Expression of Toll-like receptors in oral squamous cell carcinoma.

Almost 380,000 new cases of oral cancer were reported worldwide in 2020. Oral squamous cell carcinoma (OSCC) accounts for 90% of all types of oral cancers. Emerging studies have shown association of Toll-like receptors (TLRs) in carcinogenesis. The present study aimed to investigate the expression levels and tissue localization of TRL1 to TRL10 and NF-κB between OSCC and healthy oral mucosa, as well as effect of Candida colonization in TRL expression in OSCC. Full thickness biopsies and microbial samples from 30 newly diagnosed primary OSCC patients and 26 health controls were collected. The expression of TLR1 to TLR10 and NF-κB was analyzed by immunohistochemistry. Microbial samples were collected from oral mucosa to detect Candida. OSCC epithelium showed lower staining intensity of TRL1, TRL2 TRL5, and TRL8 as compared to healthy controls. Similarly, staining intensity of TRL3, TRL4, TRL7, and TRL8 were significantly decreased in basement membrane (BM) zone. Likewise, OSCC endothelium showed lower staining intensity of TLR4, TLR7 and TLR8. Expression of NF-κB was significantly stronger in normal healthy tissue compared to OSCC sample. Positive correlation was found between the expression of NF-κB, TRL9 and TRL10 in basal layer of the infiltrative zone OSCC samples (P = 0.04 and P = 0.002, respectively). Significant increase in TRL4 was seen in BM zone of sample colonized with Candida (P = 0.01). According to the limited number of samples, our data indicates downregulation of TLRs and NF-κB in OSCC, and upregulation of TLR4 expression with presence of Candida.

Expression of p53 is associated with microbial acetaldehyde production in oralsquamous cell carcinoma.

OBJECTIVES: The objective of this study was to investigate the association between p53 expression and microbial acetaldehyde production in patients with oral squamous cell carcinoma (OSCC). STUDY DESIGN: Oral mucosal biopsies from 22 patients with OSCC and 24 healthy controls (HCs) were collected. p53 expression was analyzed by immunohistochemistry. Microbial samples were collected from the mucosa and microbial acetaldehyde production from ethanol was measured by gas chromatography. RESULTS: The majority of all OSCC (77%) and HC samples (67%) produced mutagenic levels of acetaldehyde (>100 µM). A significant positive correlation between microbial acetaldehyde production and p53 expression levels in OSCC samples was seen in the intermediate and superficial layers of the epithelium of the infiltrative zone (P = .0005 and P = .0004, respectively) and in the superficial layer of the healthy appearing mucosa next to the tumor (P = .0391). There was no significant correlation between acetaldehyde levels and p53 expression in HC samples. CONCLUSIONS: Our results show an association between microbial acetaldehyde production and immunostaining of p53 in OSCC samples.

TLR1-10, NF-κB and p53 expression is increased in oral lichenoid disease.

Toll-like receptors (TLRs) and nuclear factor-κB (NF-κB) in keratinocytes play an important role in dermatological autoimmune diseases. Tumour suppressor protein p53 regulates TLR expression. The aim of this study was to compare the expression of TLR1-TLR10, p53 and NF-κB in patients with oral lichenoid disease (OLD) with healthy mucosa. Oral mucosal biopsies from 24 patients with OLD and 26 healthy controls (HC) were analysed for the expression of TLR1-TLR10, NF-κB and p53 by immunohistochemistry. The expression of all TLRs was increased in OLD epithelia compared to HC samples and the difference was significant in TLR1, TLR3, TLR4, TLR5, TLR6 and TLR7. In the basement membrane zone, the immunoreactivity of TLR5 was significantly more intense in OLD compared to HC. In the intermediate layer, the immunoreactivity of NF-κB was significantly stronger in OLD, whereas the staining for p53 was more intense in all layers of OLD compared to HC samples. In OLD, a positive correlation between TLR2 and NF-κB in the basal layer and between TLR5, p53 and NF-κB in the intermediate layers was discovered. The expression of TLRs, p53 and NF-κB is increased in OLD, which may play a role in the pathogenesis of this chronic immune-mediated mucosal disease.

Acetaldehyde production and microbial colonization in oral squamous cell carcinoma and oral lichenoid disease.

OBJECTIVE: The main aim of this prospective study was to explore the ability of the oral microbiome to produce acetaldehyde in ethanol incubation. STUDY DESIGN: A total of 90 patients [30 oral squamous cell carcinoma (OSCC); 30 oral lichenoid disease (OLD); 30 healthy controls (CO)] were enrolled in the study. Microbial samples were taken from the mucosa using a filter paper method. The density of microbial colonization was calculated and the spectrum analyzed. Microbial acetaldehyde production was measured by gas chromatography. RESULTS: The majority (68%) of cultures produced carcinogenic levels of acetaldehyde (>100 µM) when incubated with ethanol (22 mM). The mean acetaldehyde production by microbes cultured from smoker samples was significantly higher (213 µM) than from non-smoker samples (141 µM) (P=.0326). CONCLUSIONS: The oral microbiota from OSCC, OLD patients and healthy individuals are able to produce carcinogenic levels of acetaldehyde. The present provisional study suggests smoking may increase the production of acetaldehyde.

A novel method for sampling the microbiota from the oral mucosa.

The purpose of this study was to develop a site-specific sampling method that could give representative and quantitative results for defined areas of the oral mucosa and would be easy to use. Two site-specific sampling methods (swab and filter paper imprint) were compared. The filter paper sampling method was developed for this study. Samples were collected from 14 volunteers. All samples were cultured under aerobic and anaerobic conditions. The number of viable bacteria and yeasts was determined and expressed per unit area. The filter paper recovered a significantly higher number of colony types of bacteria compared to the swab sample. Both collected a large number and variety of different oral microbes. The filter paper sampling method could be the optimal technique for quantitative site-specific oral mucosal samples and is highly suitable for both culture-based and non-culture-based identification of oral microbes.

Optimal sampling site for mucosal candidosis in oral cancer patients is the labial sulcus.

Traditional sampling methods for the diagnosis of oral candidosis in head and neck cancer patients, i.e. saliva collection or tongue scrapings, are often impossible to perform. The aim was to determine the optimal sampling method. Eighteen oral cancer patients and five control subjects were sampled semi-quantitatively from the labial sulcus, dorsum of the tongue, dental plaque and saliva for cultivation of yeasts. The patients were examined prior to all cancer treatment (n=5), or 2-4 weeks (n=5) or 8-12 weeks (n=8) post-operatively. The incidence of Candida was found to increase from 40 % at the control and pre-operative level up to 73 % 8-12 weeks post-operatively. Candida albicans was found to be the only species until 4 weeks post-operatively. Thereafter, the incidence of species other than C. albicans was 38 %. The most sensitive sampling site was found to be the vestibular sulcus, from which all culture-positive cases could be confirmed. Tongue surface scraping was found to be more sensitive than saliva collection in detecting Candida. All sampling methods and sites were equally sensitive in detecting the different Candida species. Dental plaque was found to have the highest density of Candida colonization, and was thus found to be the most significant source of Candida infection, which emphasizes the role of dental care in these patients.