Current concepts and future of noninvasive procedures for diagnosing oral squamous cell carcinoma--a systematic review

Expanding salivary biomarker detection by creating a synthetic neuraminic acid sensor via chimeragenesis

Accurate and timely diagnosis of oral squamous cell carcinoma (OSCC) is crucial in preventing its progression to advanced stages with a poor prognosis. As such, the construction of sensors capable of detecting previously established disease biomarkers for the early and non-invasive diagnosis of this and many other conditions has enormous therapeutic potential. In this work, we apply synthetic biology techniques for the development of a whole-cell biosensor (WCB) that leverages the physiology of engineered bacteria in vivo to promote the expression of an observable effector upon detection of a soluble molecule. To this end, we have constructed a bacterial strain expressing a novel chimeric transcription factor (Sphnx) for the detection of N-acetylneuraminic acid (Neu5Ac), a salivary biomolecule correlated with the onset of OSCC. This WCB serves as the proof-of-concept of a platform that can eventually be applied to clinical screening panels for a multitude of oral and systemic medical conditions whose biomarkers are present in saliva.

Intronic miR-6741-3p targets the oncogene SRSF3: Implications for oral squamous cell carcinoma pathogenesis

Epigenetic silencing through methylation is one of the major mechanisms for downregulation of tumor suppressor miRNAs in various malignancies. The aim of this study was to identify novel tumor suppressor miRNAs which are silenced by DNA hypermethylation and investigate the role of at least one of these in oral squamous cell carcinoma (OSCC) pathogenesis. We treated cells from an OSCC cell line SCC131 with 5-Azacytidine, a DNA methyltransferase inhibitor, to reactivate tumor suppressor miRNA genes silenced/downregulated due to DNA methylation. At 5-day post-treatment, total RNA was isolated from the 5-Azacytidine and vehicle control-treated cells. The expression of 2,459 mature miRNAs was analysed between 5-Azacytidine and control-treated OSCC cells by the microRNA microarray analysis. Of the 50 miRNAs which were found to be upregulated following 5-Azacytidine treatment, we decided to work with miR-6741-3p in details for further analysis, as it showed a mean fold expression of >4.0. The results of qRT-PCR, Western blotting, and dual-luciferase reporter assay indicated that miR-6741-3p directly targets the oncogene SRSF3 at the translational level only. The tumor-suppressive role of miR-6741-3p was established by various in vitro assays and in vivo study in NU/J athymic nude mice. Our results revealed that miR-6741-3p plays a tumor-suppressive role in OSCC pathogenesis, in part, by directly regulating SRSF3. Based on our observations, we propose that miR-6741-3p may serve as a potential biological target in tumor diagnostics, prognostic evaluation, and treatment of OSCC and perhaps other malignancies.

Discrimination of vocal folds lesions by multiclass classification using autofluorescence spectroscopy: An ex vivo study

BACKGROUND

Autofluorescence spectroscopy is effective for noninvasive detection but underutilized in tissue with various pathology analyses. This study evaluates whether AFS can be used to discriminate between different types of laryngeal lesions in view of assisting in vocal fold surgery and preoperative investigations.

METHODS

A total of 1308 spectra were recorded from 29 vocal fold samples obtained from 23 patients. Multiclass analysis was performed on the spectral data, categorizing lesions into normal, benign, dysplastic, or carcinoma.

RESULTS

Through an appropriate selection of spectral components and a cascading classification approach based on artificial neural networks, a classification rate of 97% was achieved for each lesion class, compared to 52% using autofluorescence intensity.

CONCLUSIONS

The ex vivo study demonstrates the effectiveness of AFS combined with multivariate analysis for accurate classification of vocal fold lesions. Comprehensive analysis of spectral data significantly improves classification accuracy, such as distinguishing malignant from precancerous or benign lesions.

The emerging role of liquid biopsy in oral squamous cell carcinoma detection: advantages and challenges

INTRODUCTION

Oral Squamous Cell Carcinoma (OSCC), the sixth most widespread malignancy in the world, accounts for 90% of all cases of oral cancer. The primary risk factors are tobacco chewing, alcohol consumption, viral infection, and genetic modifications. OSCC has a high morbidity rate due to the lack of early diagnostic methods. Nowadays, liquid biopsy plays a vital role in the initial diagnosis of oral cancer. ctNAs extracted from saliva and serum/plasma offer meaningful insights into tumor genetics and dynamics. The interplay of these elements in saliva and serum/plasma showcases their significance in advancing noninvasive, effective OSCC detection and monitoring.

AREAS COVERED

This review mainly focused on the role of liquid biopsy as an emerging point in the diagnosis and prognosis of OSCC and the current advancements and challenges associated with liquid biopsy.

EXPERT OPINION

Liquid biopsy is regarded as a new, minimally invasive, real-time monitoring tool for cancer diagnosis and prognosis. Many biomolecules found in bodily fluids, including ctDNA, ctRNA, CTCs, and EVs, are significant biomarkers to identify cancer in its early stages. Despite these groundbreaking strides, challenges persist. Standardization of sample collection, isolation, processing, and detection methods is imperative for ensuring result reproducibility across diverse studies.

A Potential biomarker for the early diagnosis of OSCC: saliva and serum PrPC

Background: Oral squamous cell carcinoma (OSCC) is frequently diagnosed at an advanced stage, and the high mortality of patients is mainly due to the delay of diagnosis. Cellular prion protein (PrPC) contributes to the occurrence and development of many malignant tumors. However, little has been known about the clinical and diagnostic value of PrPC in OSCC. This study investigated the levels of PrPC in the saliva and serum of patients with OSCC, OPMD and control group and their diagnostic value. Methods: The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO) and Clinical Proteome Tumor Analysis Consortium (CPTAC) databases were analyzed to evaluate the expression of human prion protein gene (PRNP) mRNA and PrPC in OSCC. Enzyme-linked Immunosorbent Assay (ELISA) was utilized to detect the expression of PrPC in saliva and serum samples of OSCC, OPMD and control groups. Furthermore, diagnostic value and clinical significance of PrPC in OSCC was identified. Protein-protein interaction (PPI) network was constructed by STRING. GO and KEGG analysis were performed by ClusterProfiler. Results: The levels of PRNP mRNA and PrPC in OSCC were significantly higher than those in the control group from databases (P<0.05). Besides, salivary and serum PrPC of OSCC patients showed increased levels compared with OPMD and control groups (P<0.05). The expression of salivary and serum PrPC of OSCC was correlated with the degree of differentiation (P<0.05), and the expression of PrPC from CPTAC was related to tumor stage of OSCC (P<0.05). The areas under the diagnostic curves (AUCs) of salivary and serum PrPC were 0.807 and 0.671, respectively. GO and KEGG analysis revealed that PrPC might be related to cell adhesion, cell differentiation, signal transduction and apoptosis, and participate in the pathways of focal adhesion, PI3K-Akt signaling pathway and ECM- receptor interaction in OSCC. Conclusion: PrPC in saliva and serum may be a potential biomarker for early diagnosis of OSCC.

Detection of oral mucosal lesions by the fluorescence spectroscopy and classification of cancerous stages by support vector machine

Detection of oral mucosal lesions has been performed by an in-house developed fluorescence-based portable device in the present study. A laser diode of 405 nm wavelength and a UV-visible spectrometer are utilized in the portable device as excitation and detection sources. At the 405 nm excitation wavelength, the flavin adenine dinucleotide (FAD) band at 500 nm and three porphyrin bands at 634, 676, and 703 nm are observed in the fluorescence spectrum of the oral cavity tissue. We have conducted this clinical study on a total of 189 tissue sites of 36 oral squamous cell carcinoma (OSCC) patients, 18 dysplastic (precancerous) patients, and 34 volunteers. Analysis of the fluorescence data has been performed by using the principal component analysis (PCA) method and support vector machine (SVM) classifier. PCA is applied first in the spectral data to reduce the dimension, and then classification among the three groups has been executed by employing the SVM. The SVM classifier includes linear, radial basis function (RBF), polynomial, and sigmoid kernels, and their classification efficacies are computed. Linear and RBF kernels on the testing data sets differentiated OSCC and dysplasia to normal with an accuracy of 100% and OSCC to dysplasia with an accuracy of 95% and 97%, respectively. Polynomial and sigmoid kernels showed less accuracy values among the groups ranging from 48 to 88% and 51 to 100%, respectively. The result indicates that fluorescence spectroscopy and the SVM classifier can help to identify early oral mucosal lesions with significant high accuracy.

