Cancer et mycoses et revue de la littérature

A Putative Role of Candida albicans in Promoting Cancer Development: A Current State of Evidence and Proposed Mechanisms

Candida albicans is a commensal fungal species that commonly colonizes the human body, but it is also a pervasive opportunistic pathogen in patients with malignant diseases. A growing body of evidence suggests that this fungus is not only coincidental in oncology patients, but may also play an active role in the development of cancer. More specifically, several studies have investigated the potential association between C. albicans and various types of cancer, including oral, esophageal, and colorectal cancer, with a possible role of this species in skin cancer as well. The proposed mechanisms include the production of carcinogenic metabolites, modulation of the immune response, changes in cell morphology, microbiome alterations, biofilm production, the activation of oncogenic signaling pathways, and the induction of chronic inflammation. These mechanisms may act together or independently to promote cancer development. Although more research is needed to fully grasp the potential role of C. albicans in carcinogenesis, the available evidence suggests that this species may be an active contributor and underscores the importance of considering the impact of the human microbiome on cancer pathogenesis. In this narrative review, we aimed to summarize the current state of evidence and offer some insights into proposed mechanisms.

The Influence of the Oral Microbiome on Oral Cancer: A Literature Review and a New Approach

In our recent article (Smędra et al.: Oral form of auto-brewery syndrome. J Forensic Leg Med. 2022; 87: 102333), we showed that alcohol production can occur in the oral cavity (oral auto-brewery syndrome) due to a disruption in the microbiota (dysbiosis). An intermediate step on the path leading to the formation of alcohol is acetaldehyde. Typically, acetic aldehyde is transformed into acetate particles inside the human body via acetaldehyde dehydrogenase. Unfortunately, acetaldehyde dehydrogenase activity is low in the oral cavity, and acetaldehyde remains there for a long time. Since acetaldehyde is a recognised risk factor for squamous cell carcinoma arising from the oral cavity, we decided to analyse the relationship linking the oral microbiome, alcohol, and oral cancer using the narrative review method, based on browsing articles in the PubMed database. In conclusion, enough evidence supports the speculation that oral alcohol metabolism must be assessed as an independent carcinogenic risk. We also hypothesise that dysbiosis and the production of acetaldehyde from non-alcoholic food and drinks should be treated as a new factor for the development of cancer.

Chromoblastomycosis in Latin America and the Caribbean: epidemiology over the past 50 years

Chromoblastomycosis is a chronic disease caused by melanized fungi that mainly affect individuals performing soil-related labour. The objective of this study was to analyse the epidemiological and clinical characteristics of chromoblastomycosis in Latin America and the Caribbean by an extensive literature review. An integrative review was performed of English, French, Portuguese, and Spanish publications in LILACS, SciELO, PubMed, SCOPUS and Web of Science databases covering the period 1969-2019. A total of 1,211 articles were identified, of which 132 were included in the review, covering 2,081 patients, 80.3% were male, the mean age was 56.1 years. The mean duration of the disease was 10.8 years. The lesions were mainly described in the lower limbs (60%). The most frequent clinical forms were verrucous (46.4%) and tumorous (21.7%). Major disease symptoms and signs consisted of itching and pain. Bacterial infection and functional limitation were important complications. Immunosuppression post-kidney transplantation was the most frequent comorbidity while leprosy was the main concomitant infectious disease. Fonsecaea pedrosoi and Cladophialophora carrionii were the predominant etiological agents. Majority of the cured cases were treated with itraconazole as monotherapy or in combination with other antifungals, surgery or cryosurgery. Chromoblastomycosis affects hundreds of rural workers in Latin America and the Caribbean, causing disability and personal, family and economic losses. It is important to prioritize epidemiological surveillance and early diagnosis of this disease in order to reveal its real prevalence and direct resources to preventive actions, diagnosis and early treatment.

LAY SUMMARY

Chromoblastomycosis is a slowly progressing chronic disease caused by melanized fungi. We collected data from South America and the Caribbean covering 1969-2019, the 132 articles included 2 081 patients, mean disease duration was 10.8 years. Fonsecaea pedrosoi and Cladophialophora carrionii predominated.

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.

Diagnosis at different stages of paracoccidioidomycosis with oral manifestation: Report of two cases

Paracocciodiomycosis (PCDM) is a chronic systemic fungal infection, mainly affecting residents and rural workers, being characterized by a long incubation period, which it can take months or years without clinical manifestations, making diagnosis late and difficult. Depending on the stage of the disease, it can cause sequelae and low quality of life, so its correct diagnosis is of great importance for the accurate treatment. Therefore, the aim of this report is to present two cases of diagnosis of patients with PCDM at different stages, who developed chronic manifestations, pain, clinical involvement of the oral cavity and in one case also presented lung injury with fibrosis, as well as to weight loss, dysphagia and cachexia. Both of patients were treated with antifungal therapy and it was observed total remission of the lesions and no recurrences were detected.

