance program could lead to earlier cancer detection and thereby reduce mortality and morbidity.

Salivary mycobiome dysbiosis and its potential impact on bacteriome shifts and host immunity in oral lichen planus

The biodiversity of the mycobiome, an important component of the oral microbial community, and the roles of fungal–bacterial and fungal–immune system interactions in the pathogenesis of oral lichen planus (OLP) remain largely uncharacterized. In this study, we sequenced the salivary mycobiome and bacteriome associated with OLP. First, we described the dysbiosis of the microbiome in OLP patients, which exhibits lower levels of fungi and higher levels of bacteria. Significantly higher abundances of the fungi Candida and Aspergillus in patients with reticular OLP and of Alternaria and Sclerotiniaceae_unidentified in patients with erosive OLP were observed compared to the healthy controls. Aspergillus was identified as an “OLP-associated” fungus because of its detection at a higher frequency than in the healthy controls. Second, the co-occurrence patterns of the salivary mycobiome–bacteriome demonstrated negative associations between specific fungal and bacterial taxa identified in the healthy controls, which diminished in the reticular OLP group and even became positive in the erosive OLP group. Moreover, the oral cavities of OLP patients were colonized by dysbiotic oral flora with lower ecological network complexity and decreased fungal–Firmicutes and increased fungal–Bacteroidetes sub-networks. Third, several keystone fungal genera (Bovista, Erysiphe, Psathyrella, etc.) demonstrated significant correlations with clinical scores and IL-17 levels. Thus, we established that fungal dysbiosis is associated with the aggravation of OLP. Fungal dysbiosis could alter the salivary bacteriome or may reflect a direct effect of host immunity, which participates in OLP pathogenesis.

Imbalance in the oral fungal community could lead to the development of oral lichen planus (OLP), a chronic inflammatory disease that affects the mucous membranes in the mouth. The exact cause of OLP is uncertain, which is a major obstacle to therapeutic development. Using salivary samples, a team headed by Xuedong Zhou at Sichuan University in China investigated the composition and diversity of the fungal community in OLP patients and healthy individuals. The authors found that the oral fungal community was less diverse and that there were higher levels of bacteria in OLP patients. The team concluded that fungal community imbalance could affect the bacterial community in the saliva and the host immunity in the mucous membrane, thereby constituting a direct or indirect cause of the development of OLP.

Assessment of the cancerization risk for oral potentially malignant disorders by clinical risk model combined with autofluorescence and brush biopsy with DNA-image cytometry

PURPOSE

To explore the feasibility of assessing the cancerization risk of oral potentially malignant disorders (OPMD) through a clinical risk model combined with autofluorescence and brush biopsy with DNA-image cytometry.

METHODS

We collected the baseline clinical data of 269 patients; then, performed autofluorescence, brush biopsy with DNA-image cytometry and histopathological examination. Then, we obtained the significant factors by univariate logistic analysis, constructed the clinical risk model by multiple logistic regression and selected the optimal cutoff value according to the maximum Youden index. Finally, we calculated the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the clinical risk score ≥ cutoff value, autofluorescence and brush biopsy with DNA-image cytometry, and plotted the receiver-operating characteristic (ROC) curves and decision curve analysis (DCA).

RESULTS

The clinical risk model is represented by the formula: 1 × gender + 1.6 × age group + 1 × lesion site + 1.4 × local stimulus + 1.5 × drink. The area under the curve (AUC) was 0.83, and the optimal cutoff score was 3. The AUC indicated that the clinical risk score ≥ 3 (0.74) and autofluorescence (0.77) had a certain diagnostic values, while brush biopsy with DNA-image cytometry (0.92) displayed a good value. Besides, the DCA showed that all three tests had clinical significance.

CONCLUSIONS

The cancerization risk of patients can be assessed by the clinical risk model combined with sequence application of autofluorescence and brush biopsy with DNA-image cytometry, to decide whether histopathological examination or other intervention measures should be selected.