"Salivary LINC00657 and miRNA-106a as diagnostic biomarkers for oral squamous cell carcinoma, an observational diagnostic study"

BACKGROUND

Early detection and diagnosis of malignant tumors is critical for improving the survival rate and treatment outcomes of oral cancer. Thus, the current prospective investigation was designed to verify the role, sensitivity, and specificity of salivary LINC00657 and miRNA-106a as diagnostic markers in oral squamous cell carcinoma patients as compared to oral lichen planus (as an example of oral potentially malignant disorders) and normal individuals, and to show LINC00657 relation to miR-106a.

METHODS

A total of 36 participants were included, subdivided into 3 groups: Group I: 12 patients diagnosed with oral squamous cell carcinoma (OSCC). Group II: 12 patients diagnosed with oral lichen planus (OLP). Group III: 12 systemically free individuals with no oral mucosal lesions. Unstimulated salivary samples were collected from all participants to evaluate level of LINC00657 and miR-106a in different groups using quantitative real-time PCR.

RESULTS

OSCC showed the highest LINC00657 and lowest miR-106a fold change among included groups. Receiver Operating Characteristic (ROC) curve analysis of the two biomarkers for detecting OSCC revealed that LINC00657 had higher diagnostic accuracy (DA) (83.3%) compared to miR-106a (80.4%). As for detecting OLP, ROC analysis showed that miR-106a had higher (DA) (61%) compared to LINC00657 (52.5%). To discriminate OSCC from OLP, the diagnostic accuracy of both markers is the same (75%). Moreover, differentiating OSCC grades II and III, ROC analysis showed that miR-106a had lower (DA) (60%) compared to LINC00657 (DA) (83.3%).

CONCLUSIONS

Salivary LINC00657 and miR-106a could be promising diagnostic markers for oral squamous cell carcinoma. Salivary LINC00657 may differentiate oral squamous cell carcinoma from oral potentially malignant disorders with considerable diagnostic accuracy. Moreover, low levels of salivary miR-106a could have the potential to indicate malignancy.

TRIAL REGISTRATION

The study was retrospectively registered on clinicaltrial.gov with NCT05821179 (first trial registration in 26/3/2023), date of registration: 19/4/2023.

Human Saliva as a Substitute Diagnostic Medium for the Detection of Oral Lesions Using the Stokes Shift Spectroscopy: Discrimination among the Groups by Multivariate Analysis Methods

OBJECTIVE

Our objective in the present study is to detect oral mucosal lesions non-invasively by probing two solutions with reference to diagnostic technique and non-invasive media. In the diagnostic technique, Stokes shift (SS) spectroscopy (SSS) has been utilized for the detection of oral lesions. In the diagnostic media, human oral tissue and saliva are included.

METHODS

SS measurements are carried out on oral squamous cell carcinoma (OSCC), dysplastic (precancer), and normal/control tissue and saliva samples. Measurements are performed on 86 tissue and 86 saliva samples using the commercially available spectrofluorometer. Offset wavelength of 120 nm, which is the Stoke shift of nicotinamide adenine dinucleotide (NADH) has been selected over the other offsets (i.e., 20, 40, 70 and 90 nm).

RESULT

Presence of tryptophan, collagen, NADH, and flavin adenine dinucleotide (FAD) bands were noticed in the SS spectra of tissue. Like the tissue spectra, presence of these bands was also found in the SS spectra of saliva except the collagen band. Classification among the samples accomplished by the make use of multivariate analysis methods. In the multivariate analysis methods, principal component analysis (PCA) is applied first on SS data of tissue and saliva and then Mahalanobis distance (MD) model and receiver operating characteristic (ROC) analysis employed successively. Overall accuracy values of 94.91 %, 84.61 %, and 85.24 % were obtained among OSCC to normal, dysplasia to normal, and OSCC to dysplasia for tissue samples and 88.46 %, 90.16 % and 94.91 % accuracy values were obtained for saliva using the SS spectroscopy.

CONCLUSION

Obtained results of human saliva are equivalent to human oral tissue using the SS spectroscopy. It indicates that saliva may be utilized as a substitute diagnostic medium and SS spectroscopy as a diagnostic technique for non-invasive detection of oral lesions at the primarily stage.

Survival analysis of age-related oral squamous cell carcinoma: a population study based on SEER

BACKGROUND

This research aimed to investigate the prognostic factors of oral squamous cell carcinoma (OSCC), especially the role of age.

METHODS

A total of 33,619 cases of OSCC were received from the Surveillance, Epidemiology, and End Results (SEER) database during 2005-2015. Kaplan-Meier curves of 5-year overall survival rates and 5-year cancer-specific survival rates were performed, and univariate and multivariate Cox regression analyses as well as competing risk model were used to help understand the relationship between various factors and mortality of OSCC.

RESULTS

Compared to 18-39-year-old group, the older age was an important predictor of worse prognosis. The multivariate analysis of overall survival (OS) was 50-59 years (HR, 1.32; 95% CI 1.17-1.48; p ≤ .001), 60-69 years (HR, 1.66; 95% CI 1.42-1.87; p ≤ .001) and 70 + years (HR, 3.21; 95% CI 2.86-3.62; p ≤ .001), respectively, while the specific value of competing risk model was 60-69 years (HR, 1.21; 95% CI 1.07-1.38; p = .002) and 70 + years (HR, 1.85; 95% CI 1.63-2.10; p ≤ .001). In addition, female gender, unmarried, Blacks, tumor in floor of mouth, size and higher Tumor Node Metastasis (TNM) classification were also other predictors that signify significant clinically deterioration of OS/cancer-specific survival (CSS).

CONCLUSIONS

Our research revealed that age was an important factor in explaining the difference of survival in the whole process of OSCC. It is suggested that we should pay attention to the influence of age on diagnosis, treatment and prognosis in the clinical process.

Therapeutic potential of curcumin and its nanoformulations for treating oral cancer

The global incidence of oral cancer has steadily increased in recent years and is associated with high morbidity and mortality. Oral cancer is the most common cancer in the head and neck region, and is predominantly of epithelial origin (i.e. squamous cell carcinoma). Oral cancer treatment modalities mainly include surgery with or without radiotherapy and chemotherapy. Though proven effective, chemotherapy has significant adverse effects with possibilities of tumor resistance to anticancer drugs and recurrence. Thus, there is an imperative need to identify suitable anticancer therapies that are highly precise with minimal side effects and to make oral cancer treatment effective and safer. Among the available adjuvant therapies is curcumin, a plant polyphenol isolated from the rhizome of the turmeric plant Curcuma longa. Curcumin has been demonstrated to have anti-infectious, antioxidant, anti-inflammatory, and anticarcinogenic properties. Curcumin has poor bioavailability, which has been overcome by its various analogues and nanoformulations, such as nanoparticles, liposome complexes, micelles, and phospholipid complexes. Studies have shown that the anticancer effects of curcumin are mediated by its action on multiple molecular targets, including activator protein 1, protein kinase B (Akt), nuclear factor κ-light-chain-enhancer of activated B cells, mitogen-activated protein kinase, epidermal growth factor receptor (EGFR) expression, and EGFR downstream signaling pathways. These targets play important roles in oral cancer pathogenesis, thereby making curcumin a promising adjuvant treatment modality. This review aims to summarize the different novel formulations of curcumin and their role in the treatment of oral cancer.

