The Role of the Microbiome in Oral Squamous Cell Carcinoma with Insight into the Microbiome-Treatment Axis.

Oral squamous cell carcinoma (OSCC) is one of the leading presentations of head and neck cancer (HNC). The first part of this review will describe the highlights of the oral microbiome in health and normal development while demonstrating how both the oral and gut microbiome can map OSCC development, progression, treatment and the potential side effects associated with its management. We then scope the dynamics of the various microorganisms of the oral cavity, including bacteria, mycoplasma, fungi, archaea and viruses, and describe the characteristic roles they may play in OSCC development. We also highlight how the human immunodeficiency viruses (HIV) may impinge on the host microbiome and increase the burden of oral premalignant lesions and OSCC in patients with HIV. Finally, we summarise current insights into the microbiome-treatment axis pertaining to OSCC, and show how the microbiome is affected by radiotherapy, chemotherapy, immunotherapy and also how these therapies are affected by the state of the microbiome, potentially determining the success or failure of some of these treatments.

Clinical relevance of the utilization of vital Lugol's iodine staining in detection and diagnosis of oral cancer and dysplasia.

OBJECTIVES: The aim of this study is to assess the clinical relevance of the utilization of vital Lugol's iodine staining in detection of oral cancer and dysplastic lesions as well as demarcation of the extent of these lesions. MATERIALS AND METHODS: A prospective, cross-sectional, hospital-based study was performed in Khartoum Teaching Dental Hospital, Sudan. Suspicious oral epithelial lesions indicating incisional biopsy were stained with 10 % Lugol's iodine solution and were clinically designated as "negative" for dysplasia or neoplasia when no unstained lesion (USL) area was observed, or as "positive" when a USL area is observed. Incisional biopsies involving both the unstained portion and the stained portion were obtained and histologically evaluated for definitive diagnosis. RESULTS: Forty-five biopsies were obtained from 28 patients. Histopathological examination of the specimens confirmed some degree of dysplasia or neoplasia in all clinically positive specimens with oral squamous cell carcinoma (OSCC) being the most common definitive diagnosis (17 patients, 60.7 %). Clinical relevance level of vital Lugol's iodine staining in detecting oral cancer and dysplasia was found to be 90.9 % (SE = 0.05, P = 0.05). CONCLUSION: The findings of this study showed that Lugol's iodine is an easy, safe, and effective method of visualizing oral epithelial lesions and differentiating epithelial carcinoma and dysplasia from other benign mucosal lesions. Despite certain limitations, its use is of great value in detection and diagnosis of oral cancer and dysplasia. CLINICAL RELEVANCE: Lugol's iodine staining can effectively be used in detection of the dysplastic and malignant superficial lesions of the oral epithelium.

Sudanese Toombak smokeless tobacco users harbour significantly altered long-term cortisol body production.

The Sudanese, in particular its male population, are known to utilise a smokeless tobacco product (Toombak) which is placed in the oral cavity and can be replaced several times a day. Toombak has been shown to harm human health and is highly addictive. The effect on body cortisol response over a retrospective period in users of this product has not been previously explored. In addition, psycho-dependency scores of Toombak users have not been analysed. In this study, 37 male subjects, age 18-45 years were recruited, of which 18 were non-users of Toombak and 19 were Toombak users. One hair sample was collected from each user and non-user of Toombak. Each hair sample (n=37) was placed in a pre-prepared long piece of foil with two labels on either side marked: 'scalp-side' and 'distant-side'. Cortisol was extracted by mincing 10 mg of 'scalp-side' hair, not exceeding 3 cm, with methanol addition, incubation, and sonication. Cortisol was measured using the enzyme-linked immunosorbent assay kit (Enzo Life Sciences, UK). The amount of hair cortisol in the samples was determined using spectrophotometry at wavelength 405 nm measured in pg/ml and visualised with a four parametric logistic curve. Toombak users were further asked to complete the Fagerstrom Test for Nicotine Dependence-Smokeless Tobacco questionnaire (FTND-ST) comprising of six questions. Scores of > 5 indicated a significant dependence, while a score of < 4 marked low to moderate dependence. The mean concentration of hair cortisol in Toombak users (9.7 pg/ml) was significantly lower (p=0.023) compared to non-users (19.4 pg/ml), with total concentrations ranging from 2.1 to 55.6 pg/ml. FTND-ST scores ranged from 4 to 9, with high levels of psycho-dependency (score > 5) and nicotine tolerance found in 85 % of Toombak users. Cortisol body release in Sudanese smokeless tobacco users was found to be significantly altered. While low cortisol levels do lead to anxiolytic effects, in the long-term, this can allow for increased susceptibility to low cortisol-associated diseases.

