Genetics/epigenetics of oral premalignancy: current status and future research

MALAT1 as a potential salivary biomarker in oral squamous cell carcinoma through targeting miRNA-124

OBJECTIVES

To determine the diagnostic accuracy of the long non-coding RNA "MALAT1" measured in the saliva of patients with oral squamous cell carcinoma (OSCC) and assess the salivary expression of microRNA-124, which MALAT1 targets.

SUBJECTS AND METHODS

Forty subjects were collected in a consecutive pattern and allocated into two groups. Group A included 20 patients with OSCC, while Group B included 20 healthy subjects. Salivary expression of MALAT1 and microRNA (miRNA)-124 was evaluated in the two study groups using quantitative real-time polymerase chain reaction and correlated with histopathological examination of OSCC subjects.

RESULTS

OSCC yielded a statistically significant higher expression of MALAT1 than healthy controls and a lower expression of miRNA-124 in OSCC than controls. There is a statistically significant inverse relationship between salivary MALAT1 and miRNA-124. Moreover, there is a statistically significant difference in the MALAT1 expression in saliva samples from metastatic cases compared with non-metastatic cases, as well as in patients with lymph node involvement compared with those without involvement. At a cut-off value of 2.24, salivary MALAT1 exhibited 95% sensitivity and 90% specificity in differentiating OSCC from healthy subjects.

CONCLUSION

Salivary MALAT1 acts as a sponge for miRNA-124 and could be a potential salivary biomarker for OSCC.

Modulatory effects of Moringa oleifera leaf extract on sodium nitrate-induced experimental colitis via regulation of P53, Ki-67 and PCNA biomarkers

BACKGROUND

Ulcerative colitis is a risk factor for colorectal carcinoma. Different mechanisms are related to colitis like apoptosis and hyperproliferation. Moringa oleifera leaves extract (MO) provides a promising option to overcome the risk.

PURPOSE

To examine the colonic changes in a rat model of colitis induced by sodium nitrate (SN) and study the effects of MO.

STUDY DESIGN

Eight adult male rats were allocated in each of the three group; control (distilled water), SN (100 mg/kg/day, orally via gastric gavage), and SN + MO (100 mg/kg/day, orally via gastric gavage).

METHODS

Body weight was measured after the end of the experiment. Colonic homogenates were tested for levels of oxidative stress indicators. Immunohistochemistry for P53, PCNA and Ki-67 was performed. Fresh colon specimens were used for quantitative real-time PCR for assessment of P53, PCNA and Ki-67 gene expression.

RESULTS

SN group revealed a significant decreased weight (p = 0.002). MDA and NO levels were higher with SN administration than with MO co-administration (p= 0.04, 0.01 respectively). GSH level was reduced in SN group (p = 0.02) and significantly increased with MO intake (p = 0.04). SN-induced colonic destructive changes were reversed with MO. P53, PCNA and Ki-67 levels of gene expression were reduced in SN + MO group than SN group (P = 0.007, 0.02, 0.001 respectively).

CONCLUSION

MO protected the colonic mucosa against SN-induced changes regulating apoptosis, and cell proliferation.

Potential of melatonin to reverse epigenetic aberrations in oral cancer: new findings

It is now an accepted principle that epigenetic alterations cause cellular dyshomeostasis and functional changes, both of which are essential for the initiation and completion of the tumor cycle. Oral carcinogenesis is no exception in this regard, as most of the tumors in the different subsites of the oral cavity arise from the cross-reaction between (epi)genetic inheritance and the huge challenge of environmental stressors. Currently, the biochemical machinery is put at the service of the tumor program, halting the cell cycle, triggering uncontrolled proliferation, driving angiogenesis and resistance to apoptosis, until the archetypes of the tumor phenotype are reached. Melatonin has the ability to dynamically affect the epigenetic code. It has become accepted that melatonin can reverse (epi)genetic aberrations present in oral and other cancers, suggesting the possibility of enhancing the oncostatic capacity of standard multimodal treatments by incorporating this indolamine as an adjuvant. First steps in this direction confirm the potential of melatonin as a countermeasure to mitigate the detrimental side effects of conventional first-line radiochemotherapy. This single effect could produce synergies of extraordinary clinical importance, allowing doses to be increased and treatments not to be interrupted, ultimately improving patients' quality of life and prognosis. Motivated by the urgency of improving the medical management of oral cancer, many authors advocate moving from in vitro and preclinical research, where the bulk of melatonin cancer research is concentrated, to systematic randomized clinical trials on large cohorts. Recognizing the challenge to improve the clinical management of cancer, our motivation is to encourage comprehensive and robust research to reveal the clinical potential of melatonin in oral cancer control. To improve the outcome and quality of life of patients with oral cancer, here we provide the latest evidence of the oncolytic activity that melatonin can achieve by manipulating epigenetic patterns in oronasopharyngeal tissue.

Podoplanin Expression Independently and Jointly with Oral Epithelial Dysplasia Grade Acts as a Potential Biomarker of Malignant Transformation in Oral Leukoplakia

Our aim was to evaluate the expression of biomarkers, CD44v6, CD147, EGFR, p53, p63, p73, p16, and podoplanin in oral leukoplakias (OL) and to assess their potential for prediction of malignant transformation (MT). We analyzed the expression of CD44v6, CD147, EGFR, p53, p63, p73, p16, and podoplanin by immunohistochemistry in 52 OL, comprised of 41 low-grade (LG) dysplasia and 11 high-grade (HG) cases. Twelve healthy normal tissues (NT) were also included. Univariate and multivariate analysis were performed to evaluate any association with MT. Variable expression among the studied markers was observed, with a significant increase of high expression from NT to LG and HG cases in CD44v6 (p = 0.002), P53 (p = 0.002), P73 (p = 0.043), and podoplanin (p < 0.001). In multivariate analysis, cases with high podoplanin score showed a significant increased risk of MT (HR of 10.148 (95% CI of 1.503−68.532; p = 0.017). Furthermore, podoplanin combined with binary dysplasia grade obtained a HR of 10.238 (95% CI of 2.06−50.889; p = 0.004). To conclude, CD44v6, p53, p73, and podoplanin showed an increasing expression along the natural history of oral carcinogenesis. Podoplanin expression independently or combined with dysplasia grade could be useful predictive markers of MT in OL.

Expression of Ki-67, Cornulin and ISG15 in non-involved mucosal surgical margins as predictive markers for relapse in oral squamous cell carcinoma (OSCC)

Background

Local relapse of oral squamous cell carcinoma in non-involved mucosal surgical margins indicated possibility of field alteration in the margins, which could be predicted with certain biomarkers. The objectives were to evaluate the expression of Ki-67, Cornulin and ISG15 in non-involved mucosal surgical margins and the association of clinicopathological prognosticators with local relapse in oral squamous cell carcinoma.

Methods

Surgical margins from the study (relapse) group (n = 23), control (non-relapse) group (n = 32) and normal oral mucosa (n = 5) were immunohistochemically stained using Ki-67, Cornulin and ISG15 antibodies. Association between expression of markers and clinicopathological prognosticators with local relapse in oral squamous cell carcinoma was analyzed statistically.