Stepwise activation of p63 and the MEK/ERK pathway induces the expression of ARL4C to promote oral squamous cell carcinoma cell proliferation

Carcinogenesis is a multistep process wherein cells accumulate multiple genetic alterations and progress to a more malignant phenotype. It has been proposed that sequential accumulation of gene abnormalities in specific genes drives the transition from non-tumorous epithelia through a preneoplastic lesion/benign tumor to cancer. Histologically, oral squamous cell carcinoma (OSCC) progresses in multiple ordered steps that begin with mucosal epithelial cell hyperplasia, which is followed by dysplasia, carcinoma in situ and invasive carcinoma. It is therefore hypothesized that genetic alteration-mediated multistep carcinogenesis would be involved in the development of OSCC; however, the detailed molecular mechanisms are unknown. We clarified the comprehensive gene expression patterns and carried out an enrichment analysis using DNA microarray data from a pathological specimen of OSCC (including a non-tumor region, carcinoma in situ lesion and invasive carcinoma lesion). The expression of numerous genes and signal activation were altered in the development of OSCC. Among these, the p63 expression was increased and the MEK/ERK-MAPK pathway was activated in carcinoma in situ lesion and in invasive carcinoma lesion. Immunohistochemical analyses revealed that p63 was initially upregulated in carcinoma in situ and ERK was sequentially activated in invasive carcinoma lesions in OSCC specimens. ADP-ribosylation factor (ARF)-like 4c (ARL4C), the expression of which is reportedly induced by p63 and/or the MEK/ERK-MAPK pathway in OSCC cells, has been shown to promote tumorigenesis. Immunohistochemically, in OSCC specimens, ARL4C was more frequently detected in tumor lesions, especially in invasive carcinoma lesions, than in carcinoma in situ lesions. Additionally, ARL4C and phosphorylated ERK were frequently merged in invasive carcinoma lesions. Loss-of-function experiments using inhibitors and siRNAs revealed that p63 and MEK/ERK-MAPK cooperatively induce the expression of ARL4C and cell growth in OSCC cells. These results suggest that the stepwise activation of p63 and MEK/ERK-MAPK contributes to OSCC tumor cell growth through regulation of ARL4C expression.

A prognostic model for oral squamous cell carcinoma patients with type 2 diabetes mellitus

OBJECTIVE

To build a prognostic model for oral squamous cell carcinoma patients with type 2 diabetes mellitus.

DESIGN

Oral squamous cell carcinoma patients with type 2 diabetes mellitus in Xiangya Hospital were studied. Patients during January 2011 to January 2015 were included in training set (n = 146), and those during January 2017 to December 2020 were included in test set (n = 81). Univariate and multivariate Cox regressions were used to screen independent prognostic variables. Nomogram was used to show the model. C-index, internal bootstrap resampling and external validation were used to evaluate the model.

RESULTS

Six independent prognostic factors (T stage, N stage, pathological grade, metformin use, sulfonylureas use, and fasting blood glucose) were screened from training set. Based on the six variables, nomogram was constructed to predict the prognosis of oral squamous cell carcinoma patients with type 2 diabetes mellitus. C-index value was 0.728, and result of internal bootstrap resampling showed better prediction efficiency for one-year survival. All patients were divided into two groups according to total points calculated based on the model. Group with low total points experienced better survival than that with high total points both in training set and test set.

CONCLUSIONS

The model provides a relatively accurate method to predict the prognosis of oral squamous cell carcinoma patients with type 2 diabetes mellitus.

In-vivo Testing of Oral Mucosal Lesions with an In-house Developed Portable Imaging Device and Comparison with Spectroscopy Results

Progression of oral mucosal lesions is generally marked by changes in the concentration of the intrinsic fluorophores such as collagen, nicotinamide adenine dinucleotide (NADH), flavin adenine dinucleotide (FAD) and porphyrin present in the human oral tissue. In this study, we have probed the changes in FAD and porphyrin by exciting with 405 nm laser light on different sites (tongue, buccal mucosa, lip etc.) of the oral cavity. Testing has been done by an in-house developed fluorescence-based portable imaging device on oral squamous cell carcinoma (OSCC) patients, dysplastic patients and control (normal) group. Fluorescence images recorded from OSCC and dysplastic patients have displayed an enhancement in the red band (porphyrin) as compared to those from the normal volunteers. Porphyrin to FAD intensity ratio (I_Porphyrin/I_FAD), referred to red to green ratio (I_red/I_green) has been taken as the diagnostic marker for classification among the groups. Receiver operating characteristic (ROC) analysis applied on I_Porphyrin/I_FAD is able to discriminate OSCC to normal, dysplasia to normal and OSCC to dysplasia with sensitivities of 100%, 81%, 92% and specificities of 100%, 93% and 92% respectively. Fluorescence imaging probe can capture a large area of oral lesions in a single scan and hence would be useful for initial scanning. On comparison with spectroscopy studies performed by our group, it is found that combining both spectroscopy and imaging as a device may be effective for the early detection of oral lesions. This clinical study was registered on the date 13/10/2017 in the clinical trials registry-India (CTRI) with registration number CTRI/2017/10/010102.

Clinical Evaluation of the Optical Filter for Autofluorescence Glasses for Oral Cancer Curing Light Exposed (GOCCLES®) in the Management of Potentially Premalignant Disorders: A Retrospective Study

Background: Any oral potentially malignant disorders (OPMDs) must be regularly monitored through clinical examination to detect any possible malignant transformation. Conventional intraoral exams, however, can be difficult because these conditions may resemble benign lesions. For this reason, several non-invasive diagnostic technologies have been developed to help the clinician in detecting and distinguishing between cancerous and benign lesions. Epithelial dysplasia can be considered the most important predictor of malignant evolution. Therefore, in this study we aim to evaluate the ability of an optical filter for autofluorescence Glasses for Oral Cancer Curing Light Exposed (GOCCLES^®) and of toluidine blue staining in identifying dysplastic areas in patients with OPMDs. Methods: In this retrospective study, medical records, photographs and videos of 25 patients with oral lesions were analyzed. Forty-two biopsy samples in 25 patients with OPMDs and at least one suspicious oral mucosa lesion that were evaluated in white light, autofluorescence with optical filter GOCCLES^®, toluidine blue staining and then biopsied with histopathological analysis were analyzed. Results: The sensitivity and specificity for the autofluorescence evaluation with GOCCLES^® for identifying dysplasia or carcinoma were 66% and 48%, respectively. The positive and negative predictive values were 34% and 77%, respectively, and the accuracy was 53%. The sensitivity and specificity for toluidine blue staining were 91% and 68%, respectively. The positive and negative predictive values were 55% and 95%, respectively, and the accuracy was 75%. Conclusions: The optical filter for autofluorescence (GOCCLES^®) and toluidine blue staining are simple, inexpensive, rapid and non-invasive procedures that can assist the clinician in distinguishing OPMDs from healthy mucosa but they are not able to distinguish benign and malignant lesions.

Novel cytological model for the identification of early oral cancer diagnostic markers: The carcinoma sequence model

Most oral squamous cell carcinomas (OSCCs) arise from a premalignant lesion, oral epithelial dysplasia; however, useful markers for the early detection of OSCC are lacking. The present study aimed to establish a novel experimental model to observe changes in the sequential expression patterns of mRNAs and proteins in a rat model of tongue cancer using liquid-based cytology techniques. Cytology specimens were collected at 2, 5, 8, 11, 14, 17 and 21 weeks from rats treated with 4-nitroquinoline 1-oxide to induce tongue cancer. The expression of candidate biomarkers was examined by performing immunocytochemistry and reverse transcription-quantitative PCR. The percentage of positively stained nuclei was calculated as the labeling index (LI). All rats developed OSCC of the tongue at 21 weeks. The mRNA expression levels of bromodomain protein 4 (Brd4), c-Myc and Tp53 were upregulated during the progression from negative for intraepithelial lesion or malignancy to squamous cell carcinoma (SCC). Brd4- and c-Myc-LI increased in low-grade squamous intraepithelial lesion, high-grade squamous intraepithelial lesion and SCC specimens. p53-LI was significantly increased in SCC specimens. This novel experimental model allowed the observation of sequential morphological changes and the expression patterns of mRNAs and proteins during carcinogenesis. Combining immunocytochemistry with cytology-based diagnoses may potentially improve the diagnostic accuracy of OSCC.

