The role of yeasts in oral cancer by means of endogenous nitrosation

The evil companion of OSCC: Candida albicans

OBJECTIVE

Microbial dysbiosis and microbiome-induced inflammation may play a role in the etiopathogenesis of oral squamous cell carcinoma (OSCC). Candida albicans (C. albicans) is the most prevalent opportunistic pathogenic fungus in the oral cavity, and Candida infection is considered as one of its high-risk factors. Although oral microbiota-host interactions are closely associated with the development of OSCC, the interrelationship between fungi and OSCC is poorly understood compared to that between bacteria and viruses.

RESULTS

We accumulated knowledge of the evidence, pathogenic factors, and possible multiple mechanisms by which C. albicans promotes malignant transformation of OSCC, focusing on the induction of epithelial damage, production of carcinogens, and regulation of the tumor microenvironment. In addition, we highlight the latest treatment strategies for Candida infection.

CONCLUSION

This review provides a new perspective on the interrelationship between C. albicans and OSCC and contributes to the establishment of a systematic and reliable clinical treatment system for OSCC patients with C. albicans infection.

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.

Mechanisms and Potential Clinical Implications of Oral Microbiome in Oral Squamous Cell Carcinoma

Microorganisms in the oral cavity are abundant in the human body. At present, more than 700 species of oral microorganisms have been identified. Recently, a lot of literature has indicated that the oral microbiota plays an important role in the occurrence, development, and prognosis of oral squamous cell carcinoma (OSCC) through various mechanisms. And researchers are now trying to utilize oral microbiota in cancer diagnosis and treatment. However, few articles systematically summarize the effects of oral microbes in the diagnosis, treatment, and disease outcomes of oral cancer. Herein, we made a summary of the microbial changes at cancerous sites and placed more emphasis on the mechanisms by which the oral microbiome promotes cancerization. Moreover, we aimed to find out the clinical value of the oral microbiome in OSCC.

The research progress in the interaction between Candida albicans and cancers

Candida albicans is an opportunistic pathogenic fungus, which tends to infect the host with defective immune function including cancer patients. A growing number of studies have shown that C. albicans infection increases the host susceptibility to cancer such as oral, gastric, and colorectal cancer. Cancer and anti-cancer treatment may also affect the colonization of C. albicans. C. albicans may promote the development of cancer by damaging mucosal epithelium, inducing the production of carcinogens, triggering chronic inflammation including Th17 cell-mediated immune response. In this article, we aim to elaborate the interaction between C. albicans and cancers development and summarize the potential molecular mechanisms, so as to provide theoretical basis for prevention, diagnosis and treatment of cancers.

Revisão dos fatores de risco para o câncer de boca e faringe

O presente artigo realizou breve análise de perfil epidemiológico de tumores de boca e faringe no Brasil e no mundo, bem como uma revisão da literatura pertinente a seus fatores de risco. Sua incidência, geralmente, varia entre 2% a 30% do total dos novos casos de câncer no mundo, e é fortemente influenciada pela localização geográfica. No Brasil, é a sexta localização anatômica mais comum nos Registros de Base Populacional entre os homens, sendo que a localização envolvendo a língua corresponde a 40% do total de casos. Os principais fatores de risco são o tabaco, o álcool e a interação entre ambos, que exibem forte efeito multiplicativo sobre o risco. A quantidade consumida e o tempo de exposição a estes dois fatores exibem, comumente, gradiente crescente de risco para o câncer. Elementos da dieta são considerados fatores de proteção, especialmente oβ-caroteno, enquanto estados de carência nutricional são comumente percebidos entre os casos. Condições de precária saúde bucal são achados comuns entre os casos de câncer de boca e faringe. As recentes linhas de pesquisa em patogênese e prevenção do câncer de boca e faringe têm estudado a contribuição viral e genética. O comprometimento de grupos etários mais jovens e de mulheres provavelmente deve-se à universalização dos fatores de risco, levando a esta modificação do perfil epidemiológico.

Evaluation of Candidiasis in Upper-Aerodigestive Squamous Cell Carcinoma Patients—A Clinico-Mycological Aspect

Candida is a commensal yeast. It can be infective when the host’s defense mechanism is weakened, as in the case of squamous cell carcinoma patients. We aimed to evaluate the prevalence and clinical mycological manifestation of candidiasis in 150 cancer cases comprised of preoperative and post-operative (with or without radiotherapy) upper aerodigestive squamous cell carcinoma. A total of 150 patients suffering from squamous cell carcinoma of the Upper Aero-Digestive Tract (UADT) were divided into preoperative (n = 48), post-operative without radiotherapy (n = 29) and post-operative with radiotherapy (n = 73). Samples were collected using cotton swabs and cultured. Candida species were identified according to color pigmentation on Candida Differential Agar (CDA) plate. The clinico-mycological association of patients was evaluated by the chi-square test, and 98 out of 150 patients showed the presence of various Candida species. The major species isolated was Candida albicans (53%), followed by Candida tropicalis (16%). There was a significant statistical difference between patients who showed mycological associations and patients who did not have any such association (p = 0.0008). The prevalence of oral candidiasis was found to be 65.33% among total cases of upper aero-digestive squamous cell carcinoma. Chronic erythematous cases of candidiasis were mainly seen in preoperative squamous cell carcinoma cases, whereas the acute erythematous type of candidiasis was mainly seen in post-operative cases who received radiotherapy. The clinicomycological assessment can help to correlate the signs and symptoms with the presence of candidiasis in upper aerodigestive squamous cell carcinoma patients. Meticulous testing and examination can help in the early detection of candidiasis. Future studies are needed to develop advance scientific preventive strategies for high-risk cases.