Results

The study group surgical margins demonstrated significantly decreased Cornulin expression (p = 0.032). Low Cornulin expression was significantly associated with local relapse (p = 0.004) and non-tongue primary tumor (p = 0.013). Although not significantly associated with local relapse, expression of Ki-67 was significantly reduced in female patients (p = 0.041). Age above 57.5 years, Chinese & Indian ethnicity, alcohol consumption, epithelial dysplasia in surgical margins, and type III and IV patterns of invasion of tumor were also significantly related to local relapse. Regression analysis showed low expression of Cornulin (p = 0.018), and increased patient’s age (p = 0.008) were predictors of local relapse in oral squamous cell carcinoma, with 34-fold risk and 18-fold risk, respectively. Expression of Ki-67 and ISG15 did not show significant association with local relapse in oral squamous cell carcinoma.

Conclusion

Low expression of Cornulin is an independent predictor of relapse in oral squamous cell carcinoma.

Influence of Life Style Factors on Oral Potentially Malignant and Malignant Disorders: A Cross Sectional Study

The incidence of oral cancer has risen in the past decades and is usually recognised when symptomatic and at a late stage. A premalignant lesion is like smoldering volcano, which if not taken care of, may erupt, often with disastrous consequences. Early detection is therefore very important to reduce morbidity and mortality. A descriptive cross-sectional study was done to assess the prevalence, clinical presentation, and association of various addiction habits in the patients who presented with potentially malignant and malignant lesions of the oral cavity in outdoor clinics of ENT and HNS department of a tertiary care center in Jaipur (Rajasthan). 351 patients of different oral mucosal lesions were examined from August 2019 to January 2020 among which 173(49.2%) patients of potentially malignant and malignant lesions comprise the study group. Clinical findings and detailed history including addiction habits with frequency and duration were noted. Cytological and histopathological examinations were done to conclude the diagnosis. Out of 173 patients of the study group, 146(84.4%) were diagnosed with potentially malignant lesions (PMLs) and 27(15.6%) with malignant lesions (MLs). The most prevalent PML was Oral submucous fibrosis (23%) followed by leukoplakia (7.6%). The most common involved site was buccal mucosa (45.0%) followed by the tongue (26.5%). Tobacco consumption was the most prevalent addiction habit (80%) in the study group. High prevalence of tobacco abuse in patients with potentially malignant and malignant lesions suggested a strong relationship between two. It necessitates adequate awareness in the general population as well as early detection and management of these lesions by an expert Otolaryngologist.

Understanding the complex pathogenesis of oral cancer: A comprehensive review

The pathogenesis of oral cancer is a complex and multifactorial process that requires a deep understanding of the underlying mechanisms involved in the development and progress of malignancy. The ever-improving comprehension of the diverse molecular characteristics of cancer, the genetic and epigenetic alterations of tumor cells, and the complex signaling pathways that are activated and frequently cross talk open up promising horizons for the discovery and application of diagnostic molecular markers and set the basis for an era of individualized management of the molecular defects underlying and governing oral premalignancy and cancer. The purpose of this article is to review the key molecular concepts that are implicated in oral carcinogenesis, especially focusing on oral squamous cell carcinoma, and to review selected biomarkers that play a substantial role in controlling the so-called "hallmarks of cancer," with special reference to recent advances that shed light on their deregulation during the different steps of oral cancer development and progression.

Predicting the clinical outcome of oral potentially malignant disorders using transcriptomic-based molecular pathology

BACKGROUND

This study was undertaken to develop and validate a gene expression signature that characterises oral potentially malignant disorders (OPMD) with a high risk of undergoing malignant transformation.

METHODS

Patients with oral epithelial dysplasia at one hospital were selected as the 'training set' (n = 56) whilst those at another hospital were selected for the 'test set' (n = 66). RNA was extracted from formalin-fixed paraffin-embedded (FFPE) diagnostic biopsies and analysed using the NanoString nCounter platform. A targeted panel of 42 genes selected on their association with oral carcinogenesis was used to develop a prognostic gene signature. Following data normalisation, uni- and multivariable analysis, as well as prognostic modelling, were employed to develop and validate the gene signature.

RESULTS

A prognostic classifier composed of 11 genes was developed using the training set. The multivariable prognostic model was used to predict patient risk scores in the test set. The prognostic gene signature was an independent predictor of malignant transformation when assessed in the test set, with the high-risk group showing worse prognosis [Hazard ratio = 12.65, p = 0.0003].

CONCLUSIONS

This study demonstrates proof of principle that RNA extracted from FFPE diagnostic biopsies of OPMD, when analysed on the NanoString nCounter platform, can be used to generate a molecular classifier that stratifies the risk of malignant transformation with promising clinical utility.

Dysplasia in oral lichen planus: relevance, controversies and challenges. A position paper

Background

Patients with oral lichen planus (OLP) have an increased risk of oral cancer. For this reason, OLP is classified as an oral potentially malignant disorder. However, the precise personal (or individual) risk is unknown. Recent meta-analytical studies have reported that dysplastic OLP may transform to cancer in around 6% of cases, while the rate of transformation is lower (<1.5%) in non-dysplastic cases. The presence of epithelial dysplasia has emerged as the most powerful indicator for assessing cancer risk in oral potentially malignant disorders in routine practice. However, the general acceptance of epithelial dysplasia as an accompanying histologic feature in OLP is subject to great controversy. Many pathologists consider the presence of dysplasia as a criterion to exclude OLP when routinely reporting on this disease. This practice, widespread among oral pathology professionals, has resulted in the underestimation of the potential for malignancy of OLP.

Material and Methods

A review of the literature was carried out in order to critically analyze the relevance, controversies and challenges encountered across the diagnosis of epithelial dysplasia in OLP.

Results

12 studies have been published examining dysplastic changes in OLP, reporting Figures ranging from 0.54% to 25% of cases with dysplasia in the first diagnostic biopsy. The diagnosis of dysplasia in the OLP poses an additional difficulty due to the fact that the affected oral epithelium per se develops changes related to autoimmune aggression. Among the most frequent histological features of OLP that develops dysplasia are basal cell hyperplasia with basaloid appearance, loss of basal cells polarity, cellular and nuclear pleomorphism and irregular stratification.

Conclusions

Epithelial dysplasia should not be considered an exclusion criterion for OLP; its evaluation requires experienced pathologists in this field.

Key words:Oral lichen planus, epithelial dysplasia, oral cancer.

DNA methylation in oral squamous cell carcinoma: from its role in carcinogenesis to potential inhibitor drugs

DNA methylation is one of epigenetic changes most frequently studied nowadays, together with its relationship with oral carcinogenesis. A group of enzymes is responsible for methylation process, known as DNA methyltransferases (DNMT). Although essential during embryogenesis, DNA methylation pattern alterations, including global hypomethylation or gene promoter hypermethylation, can be respectively associated with chromosomal instability and tumor suppressor gene silencing. Higher expression of DNA methyltransferases is a common finding in oral cancer and may contribute to inactivation of important tumor suppressor genes, influencing development, progression, metastasis, and prognosis of the tumor. To control these alterations, inhibitor drugs have been developed as a way to regulate DNMT overexpression, and they are intended to be associated with ongoing chemo- and radiotherapy in oral cancer treatments. In this article, we aimed to highlight the current knowledge about DNA methylation in oral cancer, including main hyper/hypomethylated genes, DNMT expression and its inhibitor treatments.