Oral paracoccidioidomycosis in a non-endemic region from Brazil: A short case series

Background

Although the paracoccidioidomycosis (PCM) is endemic in Brazil, the occurrence in most states from the North and Northeastern Brazil is very unusual. The aim of this study was to evaluate the clinicopathologic features of a case series of oral PCM in a non-endemic region from Brazil (Northeastern region), discussing the clinical and histopathological differential diagnoses of the oral manifestations of the disease.

Material and Methods

Between 2000 and 2017, all cases of oral PCM were retrieved from the Oral Pathology Laboratory, Universidade Federal de Pernambuco, located at Northeastern Brazil. Clinical data, such as age, gender, origin, occupation, site, symptoms, time of complaints, clinical presentation, number of lesions, and clinical hypotheses of diagnosis, were collected from the clinical charts. All cases were histologically reviewed in hematoxylin-eosin and Gomori-Grocott staining.

Results

Six cases were identified. All patients were male, with a mean age of 53.8 years (ranging from 40 to 73 years). Four cases appeared as multiple ulcers and two presented single lesions (buccal mucosa and hard palate). Clinically, in five cases, squamous cell carcinoma was considered in the differential diagnosis. The common histopathological features consisted of hyperplastic epithelium, intraepithelial microabscesses, and formation of granulomatous chronic inflammatory reaction in a fibrous connective tissue with severe chronic inflammatory reaction. Yeasts were observed either inside of multinucleated giant cells or extracellularly.

Conclusions

Although rare in non-endemic regions, oral PCM should be considered in the differential diagnosis of oral chronic ulcers, mainly those multiple.

Key words:Oral mucosa, mycology, paracoccidoidomycosis, ulcer.

Fungicidal Potency and Mechanisms of θ-Defensins against Multidrug-Resistant Candida Species

Systemic candidiasis is a growing health care concern that is becoming even more challenging due to the growing frequency of infections caused by multidrug-resistant (MDR) Candida species. Thus, there is an urgent need for new therapeutic approaches to candidiasis, including strategies bioinspired by insights into natural host defense against fungal pathogens. The antifungal properties of θ-defensins, macrocyclic peptides expressed in tissues of Old World monkeys, were investigated against a panel of drug-sensitive and drug-resistant clinical isolates of Candida albicans and non-albicans Candida species. Rhesus θ-defensin 1 (RTD-1), the prototype θ-defensin, was rapidly and potently fungicidal against drug-sensitive and MDR C. albicans strains. Fungal killing occurred by cell permeabilization that was temporally correlated with ATP release and intracellular accumulation of reactive oxygen species (ROS). Killing by RTD-1 was compared with that by histatin 5 (Hst 5), an extensively characterized anticandidal peptide expressed in human saliva. RTD-1 killed C. albicans much more rapidly and at a >200-fold lower concentration than that of Hst 5. Unlike Hst 5, the anticandidal activity of RTD-1 was independent of mitochondrial ATP production. Moreover, RTD-1 was completely resistant to Candida proteases for 2 h under conditions that rapidly and completely degraded Hst 5. MICs and minimum fungicidal concentrations (MFCs) of 14 natural θ-defensins isoforms against drug-resistant C. albicans isolates identified peptides that are more active than amphotericin B and/or caspofungin against fluconazole-resistant organisms, including MDR Candida auris. These results point to the potential of macrocyclic θ-defensins as structural templates for the design of antifungal therapeutics.

Photodynamic inactivation of Candida ssp. on denture stomatitis. A clinical trial involving palatal mucosa and prosthesis disinfection

Denture stomatitis (DS) is the most common oral fungal infection in denture wearers. Photodynamic inactivation (PDI) has been showing to be an effective technique in vivo against fungi, including fungal infections in the oral cavity. The disinfection of both oral mucosa and denture may represent a real advantage in terms of fungus control. This clinical study was designed to explore methylene blue (MB)-mediated PDI on oral mucosa and prosthesis of patients with DS. Subjects with DS were divided into two groups. One group received treatment based on the use of oral miconazole gel 2% (MIC). The other group received treatment by PDI using MB at 450 μg/mL and a diode laser (λ = 660 nm) with 100 mW and fluence of 28 J/cm². Clinical outcome was evaluated regarding the degree of oral mucosa erythema and microbiological reduction of Candida spp. located in both palatal mucosa and prosthesis. Our results showed that PDI was significantly more effective than MIC in ameliorating inflammation after 15 days. Following 30 days, no statistically significant differences were observed between groups. Regarding the fungal burden, although the MIC group has presented more pronounced inactivation than PDI for both mucosa and prosthesis, no statistically significant differences were detected between them. This clinical study suggests that PDI can reduce fungal load and decrease the inflammation degree in patients with Candida-associated denture stomatitis.