Analysis of Salivary Mycobiome in a Cohort of Oral Squamous Cell Carcinoma Patients From Sudan Identifies Higher Salivary Carriage of Malassezia as an Independent and Favorable Predictor of Overall Survival

Background

Microbial dysbiosis and microbiome-induced inflammation have emerged as important factors in oral squamous cell carcinoma (OSCC) tumorigenesis during the last two decades. However, the “rare biosphere” of the oral microbiome, including fungi, has been sparsely investigated. This study aimed to characterize the salivary mycobiome in a prospective Sudanese cohort of OSCC patients and to explore patterns of diversities associated with overall survival (OS).

Materials and Methods

Unstimulated saliva samples (n = 72) were collected from patients diagnosed with OSCC (n = 59) and from non-OSCC control volunteers (n = 13). DNA was extracted using a combined enzymatic–mechanical extraction protocol. The salivary mycobiome was assessed using a next-generation sequencing (NGS)-based methodology by amplifying the ITS2 region. The impact of the abundance of different fungal genera on the survival of OSCC patients was analyzed using Kaplan–Meier and Cox regression survival analyses (SPPS).

Results

Sixteen genera were identified exclusively in the saliva of OSCC patients. Candida, Malassezia, Saccharomyces, Aspergillus, and Cyberlindnera were the most relatively abundant fungal genera in both groups and showed higher abundance in OSCC patients. Kaplan–Meier survival analysis showed higher salivary carriage of the Candida genus significantly associated with poor OS of OSCC patients (Breslow test: p = 0.043). In contrast, the higher salivary carriage of Malassezia showed a significant association with favorable OS in OSCC patients (Breslow test: p = 0.039). The Cox proportional hazards multiple regression model was applied to adjust the salivary carriage of both Candida and Malassezia according to age (p = 0.029) and identified the genus Malassezia as an independent predictor of OS (hazard ratio = 0.383, 95% CI = 0.16–0.93, p = 0.03).

Conclusion

The fungal compositional patterns in saliva from OSCC patients were different from those of individuals without OSCC. The fungal genus Malassezia was identified as a putative prognostic biomarker and therapeutic target for OSCC.

Looking beyond the smokescreen: can the oral microbiome be a tool or target in the management of tobacco-associated oral cancer?

A wide range of microbes inhabit the oral cavity, and bacterial and fungal communities most often exist as structured communities or biofilms. The use of tobacco alters the structure of the oral microbiome, including that of potentially malignant lesions, and the altered oral microbiome influences key microenvironmental changes such as chronic inflammation, secretion of carcinogenic toxins, cellular and tissue remodelling and suppression of apoptosis. Given this, it is clear that the bacterial and fungal biofilms in potentially malignant states are likely not passive entities, but could play a critical role in shaping potential malignant and carcinogenic conditions. This holds potential towards leveraging the oral microbiome for the management of tobacco-associated potentially malignant lesions and oral cancer. Here, we explore this line of investigation by reviewing the effects of tobacco in shaping the oral microbiome, and analyse the available evidence in the light of the microbiome of oral potentially malignant and cancerous lesions, and the role of dysbiosis in carcinogenesis. Finally, we discuss possible interventions and approaches using which the oral microbiome could be leveraged towards precision-based oral cancer therapeutics.

Research Progress of Pancreas-Related Microorganisms and Pancreatic Cancer

Pancreatic cancer is one of the most common digestive system cancers. Early diagnosis is difficult owing to the lack of specific symptoms and reliable biomarkers. The cause of pancreatic cancer remains ambiguous. Smoking, drinking, new-onset diabetes, and chronic pancreatitis have been proven to be associated with the occurrence of pancreatic cancer. In recent years, a large number of studies have clarified that a variety of microorganisms colonized in pancreatic cancer tissues are also closely related to the occurrence and development of pancreatic cancer, and the specific mechanisms include inflammatory induction, immune regulation, metabolism, and microenvironment changes caused by microorganism. The mechanism of action of the pancreatic colonized microbiome in the tumor microenvironment, as well as immunotherapy approaches require further study in order to find more evidence to explain the complex relationship between the pancreatic colonized microbiome and PDAC. Relevant studies targeting the microbiome may provide insight into the mechanisms of PDAC development and progression, improving treatment effectiveness and overall patient prognosis. In this article, we focus on the research relating to the microorganisms colonized in pancreatic cancer tissues, including viruses, bacteria, and fungi. We also highlight the microbial diversity in the occurrence, invasion, metastasis, treatment, and prognosis of pancreatic cancer in order to elucidate its significance in the early diagnosis and new therapeutic treatment of pancreatic cancer, which urgently need to be improved in clinical practice. The elimination or increase in diversity of the pancreatic microbiome is beneficial for prolonging the survival of PDAC patients, improving the response to chemotherapy drugs, and reducing tumor burden. The colonization of microorganisms in the pancreas may become a new hotspot in the diagnosis and treatment of pancreatic cancer.

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.

