Automated immunohistochemical quantification of hypoxia biomarkers shows correlation with dysplastic epithelial changes.

BACKGROUND: Dysregulation of the hypoxia-aerobic system has been postulated in various malignancies. Nonetheless, the contribution of hypoxia to oral carcinogenesis is yet to be elucidated. Understanding this mechanism is important for improving diagnostic tools and targeted therapies. This study aimed to assess the dysregulation of hypoxia-related factors during different stages of oral squamous cell carcinoma (OSCC) development. METHODS: Ninety-two patients diagnosed clinically with oral leukoplakia or OSCC were included and classified according to their histopathological diagnoses. A panel of seven hypoxia-related antibodies were used for immunohistochemical staining of each case. Automated quantification of immunostaining was used for objective reporting. Microvessel density was also assessed. RESULTS: Significant associations were reported for non-dysplastic epithelial changes and malignancy for Glut1, HIF-1α, vascular endothelial growth factor, and signal transducer and activator of transcription 3(p < 0.005). Similarly, microvessel density significantly increased with the severity of epithelial disorders. A multiple regression model including the H-score of HIF-1α and microvessel density could statistically significantly predict the grade of epithelial disorder (p < 0.005). The associated diagnostic accuracy of this approach was 88%. CONCLUSIONS: Hypoxia-associated events are observed during early epithelial dysplastic changes and have a potential role in oral carcinogenesis. The level of hypoxia may assist in stratifying the severity of epithelial changes among patients with oral leukoplakia.

Dynamic real-time optical microscopy of oral mucosal lesions using confocal laser endomicroscopy.

OBJECTIVES: Confocal laser endomicroscopy (CLE) is a novel non-invasive point-of-care optical biopsy technology that enables real-time in vivo microscopic visualisation of cellular and tissue architecture. In this study, we assessed the diagnostic accuracy of a hand-held fluorescence single-fibre distal-scanning CLE (fsdCLE) platform for diagnosing oral epithelial dysplasia (OED) and oral squamous cell carcinoma (OSCC). MATERIALS AND METHODS: Forty-seven patients presenting with 63 distinct oral mucosal lesions were subjected to optical biopsy using a miniaturised fsdCLE system (ViewnVivo®, Optiscan Imaging Ltd) and topical exogenous acriflavine hydrochloride contrast agent before undergoing tissue biopsy and histopathological consensus review by four pathologists. CLE images were captured in vivo in real-time during clinical examination and assessed on-the-fly for the presence of cellular and architectural features of OED/OSCC offering an instantaneous diagnosis. Predicted optical diagnoses were compared to definitive consensus tissue histopathology. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy were calculated for the presence/absence of dysplasia/malignancy on optical biopsy. Percentage agreement, Fleiss' kappa, and intraclass correlation coefficient (ICC) were calculated for each assessment stage during the consensus histopathology process. RESULTS: Diagnostic accuracy was extremely high at 88.9%. Other metrics were sensitivity 86.8%, specificity 92%, PPV 94.3% and NPV 82.1%. One hundred percent of carcinoma cases were detected accurately using CLE in the clinic. CONCLUSION: fsdCLE is a highly accurate, easy-to-use, rapid and slide-free point-of-care in vivo optical technology for diagnosing OED/OSCC and discriminating between dysplastic and non-dysplastic pathology. It demonstrates near-perfect agreement with traditional consensus histopathology without the need for physical tissue biopsy.

Narrow-band imaging features of oral lichenoid conditions: A multicentre retrospective study.