Head and Neck Squamous Cell Carcinoma: Risk Factors, Molecular Alterations, Immunology and Peptide Vaccines

Head and neck squamous cell carcinoma (HNSCC) arises from the epithelial lining of the oral cavity, hypopharynx, oropharynx, and larynx. There are several potential risk factors that cause the generation of HNSCC, including cigarette smoking, alcohol consumption, betel quid chewing, inadequate nutrition, poor oral hygiene, HPV and Epstein–Barr virus, and Candida albicans infections. HNSCC has causative links to both environmental factors and genetic mutations, with the latter playing a more critical role in cancer progression. These molecular changes to epithelial cells include the inactivation of cancer suppressor genes and proto-oncogenes overexpression, resulting in tumour cell proliferation and distant metastasis. HNSCC patients have impaired dendritic cell (DC) and natural killer (NK) cell functions, increased production of higher immune-suppressive molecules, loss of regulatory T cells and co-stimulatory molecules and major histocompatibility complex (MHC) class Ι molecules, lower number of lymphocyte subsets, and a poor response to antigen-presenting cells. At present, the standard treatment modalities for HNSCC patients include surgery, chemotherapy and radiotherapy, and combinatorial therapy. Despite advances in the development of novel treatment modalities over the last few decades, survival rates of HNSCC patients have not increased. To establish effective immunotherapies, a greater understanding of interactions between the immune system and HNSCC is required, and there is a particular need to develop novel therapeutic options. A therapeutic cancer vaccine has been proposed as a promising method to improve outcome by inducing a powerful adaptive immune response that leads to cancer cell elimination. Compared with other vaccines, peptide cancer vaccines are more robust and specific. In the past few years, there have been remarkable achievements in peptide-based vaccines for HNSCC patients. Here, we summarize the latest molecular alterations in HNSCC, explore the immune response to HNSCC, and discuss the latest developments in peptide-based cancer vaccine strategies. This review highlights areas for valuable future research focusing on peptide-based cancer vaccines.

Clinical assessment for the detection of oral cavity cancer and potentially malignant disorders in apparently healthy adults

BACKGROUND

The early detection of oral cavity squamous cell carcinoma (OSCC) and oral potentially malignant disorders (OPMD), followed by appropriate treatment, may improve survival and reduce the risk for malignant transformation respectively. This is an update of a Cochrane Review first published in 2013.

OBJECTIVES

To estimate the diagnostic test accuracy of conventional oral examination, vital rinsing, light-based detection, mouth self-examination, remote screening, and biomarkers, used singly or in combination, for the early detection of OPMD or OSCC in apparently healthy adults.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 20 October 2020), MEDLINE Ovid (1946 to 20 October 2020), and Embase Ovid (1980 to 20 October 2020). The US National Institutes of Health Trials Registry (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases. We conducted citation searches, and screened reference lists of included studies for additional references.

SELECTION CRITERIA

We selected studies that reported the test accuracy of any of the aforementioned tests in detecting OPMD or OSCC during a screening procedure. Diagnosis of OPMD or OSCC was provided by specialist clinicians or pathologists, or alternatively through follow-up.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles and abstracts for relevance. Eligibility, data extraction, and quality assessment were carried out by at least two authors independently and in duplicate. Studies were assessed for methodological quality using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2). We reported the sensitivity and specificity of the included studies. We provided judgement of the certainty of the evidence using a GRADE assessment.

MAIN RESULTS

We included 18 studies, recruiting 72,202 participants, published between 1986 and 2019. These studies evaluated the diagnostic test accuracy of conventional oral examination (10 studies, none new to this update), mouth self-examination (four studies, two new to this update), and remote screening (three studies, all new to this update). One randomised controlled trial of test accuracy directly evaluated conventional oral examination plus vital rinsing versus conventional oral examination alone. There were no eligible studies evaluating light-based detection or blood or salivary sample analysis (which tests for the presence of biomarkers for OPMD and OSCC). Only one study of conventional oral examination was judged as at overall low risk of bias and overall low concern regarding applicability. Given the clinical heterogeneity of the included studies in terms of the participants recruited, setting, prevalence of the target condition, the application of the index test and reference standard, and the flow and timing of the process, the data could not be pooled within the broader categories of index test. For conventional oral examination (10 studies, 25,568 participants), prevalence in the test accuracy sample ranged from 1% to 51%. For the seven studies with prevalence of 10% or lower, a prevalence more comparable to the general population, the sensitivity estimates were variable, and ranged from 0.50 (95% confidence interval (CI) 0.07 to 0.93) to 0.99 (95% CI 0.97 to 1.00); the specificity estimates were more consistent and ranged from 0.94 (95% CI 0.88 to 0.97) to 0.99 (95% CI 0.98 to 1.00). We judged the overall certainty of the evidence to be low, and downgraded for inconsistency and indirectness. Evidence for mouth self-examination and remote screening was more limited. We judged the overall certainty of the evidence for these index tests to be very low, and downgraded for imprecision, inconsistency, and indirectness. We judged the evidence for vital rinsing (toluidine blue) as an adjunct to conventional oral examination compared to conventional oral examination to be moderate, and downgraded for indirectness as the trial was undertaken in a high-risk population.

AUTHORS' CONCLUSIONS

There is a lack of high-certainty evidence to support the use of screening programmes for oral cavity cancer and OPMD in the general population. Frontline screeners such as general dentists, dental hygienists, other allied professionals, and community healthcare workers should remain vigilant for signs of OPMD and OSCC.

Detection of inaccessible head and neck lesions using human saliva and fluorescence spectroscopy

Head and neck cancer detection using fluorescence spectroscopy from human saliva is reported here. This study has been conducted on squamous cell carcinoma (SCC), and dysplastic (precancer) and control (normal) groups using an in-house developed compact set-up. Fluorescence set-up consists of a 375-nm laser diode and optical components. Spectral bands of flavin adenine dinucleotide (FAD), porphyrins, and Raman are observed in the spectral range of 400 to 800 nm. Presence of FAD and porphyrin bands in human saliva is confirmed by the liquid phantoms of FAD and porphyrin. Significant differences in fluorescence intensities among all the three groups are observed. Three spectral ranges from 455 to 600, 605 to 770, and 400 to 800 nm are selected for each group and area values under each spectral range are computed. To differentiate among the groups, receiver operating characteristic (ROC) analysis is employed on the area values. ROC differentiates among the groups with accuracies of 98%, 92.85%, and 81.13% respectively in the spectral ranges of 400 to 800 nm. However, in other two spectral ranges (455 to 600 and 605 to 770 nm), low accuracy values are found. Obtained accuracy values indicate that selection of human saliva for head and neck cancer detection may be a good alternative.

Diagnostic tests for oral cancer and potentially malignant disorders in patients presenting with clinically evident lesions

BACKGROUND

Squamous cell carcinoma is the most common form of malignancy of the oral cavity, and is often proceeded by oral potentially malignant disorders (OPMD). Early detection of oral cavity squamous cell carcinoma (oral cancer) can improve survival rates. The current diagnostic standard of surgical biopsy with histology is painful for patients and involves a delay in order to process the tissue and render a histological diagnosis; other diagnostic tests are available that are less invasive and some are able to provide immediate results. This is an update of a Cochrane Review first published in 2015.

OBJECTIVES

Primary objective: to estimate the diagnostic accuracy of index tests for the detection of oral cancer and OPMD, in people presenting with clinically evident suspicious and innocuous lesions.

SECONDARY OBJECTIVE

to estimate the relative accuracy of the different index tests.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: MEDLINE Ovid (1946 to 20 October 2020), and Embase Ovid (1980 to 20 October 2020). The US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were also searched for ongoing trials to 20 October 2020. No restrictions were placed on the language or date of publication when searching the electronic databases. We conducted citation searches, and screened reference lists of included studies for additional references.

SELECTION CRITERIA

We selected studies that reported the diagnostic test accuracy of the following index tests when used as an adjunct to conventional oral examination in detecting OPMD or oral cavity squamous cell carcinoma: vital staining (a dye to stain oral mucosa tissues), oral cytology, light-based detection and oral spectroscopy, blood or saliva analysis (which test for the presence of biomarkers in blood or saliva).

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles and abstracts for relevance. Eligibility, data extraction and quality assessment were carried out by at least two authors, independently and in duplicate. Studies were assessed for methodological quality using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2). Meta-analysis was used to combine the results of studies for each index test using the bivariate approach to estimate the expected values of sensitivity and specificity.