LDOC1 Suppresses Microbe-Induced Production of IL-1β in Human Normal and Cancerous Oral Cells through the PI3K/Akt/GSK-3β Axis

Simple Summary

Oral microbes often proliferate due to poor oral hygiene (POH). POH is associated with OSCC (oral squamous cell carcinoma). We investigated the role of LDOC1 in the production of IL-1β, an oncogenic proinflammatory cytokine in OSCC, induced by microorganisms in human oral cells. Candida albicans (CA) was detected in OSCC tissues. CA and the oral bacterium Fusobacterium nucleatum stimulate higher levels of IL-1β production in LDOC1-deficient OSCC cells than in LDOC1-expressing oral cells. CA SC5314 increased OSCC incidence in carcinogen-treated mice. Loss and gain of LDOC1 function resulted in increased and decreased, respectively, CA SC5314-induced IL-1β production. LDOC1 deficiency increased active pAkt^S473 upon SC5314 stimulation and inactive pGSK-3β^S9 phosphorylated by pAkt^S473. PI3K and Akt inhibitors and expression of constitutively active mutant GSK-3β^S9A reduced the SC5314-stimulated IL-1β production in LDOC1-deficient cells. These results indicate that the PI3K/Akt/pGSK-3β signaling contributes to LDOC1-mediated inhibition of microbe-induced IL-1β production, suggesting LDOC1 may determine the role of oral microbes in POH-associated OSCC.

Abstract

Poor oral hygiene (POH) is associated with oral squamous cell carcinoma (OSCC). Oral microbes often proliferate due to POH. Array data show that LDOC1 plays a role in immunity against pathogens. We investigated whether LDOC1 regulates the production of oral microbe-induced IL-1β, an oncogenic proinflammatory cytokine in OSCC. We demonstrated the presence of Candida albicans (CA) in 11.3% of OSCC tissues (n = 80). CA and the oral bacterium Fusobacterium nucleatum stimulate higher levels of IL-1β secretion by LDOC1-deficient OSCC cells than by LDOC1-expressing oral cells. CA SC5314 increased OSCC incidence in 4-NQO (a synthetic tobacco carcinogen) and arecoline-cotreated mice. Loss and gain of LDOC1 function significantly increased and decreased, respectively, CA SC5314-induced IL-1β production in oral and OSCC cell lines. Mechanistic studies showed that LDOC1 deficiency increased active phosphorylated Akt upon CA SC5314 stimulation and subsequent inhibitory phosphorylation of GSK-3β^S9 by activated Akt. PI3K and Akt inhibitors and expression of the constitutively active mutant GSK-3β^S9A significantly reduced the CA SC5314-stimulated IL-1β production in LDOC1-deficient cells. These results indicate that the PI3K/Akt/pGSK-3β signaling pathway contributes to LDOC1-mediated inhibition of oral microbe-induced IL-1β production, suggesting that LDOC1 may determine the pathogenic role of oral microbes in POH-associated OSCC.

Histopathologic aspects of the so-called chronic hyperplastic candidiasis: An analysis of 36 cases

BACKGROUND

The present study aimed to analyze the histopathologic aspects of cases diagnosed as chronic hyperplastic candidiasis (CHC) in an oral pathology service, pointing out the most important features found.

METHODS

All cases histopathologically diagnosed as CHC between 2002 and 2018 were retrieved from the files of the service. Data of the patients and the lesions were collected. Histopathological analysis was performed to evaluate the microscopic characteristics and the amount of Candida present.

RESULTS

Thirty-six cases of CHC were retrieved. Women were more affected and there was a predilection for Whites. Most lesions appeared as a nodule or a white plaque, asymptomatic, on the tongue or buccal mucosa. Histopathologically, statistical significance was noted for the presence of epithelial hyperplasia, exocytosis, and mononuclear inflammatory infiltrate. Interestingly, only the association between dysplasia and the amount of fungus was noted.

CONCLUSIONS

CHC appears to be a distinct entity presenting typical histopathologic aspects. CHC might even show epithelial dysplasia. In those cases, the presence of a large amount of Candida together with other histopathological features should lead to the diagnosis of CHC and subsequent treatment. However, close follow up is important.

Oral microbial profile in oral cancer patients before and after radiation therapy in a cancer care center - A prospective study

Background:

Head and neck cancer is the sixth most common cancer reported worldwide. In many cases, the level of aggressiveness of therapy adopted in cancer patients may cause the alteration in oral microbiota; the emergence of potential pathogens may cause opportunistic infections in already immune-compromised individuals leading to increases in morbidity and mortality. Hence, this study was conducted to assess the oral microbial profile in oral cancer patients before and after radiotherapy.

Materials and Methods:

A total of 145 oral swabs were collected before radiotherapy (n = 96), 3 months postradiotherapy (n = 25), 6 months postradiotherapy (n = 12) and controls (n = 12). The samples were inoculated into brain–heart infusion broth and later in different media for bacterial isolation. The isolates were subjected to phenotypic characterization by automatic identification system.

Results:

Among the 96 samples studied from the preradiotherapy patient samples, Streptococcus species (n = 28) were the predominant isolate, followed by Staphylococcus species (n = 16), Enterobacter species (n = 6) and Enterococcus species (n = 6). Of the 25 samples studied 3 months after radiotherapy, Klebsiella pneumoniae (n = 4) was isolated and 12 samples studied after 6 months of radiotherapy Candida species (n = 4) and Pediococcus species (n = 3) were isolated. Among the control group (n = 12) screened, Streptococcus acidominimus (n = 3) is the predominant bacteria isolated.

Conclusion:

High prevalence of Streptococcus sp. was found in patients of oral cancer before radiotherapy, while Candida albicans and Klebsiella species and Pediococcus species are the significant pathogens isolated in postradiotherapy cancer patients.