OBJECTIVE: Narrow-band imaging (NBI), which highlights epithelial intrapapillary capillary loops (IPCLs) classified into five patterns (0 toIV) with increasing correlation to malignancy, has demonstrated effectiveness for detection of oral squamous cell carcinoma (OSCC). Lack of standardised procedures limits its use for routine inspection of oral lichenoid lesions including oral lichen planus (OLP), oral lichenoid lesion (OLL) and oral lichenoid reaction (OLR). The aim of this study was to analyse IPCL patterns of such lesions, assessing correlations with histopathological outcomes. MATERIALS AND METHODS: A multicentre, retrospective study was performed on 84 patients who underwent NBI and subsequent biopsy for suspected OLP/OLL/OLR. Patients were examined with Evis Exera III NBI system. Recorded NBI video endoscopies were evaluated to assess IPCL patterns and correlated with histopathological outcomes. RESULTS: No significant differences were detected among OLP/OLL/OLR on NBI inspection. All lichenoid lesions were significantly related to low-grade (0-II) IPCL patterns, clearly distinguishable from OSCC, showing pattern IV (p < 0.05). CONCLUSIONS: NBI cannot discern among OLP/OLL/OLR lesions. Interpretation should be modulated when assessing lichenoid lesions. NBI has potential to discern malignant transformation occurring in lichenoid lesions undergoing long-term follow-up, as IPCL pattern IV may be used as a clinical marker of malignancy arising in chronic inflammatory lesions.

Oral leukoplakia diagnosis and treatment in Europe and Australia: Oral Medicine Practitioners' attitudes and practice.

The management of oral potentially malignant disorders (OPMD) including oral leukoplakia (OL) is not currently structured according to agreed guidelines. The current report presents survey data gathered from Oral Medicine Practitioners (OMPs) in Europe and Australia and is aimed to investigate attitudes and practice in the diagnosis, risk stratification and treatment of OL. In the presence of a clinical provisional diagnosis of OL, respondents reported always undertaking biopsy in 83% of cases, with most OMPs also relying on diagnostic adjuncts. The potential for malignant transformation is almost invariably assessed through epithelial dysplasia status, with other biomarkers described in the literature used less often. Active treatment of OL was considered mandatory by 20% of OMPs, while others reserve treatment for selected cases only. OMPs are mostly driven to active treatment by lesion-related features which are frequently jointly considered including lesion site, clinical appearance and dysplasia status. Inconsistent assessment was observed regarding mild dysplasia, lesion size, presence of unavoidable trauma, exposure to tobacco and patient age. Frequently observed geographical variations were seldom statistically significant. In agreement with previous surveys, a lack of consensus around the management of OL was observed, supporting claims from learned academies and societies for treatment guidelines aiming to reduce inter-practitioner variability.

A Novel Preclinical In Vitro 3D Model of Oral Carcinogenesis for Biomarker Discovery and Drug Testing.

This study aimed to develop an in vitro three-dimensional (3D) cell culture model of oral carcinogenesis for the rapid, scalable testing of chemotherapeutic agents. Spheroids of normal (HOK) and dysplastic (DOK) human oral keratinocytes were cultured and treated with 4-nitroquinoline-1-oxide (4NQO). A 3D invasion assay using Matrigel was performed to validate the model. RNA was extracted and subjected to transcriptomic analysis to validate the model and assess carcinogen-induced changes. The VEGF inhibitors pazopanib and lenvatinib were tested in the model and were validated by a 3D invasion assay, which demonstrated that changes induced by the carcinogen in spheroids were consistent with a malignant phenotype. Further validation was obtained by bioinformatic analyses, which showed the enrichment of pathways associated with hallmarks of cancer and VEGF signalling. Overexpression of common genes associated with tobacco-induced oral squamous cell carcinoma (OSCC), such as MMP1, MMP3, MMP9, YAP1, CYP1A1, and CYP1B1, was also observed. Pazopanib and lenvatinib inhibited the invasion of transformed spheroids. In summary, we successfully established a 3D spheroid model of oral carcinogenesis for biomarker discovery and drug testing. This model is a validated preclinical model for OSCC development and would be suitable for testing a range of chemotherapeutic agents.

Immunoexpression of oral brush biopsy enhances the accuracy of diagnosis for oral lichen planus and lichenoid lesions.