MAIN RESULTS

This update included 63 studies (79 datasets) published between 1980 and 2020 evaluating 7942 lesions for the quantitative meta-analysis. These studies evaluated the diagnostic accuracy of conventional oral examination with: vital staining (22 datasets), oral cytology (24 datasets), light-based detection or oral spectroscopy (24 datasets). Nine datasets assessed two combined index tests. There were no eligible diagnostic accuracy studies evaluating blood or salivary sample analysis. Two studies were classed as being at low risk of bias across all domains, and 33 studies were at low concern for applicability across the three domains, where patient selection, the index test, and the reference standard used were generalisable across the population attending secondary care. The summary estimates obtained from the meta-analysis were: - vital staining: sensitivity 0.86 (95% confidence interval (CI) 0.79 to 0.90) specificity 0.68 (95% CI 0.58 to 0.77), 20 studies, sensitivity low-certainty evidence, specificity very low-certainty evidence; - oral cytology: sensitivity 0.90 (95% CI 0.82 to 0.94) specificity 0.94 (95% CI 0.88 to 0.97), 20 studies, sensitivity moderate-certainty evidence, specificity moderate-certainty evidence; - light-based: sensitivity 0.87 (95% CI 0.78 to 0.93) specificity 0.50 (95% CI 0.32 to 0.68), 23 studies, sensitivity low-certainty evidence, specificity very low-certainty evidence; and - combined tests: sensitivity 0.78 (95% CI 0.45 to 0.94) specificity 0.71 (95% CI 0.53 to 0.84), 9 studies, sensitivity very low-certainty evidence, specificity very low-certainty evidence.

AUTHORS' CONCLUSIONS

At present none of the adjunctive tests can be recommended as a replacement for the currently used standard of a surgical biopsy and histological assessment. Given the relatively high values of the summary estimates of sensitivity and specificity for oral cytology, this would appear to offer the most potential. Combined adjunctive tests involving cytology warrant further investigation. Potentially eligible studies of blood and salivary biomarkers were excluded from the review as they were of a case-control design and therefore ineligible. In the absence of substantial improvement in the tests evaluated in this updated review, further research into biomarkers may be warranted.

Binary and WHO dysplasia grading systems for the prediction of malignant transformation of oral leukoplakia and erythroplakia: a systematic review and meta-analysis

OBJECTIVES

The aim of this systematic review was to examine the evidence of the binary histologic grading system capacity for predicting malignant transformation and to compare it with that of the WHO systems.

MATERIAL AND METHODS

A systematic review was conducted, using PubMed, EMBASE, LILACS, Web of Science, Scopus, and LIVIVO databases without any language or timeframe restrictions. Studies were included if they compared the binary and the WHO histologic grading systems in the prediction of malignant transformation of oral epithelial dysplasia (OED).

RESULTS

The capacity of the WHO and binary grading systems to predict malignant transformation ranged from 16 to 80% and from 5 to 80%, respectively. The pooled malignant transformation rate of lesions classified as severe dysplasia or carcinoma in situ by the WHO grading was 40% (95% confidence interval (CI), 0.02-0.87; I² = 92%; P = 0.00), while the corresponding value for lesions classified as high-risk by the binary grading system was 31% (95% CI, 0.00-0.84; I² = 97%; P = 0.00). Overall, there was no significant difference in prognostication accuracy between the WHO and the binary systems (odds ratio = 2.02; 95% CI, 0.88-4.64).

CONCLUSIONS

Although some studies suggest that the binary system is associated with lower inter-rater variability when grading OED, the evidence remains inconclusive on whether this system is superior to that of the WHO at predicting malignant transformation.

CLINICAL RELEVANCE

The reproducibility of the binary system has the potential to be better for prognostic purposes. However, there is no high-quality evidence to confirm if this advantage may assist clinicians in decision-making.

Markers associated with malignant transformation of oral lichen planus: A review article

Oral lichen planus (OLP) is one of the autoimmune diseases associated with chronic inflammation that involves several complications including the potential for malignant transformation into oral squamous cell carcinoma. Pathogenesis of OLP are yet to be fully comprehended however, it has been demonstrated that the epithelial cells in OLP lesions are affected by cytotoxic T lymphocytes leading to immunological reactions. Various factors are reported to act as diagnostic markers for predicting and monitoring the cancerous progression. Hence, in this review, we summarize and present the latest studies regarding the predictive markers associated with malignant potential of OLP.

Recent advances in point-of-care diagnostics for oral cancer

Early-stage diagnosis is a crucial step in reducing the mortality rate in oral cancer cases. Point-of-care (POC) devices for oral cancer diagnosis hold great future potential in improving the survival rates as well as the quality of life of oral cancer patients. The conventional oral examination followed by needle biopsy and histopathological analysis have limited diagnostic accuracy. Besides, it involves patient discomfort and is not feasible in resource-limited settings. POC detection of biomarkers and diagnostic adjuncts has emerged as non- or minimally invasive tools for the diagnosis of oral cancer at an early stage. Various biosensors have been developed for the rapid detection of oral cancer biomarkers at the point-of-care. Several optical imaging methods have also been employed as adjuncts to detect alterations in oral tissue indicative of malignancy. This review summarizes the different POC platforms developed for the detection of oral cancer biomarkers, along with various POC imaging and cytological adjuncts that aid in oral cancer diagnosis, especially in low resource settings. Various immunosensors and nucleic acid biosensors developed to detect oral cancer biomarkers are summarized with examples. The different imaging methods used to detect oral tissue malignancy are also discussed herein. Additionally, the currently available commercial devices used as adjuncts in the POC detection of oral cancer are emphasized along with their characteristics. Finally, we discuss the limitations and challenges that persist in translating the developed POC techniques in the clinical settings for oral cancer diagnosis, along with future perspectives.

Dioscin inhibits SCC15 cell proliferation via the RASSF1A/MST2/YAP axis

Dioscin, an extract from traditional Chinese herbal plants, displays various biological and pharmacological effects on tumors, including inhibition of cell proliferation and induction of DNA damage. However, the effects of dioscin on oral squamous cell carcinoma (OSCC) cells are not completely understood. The present study aimed to evaluate the impact of dioscin on OSCC cell proliferation. Cell Counting Kit-8 and 5-ethynyl-2′-deoxyuridine incorporation assays were performed to assess cell proliferation. Flow cytometry was conducted to detect alterations in the cell cycle and cell apoptosis. Western blotting and coimmunoprecipitation were performed to determine protein expression levels. In SCC15 cells, dioscin treatment significantly induced cell cycle arrest, increased apoptosis and inhibited proliferation compared with the control group. Mechanistically, the tumor suppressor protein Ras association domain-containing protein 1A (RASSF1A) was activated and oncoprotein yes-associated protein (YAP) was phosphorylated by dioscin. Furthermore, YAP overexpression and knockdown reduced and enhanced the inhibitory effects of dioscin on SCC15 cells, respectively. In summary, the results demonstrated that, compared with the control group, dioscin upregulated RASSF1A expression in OSCC cells, which resulted in YAP phosphorylation, thus weakening its transcriptional coactivation function, enhancing cell cycle arrest and apoptosis, and inhibiting cell proliferation. The present study indicated that dioscin may serve as a therapeutic agent for OSCC.

Optical diagnosis of oral cavity lesions by label-free Raman spectroscopy

Oral squamous cell carcinoma (OSCC) is one of the most prevalent cancers and frequently preceded by non-malignant lesions. Using Shifted-Excitation Raman Difference Spectroscopy (SERDS), principal component and linear discriminant analysis in native tissue specimens, 9500 raw Raman spectra of OSCC, 4300 of non-malignant lesions and 4200 of physiological mucosa were evaluated. Non-malignant lesions were distinguished from physiological mucosa with a classification accuracy of 95.3% (95.4% sensitivity, 95.2% specificity, area under the curve (AUC) 0.99). Discriminating OSCC from non-malignant lesions showed an accuracy of 88.4% (93.7% sensitivity, 76.7% specificity, AUC 0.93). OSCC was identified against physiological mucosa with an accuracy of 89.8% (93.7% sensitivity, 81.0% specificity, AUC 0.90). These findings underline the potential of SERDS for the diagnosis of oral cavity lesions.

Oral Cancer and Precancer: A Narrative Review on the Relevance of Early Diagnosis

Oral cancer (OC) is an uncommon malignancy in Western countries, being one of the most common cancers in some high-risk areas of the world. It is a largely preventable cancer, since most of the different risk factors identified, such as tobacco use, alcohol consumption, and betel nut chewing, are behaviors that increase the likelihood of the disease. Given its high mortality, early diagnosis is of utmost importance. Prevention and the anticipation of diagnosis begin with identification of potentially malignant lesions of the oral mucosa and with local conditions promoting chronic inflammation. Therefore, every lesion must be recognized promptly and treated adequately. The clinical recognition and evaluation of oral mucosal lesions can detect up to 99% of oral cancers/premalignancies. As stated by the World Health Organization, any suspicious lesion that does not subside within two weeks from detection and removal of local causes of irritation must be biopsied. Surgical biopsy remains the gold standard for diagnosis of oral cancer. Adjunctive tools have been developed and studied to help clinicians in the diagnostic pathway, such as toluidine blue vital staining and autofluorescence imaging. In the near future other methods, i.e., identification of salivary markers of progression may help in reducing mortality due to oral cancer.