Molecular markers associated with potentially malignant oral lesions (Review)

According to literature data, potentially premalignant oral lesions are the basis of over 85% of cell carcinomas. Despite multiple advances achieved during the last few decades in the diagnosis and treatment of oral squamous cell carcinomas, there has not been a significant change in the prognosis and 5-year survival rate. The prevention of malignant transformation of these tumors by diagnosis and targeted treatment would be the ideal scenario. These potentially premalignant oral lesions represent an important subject for either the clinical or the research field, due to the higher malignant transformation observed in the last few years at different ages. To date, histopathological examination based on TNM criteria is considered the 'golden standard'. However, this type of examination has its limitation due to staining procedures and photonic microscope examination. Identification of cellular and molecular markers specific to these oral lesions with potentially malignant transformation could lead to early detection, accurate diagnosis, prevention of the development of oral squamous cell carcinoma (OSCC) and facilitate a targeted therapeutic approach. In this review, we focused on a series of molecules that are implicated in the malignant transformation of these lesions and considered potential biomarkers.

The link among microbiota, epigenetics, and disease development

The microbiome is a community of various microorganisms that inhabit or live on the skin of humans/animals, sharing the body space with their hosts. It is a sort of complex ecosystem of trillions of commensals, symbiotic, and pathogenic microorganisms, including trillions of bacteria, archaea, protozoa, fungi, and viruses. The microbiota plays a role in the health and disease status of the host. Their number, species dominance, and viability are dynamic. Their long-term disturbance is usually accompanied by serious diseases such as metabolic disorders, cardiovascular diseases, or even cancer. While epigenetics is a term that refers to different stimuli that induce modifications in gene expression patterns without structural changes in the inherited DNA sequence, these changes can be reversible or even persist for several generations. Epigenetics can be described as cell memory that stores experience against internal and external factors. Results from multiple institutions have contributed to the role and close interaction of both microbiota and epigenetics in disease induction. Understanding the mechanisms of both players enables a better understanding of disease induction and development and also opens the horizon to revolutionary therapeutic approaches. The present review illustrates the roles of diet, microbiome, and epigenetics in the induction of several chronic diseases. In addition, it discusses the application of epigenetic data to develop diagnostic biomarkers and therapeutics and evaluate their safety for patients. Understanding the interaction among all these elements enables the development of innovative preventive/therapeutic approaches for disease control.

Recurrence in Oral Premalignancy: Clinicopathologic and Immunohistochemical Analysis

Oral leukoplakia (OL) has a propensity for recurrence and malignant transformation (MT). Herein, we evaluate sociodemographic, clinical, microscopic and immunohistochemical parameters as predictive factors for OL recurrence, also comparing primary lesions (PLs) with recurrences. Thirty-three patients with OL, completely removed either by excisional biopsy or by laser ablation following incisional biopsy, were studied. Selected molecules associated with the STAT3 oncogenic pathway, including pSTAT3, Bcl-xL, survivin, cyclin D1 and Ki-67, were further analyzed. A total of 135 OL lesions, including 97 PLs and 38 recurrences, were included. Out of 97 PLs, 31 recurred at least once and none of them underwent MT, during a mean follow-up time of 48.3 months. There was no statistically significant difference among the various parameters in recurrent vs. non-recurrent PLs, although recurrence was most frequent in non-homogeneous lesions (p = 0.087) and dysplastic lesions recurred at a higher percentage compared to hyperplastic lesions (34.5% vs. 15.4%). Lower levels of Bcl-xL and survivin were identified as significant risk factors for OL recurrence. Recurrences, although smaller and more frequently homogeneous and non-dysplastic compared to their corresponding PLs, exhibited increased immunohistochemical expression of oncogenic molecules, especially pSTAT3 and Bcl-xL. Our results suggest that parameters associated with recurrence may differ from those that affect the risk of progression to malignancy and support OL management protocols favoring excision and close monitoring of all lesions.

Impact of Epigenetic Alterations in the Development of Oral Diseases

BACKGROUND

Epigenetic mechanisms alter gene expression and regulate vital cellular processes that contribute to the onset and progression of major dental diseases. Their reversible character may prove beneficial for therapeutic targeting. This review aims to provide an update on the main epigenetic changes that contribute to the pathogenesis of Oral Squamous Cell Carcinoma (OSCC), pulpitis and periodontitis as well as dental caries and congenital orofacial malformations, in an effort to identify potential therapeutic targets.

METHODS

We undertook a structured search of bibliographic databases (PubMed and MEDLINE) for peer-reviewed epigenetic research studies focused on oral diseases in the last ten years. A qualitative content analysis was performed in screened papers and a critical discussion of main findings is provided.

RESULTS

Several epigenetic modifications have been associated with OSCC pathogenesis, including promoter methylation of genes involved in DNA repair, cell cycle regulation and proliferation leading to malignant transformation. Additionally, epigenetic inactivation of tumor suppressor genes, overexpression of histone chaperones and several microRNAs are implicated in OSCC aggressiveness. Changes in the methylation patterns of IFN-γ and trimethylation of histone Η3Κ27 have been detected in pulpitis, along with an aberrant expression of several microRNAs, mainly affecting cytokine production. Chronic periodontal disease has been associated with modifications in the methylation patterns of Toll-Like Receptor 2, Prostaglandin synthase 2, E-cadherin and some inflammatory cytokines, along with the overexpression of miR-146a and miR155. Furthermore, DNA methylation was found to regulate amelogenesis and has been implicated in the pathogenesis of dental caries as well as in several congenital orofacial malformations.

CONCLUSION

Strong evidence indicates that epigenetic changes participate in the pathogenesis of oral diseases and epigenetic targeting may be considered as a complementary therapeutic scheme to the current management of oral health.

Oral leukoplakia, leukoerythroplakia, erythroplakia and actinic cheilitis: Analysis of 953 patients focusing on oral epithelial dysplasia

BACKGROUND

To analyse the clinical and histological characteristics from a series of oral leukoplakias, leukoerythroplakias, erythroplakias and actinic cheilitis diagnosed in a 14-year period.

METHODS

The files were reviewed and all cases diagnosed as leukoplakia, leukoerythroplakia, erythroplakia and actinic cheilitis were selected. Clinical information was obtained from the biopsy submission forms, and histological review was performed in all cases.

RESULTS

Final sample included 953 lesions, mostly affecting females (534, 56%), and 87.5% of the patients were 41 to 80 years old. The most commonly affected regions were the lower lip (20.1%), tongue (18.1%) and buccal mucosa (16.9%). Leukoplakias, actinic cheilitis, leukoerythroplakias and erythroplakias represented, respectively, 74.6%, 15.2%, 9.3% and 0.8% of the sample. Most cases presented no dysplasia (42.1%) or mild dysplasia (33.5%). Lesions in the tongue, floor of mouth and lower lip, as well as lesions that presented hyperparakeratosis, showed higher frequencies of moderate dysplasia and severe dysplasia/carcinoma in situ. The most common histological criteria were the increase in number and size of nucleoli, loss of polarity of the basal cells and variations in cellular size and shape. Classification by the binary system showed that 7% were high-risk lesions.

CONCLUSION

All histological criteria for classification of oral epithelial dysplasia recommended by the World Health Organization showed increased frequency as grading increased. Additional criteria seem to be useful in grading oral epithelial dysplasia, such as the presence of normal and abnormal superficial mitotic figures and endophytic epithelial proliferation.

Narrative therapy to relieve stigma in oral cancer patients: A randomized controlled trial

AIMS AND OBJECTIVES

This study aimed to evaluate the efficacy of narrative therapy in relieving stigma in oral cancer patients who underwent major surgical treatment.

BACKGROUND

Health-related stigma compromises mental health and life quality in people with physical or mental abnormalities. Narrative therapy has been implemented to overcome stigma among populations in a diversity of disease states. However, the effectiveness of narrative therapy in relieving stigma among patients with oral cancer is not known.