Virulence and antifungal susceptibility of microsatellite genotypes of Candida albicans from superficial and deep locations

A set of 185 strains of Candida albicans from patients with vulvovaginal candidiasis (VVC) and from non‐VVC clinical sources in southwest China was analysed. Strains were subjected to genotyping using CAI microsatellite typing and amplification of an intron‐containing region of the 25S rRNA gene. Microsatellite genotypes of strains from non‐VVC sources showed high polymorphism, whereas those of VVC were dominated by few, closely similar genotypes. However, among non‐VVC strains, two genotypes were particularly prevalent in patients with lung cancer. 25S rDNA genotype A was dominant in VVC sources (86.7%), whereas genotypes A, B, and C were rather evenly distributed among non‐VVC sources; known genotypes D and E were not found. In an experimental mouse model, isolates from lung cancer and AIDS patients proved to have higher virulence than VVC strains. Among 156 mice infected with C. albicans, 19 developed non‐invasive urothelial carcinoma. No correlation could be established between parameters of virulence, source of infection, and incidence of carcinoma. C. albicans strains from VVC were less susceptible to itraconazole than the strains from non‐VVC sources, whereas there was small difference in antifungal susceptibility between different 25S rDNA genotypes of C. albicans tested against amphotericin B, itraconazole, fluconazole, and flucytosine.

Body site-dependent variations of microbiota in pancreatic cancer pathophysiology

Lack of specific symptoms and reliable biomarkers, along with aggressive nature and resistance to therapies makes pancreatic cancer (PC) one of the leading causes of death from cancer worldwide. The search for new diagnostic, prognostic, predictive, and therapeutic tools that could improve clinical outcomes of patients has led, in recent years, to the investigation of potential roles for the microbiota in the pathogenesis of this disease. The human microbiota encompasses trillions of microorganisms residing within several body tissues and organs, where they provide beneficial functions for host homeostasis and health. Derangements of the microbial ecology in different anatomic districts have been described in PC, as in many other diseases, both in patients and in animal models. In detail, infection from the gastric pathogen Helicobacter pylori and changes in composition and diversity of oral, intestinal, and pancreatic microbiota have been found to associate with PC. Future research should assess how to potentially exploit such differences in microbiota composition as diagnostic, prognostic, or predictive biomarkers, and as targets for therapeutic interventions, in the hope of improving the dismal prognosis of this insidious cancer.

Role of Candida infection in the malignant transformation of oral leukoplakia: A systematic review of observational studies

The aim of this systematic review was to investigate the malignant transformation of oral leukoplakia (OL) infected with Candida. Literature search was conducted using Medical Subject Heading terms ‘leukoplakia’, ‘neoplasms’, ‘ Candida’, ‘malignant transformation’ and ‘oral’ and included all results until February 2017. The initial search identified 372 articles, which was consolidated to 16 articles after applying inclusion and exclusion criteria. The occurrence of candidal infection in OL ranged from 6.8% to 100.0%. Only 3 of 16 studies reported malignant transformation rates of leukoplakia with Candida infection. The overall malignant transformation rates reported in these studies were 2.5%, 6.5% and 28.7%. This review supports the contention that candidal infection promotes cellular and dysplastic changes in OL. However, further follow-up studies are recommended to confirm the role of Candida infection in malignant transformation of OL lesions.

Chronic mucocutaneous candidiasis due to gain-of-function mutation in STAT1

Chronic mucocutaneous candidiasis (CMC) is a heterogenous group of primary immunodeficiency diseases characterised by susceptibility to chronic or recurrent superficial Candida infection of skin, nails and mucous membranes. Gain-of-function mutations in the STAT1 gene (STAT1-GOF) are the most common genetic aetiology for CMC, and mutation analysis should be considered. These mutations lead to defective responses in Type 1 and Type 17 helper T cells (Th1 and Th17), which, depending on the mutation, also predispose to infection with Staphylococci, Mycobacteria and Herpesviridae. We describe the clinical and genetic findings for three patients with CMC due to gain-of-function mutations in the STAT1 gene.

Cancer risk in patients with candidiasis: a nationwide population-based cohort study

BACKGROUND

Candidiasis and certain types of cancer are related to immunocompromised status. This study aimed to evaluate whether Candida infection (CI) is associated with subsequent cancer risk in Taiwan.

METHODS

Data from the National Health Insurance system of Taiwan were used to evaluate the association between CI and cancer risk. The CI cohort comprised 34,829 patients. Each patient was randomly frequency matched with one person from the general population without CI on the basis of age, sex, year of index date of CI diagnosis, and other characteristics to generate the control group. We used Cox's proportional hazard regression analysis to estimate the effects of CI on subsequent cancer risk.

RESULTS

Compared with the control group, patients with CI had a significantly higher risk of overall cancer (adjusted hazard ratio = 1.19, 95% confidence interval = 1.09-1.30). For subsite analysis, the risks of hematologic malignancy and head and neck, pancreatic, skin, and thyroid cancers were significantly higher in the CI group. Stratified analyses by sex, age, and follow-up time revealed different patterns.

CONCLUSION

Our study suggested that CI can significantly increase overall and some individual cancer risks, which is partially compatible with previous findings.