BACKGROUND: This study assessed the efficacy of using oral liquid-based brush cytology (OLBC) coupled with immunostained cytology-derived cell-blocks, quantified using machine-learning, in the diagnosis of oral lichen planus (OLP). METHODS: Eighty-two patients diagnosed clinically with either OLP or oral lichenoid lesion (OLL) were included. OLBC samples were obtained from all patients before undergoing surgical biopsy. Liquid-based cytology slides and cell-blocks were prepared and assessed by cytomorphology and immunocytochemistry for four antibodies (Ki-67, BAX, NF-κB-p65, and AMACR). For comparison purposes, a sub-group of 31 matched surgical biopsy samples were selected randomly and assessed by immunohistochemistry. Patients were categorized according to their definitive diagnoses into OLP, OLL, and clinically lichenoid, but histopathologically dysplastic lesions (OEDL). Machine-learning was utilized to provide automated quantification of positively stained protein expression. RESULTS: Cytomorphological assessment was associated with an accuracy of 77.27% in the distinction between OLP/OLL and OEDL. A strong concordance of 92.5% (κ = 0.84) of immunostaining patterns was evident between cell-blocks and tissue sections using machine-learning. A diagnostic index using a Ki-67-based model was 100% accurate in detecting lichenoid cases with epithelial dysplasia. A BAX-based model demonstrated an accuracy of 92.16%. The accuracy of cytomorphological assessment was greatly improved when it was combined with BAX immunoreactivity (95%). CONCLUSIONS: Cell-blocks prepared from OLBC are reliable and minimally-invasive alternatives to surgical biopsies to diagnose OLLs with epithelial dysplasia when combined with Ki-67 immunostaining. Machine-learning has a promising role in the automated quantification of immunostained protein expression.

Transcriptional regulation of glucose transporters in human oral squamous cell carcinoma cells.

The increased glucose uptake observed in cancer cells is mediated by glucose transporters (GLUTs), a class of transmembrane proteins that facilitate the transport of glucose and other substrates across the plasma membrane. Despite the important role of glucose in the pathophysiology of oral squamous cell carcinoma (OSCC), there is very limited data regarding the expression of GLUTs in normal or malignant cells from the oral mucosa. We analysed the messenger RNA (mRNA) expression of all 14 GLUTs in two OSCC (H357/H400) and one non-malignant oral keratinocyte (OKF6) cell line using a quantitative polymerase chain reaction. GLUT expression was evaluated at baseline and after treatment with two specific GLUT inhibitors, namely, BAY876 (GLUT1) and WZB117 (GLUT1, GLUT3 and GLUT4). Here, we show that GLUT1, GLUT3, GLUT4, GLUT5, GLUT6, GLUT8, GLUT12 and GLUT13 transcripts were measurably expressed in all cell lines while GLUT2, GLUT7, GLUT9, GLUT11 and GLUT14 were not expressed. GLUT10 was only found in H357. In the presence of BAY876 and WZB117, OSCC cells exhibited significant alterations in the transcriptional profile of GLUTs. In particular, we observed distinct proliferation-dependent changes of mRNAs to GLUT1, GLUT3, GLUT4, GLUT5 and GLUT6 in response to selective GLUT inhibitors. In summary, we documented for the first time the expression of GLUT5, GLUT6 and GLUT12 in normal and malignant oral keratinocytes. Whilst regulation of GLUT transcripts was cell line and inhibitor specific, GLUT3 was consistently upregulated in actively proliferating OSCC cell lines, but not in OKF6, regardless of the inhibitor used, suggesting that modulation of this transporter may act as one of the primary compensation mechanisms for OSCC cells upon inhibition of glucose uptake.

Oral medicine practice in Europe and Australia: Identifying practitioner characteristics and their clinical activity.

Oral Medicine is a young dental specialty born almost a century ago and deals with orofacial conditions not directly attributable to the most prevalent tooth pathologies such as dental caries or periodontal diseases. Presentations may reflect local disease or orofacial manifestations of more widespread pathology affecting other parts of the body. Due to its recency as a distinct discipline and to heterogeneous global settings, Oral Medicine has not yet achieved a shared scope and definition, as well as a recognized status across the globe. The current report presents survey data gathered from Oral Medicine practitioners in Europe and Australia and aimed to identify practitioner characteristics including demographics, training, clinical and research activity. As expected, Oral Medicine clinical practice commonly deals with conditions such as immune-mediated disorders, potentially malignant disorders, oral mucosal infections and chronic pain disorders, but geographical heterogeneities are observed. The present data, representative of current clinical practice, are valuable in order to understand the evolution of Oral Medicine as a distinct discipline and should be taken into consideration in order to create or update postgraduate training curricula able to meet the needs of future practitioners and the communities they serve.