DESIGN

This study was a randomized controlled trial, in which 100 oral cancer patients were selected and randomly assigned to the 'narrative therapy' group, who received narrative therapy treatment in addition to standard care, and the 'control' group, who was provided standard care only.

METHODS

This research combined measurement of several questionnaires to evaluate stigma. Analysis of variance and paired t tests were employed for data analysis.

RESULTS

Findings in this study demonstrated that narrative therapy treatment effectively relieved oral cancer patients' sense of shame, reducing overall stigma and significantly improving self-esteem and social relationships.

CONCLUSIONS

Narrative therapy was demonstrated to be a promising therapeutic intervention for stigma relief in oral cancer patients.

SUMMARY STATEMENT

What is already known about this topic? Stigma is common among oral cancer patients, especially those who undergo major surgical resection. Psychological intervention is highly recommended in addition to postsurgical care. Narrative therapy might help relieve stigma among oral cancer patients. What this paper adds? Conventional postsurgical care did not improve oral cancer patients' psychological situation. A 7-week intervention of narrative therapy treatment significantly reduced stigma and enhanced sense of self-worth and social support among oral cancer patients. The implications of this paper: Narrative therapy can be clinically accepted as a therapeutic approach to assist oral cancer patients with stigma after major surgery. Tailored approaches, including patient-customized methods, should be encouraged in conducting narrative therapy.

Analysis of DNA methylation of E-cadherin and p16ink4a in oral lichen planus/oral lichenoid lesions

OBJECTIVES

Epigenetic phenomena are changes in gene expression not involving the DNA sequence. DNA methylation is a major occurrence underlying epigenetic changes in human cells. Although aberrant DNA methylation is well documented in malignant lesions, limited information has been shown on the involvement of DNA methylation in oral lichen planus and oral lichenoid lesions (OLP). The present study aimed to investigate DNA methylation of E-cadherin and p16 in OLP, and compare the findings with those in non-inflamed gingiva (Non), radicular cyst (RC), and oral squamous cell carcinoma (SCC).

MATERIALS AND METHODS

Paraffin-embedded surgical biopsy specimens were sliced, DNA was extracted, bisulfite treatment was applied, and methylation-specific polymerase chain reaction was performed. Immunohistochemistry was performed to observe the relative expression patterns of these genes.

RESULTS

E-cadherin was hypermethylated in OLP (p < 0.01), SCC (p < 0.01), and RC (p < 0.05), when compared with Non; DNA hypermethylation was confirmed in OLP and SCC when compared to Non and RC. Hypermethylation of p16^ink4a was observed only in SCC (p < 0.01).

CONCLUSION

DNA methylation levels of E-cadherin and p16^ink4a were significantly higher in OLP than in normal tissues, and may be associated with the pathogenesis and progression of the disease.

Promoter-associated DNA methylation & expression profiling of genes (FLT 3, EPB41L3 & SFN) in patients with oral squamous cell carcinoma in the Khasi & Jaintia population of Meghalaya, India

Background & objectives:

Oral squamous cell carcinoma is one of the most lethal forms of cancer, and its aetiology has been attributed to both genetic and epigenetic factors working in liaison to contribute to the disease. Epigenetic changes especially DNA methylation is involved in the activation or repression of gene functions. The aim of this study was to investigate the DNA methylation pattern and expression profiling of the promoter regions of FMS-related tyrosine kinase 3 (FLT3), erythrocyte membrane protein band 4.1-like 3 (EPB41L3) and stratifin (SFN) genes in oral cancer within the Khasi and Jaintia tribal population of Meghalaya in North East India.

Methods:

Quantitative methylation analyses of the selected genes were carried out by MassARRAY platform System, and the relative expression profiling was carried out by real-time polymerase chain reaction.

Results:

Quantitative methylation results indicated that the level of methylation was significantly higher (hypermethylated) for FLT3 and EPB41L3 and significantly lower (hypomethylated) for SFN in tumour tissues as compared to the adjacent paired normal tissue. Expression profiling was in concurrence with the methylation data whereby hypermethylated genes showed low mRNA level and vice versa for the hypomethylated gene.

Interpretation & conclusions:

The findings show that hyper- and hypomethylation of the selected genes play a potential role in oral carcinogenesis in the selected Khasi and Jaintia tribal population of Meghalaya. The methylation status of these genes has not been reported in oral cancer, so these genes may serve as promising biomarkers for oral cancer diagnosis as well as in disease monitoring.

Long-term follow-up of oral epithelial dysplasia: A hospital based cross-sectional study

Background/purpose

Oral epithelial dysplasia (OED) is characterized histopathologically by cellular and morphological changes that remain the single most important factor predicting risk for subsequent development of invasive neoplasia. Hence the aims of the present study were to determine the rate of malignant change of OED in a group of patients followed-up for a number of years, and hence determine factors likely to influence this malignant change, and to describe the clinical characteristics of patients who developed recurrence of OED and second dysplastic lesions.

Materials and methods

This is hospital based cross-sectional study of all biopsy reports with histologically confirmed OED between 2012 and 2018 were retrospectivelly reviewed.

Results

A total of 359 patients with histologically confirmed OED were reviewed, twenty (5.5%) of the 359 patients developed an invasive squamous cell carcinoma (SCC) of the oral mucosa over a period of 2 to 274 months with mean transformation time of 3.3 years.

Conclusion

The high risk of malignant transformation of OED seems to be related to patients older than 50 years when lesions were on the floor of mouth with severe dysplastic changes.

Atypical immunohistochemical patterns can complement the histopathological diagnosis of oral premalignant lesions

BACKGROUND

The histopathological diagnosis of oral premalignant lesions (OPLs) such as oral epithelial dysplasia (ED) and carcinoma in situ (CIS), as well as epithelial hyperplasia (EHP), is important for the early detection and precise treatment of oral squamous cell carcinoma. However, the standardization of detection and treatment by histological criteria alone remains challenging owing to the complicated and varied histology. We evaluated practically useful immunohistochemical (IHC) markers that might complement the histopathological diagnosis of OPLs.

METHODS

We re-evaluated the histopathological diagnoses and IHC patterns of Ki-67, TP53, CK13, and CK17 in 200 cases of OPLs and performed multiple logistic regression analyses for their predictive accuracy.

RESULTS

We identified and compared atypical IHC patterns in OPLs and in the normal epithelium. Ki-67 expression showed specific patterns in categorized OPLs as EHP, low-grade dysplasia (LED), high-grade dysplasia (HED), and CIS. Multiple logistic regression analyses in the quadrant categories revealed that EHP and CIS had high predictive accuracies of 90.1% and 96.2%, respectively, and in binary categories, combined EHP and LED versus combined HED and CIS showed predictive accuracies of 92.1% and 89.9%, respectively. Binominal logistic regression analysis between each quadrant category revealed satisfactory predictive accuracy of EHP vs. LED, LED vs. HED, and HED vs. CIS (75.2%, 78.9%, and 87.9%, respectively), and Ki-67 showed the highest adjusted odds ratio, followed by TP53.

CONCLUSION

The proposed atypical IHC patterns might serve as useful markers to supplement the morphological diagnosis of OPLs, and established IHC methods for Ki-67 and TP53 might provide stable results.