Infectious Agents Associated with Head and Neck Carcinomas

In addition to traditional risk factors such as smoking habits and alcohol consumption, certain microbes also play an important role in the generation of head and neck carcinomas. Infection with high-risk human papillomavirus types is strongly associated with the development of oropharyngeal carcinoma, and Epstein-Barr virus appears to be indispensable for the development of non-keratinizing squamous cell carcinoma of the nasopharynx. Other viruses including torque teno virus and hepatitis C virus may act as co-carcinogens, increasing the risk of malignant transformation. A shift in the composition of the oral microbiome was associated with the development of oral squamous cell carcinoma, although the causal or casual role of oral bacteria remains to be clarified. Conversion of ethanol to acetaldehyde, a mutagenic compound, by members of the oral microflora as well as by fungi including Candida albicans and others is a potential mechanism that may increase oral cancer risk. In addition, distinct Candida spp. also produce NBMA (N-nitrosobenzylmethylamine), a potent carcinogen. Inflammatory processes elicited by microbes may also facilitate tumorigenesis in the head and neck region.

Elevated urinary levels of carcinogenic N-nitrosamines in patients with urinary tract infections measured by isotope dilution online SPE LC-MS/MS

N-nitrosamines (NAms) are well-documented for their carcinogenic potential. Human exposure to NAms may arise from the daily environment and endogenous formation via the reaction of secondary amines with nitrites or from bacteria infection. We describe the use of isotope dilution online solid-phase extraction (SPE) LC-MS/MS to quantify nine NAms in human urine. This method was validated and further applied to healthy subjects and patients with urinary tract infection (UTI). N-nitrosodimethylamine (NDMA), N-nitrosomethylethylamine (NMEA), N-nitrosopyrrolidine (NPYR) and N-nitrosomorpholine (NMOR) were analyzed with an APCI source, while N-nitrosodiethylamine (NDEA), N-nitrosopiperidine (NPIP), N-nitrosodi-n-propylamine (NDPA), N-nitrosodibutylamine (NDBA) and N-nitrosodiphenylamine (NDPhA) were quantified with an ESI source, due to their effect on the sensitivity and chromatography. NDMA was the most abundant N-nitrosamine, while NDPhA was firstly identified in human. UTI patients had three to twelve-fold higher concentrations for NDMA, NPIP, NDEA, NMOR and NDBA in urine than healthy subjects, and the NAms were significantly decreased after antibiotics treatment. NDMA concentrations were also significantly correlated with the pH value, leukocyte esterase activity or nitrite in urines of UTI patients. Our findings by online SPE LC-MS/MS method evidenced that UTI patients experienced various NAms exposures, especially the potent carcinogen NDMA, which was likely induced by bacteria infection.

Estimating the frequency of Candida in oral squamous cell carcinoma using Calcofluor White fluorescent stain

OBJECTIVE

To determine the frequency of Candida in oral squamous cell carcinoma (OSCC) using Calcofluor White (CFW) fluorescent stain and to evaluate the association of the same in different grades of OSCC.

METHODS

One hundred archival formalin fixed paraffin embedded tissues of diagnosed cases of OSCC were retrieved. The samples comprised of 81, 18 and 1 case of well, moderately, and poorly differentiated squamous cell carcinomas (WSCC, MSCC, PSCC) respectively. Each section was subjected to staining with CFW fluorescent stain for the detection of frequency of candidal hyphae. A chi square test was used to compare the proportion of occurrence of candidal hyphae between different grades of OSCC.

RESULTS

Ten of the 100 cases of OSCCs stained positive for Candida with CFW. Positive staining for Candida was seen in six out of 81 and four out of 18 cases of WSCCs and MSCCs respectively. The chi square test used for comparison of the proportion of occurrence of candidal hyphae between WSCC and MSCC (P = 0.059) and all grades of OSCC (P = 0.157) did not yield any statistically significant value.

CONCLUSION

The presence of Candida in OSCC solely does not justify its role in carcinogenesis. Further appraisal to evaluate a direct causal role of the micro-organism in potentially malignant disorders and OSCC is required.

Clinical manifestations associated with novel mutations in the coiled-coil domain of STAT1

Monoallelic mutations in STAT1 are associated with a variety of clinical patterns. We studied patients with novel mutations in the coiled-coil domain of STAT1. We found that clinical manifestations can vary from mild Candida infections limited to the oropharyx to serious serial strokes and skin cancer. Autoimmune manifestations were found to be rare and limited to hypothyroidism. Immune evaluations were normal or near normal in all patients with the exception of anergy to Candida. Mutation in the coiled-coil domain results in susceptibility to mucus membrane candidiasis as well as brain vascular anomalies.

Statement of novelty: We describe novel mutations in the coiled-coil domain of STAT1.

Candida albicans and cancer: Can this yeast induce cancer development or progression?

There is currently increasing concern about the relation between microbial infections and cancer. More and more studies support the view that there is an association, above all, when the causal agents are bacteria or viruses. This review adds to this, summarizing evidence that the opportunistic fungus Candida albicans increases the risk of carcinogenesis and metastasis. Until recent years, Candida spp. had fundamentally been linked to cancerous processes as it is an opportunist pathogen that takes advantage of the immunosuppressed state of patients particularly due to chemotherapy. In contrast, the most recent findings demonstrate that C. albicans is capable of promoting cancer by several mechanisms, as described in the review: production of carcinogenic byproducts, triggering of inflammation, induction of Th17 response and molecular mimicry. We underline the need not only to control this type of infection during cancer treatment, especially given the major role of this yeast species in nosocomial infections, but also to find new therapeutic approaches to avoid the pro-tumor effect of this fungal species.