The TRPV4-AKT axis promotes oral squamous cell carcinoma cell proliferation via CaMKII activation

Most human malignant tumor cells arise from epithelial tissues, which show distinctive characteristics, such as polarization, cell-to-cell contact between neighboring cells, and anchoring to a basement membrane. When tumor cells invaginate into the stroma, the cells are exposed to extracellular environments, including the extracellular matrix (ECM). Increased ECM stiffness has been reported to promote cellular biological activities, such as excessive cellular growth and enhanced migration capability. Therefore, tumorous ECM stiffness is not only an important clinical tumor feature but also plays a pivotal role in tumor cell behavior. Transient receptor potential vanilloid 4 (TRPV4), a Ca²⁺-permeable nonselective cation channel, has been reported to be mechano-sensitive and to regulate tumorigenesis, but the underlying molecular mechanism in tumorigenesis remains unclear. The function of TRPV4 in oral squamous cell carcinoma (OSCC) is also unknown. The current study was conducted to investigate whether or not TRPV4 might be involved in OSCC tumorigenesis. TRPV4 mRNA levels were elevated in OSCC cell lines compared with normal oral epithelial cells, and its expression was required for TRPV4 agonist-dependent Ca²⁺ entry. TRPV4-depleted tumor cells exhibited decreased proliferation capabilities in three-dimensional culture but not in a low-attachment plastic dish. A xenograft tumor model demonstrated that TRPV4 expression was involved in cancer cell proliferation in vivo. Furthermore, loss-of-function experiments using siRNA or an inhibitor revealed that the TRPV4 expression was required for CaMKII-mediated AKT activation. Immunohistochemical analyses of tissue specimens obtained from 36 OSCC patients showed that TRPV4 was weakly observed in non-tumor regions but was strongly expressed in tumor lesions at high frequencies where phosphorylated AKT expression was frequently detected. These results suggest that the TRPV4/CaMKII/AKT axis, which might be activated by extracellular environments, promotes OSCC tumor cell growth.

PAR-2 promotes cell proliferation, migration, and invasion through activating PI3K/AKT signaling pathway in oral squamous cell carcinoma

Objective: This research aimed to explore the function of protease activated receptor 2 (PAR-2) in oral squamous cell carcinoma (OSCC) development and progression, as well as underlying molecular mechanism.

Methods: Tissue samples were collected from 115 OSCC patients. Quantitative real-time PCR (qRT-PCR) was performed to measure the expression of PAR-2 mRNA in OSCC tissues and cells. MTT and Transwell assays were used to detect the proliferation, migration, and invasion of OSCC cells, respectively. Western blot was performed to determine protein expression.

Results: The expression of PAR-2 mRNA was up-regulated in OSCC tissue and cells (P<0.01), and its mRNA level was obviously correlated to tumor differentiation and TNM stage in OSCC (P<0.05 for both). The activation of PAR-2 with PAR-2AP (PAR-2 agonist) significantly promoted the proliferation, migration, and invasion of OSCC cells, while its knockout could inhibit malignant behaviors of OSCC cells (P<0.05). Excessive activation of PAR-2 enhanced phosphorylation level of PI3K, AKT, and mTOR revealing the activation of PI3K/AKT pathway. Moreover, LY294002, the inhibitor of PI3K/AKT pathway, could reverse oncogenic action caused by PAR-2 activation.

Conclusion:PAR-2 can promote OSCC growth and progression via activating PI3K/AKT signaling pathway.

Guidelines for the Surgical Management of Oral Cancer: Korean Society of Thyroid-Head and Neck Surgery

Korean Society of Thyroid-Head and Neck Surgery appointed a Task Force to provide guidance on the implementation of a surgical treatment of oral cancer. MEDLINE databases were searched for articles on subjects related to “surgical management of oral cancer” published in English. Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. The quality of evidence was rated with use RoBANS (Risk of Bias Assessment Tool for Nonrandomized Studies) and AMSTAR (A Measurement Tool to Assess the Methodological Quality of Systematic Reviews). Evidence-based recommendations for practice were ranked according to the American College of Physicians grading system. Additional directives are provided as expert opinions and Delphi questionnaire when insufficient evidence existed. The Committee developed 68 evidence-based recommendations in 34 categories intended to assist clinicians and patients and counselors, and health policy-makers. Proper surgical treatment selection for oral cancer, which is directed by patient- and subsite-specific factors, remains the greatest predictor of successful treatment outcomes. These guidelines are intended for use in conjunction with the individual patient’s treatment goals.

In vivo detection of oral precancer using a fluorescence-based, in-house-fabricated device: a Mahalanobis distance-based classification

In vivo detection of oral precancer has been carried out by a fluorescence-based, in-house-developed handheld probe on three groups: oral squamous cell carcinoma (OSCC), dysplastic (precancer), and control (normal). Measurements have been performed on a total of 141 patients and volunteers of different age groups. Excitation wavelength of 405 nm was used and fluorescence emission spectra were recorded in the scan range of 450.14 to 763.41 nm at very low incident power (122 μW) from different oral sites buccal mucosa (BM), lateral boarder of tongue (LBT), and dorsal surface of tongue (DST). Spectral profiles are found to vary among the three groups as well as among the different oral sites. Major and minor bands of flavin adenine dinucleotide (FAD) and porphyrins near 500, 634, 676, 689, and 703 nm have been obtained. Porphyrin contribution is found to be more dominant than the FAD in OSCC and dysplastic groups as compared to the control group. A better classification has been observed using the entire spectral range rather than restricting to individual bands, by application of principal component analysis (PCA), Mahalanobis distance model, and receiver operating characteristic analysis (ROC). ROC on Mahalanobis distance differentiates OSCC to normal, dysplastic to normal, and OSCC to dysplastic with sensitivities from 71% to 98%, 92% to 94% and 81% to 93% and specificities 91% to 100%, 86% to 100% and 79% to 97% for oral sites BM, LBT and DST. LBT and DST appear to be more sensitive to dysplasia detection as compared to BM.

Role of Chemiluminescence examination as non-invasive diagnostic tool in early detection of Leukoplakia

OBJECTIVES

To assess the efficacy of Chemiluminescent light (Vizilite plus) in enhancing visualization and its ability to highlight Leukoplakia lesion.

MATERIAL AND METHODS

This was a cross-sectional study done on 40 study subjects. Subjects were inducted into the study irrespective of age and sex based on the specific inclusion and exclusion criteria. The lesion parameters like the location of the lesion, the shape of lesion, the size, the extent, borders and the presence or absence of any adjacent satellite lesions were assessed under Incandescent light followed by Toluidine blue and Vizilite plus examinations. Histopathological examination results were considered as the gold standard and TBLU and CHEM outcomes were compared to them.

RESULTS

Vizilite plus examination method was most effective in assessing the size, borders and shape of the lesions followed by Toluidine blue and Incandescent light examinations. Toluidine blue and Vizilite plus examination methods demonstrated the sensitivity of 100% and specificity of 97.3%. They also demonstrated PPV of 100% and NPV of 75% with reliable accuracy of 97.5%.

CONCLUSION

Chemiluminescent light is a stepping stone and has the potential to revolutionize the diagnostic protocol for patients with potentially premalignant lesions. The device can be used as a general oral mucosal examination system and may in particular improve the visualization of potentially premalignant lesions.

Inter-and intra-observer agreement on the judgment of toluidine blue staining for screening of oral potentially malignant disorders and oral cancer

OBJECTIVE

Toluidine blue staining (TBS) is used for screening of oral potentially malignant disorders (OPMDs) and oral cancer. Nevertheless, the judgment of TBS is based on the observer's personal experience and largely considered subjective. The aim of this study was to evaluate the inter- and intra-observer agreement on the judgment of TBS for screening of OPMDs and oral cancer.