Immunohistochemical Analysis Revealed a Correlation between Musashi-2 and Cyclin-D1 Expression in Patients with Oral Squamous Cells Carcinoma

Aim: Musashi 2 (MSI2), which is an RNA-binding protein, plays a fundamental role in the oncogenesis of several cancers. The aim of this study is to investigate the expression of MSI2 in Oral Squamous Cell Carcinoma (OSCC) and evaluate its correlation to clinic-pathological variables and prognosis. Materials and Methods: A bioinformatic analysis was performed on data downloaded from The Cancer Genome Atlas (TCGA) database. The MSI2 expression data were analysed for their correlation with clinic-pathological and prognostic features. In addition, an immmunohistochemical evaluation of MSI2 expression on 108 OSCC samples included in a tissue microarray and 13 healthy mucosae samples was performed. Results: 241 patients’ data from TCGA were included in the final analysis. No DNA mutations were detected for the MSI2 gene, but a hyper methylated condition of the gene emerged. MSI2 mRNA expression correlated with Grading (p = 0.009) and overall survival (p = 0.045), but not with disease free survival (p = 0.549). Males presented a higher MSI2 mRNA expression than females. The immunohistochemical evaluation revealed a weak expression of MSI2 in both OSCC samples and in healthy oral mucosae. In addition, MSI2 expression directly correlated with Cyclin-D1 expression (p = 0.022). However, no correlation has been detected with prognostic outcomes (overall and disease free survival). Conclusions: The role of MSI2 expression in OSCC seems to be not so closely correlated with prognosis, as in other human neoplasms. The correlation with Cyclin-D1 expression suggests an indirect role that MSI2 might have in the proliferation of OSCC cells, but further studies are needed to confirm such results.

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.

Aberrant Kank1 expression regulates YAP to promote apoptosis and inhibit proliferation in OSCC

The kidney ankyrin repeat-containing protein 1 (Kank1) gene is one of the most important members of the KANK family. Kank1 has hybridity deletion and promoter methylation in the cancer tissues of the brain, lung, kidney and the corresponding cell lines, leading to downregulation of the gene expression. Meanwhile, Kank1 also plays a key role in the occurrence and development of various types of tumors, suggesting that Kank1 may be an anti-oncogene. However, its role and the potential mechanisms in the Oral Squamous Cell Carcinoma (OSCC) remain unclear. We examined the expression of Kank1 in OSCC tissues and explored its clinical significance. In addition, we investigated the effects of Kank1 on the biological behavior of OSCC cells and their specific molecular mechanisms. We found that Kank1 was poorly expressed in OSCC tissues and it is correlated with the OSCC stage and the patient's poor prognosis. By overexpression of Kank1, we found that the proliferation ability of the OSCC cells decreased both in vitro and in vivo, the proportion of apoptotic cells increased, and the mitochondrial transmembrane potential decreased. In terms of the molecular mechanism, we confirmed that Kank1 could inhibit the occurrence of OSCC by regulating Yap to inhibit the proliferation and promote apoptosis of the OSCC cells. Moreover, it was found that the overexpression of YAP reversed those effects caused by Kank1 overexpression on the OSCC cells. In conclusion, the research indicated that Kank1 might play an anti-oncogenic role in OSCC and it could be considered to be a target for the diagnosis and the treatment of OSCC.

Development and validation of nomogram for prediction of malignant transformation in oral leukoplakia: A large-scale cohort study

PURPOSE

Oral leukoplakia (OL) is the well-known disorder of oral mucosa, which has potential to be malignant and can lead to squamous cell carcinoma (OSCC). In the following study, we developed a comprehensive nomogram for predicting the malignant progression of OL, based on analysis of clinicopathological variables.

METHODS

A retrospective analysis of patients diagnosed with OL was performed between 1998 and 2017 at the Peking University School and Hospital of Stomatology. OL was confirmed by pre-treatment biopsy. The candidate risk factors for OL malignant transformation were screened from clinicopathological variables using the Cox proportional hazard regression analysis. The nomogram model was generated based on the COX regression results and was validated through Harrell concordance index (c-index) and calibration plots RESULTS: The incidence of OL malignant transformation (MT) was 12.2% (107/875), and the mean follow-up time was 4.5 years. The risk factors (age, histologic grade, site of lesion and smoking habit) derived from Cox proportional hazard regression analysis were incorporated in a novel nomogram model for prediction of MT severity. The c-index value of the nomogram model was 0.752, which confirmed the prediction ability; and was further confirmed by calibration plots results.

CONCLUSION

Our data suggest that patients with OL who are over 50 years old, non-smokers with dysplasia, and OL lesions involving the lip, the floor of mouth, and tongue have an enhanced risk of MT. The established nomogram model has the predictive value of malignant progression, which is conductive to screen high-risk patients and guide treatment strategy.

Variants in FAT1 and COL9A1 genes in male population with or without substance use to assess the risk factors for oral malignancy

A number of genetic variants were suggested to be associated with oral malignancy, few variants can be replicated. The aim of this study was to identify significant variants that enhanced personal risk prediction for oral malignancy. A total of 360 patients diagnosed with oral squamous cell carcinoma, 486 controls and 17 newly diagnosed patients with OPMD including leukoplakia or oral submucous fibrosis were recruited. Fifteen tagSNPs which were derived from somatic mutations were genotyped and examined in associations with the occurrence of oral malignancy. Environmental variables along with the SNPs data were used to developed risk predictive models for oral malignancy occurrence. The stepwise model analysis was conducted to fit the best model in an economically efficient way. Two tagSNPs, rs28647489 in FAT1 gene and rs550675 in COL9A1 gene, were significantly associated with the risk of oral malignancy. The sensitivity and specificity were 85.7% and 85.5%, respectively (area under the receiver operating characteristic curve (AUC) was 0.91) for predicting oral squamous cell carcinoma occurrence with the combined genetic variants, betel-quid, alcohol and age. The AUC for OPMD was only 0.69. The predictive probability of squamous cell carcinoma occurrence for genetic risk score without substance use increased from 10% up to 43%; with substance use increased from 73% up to 92%. Genetic variants with or without substance use may enhance risk prediction for oral malignancy occurrence in male population. The prediction model may be useful as a clinical index for oral malignancy occurrence and its risk assessments.

Detection of salivary heat shock protein 27 by enzyme-linked immunosorbent assay and its correlation with histopathology of oral leukoplakia

Context

Salivary analytes may be used as biomarkers for translational and clinical applications. Heat shock proteins (Hsps) are ubiquitous, highly conserved proteins found in all prokaryotic and eukaryotic species. Hsp27, a low molecular weight protein, may act as a salivary biomarker. Leukoplakia is the most common oral potentially malignant disorder and various salivary biomarkers such as interleukin-6, 8, tumor necrosis factor-α and MMPs have been detected in it. Oral leukoplakia presents clinically as homogenous and nonhomogenous forms; the microscopic pattern ranges from simple epithelial hyperplasia to carcinoma in situ.

Aims

This study aims to detect salivary Hsp27 in oral leukoplakia by enzyme-linked immunosorbent assay (ELISA) and to correlate its expression pattern with histopathology.

Materials and Methods

A total of 45 cases had constituted the study group. Salivary Hsp27 levels were assessed by ELISA in histopathologically confirmed cases of oral leukoplakia and were compared with that of healthy volunteers.

Statistical Analysis

Mann-Whitney U-test and Spearman's correlation coefficient were used for the detection of Hsp27 and its correlation with mean absorbance levels.

Results

The mean absorbance values had shown elevated expression of Hsp27 in oral leukoplakia when compared to that in healthy volunteers.

Conclusions

The present study had shown elevated expression of salivary Hsp27 in oral leukoplakia which could be attributed to altered redox potential.