Saliva: A Cutting Edge in Diagnostic Procedures

The ability to monitor the health and disease status of the patient through saliva is a highly desirable goal for the health professionals. Considering the microconcentration of salivary constituents, saliva is explored to be diagnostic tool as it also meets the demands for an inexpensive, noninvasive and easy to use screening method. The incorporation of salivary diagnostics into clinical practice is gaining reality and will be of diagnostic value in the prospective future. The investigative use of saliva is not being applied only in dental health but also in various other systemic disorders. The advent of molecular techniques is gaining attention and this has triggered its application as a specific and sensitive biomarker in proteomics, genomics, and transcriptomics. This review discusses the basics of salivary diagnostics, expectoration techniques, and its application in various local and systemic disorders.

Family history of cancer, personal history of medical conditions and risk of oral cavity cancer in France: the ICARE study

BACKGROUND

The aim of this study was to evaluate the role of family history of cancer and personal history of other medical conditions in the aetiology of the oral cavity cancer in France.

METHODS

We used data from 689 cases of oral cavity squamous cell carcinoma and 3481 controls included in a population-based case-control study, the ICARE study. Odds-ratios (ORs) associated with family history of cancer and personal medical conditions and their 95% confidence intervals (95% CI) were estimated by unconditional logistic regression and were adjusted for age, gender, area of residence, education, body mass index, tobacco smoking and alcohol drinking.

RESULTS

Personal history of oral candidiasis was related to a significantly increased risk of oral cavity cancer (OR 5.0, 95% CI 2.1-12.1). History of head and neck cancers among the first-degree relatives was associated with an OR of 1.9 (95% CI 1.2-2.8). The risk increased with the number of first-degree relatives with head and neck cancer.

CONCLUSION

A family history of head and neck cancer is a marker of an increased risk of oral cavity cancer and should be taken into account to target prevention efforts and screening. Further studies are needed to clarify the association between oral cavity cancer and personal history of candidiasis.

Genotyping Candida albicans from Candida leukoplakia and non-Candida leukoplakia shows no enrichment of multilocus sequence typing clades but enrichment of ABC genotype C in Candida leukoplakia

Oral leukoplakias are histopathologically-diagnosed as Candida leukoplakia or non-Candida leukoplakia by the presence or absence of hyphae in the superficial epithelium. Candida leukoplakia lesions have significantly increased malignant potential. Candida albicans is the most prevalent fungal species associated with oral leukoplakia and may contribute to malignant transformation of Candida leukoplakia. To date, no detailed population analysis of C. albicans isolates from oral leukoplakia patients has been undertaken. This study investigated whether specific C. albicans genotypes were associated with Candida leukoplakia and non-Candida leukoplakia in a cohort of Irish patients. Patients with histopathologically-defined Candida leukoplakia (n = 31) or non-Candida leukoplakia (n = 47) were screened for Candida species by culture of oral rinse and lesional swab samples. Selected C. albicans isolates from Candida leukoplakia patients (n = 25), non-Candida leukoplakia patients (n = 19) and oral carriage isolates from age and sex matched healthy subjects without leukoplakia (n = 34) were subjected to multilocus sequence typing (MLST) and ABC genotyping. MLST revealed that the clade distribution of C. albicans from both Candida leukoplakia and non-Candida leukoplakia lesions overlapped with the corresponding clade distributions of oral carriage isolates and global reference isolates from the MLST database indicating no enrichment of leukoplakia-associated clones. Oral leukoplakia isolates were significantly enriched with ABC genotype C (12/44, 27.3%), particularly Candida leukoplakia isolates (9/25, 36%), relative to oral carriage isolates (3/34, 8.8%). Genotype C oral leukoplakia isolates were distributed in MLST clades 1,3,4,5,8,9 and 15, whereas genotype C oral carriage isolates were distributed in MLST clades 4 and 11.

Oral microbial carriage in oral squamous cell carcinoma patients at the time of diagnosis and during radiotherapy - a comparative study

OBJECTIVES

Tobacco chewing habit, presence of squamous cell carcinoma in oral cavity and radiotherapy causes alterations in healthy oral microflora. Abnormal flora developed due to radiotherapy in oral squamous cell carcinoma (OSCC) patients can exacerbate mucositis and can cause systemic infections. The role of oral microorganisms in carcinogenesis is gaining interest recently. Abnormal flora in development of second tumor in the field of first tumor is to be established. The study fundamentally tries to evaluate the shift that occurs during the radiotherapy in OSCC patients.

METHODS

Microbial analysis of saliva samples from OSCC patients undergoing radiotherapy, tobacco chewers and controls was undertaken. The microorganisms were grouped into categories as total aerobes, total anaerobes, candida, coliforms and gram negative anaerobic bacteria.

RESULTS

The frequency of isolation of total aerobes, total anaerobes, coliforms and gram negative anaerobic bacteria was significantly high in OSCC patients compared to healthy controls whereas candida was isolated most frequently during radiation period. The tobacco chewers showed significant increase in colony forming units of total aerobes and coliforms. All the microbial groups were high in OSCC and radiotherapy patients. While OSCC patients showed significant increase in total anaerobes and gram negative anaerobes, candida was increased in radiotherapy patients only.

CONCLUSION

Habits promote coliforms. Tumor supports efficiently anaerobes and candida. The latter is supported more by radiation. The study stresses the importance on administration of appropriate antimicrobial therapy right at the time of diagnosis of the lesion.

Association of esophageal candidiasis and squamous cell carcinoma

Chronic esophageal candidiasis is an infection that is mostly seen in immunocompromised conditions, among which is chronic mucocutaneous candidiasis (CMC). Recently an association between CMC and esophageal carcinoma has been reported. Here we present two patients with chronic esophageal candidiasis who developed esophageal squamous cell carcinoma and we discuss the etiologic role of Candida-induced nitrosamine production, the loss of STAT1 function and impaired tumor surveillance and T-lymphocyte function in the development of esophageal carcinoma.