A Wnt-mediated phenotype switch along the epithelial-mesenchymal axis defines resistance and invasion downstream of ionising radiation in oral squamous cell carcinoma.

BACKGROUND: Dynamic transitions of tumour cells along the epithelial-mesenchymal axis are important in tumorigenesis, metastasis and therapy resistance. METHODS: In this study, we have used cell lines, 3D spheroids and tumour samples in a variety of cell biological and transcriptome analyses to highlight the cellular and molecular dynamics of OSCC response to ionising radiation. RESULTS: Our study demonstrates a prominent hybrid epithelial-mesenchymal state in oral squamous cell carcinoma cells and tumour samples. We have further identified a key role for levels of E-cadherin in stratifying the hybrid cells to compartments with varying levels of radiation response and radiation-induced epithelial-mesenchymal transition. The response to radiation further entailed the generation of a new cell population with low expression levels of E-cadherin, and positive for Vimentin (ECADLow/Neg-VIMPos), a phenotypic signature that showed an enhanced capacity for radiation resistance and invasion. At the molecular level, transcriptome analysis of spheroids in response to radiation showed an initial burst of misregulation within the first 30 min that further declined, although still highlighting key alterations in gene signatures. Among others, pathway analysis showed an over-representation for the Wnt signalling pathway that was further confirmed to be functionally involved in the generation of ECADLow/Neg-VIMPos population, acting upstream of radiation resistance and tumour cell invasion. CONCLUSION: This study highlights the functional significance and complexity of tumour cell remodelling in response to ionising radiation with links to resistance and invasive capacity. An area of less focus in conventional radiotherapy, with the potential to improve treatment outcomes and relapse-free survival.

Electronic nicotine delivery systems: Oral health implications and oral cancer risk.

There is a paucity of evidence surrounding the potential detrimental effects of electronic nicotine delivery systems (ENDS) for both systemic and oral health. The effects of conventional cigarettes on the development of oral cancer are well known; however, the role of ENDS in oral carcinogenesis is yet to be elucidated. Furthermore, the exponential rise of the use of ENDS by the general public means that dental healthcare providers are more likely to encounter questions on their safety in the oral cavity, and on their effectiveness as a smoking cessation aid. Herein, we review the most up to date literature on the systemic and oral health complications of ENDS. Moreover, evidence-based recommendations on the use of ENDS as a smoking cessation tool within the dental setting are discussed.

Oral lichen planus has a very low malignant transformation rate: A systematic review and meta-analysis using strict diagnostic and inclusion criteria.

BACKGROUND: The malignant transformation (MT) potential of oral lichen planus (OLP) has sparked heated debates for almost a century, despite the fact that global figures of OLP prevalence and oral cancer incidence do not support an association mathematically. In this study, we performed a systematic review and meta-analysis, using strict inclusion criteria, to more precisely assess the malignant potential rate of OLP and the influence of associated risk factors. METHODS: All reports that documented MT of OLP and published in the English language until January 2020 were included if they met the following strict criteria: (a) the presence of a properly verified OLP diagnosis, (b) a clear description of the cancerous lesion developing at the same site as the verified OLP lesion; and (c) a follow-up period of a minimum of 6 months prior to carcinoma development. RESULTS: Thirty-three studies were included in this analysis with a total of 12 838 OLP patients. Of these, 151 cases were initially considered to have progressed to carcinoma (1.2%). However, after applying strict criteria, only 56 cases were considered to have undergone MT from OLP (0.44%). The risk of MT was significantly higher among OLP patients who smoked (OR = 4.62), consumed alcohol (OR = 3.22), were seropositive for HCV (OR = 3.77) and/or displayed a red OLP subtype (OR = 0.37). CONCLUSIONS: Our results suggest that the reported OLP malignant transformation rates are exaggerated, and these do not reflect the actual clinical course of the disease according to strict clinical and histopathological criteria.