Overexpression of ADAR1 into the cytoplasm correlates with a better prognosis of patients with oral squamous cells carcinoma

BACKGROUND

ADAR1 is an enzymatic protein, which catalyzes a RNA editing reaction by converting Adenosine to Inosine, and its expression has been found to be dysregulated in many cancer types. The aim of this study was to analyze the expression of ADAR1 in oral squamous cells carcinoma.

METHODS

In order to analyze the ADAR1 mRNA expression, data from The Cancer Genome Atlas (TCGA) database were downloaded and analyzed. In addition, immunohistochemistry analysis was performed on an institutional database including 46 samples of oral squamous cell carcinoma in a tissue microarray (TMA).

RESULTS

No statistically significant correlation linked the mRNA ADAR1 expression to any clinic-pathological variables in the TCGA database. Immunohistochemistry analysis of ADAR1 showed different expressions between normal mucosa and tumor tissue. Focusing on the subcellular localization, the nuclear expression of ADAR1 correlated with higher grading of differentiation (ρ = 0.442; P-value = 0.002); the general expression of ADAR1 either in cytoplasm or in nuclei, correlated with the Gender of patients (Cytoplasm expression: ρ = -0.295; P-value = 0.049; while for nuclear expression: ρ = +0.374; P = 0.011); cytosol expression resulted to be an independent protective prognostic factor (HR = 0.047; C.I. 95% 0.007-0.321; P-value = 0.002).

CONCLUSION

Higher expression of ADAR1 into the cytoplasm resulted to be an independent prognostic factor. In order to understand ADAR1 role in cancer, further studies should be performed, in bigger cohort and under a bio-molecular point of view.

An Evaluation of Clinical and Histopathological Aspects of Patients with Oral Submucous Fibrosis in the Background of Oral Squamous Cell Carcinoma

Background

The behavior and prognosis of oral squamous cell carcinoma (OSCC) is presumably different in patients with oral submucous fibrosis (OSF). The objective of this study was to assess the effects of demographic features, habits, and histopathological features in the transformation of OSF to OSCC.

Methods

Data were extracted from the archives and histopathological evaluation and presence of nodal metastasis were recorded.

Results

OSF was detected in 130 (48%) out of 273 OSCC patients. The mean age of presentation among OSF-positive patients was 57.7 years, while patients diagnosed only with OSCC had a comparatively higher age, 59.5 years. In the below 50 years of age group, presence of OSF with OSCC was less (40%). In the OSF-positive group, male to female ratio was 3.2:1. The common primary sites were buccal mucosa and tongue in both groups. Betel quid chewing was present in more than 95% of the sample. Betel chewing, smoking, and alcohol consumption were present in 26.15% of OSF-positive patients. Degree of fibrosis was neither associated with the level of histological differentiation of the tumor (p= 0.195) nor associated with the malignant transformation (p =0.373). Lymph node metastasis was not seen in 76.63% and 68.54% of the patients with and without OSF, respectively.

Conclusions

High degree of prevalence of OSF was observed among the OSCC patients. There were also a male predilection and younger age at presentation in these patients. However, a significant association was not observed in the degree of fibrosis with malignant transformation or the level of histopathological differentiation of the tumor. Lymph node metastasis also failed to express a significant relationship with the presence of OSF.

Margin Analysis: Squamous Cell Carcinoma of the Oropharynx

Because of the common shared risk factors of smoking and heavy alcohol consumption, literature involving oropharyngeal squamous cell carcinoma (OPSCC) is often combined with oral squamous cell carcinoma. Human papilloma virus is now confirmed to be a major risk factor of OPSCC with its distinct epidemiology and favorable treatment outcome. The impact of adjuvant chemoradiation in the setting of positive surgical margins remains unclear but is likely influenced by tumor biology. This article reviews the tumor biology of OPSCC and summarizes recent findings on outcomes following surgical treatment of OPSCC.

Alterations in the expression of DNA damage response-related molecules in potentially preneoplastic oral epithelial lesions

OBJECTIVES

The aim of this study was to evaluate the expression levels of DNA damage response (DDR) markers in potentially preneoplastic oral epithelial lesions (PPOELs).

STUDY DESIGN

Immunohistochemical expression of DDR markers (γΗ2 ΑΧ, pChk2, 53 BP1, p53, and phosphorylated at Ser 15 p53) was assessed in 41 oral leukoplakias, ranging from hyperplasia (H) to dysplasia (D) and in comparison with oral squamous cell carcinoma (OSCC) and normal mucosa (NM). Statistical and receiver operating characteristic curve analysis were performed.

RESULTS

γH2 AX immunoexpression demonstrated a gradual increase and upper layer extension from NM to H to higher D degrees to OSCC. pChk2 expression was minimal in NM, relatively low in PPOELs, with an increasing tendency from H to D, and higher in OSCC. 53 BP1 demonstrated higher levels in OSCC than in NM, whereas its expression in PPOELs was heterogeneous, gradually increasing according to D. p53 demonstrated progressively higher levels and upper layer extension from H to D to OSCC. Phosphorylated p53 was absent in NM and relatively low in PPOELs and OSCC.

CONCLUSIONS

DDR markers' expression is variable in PPOELs, showing a tendency to increase along with dysplasia. Activated DDR mechanisms may play an important protective role at early stages of oral carcinogenesis, but probably suffer progressive deregulation, eventually failing to suppress malignant transformation.

Predictive Prognostic Value of Tissue-Based MicroRNA Expression in Oral Squamous Cell Carcinoma: A Systematic Review and Meta-analysis

Oral squamous cell carcinoma (OSCC) is a common type of cancer characterized by a low survival rate, mostly due to local recurrence and metastasis. In view of the importance of predicting tumor behavior in the choice of treatment strategies for OSCC, several studies have attempted to investigate the prognostic value of tissue biomarkers, including microRNA (miRNA). The purpose of this study was to perform a systematic review and meta-analysis to evaluate the relationship between miRNA expression and survival of OSCC patients. Studies were identified by searching on MEDLINE/PubMed, SCOPUS, Web of Science, and Google Scholar. Quality assessment of studies was performed with the Newcastle-Ottawa Scale. Data were collected from cohort studies comparing disease-free survival and overall survival in patients with high miRNA expression compared to those with low expression. A total of 15 studies featuring 1,200 OSCC samples, predominantly from Asia, met the inclusion criteria and were included in the meta-analysis. Poor prognosis correlated with upregulation of 9 miRNAs (miR-21, miR-455-5p, miiR-155-5p, miR-372, miR-373, miR-29b, miR-1246, miR-196a, and miR-181) and downregulation of 7 miRNAs (miR-204, miR-101, miR-32, miR-20a, miR-16, miR-17, and miR-125b). The pooled hazard ratio values (95% confidence interval) related to different miRNA expression for overall survival and disease-free survival were 2.65 (2.07–3.39) and 1.95 (1.28–2.98), respectively. The results of this meta-analysis revealed that the expression levels of specific miRNAs can robustly predict prognosis of OSCC patients.

Current Insights into Oral Cancer Epigenetics

Epigenetic modifications have emerged into one of the cancer hallmarks, replacing the concept of malignant pathologies as being solely genetic-based conditions. The epigenetic landscape is responsible for normal development but also for the heterogeneity among tissues in terms of gene expression patterns. Dysregulation in these mechanisms has been associated with disease stage, and increased attention is now granted to cancer in order to take advantage of these modifications in terms of novel therapeutic strategies or diagnosis/prognosis tools. Oral cancer has also been subjected to epigenetic analysis with numerous studies revealing that the development and progression of this malignancy are partially induced by an altered epigenetic substrate together with genetic alterations and prolonged exposure to environmental risk factors. The present review summarizes the most important epigenetic modifications associated with oral cancer and also their potential to be used as new therapeutic targets.