Altered oral microbiome in Sudanese Toombak smokeless tobacco users carries a newly emerging risk of squamous cell carcinoma development and progression.

There are an estimated 6-10 million smokeless tobacco (Toombak) users in Sudan, the majority being males. Toombak is known to be a carcinogenic product that is likely to modify the oral microbiome spatiality into a high-risk potential for the development and progression of oral cancer, but previous studies are lacking in this field. Here, we endeavour for the first time the exploration of the oral microbiome in key mucosal areas of the oral cavity and assess the microbiome variations in premalignant and oral squamous cell carcinoma (OSCC) samples from both users and non-users of Toombak. 16S rRNA sequencing was performed on DNA obtained from pooled saliva, oral mucosa and supragingival plaque from 78 Sudanese users and non-users of Toombak, aged between 20 and 70 years. In 32 of the pooled saliva samples, the mycobiome (fungal) environment was analysed through ITS sequencing. Then, 46 formalin-fixed paraffin-embedded samples of premalignant and OSCC samples were collected, and their associated microbiomes sequenced. The oral Sudanese microbiome was found to be enriched in Streptococcaceae, but Staphylococcaceae were significantly more abundant amongst Toombak users. Genera enriched in the oral cavity of Toombak users included Corynebacterium_1 and Cardiobacterium while in non-users, Prevotella, Lactobacillus and Bifidobacterium were prominent. Aspergillus was the most abundant fungus in the mouths of Toombak users with a marked loss of Candida. The genus Corynebacterium_1 was abundant in the buccal, floor of the mouth and saliva microbiomes as well as in oral cancer samples from Toombak users indicating a possible role for this genus in the early stages of oral cancer development. An oral cancer microbiome that favours poor survival and metastasis in those who use Toombak also emerged that includes the genera Stenotrophomonas and Schlegelella. Those utilising Toombak carry an altered oral microbiome that may be an additional risk factor for this products carcinogenicity to the oral structures. These significant microbiome modulations are a newly emerging key driving factor in oral cancer development and progression in Toombak users while it is also shown that Toombak users carry an oral cancer microbiome that may increase the potential for a poorer prognosis.

The ultra-structural, metabolomic and metagenomic characterisation of the sudanese smokeless tobacco 'Toombak'.

Toombak is a smokeless tobacco produced from the Nicotiana rustica tobacco plant from Sudan. Pre-prepared and ready to buy Toombak samples were analysed using mass spectrometry (heavy metals), gas and liquid chromatography (metabolomics), 16S rRNA metagenomic sequencing (microbiome) and Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) and pH analysis. Chromium, cobalt, and copper were high in the pre-prepared form of Toombak while iron, tobacco specific nitrosamines (TSNAs), formaldehyde and acetaldehyde were high in both types. Firmicutes and Actinobacteria dominated Toombak. Samples of ready to buy Toombak showed inter-variational differences depending on place of purchase. We found Virgibacillus were increased in the pre-prepared form while Corynebacterium casei, Atopococus tabaci, Atopostipes suicloacalis, Oceanobacillus chironomi and Staphylococcus gallinarum were the most abundant species in the ready to buy forms. PICRUSt analysis highlighted increased activity of metal transport systems in the ready to buy samples as well as an antibiotic transport system. SEM-EDX highlighted large non-homogenous, irregular particles with increased sodium, while pH of samples was in the alkaline range. The final composition of Toombak is affected by its method of preparation and the end product has the potential to impart many negative consequences on the health of its users. TSNA levels observed in Toombak were some of the highest in the world while the micro-environment of Toombak supports a distinct microbiota profile.

Eagle's Syndrome.

Eagle's Syndrome (ES) refers to a symptomatic anomaly due to elongation of the styloid process or mineralization of the styloid complex. If not diagnosed timely and treated properly, elongation of the styloid process or the hyper-mineralization of the stylohyoid ligament may eventually lead to complete ossification of the stylohyoid complex. Non-specific head and neck symptoms of the ES may pose diagnostic challenges to the clinician. Therefore it is crucial to include ES among differential diagnosis when evaluating patients with similar head and neck symptoms. Once the diagnosis is confirmed, treatment plan should be tailored in accordance with the individual requirements of the case and performed without delay. Both pharmacological and surgical methods have been described for the treatment of the patients with ES. However for those who suffer from persistent symptoms, surgical removal of the elongated styloid process is the treatment of choice and can be done with an intraoral or an extraoral approach. The aim of this work is to present unusual clinical symptoms and radiologic findings of ES due to complete ossification of the stylohyoid complex. The importance of a correct diagnosis and appropriate treatment are highlighted.