A machine-learning algorithm for the reliable identification of oral lichen planus.

BACKGROUND: Oral lichen planus (OLP) is a relatively common oral disorder which shares clinical and histopathological features with other lichenoid lesions, leading to considerable inter-observer disagreement. This negatively impacts understanding of the pathogenesis and malignant transformation potential of this condition. METHODS: Artificial intelligence was employed to create a machine-learning artificial neural network to identify and quantify mononuclear cells and granulocytes within the inflammatory infiltrates in digitized hematoxylin and eosin microscopic slides. Twenty-four regions of interest were extracted from OLP cases for learning purposes and validated on a retrospective cohort of 130 cases. All cases were related to patients with confirmed diagnoses of OLP, oral lichenoid lesions (OLLs), or oral epithelial dysplasia (OED) with lichenoid host response. RESULTS: The number of inflammatory cells was statistically significantly higher in OLP compared to OLLs or OED with lichenoid host response (p < 0.0005). The proposed machine-learning method was reliably capable of detecting OLP cases based on the number of inflammatory cells and the number of mononuclear cells with an area under the curve of 0.982 and 0.988, respectively. Identifying a cut-off point between OLP and other lichenoid conditions based on the number of mononuclear cells showed a sensitivity of 100% and an accuracy of 94.62%. CONCLUSION: Artificial intelligence has shown promising outcomes and provides a robust approach to enhance the accuracy of anatomical pathologists in accurately diagnosing OLP using features of disease pathogenesis.

Efficacy of oral brush cytology cell block immunocytochemistry in the diagnosis of oral leukoplakia and oral squamous cell carcinoma.

OBJECTIVES: This study assessed the efficacy of using oral liquid-based brush cytology and cell block immunocytochemistry in the diagnosis of oral leukoplakia as minimally invasive diagnostic adjuncts. METHODS: Seventy-two patients diagnosed clinically with either oral leukoplakia (OLK) or oral squamous cell carcinoma were included. Oral brush samples using Orcellex® brushes were obtained from all participants directly before undergoing surgical biopsy. Cell blocks were prepared for all samples and assessed for cytomorphology and immunocytochemistry of DNA mismatch repair proteins (MSH-6, MSH-2, MLH-1 and PMS-2). A combined index score of immunocytochemistry expression and cytology grading was compared against the gold standard (histopathological diagnosis). RESULTS: A significant association was observed between the cytological assessments of oral liquid-based brush cytology samples and the histopathological diagnosis (P < .005). In addition, there was a significant inverse correlation between the grade of oral epithelial dysplasia and the cumulative score of the studied DNA mismatch repair proteins (P < .005). Grading criteria for both oral liquid-based brush cytology and immunocytochemistry cumulative index scores are proposed based on the analysis of receiver operating characteristic curve coordinates. The diagnostic accuracy of this approach was outstanding in terms of discrimination between the presence or absence of oral epithelial dysplasia (0.961) and squamous cell carcinoma (0.977) separately. CONCLUSION: Oral liquid-based brush cytology cell block immunocytochemistry provides a reliable strategy to investigate oral mucosal epithelial disorders. This approach presents a minimally invasive, highly accurate and non-technically demanding method for the surveillance of oral potentially malignant disorders and squamous cell carcinoma.

Observer agreement in the diagnosis of oral lichen planus using the proposed criteria of the American Academy of Oral and Maxillofacial Pathology.