Single nucleotide polymorphisms as markers of genetic susceptibility for oral potentially malignant disorders risk: Review of evidence to date

•

We reviewed single nucleotide polymorphisms for oral pre-cancer susceptibility.

•

All of them were pathway based candidate gene association studies.

•

The current level of evidence is very limited.

•

Integrated characterization of germline/somatic alterations in oral cancer & pre-cancer is needed.

Background

Oral cancers are preceded by oral potentially malignant disorders (OPMD). Understanding genetic susceptibility for OPMD risk could provide an opportunity for risk assessment of oral cancer through early disease course. We conducted a review of single nucleotide polymorphism (SNP) studies for OPMD risk.

Methods

We identified all relevant studies examining associations of SNPs with OPMD (leukoplakia, erythroplakia and oral sub-mucous fibrosis) conducted world-wide between January, 2000 and February, 2016 using a combined keyword search on PubMed. Of these, 47 studies that presented results as odds ratios and 95% CI were considered for full review.

Results

The majority of eligible studies that explored candidate gene associations for OPMD were small (N < 200 cases), limiting their scope to provide strong inference for any SNP identified to date in any population. Commonly studied SNPs were genes of carcinogen metabolism (n = 18 studies), DNA repair (n = 11 studies), cell cycle control (n = 8 studies), extra-cellular matrix alteration (n = 8 studies) and immune-inflammatory (n = 6 studies) pathways. Based on significant associations as reported by two or more studies, suggestive markers included SNPs in GSTM1 (null), CCND1 (G870A), MMP3 (-1171; promotor region), TNFα (-308; rs800629), XPD (codon 751) and Gemin3 (rs197412) as well as in p53 (codon 72) in Indian populations. However, an equal or greater number of studies reported null or mixed associations for SNPs in GSTM1 (null), p53 (codon 72), XPD (codon 751), XRCC (rs25487 C/T), GSTT1 (null) and CYP1A1m1 (MspI site).

Conclusion

Candidate gene association studies have not yielded consistent data on risk loci for OPMD. High-throughput genotyping approaches for OPMD, with concurrent efforts for oral cancer, could prove useful in identifying robust risk-loci to help understand early disease course susceptibility for oral cancer.

Epigenetic regulation of integrin β6 transcription induced by TGF-β1 in human oral squamous cell carcinoma cells

Overexpression of integrin αvβ6 is believed to play an important role in the invasion and metastasis of oral squamous cell carcinoma (OSCC). However, little is known about the molecular mechanisms leading to αvβ6 upregulation in OSCC. As the integrin β6 (ITGB6) is the only partner with αv, the expression of αvβ6 is dependent on ITGB6, it is, therefore, pivotal to investigate the mechanisms underlying ITGB6 overexpression in OSCC. We previously reported the cloning and characterization of human ITGB6 gene. In the current study, we further investigated the molecular mechanisms of ITGB6 expression and the upregulation by carcinogenesis related cytokine-transforming growth factor-β1 (TGF-β1) in OSCC cells. We first demonstrated that TGF-β1 can induce ITGB6 mRNA and protein express in a time and concentration dependent manner, and the induced-ITGB6 mRNA was not due to increase the mRNA stability, but regulated at transcriptional level. By using a luciferase reporter assay, site-mutation, RNA interference, and chromatin immunoprecipitation assay, we revealed for the first time that JunB, a member of the activator protein-1 (AP-1) family, is involved in the positive regulation to the ITGB6 transcription induced by TGF-β1 in OSCC cells. Furthermore, our data also demonstrated that histone acetyltransferase (HAT) CBP mediated histone H3 and H4 hyperacetylation, and RNA Polymerase II recruitment to ITGB6 promoter, facilitated the binding of transcription factor JunB to ITGB6 promoter after TGF-β1 stimulation. Collectively, these findings demonstrate that JunB and CBP-mediated histone hyperacetylation are responsible for TGF-β1 induced ITGB6 transcription in OSCC cells, suggesting that epigenetic mechanisms are responsible for the active transcription expression of ITGB6 induced by TGF-β1 in OSCC cells.

Adjunctive Diagnostic Techniques for Oral and Oropharyngeal Cancer Discovery

The most important prognostic factor in predicting the outcome of oral and oropharyngeal cancer (OPC) is the stage at which it is diagnosed. Only 30% of patients are diagnosed with early-stage disease. The oral health care provider performs an important role in early diagnosis of oral cancer. The conventional oral examination consists of a visual and tactile assessment of accessible oral, and head and neck structures. Any suspicious or equivocal lesion should be reevaluated within 4 weeks. Evidence supporting the use of adjunctive devices to improve the ability to screen for and identify OPCs and oral premalignant lesions remains low.

Whole genome DNA methylation profiling of oral cancer in ethnic population of Meghalaya, North East India reveals novel genes

Oral Squamous Cell Carcinoma (OSCC) is a serious and one of the most common and highly aggressive malignancies. Epigenetic factors such as DNA methylation have been known to be implicated in a number of cancer etiologies. The main objective of this study was to investigate physiognomies of Promoter DNA methylation patterns associated with oral cancer epigenome with special reference to the ethnic population of Meghalaya, North East India. The present study identifies 27,205 CpG sites and 3811 regions that are differentially methylated in oral cancer when compared to matched normal. 45 genes were found to be differentially methylated within the promoter region, of which 38 were hypermethylated and 7 hypomethylated. 14 of the hypermethylated genes were found to be similar to that of the TCGA-HNSCC study some of which are TSGs and few novel genes which may serve as candidate methylation biomarkers for OSCC in this poorly characterized ethnic group.

Semiquantifiable angiogenesis parameters in association with the malignant transformation of oral leukoplakia

BACKGROUND

Aim of the study was to assess the role of angiogenesis in the process of malignant transformation of clinical diagnosed oral leucoplakia (OL).

MATERIALS AND METHODS

A total of 131 histological preparations [oral leukoplakia/hyperkeratosis without dysplasia (OL; n = 49), oral leukoplakia/hyperkeratosis with mild dysplasia (OL-SIN1; n = 33), with moderate dysplasia (OL-SIN2; n = 13) and leukoplakia-derived oral squamous cell carcinoma (OL-OSCC; n = 36)] were evaluated for microvessel density (MVD), vessel diameter as well as for vascular endothelial growth factor (VEGF-A) expression. Data were compared within the groups.

RESULTS

For MVD, there were significant differences between OL and OL-SIN 2/OL-OSCC (P < 0.05) and between OL-SIN 1 and OL-OSCC (P < 0.05). For OL-OSCC, vessel diameters were significantly increased compared with OL (P < 0.05). Expression of VEGF-A increased significantly gradually from OL-SIN 1 to OSCC (each P < 0.05). This was especially evident for lesions of the tongue when compared to the others.

CONCLUSION

Angiogenesis increases during the transition from OL through dysplasia to OL-OSCC. In particular, OL-OSCCs of the tongue, VEGF-A expression may be used for estimation of malignant progression of OL.