MATERIALS AND METHODS

Two hundred randomly ordered TBS images of OPMDs and oral cancer were judged twice independently by four clinicians and four graduated students majored in oral medicine, with an interval of 3 months. Inter- and intra-observer agreement was evaluated by the Cohen's kappa (κ) coefficient. The correlation between κ-value and individual experience was assessed by Spearman's correlation coefficient.

RESULTS

For the two sets of observation, good overall inter-observer agreement was found in the study (κ = 0.620 and 0.667). Sub-group analysis yielded good inter-observer agreement both for clinicians (κ = 0.613 and 0.611) and students (κ = 0.610 and 0.665). Pairwise inter-observer agreement was presented to be moderate to excellent between clinician and clinician (κ = 0.41~0.87, 0.43~0.81), moderate to excellent between student and student (κ = 0.43~0.71, 0.53~0.82), and poor to excellent between clinician and student (κ = 0.25~0.81, 0.35~0.87). Good to excellent intra-observer agreement (κ = 0.69~0.85) was presented for eight observers. However, no correlation was illustrated between years of experience and inter- or intra-observer agreement.

CONCLUSION

Judgment of TBS has a good overall inter-observer agreement and good to excellent intra-observer agreement, which guarantees its utilization and popularity in detecting OPMDs and oral cancer.

CLINICAL RELEVANCE

To our knowledge, this is the first study to investigate the inter- and intra-observer agreement of TBS judgment. The present results revealed a good inter-observer agreement and good to excellent intra-observer agreement, which provide a beneficial supplement to the knowledge of TBS technique.

MicroRNA-16 functions as a tumor-suppressor gene in oral squamous cell carcinoma by targeting AKT3 and BCL2L2

Aberrant expressions of microRNAs have been reported to be strongly associated with the progression and prognosis of various tumors, including oral squamous cell carcinoma (OSCC). Recent studies on miRNA expression profiling have suggested that microRNA-16 (miR-16) may be dysregulated in OSCC. However, the tumorigenic roles and mechanisms of miR-16 in OSCC are still largely unknown. In this study, we demonstrated that miR-16 was specifically downregulated in both OSCC patients and cancer cell lines. In addition, functional roles of miR-16 in vitro suggested that the miR-16 mimic inhibited cell proliferation and induced apoptosis, whereas miR-16 inhibitor displayed the opposite effects. Luciferase reporter assay and correlation analysis showed that AKT3 and BCL2L2 were directly targeted by miR-16 and were inversely expressed with miR-16 in OSCC. Moreover, restoration of AKT3 and BCL2L2 expression could partially reverse the cell proliferation inhibition and apoptosis induction caused by miR-16. In xenograft nude mice, miR-16 mimics decreased the expression of AKT3 and BCL2L2 and reduced the tumors volumes and weights, whereas the miR-16 inhibitor exhibited adverse effects in the derived xenografts. In conclusion, the findings suggested that miR-16 functions as a tumor suppressor miRNA to inhibit cell proliferation and induce apoptosis in OSCC through decreasing the oncogenes AKT3 and BCL2L2 and that miR-16 could be a potential therapeutic target for OSCC.

Genomic and epigenetic signatures associated with survival rate in oral squamous cell carcinoma patients

Purpose: Although oral squamous cell carcinoma (OSCC) presents great mortality and morbidity worldwide, the mechanisms behind its clinical behavior remain unclear. Biomarkers are needed to forecast patients' survival and, among those patients undergoing curative therapy, which are more likely to develop tumor recurrence/metastasis. Demonstrating clinical relevance of these biomarkers could be crucial both for surveillance and in helping to establish adjuvant therapy strategies. We aimed to identify genomic and epigenetic biomarkers of OSCC prognosis as well as to explore a noninvasive strategy to perform its detection. Methods: OSCC tumor and non-tumor tissue samples and cells scrapped from the tumor surface were genomic and epigenetically evaluated by Methylation-Specific Multiplex Ligation-dependent Probe Amplification technique. Results: Copy number alterations in ATM, CASR, TP73, CADM1, RARB, CDH13, PAX5, RB1 genes and GATA5, PAX6, CADM1 and CHFR promoter methylation were shown to be associated with worse OSCC patients' survival. Copy number alterations in BRCA1, CDKN2A, CHFR, GATA5, PYCARD, STK11, TP53, VHL genes and GATA5, CADM1, KLLN, MSH6, PAX5, WT1 promoter methylation were shown to be associated with development of metastasis/relapses during or after OSCC patients' treatment. We also found a good agreement in the status of CDKN2A promoter methylation evaluated noninvasively or in the tumor tissue. Conclusions: Genomic and epigenetic signatures were validated in a larger and geographically separate cohort, from TCGA database, which reinforce their clinical applicability. Noninvasive methodologies for detection of these signatures require further studies before translation in to clinical practice.

Oridonin inhibits oral cancer growth and PI3K/Akt signaling pathway

Oridonin, a bioactive diterpenoid purified from Rabdosia rubescens, has been shown to possess anticancer capacity in several cancer types. However, its effects on oral squamous cell carcinoma (OSCC) cells remain unclear. This study aimed to investigate the anticancer ability of oridonin in OSCC cells, including proliferation, apoptosis and underlying mechanisms using the OSCC cell lines, UM1 and SCC25. The results showed that oridonin not only inhibited proliferation and clonal formation but also induced G2/M cell cycle arrest and apoptosis in UM1 and SCC25 cells in a dose-dependent manner. Western blot revealed that oridonin treatment increased the ratio of Bax/Bcl-2, and activated the cleavage of caspase-3, caspase-9 and PARP-1. Oridonin also induced G2/M phase arrest in OSCC cells via down-regulating the G2/M transition-related proteins such as cyclin B1 or up-regulating cyclin D1, cyclin D3, P21, p-CDK1 and cyclin A2. In addition, oridonin treatment significantly inhibited the phosphorylation of PI3K and Akt and inhibited tumor growth of OSCC xenograft in nude mice. Taken together, these results suggested that oridonin possesses anti-oral cancer capacity via inhibiting the PI3K/Akt signaling and induce apoptosis and G2/M-phase arrest. Therefore, oridonin may be a potential anticancer drug for the treatment of oral cancer.

Novel endoscope with increased depth of field for imaging human nasal tissue by microscopic optical coherence tomography

Intravital microscopy (IVM) offers the opportunity to visualize static and dynamic changes of tissue on a cellular level. It is a valuable tool in research and may considerably improve clinical diagnosis. In contrast to confocal and non-linear microscopy, optical coherence tomography (OCT) with microscopic resolution (mOCT) provides intrinsically cross-sectional imaging. Changing focus position is not needed, which simplifies especially endoscopic imaging. For in-vivo imaging, here we are presenting endo-microscopic OCT (emOCT). A graded-index-lens (GRIN) based 2.75 mm outer diameter rigid endoscope is providing 1.5 - 2 µm nearly isotropic resolution over an extended field of depth. Spherical and chromatic aberrations are used to elongate the focus length. Simulation of the OCT image formation, suggests a better overall image quality in this range compared to a focused Gaussian beam. Total imaging depth at a reduced sensitivity and lateral resolution is more than 200 µm. Using a frame rate of 80 Hz cross-sectional images of concha nasalis were demonstrated in humans, which could resolve cilial motion, cellular structures of the epithelium, vessels and blood cells. Mucus transport velocity was successfully determined. The endoscope may be used for diagnosis and treatment control of different lung diseases like cystic fibrosis or primary ciliary dyskinesia, which manifest already at the nasal mucosa.

Human Saliva for Oral Precancer Detection: a Comparison of Fluorescence & Stokes Shift Spectroscopy

We report here a study on human saliva tested as a diagnostic medium for oral cancer detection on three groups: oral squamous cell carcinoma (OSCC), oral sub mucous fibrosis (OSMF; precancer), and healthy controls (normal). Measurements have been conducted using fluorescence spectroscopy with 350 nm excitation and Stokes shift (SS) spectroscopy (SSS) with 120 nm shift from a total of 99 saliva samples. For classification, principal component analysis (PCA) and linear discriminant analysis (LDA) have been applied on the data sets. Linear discriminant (LD) scores of fluorescence spectra are able to differentiate OSCC to normal, OSMF to normal and OSCC to OSMF with sensitivities 91%, 92%, 91% and specificities 97%, 100%, 94% respectively, while LD scores of SS spectra differentiate respective groups with sensitivities 100%, 94%, 94% and specificities 97%, 100%, 94%. Cross-validation on the datasets of PC scores during LDA illustrates that sensitivity and specificity of SSS data are less affected than those of fluorescence data. Saliva is thus seen as a potential non-invasive and simple diagnostic medium, with SS spectroscopy as a better diagnostic tool for oral precancer.