BACKGROUND: Oral lichen planus (OLP) is a common chronic inflammatory condition with an undefined malignant transformation potential. There have been many attempts at providing a specific definition of OLP without conclusive outcomes. A new set of diagnostic criteria was proposed in 2016 by the American Academy of Oral and Maxillofacial Pathology (AAOMP) in an endeavour to resolve this issue, and this has not yet been evaluated. This study aimed to assess the utility of AAOMP proposed criteria for the diagnosis of OLP. METHODS: Five pathologists blindly assessed a cohort of 215 digital whole slide images (WSI) obtained from haematoxylin and eosin-stained microscopic slides. Forty-six WSI were included twice to assess the intra-observer agreement. Included cases were diagnosed clinically as either OLP or oral lichenoid reaction. Each pathologist was asked to utilize the AAOMP histopathological criteria while assessing slides. The variations in diagnoses were assessed by unweighted kappa statistics. RESULTS: The level of intra-observer agreement was very good (0.801 to 0.899). The level of inter-observer agreement among the observers varied from good (0.658) to very good (0.842) when the responses were categorized as evident/compatible OLP versus no OLP and was good (0.62 to 0.725) when the responses were categorized as evident OLP, versus compatible OLP, versus no OLP. The clinico-pathological correlation was 87.6%. CONCLUSION: A reliable level of agreement can be achieved by pathologists for the diagnosis of OLP using the AAOMP criteria for differentiation between lichenoid and other conditions. There are still limitations in discriminating OLP from oral lichenoid lesions microscopically.

The effect of anticoagulants on oral squamous cell carcinoma: A systematic review.

Tumour progression allows for aberrant angiogenesis. Consequently, cancer-associated thrombosis is a prevalent complication that is coupled with poor prognosis. Anticoagulants have therefore been prescribed with chemotherapeutic agents to target potential thrombo-embolic risk. A systematic review was carried out to summarise existing evidence on the interactions between anticoagulants and oral cancer. This treatment paradigm has demonstrated beneficial results in some oncology patients, thus associating anticoagulants with anticancer effects. Increasing prevalence of oral cancer presents a need to source alternative therapeutic means to prevent disease progression, and thus the use of anticoagulants in these patients may provide an avenue for this to occur. The paucity of evidence regarding the interactions between oral squamous cell carcinoma and anticoagulants emphasises the urgency with which further research should be conducted.

Molecular, genomic and mutational landscape of oral leukoplakia.

Oral leukoplakia (OLK) and its more aggressive clinical variant proliferative verrucous leukoplakia (PVL) remain enigmatic disorders clinically and histopathologically. Despite decades of research into both, there has been only incremental advancement in our understanding of their aetiology and pathogenesis and only minimal improvement in effective management strategies. Currently, no specific prognostic genetic or molecular marker has been reported for leukoplakia. There is, however, an emerging body of evidence characterising the genomic and transcriptomic profile of OLK. Regardless of the significance of cellular and architectural features of OLK and PVL, it is clear from studies reported in this review that new emerging evidence points to the presence of premalignant molecular subtypes of leukoplakia which require further investigation. This up-to-date review explores the contemporary genomic, transcriptomic and mutational landscape of leukoplakia broadly, discusses concepts that may not be widely recognised or accepted and purposefully highlights studies with juxtaposed findings in an effort to challenge dogma. It also highlights the urgent need for a concerted international effort of original collaborative research which will only occur by pooling collective efforts, resources and intellect to define the molecular fingerprint of this enigmatic disorder, in the hope it will better inform diagnosis, stratification and treatment.

World Workshop on Oral Medicine VII: Prognostic biomarkers in oral leukoplakia and proliferative verrucous leukoplakia-A systematic review of retrospective studies.

OBJECTIVE: To systematically review retrospective studies examining prognostic potentials of candidate biomarkers to stratify malignant progression of oral leukoplakia (OL) and proliferative verrucous leukoplakia (PVL). MATERIALS AND METHODS: A systematic literature search of PubMed, EMBASE, Evidence-Based Medicine and Web of Science databases targeted literature published through 29 March 2018. Inter-rater agreement was ascertained during title, abstract and full-text reviews. Eligibility evaluation and data abstraction from eligible studies were guided by predefined PICO questions and bias assessment by the Quality in Prognosis Studies tool. Reporting followed Preferred Reporting Items for Systematic Review and Meta-Analysis criteria. Biomarkers were stratified based on cancer hallmarks. RESULTS: Eligible studies (n = 54/3,415) evaluated 109 unique biomarkers in tissue specimens from 2,762 cases (2,713 OL, 49 PVL). No biomarker achieved benchmarks for clinical application to detect malignant transformation. Inter-rater reliability was high, but 65% of included studies had high "Study Confounding" bias risk. CONCLUSION: There was no evidence to support translation of candidate biomarkers predictive of malignant transformation of OL and PVL. Systematically designed, large, optimally controlled, collaborative, prospective and longitudinal studies with a priori-specified methods to identify, recruit, prospectively follow and test for malignant transformation are needed to enhance feasibility of prognostic biomarkers predicting malignant OL or PVL transformation.