Candida in oral pre-cancer and oral cancer

Oral pre-malignancies and carcinomas are common epithelial pathologies caused by a variety of etiological factors. In the oral cavity, candidiasis is the most frequent opportunistic fungal infection. Since the initial reports of an association between candidiasis with oral pre-cancer and cancer, various theories have been debated regarding the role of candida in development and transformation of oral pre-malignancies. However, the exact role is still unclear. In the present article, we hypothesize a causal role for candidiasis in oral pre-cancer and cancer albeit an indirect one. We also suggest that candida along with other co-factors may play a role in initiation and promotion of carcinogenesis.

Role of medical history and medication use in the aetiology of upper aerodigestive tract cancers in Europe: the ARCAGE study

BACKGROUND

The study aimed to investigate the role of medical history (skin warts, Candida albicans, herpetic lesions, heartburn, regurgitation) and medication use (for heartburn; for regurgitation; aspirin) in the aetiology of upper aerodigestive tract (UADT) cancer.

METHODS

A multicentre (10 European countries) case-control study [Alcohol-Related CAncers and GEnetic susceptibility (ARCAGE) project].

RESULTS

There were 1779 cases of UADT cancer and 1993 controls. History of warts or C. albicans infection was associated with a reduced risk [odds ratio (OR) 0.80, 95% confidence interval (CI) 0.68-0.94 and OR 0.73, 95% CI 0.60-0.89, respectively] but there was no association with herpetic lesions, heartburn, regurgitation or medication for related symptoms. Regurgitation was associated with an increased risk for cancer of the oesophagus (OR 1.47, 95% CI 0.98-2.21). Regular aspirin use was not associated with risk of UADT cancer overall but was associated with a reduced risk for cancer of oesophagus (OR 0.51, 95% CI 0.28-0.96), hypopharynx (OR 0.53, 95% CI 0.28-1.02) and larynx (OR 0.74, 95% CI 0.54-1.01).

CONCLUSIONS

A history of some infections appears to be a marker for decreased risk of UADT cancer. The role of medical history and medication use varied by UADT subsites with aspirin use associated with a decreased risk of oesophageal cancer and suggestive of a decreased risk of hypopharyngeal and laryngeal cancers.

Oral mucous squamous cell carcinoma-an anticipated consequence of autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED)

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a rare autosomal recessive disease caused by mutations in the AIRE gene. We report the case of a female patient with a 967-979del13 mutation in the AIRE gene. Her medical history included autoimmune hypoparathyroidism, Addison disease, and chronic mucocutaneous candidiasis. At the age of 40, she developed multiple white verrucous plaques on the oral mucosa. Histologically, the lesions appeared as moderately differentiated squamous cell carcinomas. The patient subsequently developed multiple local recurrences and therefore required repeated surgery. Notably, a higher incidence rate of oral and esophageal squamous cell carcinoma has been observed in this syndrome. However, the critical pathogenetic pathways implicated in squamous cell carcinoma development in APECED are far from being well understood.

Exploring the link between microorganisms and oral cancer: a systematic review of the literature

The majority of cases of oral cancer have been related to tobacco use and heavy alcohol consumption. However, the incidence of oral cavity carcinoma appears to be increasing in many parts of the world in a manner that it is difficult to explain with traditional risk factors alone. Meanwhile, interest in the possible relationships between microorganisms and the different stages of cancer development has been rising and numerous mechanisms by which bacteria and yeast may initiate or promote carcinogenesis are currently under investigation. In particular, a persuasive body of evidence suggests a possible etiological role involving the metabolism and production of carcinogenic products, such as acetaldehyde. Other suggested mechanisms include the induction of chronic inflammation and direct interference with eukaryotic cell cycle and signaling pathways. This review aims to summarize the known associations between microbial infection and cancer and draw attention to how they may relate to oral carcinoma.

Micronucleus rate of buccal mucosal epithelial cells in relation to oral hygiene and dental factors

Carcinogenesis of squamous cell carcinomas in the upper aero-digestive tract (UADT) is a multi-stage process. Since 1937, micronuclei (MN) have been considered a marker for genome damage in the initiation stage. By help of the micronucleus test, carcinogenic exposure can be proven in the mucosa area of the UADT. The hypothesis to be tested was that individual oral hygiene and the dental status, respectively - just like alcohol and tobacco abuse - are associated with the micronucleus rate in cytological preparations of the buccal mucosa. In a prospective clinical observation study, we determined in 100 probands the micronucleus frequency per 1000 mucosa epithelial cells. Study participants with a high number of missing teeth (M/T index, p=0.037), a below-average papillary bleeding index (PBI, p=0.032) and periodontal status, respectively (PSI, p=0.042) possessed a higher micronucleus number in comparison with restored dental conditions. Probands with composite restorations displayed a higher MN rate (p=0.006) compared to those with amalgam. However, we could not detect any significant relation with the prosthetic status (p> or =0.075). An adjustment was made according to alcohol and tobacco. We therefore conclude that subgingival plaque and synthetic dental materials in addition to chronic alcohol and tobacco consumption might have genotoxic relevance in the oral cavity.