The diagnostic value of the native fluorescence visualization device for early detection of premalignant/malignant lesions of the oral cavity

PURPOSE

The present study aimed to determine the diagnostic value of a native fluorescence visualization device in the identification of oral malignant/dysplastic lesions.

METHODS

This study involved 45 patients who had oral lesions that were suspected to be malignant, potentially malignant, or benign. The patients visited the Oral Medicine Department of the Mashhad Dental School. The sensitivity, specificity, positive and negative predictive values, and likelihood ratio of this device were determined.

RESULTS

The histopathological assessment of samples showed 9 cases of oral squamous cell carcinoma and 12 lesions with dysplasia. Ten samples of dysplastic lesions and all malignant lesions appeared dark or red/orange when examined with the native fluorescence visualization device. In 90% of the dysplastic/malignant lesions, the label-free fluorescence results were positive. The sensitivity, specificity, and positive and negative predictive values of this device were 90%, 15%, 40%, and 71%, respectively.

CONCLUSIONS

The native fluorescence visualization device can be used in specialized centers as an adjunctive device to increase the sensitivity of a clinical examination, but is not capable of distinguishing benign lesions from malignant and dysplastic ones due to its low specificity.

MicroRNA-542-3p inhibits oral squamous cell carcinoma progression by inhibiting ILK/TGF-β1/Smad2/3 signaling

In this study, we investigated the effects of microRNA-542-3p (miR-542-3p) on ILK/TGF-β1/Smad2/3 signaling and oral squamous cell carcinoma (OSCC) progression. Levels of miR-542-3p were lower in OSCC tissues (n=108) than adjacent normal tissues, whereas levels of ILK, TGF-β1 and Smad2/3 were higher. Patients with undifferentiated tumors, advanced TNM stage and lymph node metastasis showed low miR-542-3p levels. This was accompanied by high ILK expression and poor survival. Dual luciferase reporter assays of SCC-9 cells showed that miR-542-3p inhibited ILK gene expression by binding to its 3’UTR at 233-240 bp. SCC-9 cells transfected with miR-542-3p mimics exhibited elevated miR-542-3p and decreased ILK, TGF-β1 and Smad2/3 expression. They also showed reduced self-renewal (fewer CD44⁺ cells and tumor-spheres), invasiveness, migration, proliferation and survival. Conversely, miR-542-3p inhibitors promoted increased self-renewal (more CD44⁺ cells and tumor-spheres), invasiveness, migration, proliferation and survival. In xenograft experiments with nude mice, SCC-9 cells transfected with miR-542-3p mimics or siRNA-ILK yielded tumors with smaller volumes and weights than control tumors. These results demonstrate that miR-542-3p is a tumor suppressor that inhibits ILK/TGF-β1/Smad2/3 signaling, thereby inhibiting OSCC progression.

Prosthetic rehabilitation following lateral resection of the mandible with a long cantilever implant-supported fixed prosthesis: A 3-year clinical report

This clinical report describes the prosthetic management of the surgical reconstruction of a patient after mandibular resection. Complete oral rehabilitation was achieved with a maxillary complete denture and a mandibular implant-supported fixed prosthesis with a custom titanium framework and a long unilateral cantilever.

Oral squamous cell carcinoma: Focusing on interprofessional collaboration

Incidence of oral cancer is rising, and often, cases are not discovered until the cancer has metastasized to the lymphatic system. Most oral cancers are squamous cell carcinomas associated with high mortality. This article reviews oral squamous cell carcinoma relevant to primary care practice focusing on an interprofessional approach to care.

microRNA from brush biopsy to characterize oral squamous cell carcinoma epithelium

Few cancers are diagnosed based on RNA expression signatures. Oral squamous cell carcinoma (OSCC) is no exception; it is currently diagnosed by scalpel biopsy followed by histopathology. This study sought to identify oral tumor epithelial microRNA (miRNA) expression changes to determine if these changes could be used to diagnose the disease noninvasively. Analysis of miRNA profiles from surgically obtained OSCC tissue, collected under highly standardized conditions for The Cancer Genome Atlas, was done to determine the potential accuracy in differentiating tumor from normal mucosal tissue. Even when using small 20 subject datasets, classification based on miRNA was 90 to 100% accurate. To develop a noninvasive classifier for OSSC, analysis of brush biopsy miRNA was done and showed 87% accuracy in differentiating tumor from normal epithelium when using RT‐qPCR or miRNAseq to measure miRNAs. An extensive overlap was seen in differentially expressed miRNAs in oral squamous cell carcinoma epithelium obtained using brush biopsy and those reported in saliva and serum of oral squamous cell carcinoma patients in several studies. This suggested that nonselective release of these miRNAs into body fluids from tumor epithelium was largely responsible for the changes in levels in these fluids seen with this disease. Using a variation in mirRPath we identified the KEGG pathway of neurotrophin signaling as a target of these miRNAs disregulated in tumor epithelium. This highlights the utility of brush biopsy of oral mucosa to allow simple acquisition of cancer relevant miRNA information from tumor epithelium.

Monitoring carcinogenesis in a case of oral squamous cell carcinoma using a panel of new metabolic blood biomarkers as liquid biopsies

INTRODUCTION

One of the common malignant tumors of the head and neck worldwide with generally unfavorable prognosis is squamous cell carcinoma (OSCC) of the oral cavity. Early detection of primary, secondary, or recurrent OSCC by liquid biopsy tools is much needed.

CASE PRESENTATION

Twelve blood biomarkers were used for monitoring a case of OSCC suffering from precancerous oral lichen ruber planus mucosae (OLP). After curative R0 tumor resection of primary OSCC (buccal mucosa), elevated epitope detection in monocytes (EDIM)-Apo10, EDIM-transketolase-like-1 (TKTL1), squamous cell carcinoma antigen (SCC-Ag), total serum lactate dehydrogenase (LDH), and its anaerobic isoforms (LDH-4, LDH-5) decreased to normal levels. Three and six months after surgery, transformation of suspicious mucosal lesions has been accompanied with an increase of EDIM scores, total serum LDH values, and a metabolic shift from aerobic (decrease of LDH-1, LDH-2) to anaerobic (increase of LDH-4, LDH-5) conditions. Two months later, secondary OSCC was histopathologically analyzed after tissue biopsy. Cytokeratin fraction 21-1 (CYFRA 21-1), carcinoembryonic antigen (CEA), and carbohydrate antigen 19-9 (CA19-9) were not affected during the clinical course of carcinogenesis.

CONCLUSIONS

A combination strategy using a standardized panel of established (metabolic) blood biomarkers (TKTL1, LDH, LDH isoenzymes) is worth and can be recommended among others (apoptosis resistance-related Apo10, SCC-Ag) for early detection and diagnosis of primary, secondary, and recurrent OSCC. A tandem strategy utilizing (metabolic pronounced) routine liquid biopsies with imaging techniques may enhance diagnosis of OSCC in the future. Although we demonstrated the diagnostic utility of separated liquid biopsies in our previous study cohorts, further investigations in a larger patient cohort are necessary to recommend this combination strategy (EDIM blood test, LDH value, metabolic shift of LDH isoenzymes, and others, e.g., SCC-Ag or immunophenotyping) as a diagnostic tool for the addition to the OSCC staging system and as a routine procedure in the aftercare.

Diagnostic Imaging of Malignant Tumors in the Orofacial Region

Though rare, malignancies of the orofacial region often have serious consequences. Malignancies of the orofacial region are typically discovered during a clinical examination or from a patient complaint. Initial discovery from a radiograph is rare. Three-dimensional imaging using advanced imaging techniques often provides adequate information about the aggressive nature of a lesion. Radiographically based imaging demonstrates mainly hard-tissue destruction and, rarely, bone deposition. MRI provides excellent visualization of soft-tissue densities without using ionizing radiation. Functional imaging is used to visualize increased metabolic activity associated with malignancies, and is excellent for determining the metastatic spread of a lesion.