Molecular diagnostics in oral cancer and oral potentially malignant disorders-A clinician's guide.

Current risk stratification of individuals for the development of oral squamous cell carcinoma (OSCC), including those with oral potentially malignant disorders (OPMD), remains based on clinical detection of visibly abnormal mucosa and tissue biopsy with histological assessment for the presence of OSCC or oral epithelial dysplasia (OED). In OPMD, the presence of OED remains the only prognostic tool used in standard care for the development of future OSCC, despite its ample limitations. There is assured potential that the analysis of the genome, transcripts and proteome can provide insight into what is occurring at a cellular level preceding the appearance of clinically observable change. The landscape of the role of the genome and its transcriptome on the development of OSCC and relationships with OPMDs are immense with exploration occurring on several fronts. For clinicians involved in the diagnosis and care of patients with OSCC and OPMD, understanding of commonly used molecular diagnostic techniques is imperative to gain useful insight from the expanding literature investigating the development of OSCC and the relationship with the clinical presentations which encompass OPMDs. Here we present an introduction to molecular diagnostic methods used in the study of OSCC and OPMD.

Optical fluorescence imaging in oral cancer and potentially malignant disorders: A systematic review.

OBJECTIVES: This study aimed to systematically review the efficacy of direct optical fluorescence imaging as an adjunct to comprehensive oral examination in the clinical evaluation, risk assessment and surgical management of oral cancer and potentially malignant disorders. METHODS: Studies adopting autofluorescence devices, evaluating the efficacy of comprehensive oral examination and optical fluorescence imaging in detection, visualisation or management of oral squamous cell carcinoma or oral potentially malignant disorders, as well as discriminating oral epithelial dysplasia from other mucosal lesions, were included in the literature search across bibliographic databases until October 2018. RESULTS: Twenty-seven studies were found to be eligible for inclusion in qualitative analysis. Of these, only six studies demonstrated a low risk of bias across all domains of the methodological assessment tool (QUADAS-2). Optical fluorescence imaging demonstrated positive results, with higher sensitivity scores, increased lesion detection and visualisation than comprehensive oral examination alone in the clinical evaluation of oral squamous cell carcinoma and oral potentially malignant disorders. CONCLUSIONS: This review provides promising evidence for the utilisation of optical fluorescence imaging as an adjunct to comprehensive oral examination in varying clinical settings. It is important that devices utilising optical fluorescence imaging are viewed strictly as clinical adjuncts and not specifically as diagnostic devices.

Clinico-pathological correlation of optical fluorescence imaging in oral mucosal lesions.

OBJECTIVES: This study aimed to identify clinical and pathological characteristics of oral mucosal lesions that may be predictive of optical autofluorescence imaging patterns. METHODS: Clinical data and archival histopathological material were collected from patients who presented with at least one oral mucosal lesion and underwent assessment via conventional oral examination, optical autofluorescence imaging and histopathological analysis. An open-source digital pathology image analysis software was used to perform histomorphometric measurements. Classification and regression trees were used to determine histopathological characteristics most predictive of a clinical autofluorescence outcome. RESULTS: Histomorphometric features associated with tissue architecture, epithelial changes, inflammation and vasculature were found to be significantly associated with autofluorescence patterns. Diascopic fluorescence was found to be significantly predicted by lichenoid inflammation and was significantly associated with a diagnosis of oral lichen planus. Loss of autofluorescence with partial blanching was significantly associated with histopathological features noted in dysplastic and malignant lesions. CONCLUSIONS: This study provides evidence for the use of diascopic fluorescence as a technique to aid in clinical differentiation of benign inflammatory lesions from potentially malignant pathology. Based on the findings of this study, optical fluorescence imaging is a technique of added value in discernment of oral mucosal lesions, and our results support its clinical use.