The histopathological characterization of oral Candida leukoplakias

Sixty four biopsy specimens of oral Candida leukoplakias were examined. Histological sections were stained with periodic acid-Schiff (PAS) reagent and by Grocott's silver method. C. albicans isolates were cultivated from all the patients but fungal hyphae were proved histologically only in 23 of them. PAS-positive and Grocott-positive elements were exclusively observed in the superficial epithelial layers, e.g., the cornified layer and the stratum granulosum. The inflammatory reaction was characterized by an early phase during which polymorphonuclear cells predominated. The skeletal muscle fascicles immediately adjacent to the infected epithelium showed striking degeneration and atrophy associated with a marked infiltrate of chronic inflammatory cells.

Strain persistence of invasive Candida albicans in chronic hyperplastic candidosis that underwent malignant change

OBJECTIVES

The aim of this study was to assess persistence and tissue invasion of Candida albicans strains isolated from a 65 year-old patient with chronic hyperplastic candidosis (CHC), that subsequently developed into squamous cell carcinoma (SCC).

MATERIALS AND METHODS

C. albicans (n=7) were recovered from the oral cavity of the patient over seven years. Confirmation of CHC and SCC in this patient was achieved by histopathological examination of incisional biopsy tissue. DNA fingerprinting was performed on the seven isolates from the CHC patient together with a further eight isolates from patients with normal oral mucosa (n=2), chronic atrophic candidosis (n=1), SCC (n=1) and CHC (n=4). Genotyping involved the use of inter-repeat PCR using the eukaryotic repeat primer 1251. Characterisation of the tissue invasive abilities of the isolates was achieved by infecting a commercially available reconstituted human oral epithelium (RHE; SkinEthic, Nice, France). After 24 h, C. albicans tissue invasion was assessed by histopathological examination.

RESULTS

DNA fingerprinting demonstrated strain persistence of C. albicans in the CHC patient over a seven year period despite provision of systemic antifungal therapy. The strain of C. albicans isolated from this patient was categorised as a high invader within the RHE compared to other isolates.

CONCLUSIONS

Candidal strain persistence was evident in a patient with CHC over seven years. This persistence may be due to incomplete eradication from the oral cavity following antifungal therapy or subsequent recolonisation from other body sites or separate exogenous sources. The demonstration of enhanced in vitro tissue invasion by this particular strain may, in part, explain the progression to carcinoma.

Immunocytochemical detection of Candida albicans in formalin fixed, paraffin embedded material

AIM

To assess the ability of the commercially available monoclonal antibody 1B12 (BioGenex, San Ramon, USA) to identify C albicans in formalin fixed, paraffin wax embedded material (FFPE).

METHODS

Broth cultures of 20 strains of seven Candida species were resuspended in 4% agarose blocks, fixed in formalin for 24 hours, and embedded in paraffin wax. In addition, 16 blocks of FFPE tissue known to contain periodic acid-Schiff positive fungal hyphae were examined. Antigen retrieval involved microwave treatment of specimens in citrate buffer (0.01 M; pH 6.5) before addition of 1B12 antibody for 24 hours. Bound antibody was subsequently detected using a biotinylated link antibody and a peroxidase conjugated streptavidin.

RESULTS

Only C albicans strains were 1B12 positive in the agarose blocks. All FFPE tissue blocks were found to contain 1B12 positive hyphal structures, indicating the presence of C albicans.

CONCLUSIONS

The ability to identify candida organisms penetrating the lesional tissue in cases of chronic hyperplastic candidosis will help to clarify the role of individual Candida spp in this important form of oral candidosis.

A comparison of the management of potentially malignant oral mucosal lesions by oral medicine practitioners and oral & maxillofacial surgeons in the UK

This study describes the results of a survey undertaken to assess the management of potentially malignant oral mucosal lesions by oral medicine practitioners and compares their approach with that of oral & maxillofacial surgeons that we have previously described. Significant differences were noted between the two groups in the use of photography to document the lesions and in the use of certain special investigations, which included measurement of serum iron, serum ferritin, serum Vit B12, red cell folate and candidal isolation. The groups also varied in the perceived importance of the age of the patient and anatomical site of the lesion when deciding on the need for further biopsy. There was also significant variation in the use of certain treatment modalities, including excising non-dysplastic and severely dysplastic/carcinoma in-situ lesions and eliminating trauma when treating mild/moderately dysplastic and severely dysplastic/carcinoma in-situ lesions. Significant differences in the frequency and duration of follow-up were noted for non-dysplastic lesions. Finally, the two groups differed significantly when asked to rank the perceived importance of certain factors (the histopathology of the most recent biopsy and the anatomical site of the lesion) when deciding the need to follow-up. Possible reasons for the variation are discussed.

Evaluation of the levels of oral Candida in patients with Sjögren's syndrome

OBJECTIVE

The purpose of this study was to investigate the levels of oral Candida in patients with Sjögren's syndrome

METHODS

The Candida count and salivary flow rate of patients with Sjögren's syndrome were compared with those of healthy control subjects. Candida cultures were obtained from oral rinses. The numbers of colony-forming units were determined through use of the Spiral System.

RESULTS

The mean Candida count of patients with Sjögren's syndrome was 1672 +/- 1455 colony-forming units per mL; the count of healthy control subjects was 0.00 colony-forming units per mL. The mean salivary flow rate of patients with Sjögren's syndrome was significantly lower than that of healthy control subjects (0.16 +/- 0.13 mL/min/gland vs 0.55 +/- 0.24 mL/min/gland, respectively; p = 0.0001). However, Spearman rank correlation analyses did not reveal a significant correlation between salivary flow rate and Candida count (in colony-forming units per mL) among patients with Sjögren's syndrome.

CONCLUSIONS

Alteration in the oral microbial flora in patients with Sjögren's syndrome may be enhanced by the reduction in salivary output.