Epigenetics in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is the most common type of oral neoplasm, accounting for over 90% of all oral malignancies and 38% of head and neck tumors. Worldwide, OSCC is the eighth most common human cancer, with more than 500,000 new cases being diagnosed every year with a fairly onerous prognosis, encouraging further research on factors that might modify disease outcome. Genetic and/or environmental risk factors associated with the development of oral cancer have been sufficiently understood (smoking, alcohol, betel, diet, living habits, etc.). Knowledge of the genetic basis in oral carcinogenesis is still a challenging task. To improve the diagnosis and prevention, a previously unknown type of chromatin modification, known as epigenetic, which is defined as heritable DNA changes that are not encoded in the sequence itself and which are reversible and increasingly appear to serve fundamental roles in cell differentiation and development are studied. Tumors shed their DNA into the blood and epigenetic changes that occur early during tumorigenesis, sometimes even in premalignant lesions, can provide valuable biomarkers. Key components involved in epigenetic regulation are DNA methylation, histone modifications and modifications in micro ribonucleic acids (miRNAs). Epigenetic modifications may contribute to aberrant epigenetic mechanisms seen in oral precancers and cancers. In the near future, epigenetic variations found in oral dysplastic cells can act as a molecular fingerprint for malignancies.

Tetrandrine induces programmed cell death in human oral cancer CAL 27 cells through the reactive oxygen species production and caspase-dependent pathways and associated with beclin-1-induced cell autophagy

Tetrandrine, a bisbenzylisoquinoline alkaloid, is extracted from the root of the Chinese herb Radix Stephania tetrandra S Moore. This compound has antitumor activity in different cancer cell types. In this study, the effects of tetrandrine on human oral cancer CAL 27 cells were examined. Results indicated that tetrandrine induced cytotoxic activity in CAL 27 cells. Effects were due to cell death by the induction of apoptosis and accompany with autophagy and these effects were concentration- and time-dependent manners. Tetrandrine induced apoptosis was accompanied by alterations in cell morphology, chromatin fragmentation, and caspase activation in CAL 27 cells. Tetrandrine treatment also induced intracellular accumulation of reactive oxygen species (ROS). The generation of ROS may play an important role in tetrandrine-induced apoptosis. Tetrandrine triggered LC3B expression and induced autophagy in CAL 27 cells. Tetrandrine induced apoptosis and autophagy were significantly attenuated by N-acetylcysteine pretreatment that supports the involvement of ROS production. Tetrandrine induced cell death may act through caspase-dependent apoptosis with Beclin-1-induced autophagy in human oral cancer cells. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 329-343, 2017.

Involvement of DNMT 3B promotes epithelial-mesenchymal transition and gene expression profile of invasive head and neck squamous cell carcinomas cell lines

BACKGROUND

The 5-year overall survival rates for head and neck cancer (HNC) relies on distant metastasis. Importantly, the epithelial-mesenchymal transition (EMT) is believed to be an initial step of metastasis. However, the relationship of epigenetic with EMT formation is still unexplored in HNC. This study focuses on invasive subclones of HNC cell lines through the simulation of invasion in vitro; and underlying mechanisms were analyzed including DNA methylation and gene expression profile.

METHODS

Invasive subclones of NHC cell lines were successfully obtained using transwell coated with Matrixgel. Cells invaded through 8 μm pore several times were subcultured and examined with EMT features including morphology, EMT marker genes expression, and invasive ability. Moreover, compared the profile of genes expression in parental and invasive cells was analyzed using mRNA expression array.

RESULTS

DNA methyltransferase 3B (DNMT 3B) was upregulated in invasive subclones and might control the 5' region of E-cadherin (E-cad) methylation and further inhibited E-cad protein expression. Interference of DNMT 3B by siRNA or miRNA 29b could reduce EMT and cell invasion. Expression array analysis revealed the most possible involved pathways in cell invasion including arginine and proline metabolism, TGF-beta, and focal adhesion.

CONCLUSIONS

DNMT 3B might control EMT by DNA methylation manner in invasive HNC cell lines. Moreover, miR-29b mimic downregulated DNMT 3B and inhibited EMT and cell invasion indicated the role of therapeutic agent for invasive HNC. Genes identified from array data and new molecules are involved in metastasis of HNC need further validation.

Tetrandrine induces apoptosis Via caspase-8, -9, and -3 and poly (ADP ribose) polymerase dependent pathways and autophagy through beclin-1/ LC3-I, II signaling pathways in human oral cancer HSC-3 cells

Tetrandrine is a bisbenzylisoquinoline alkaloid that was found in the Radix Stephania tetrandra S Moore. It had been reported to induce cytotoxic effects on many human cancer cells. In this study, we investigated the cytotoxic effects of tetrandrine on human oral cancer HSC-3 cells in vitro. Treatments of HSC-3 cells with tetrandrine significantly decreased the percentage of viable cells through the induction of autophagy and apoptosis and these effects are in concentration-dependent manner. To define the mechanism underlying the cytotoxic effects of tetrandrine, we investigated the critical molecular events known to regulate the apoptotic and autophagic machinery. Tetrandrine induced chromatin condensation, internucleosomal DNA fragmentation, activation of caspases-3, -8, and -9, and cleavage of poly (ADP ribose) polymerase (PARP) that were associated with apoptosis, and it also enhanced the expression of LC3-I and -II that were associated with the induction of autophagy in human squamous carcinoma cell line (HSC-3) cells. Tetrandrine induced autophagy in HSC-3 cells was significantly attenuated by bafilomycin A1 (inhibitor of autophagy) pre-treatment that confirmed tetrandrine induced cell death may be associated with the autophagy. In conclusion, we suggest that tetrandrine induced cell death may be through the induction of apoptosis as well as autophagy in human oral cancer HSC-3 cells via PARP, caspases/Becline I/LC3-I/II signaling pathways.

PI3K-AKT-mTOR pathway proteins are differently expressed in oral carcinogenesis

BACKGROUND

PI3K-AKT-mTOR signaling pathway is associated with several cellular functions and is frequently changed in several malignancies. The aim of this study was to characterize the immunohistochemical expression pattern of components in PI3K-AKT-mTOR signaling pathway in oral epithelial dysplasia (OED), comparing to oral squamous cell carcinoma (OSCC) and non-dysplastic oral tissues (NDOT).

METHODS

A total of 186 cases of NDOT, OED and OSCC were retrieved. Nuclear staining and cytoplasmic staining of the keratinocytes were considered positive, and the percentage of positive cells was calculated.

RESULTS

Increased immunoreactivity from NDOT to OED and OSCC was seen for all proteins. In NDOT cases, positivity was found only for pS6 (52.9%) and p4EBP1 (13.5%). In OED, immunoreactivity was observed for pAKT (62.2%), pmTOR (28.6%), pS6 (70.8%), and p4EBP1 (42.9%). In OSCC cases, immunoreactivity was found for pAKT (83.3%), pmTOR (50%), pS6 (77.4%), and p4EBP1 (50%). The pAKT and pmTOR expression was higher in OED (<0.001, Fisher's exact test) and OSCC (<0.001, Fisher's exact test).

CONCLUSION

Our study demonstrated higher pAKT and pmTOR expression during carcinogenesis of oral mucosa, differing considerably among OED and OSCC specimens when compared to NDOT. These proteins can be considered potential diagnostic markers for early detection of cancer.

Expression of Podoplanin in Different Grades of Oral Squamous Cell Carcinoma

Background:

The expression of podoplanin is up-regulated in a number of different human cancers, including squamous cell carcinoma of the oral cavity and its relationship with tumor invasion raises the possibility that podoplanin expression could be used as a biomarker for diagnosis and prognosis.

Aim:

The aim of the present study is to evaluate the expression of podoplanin in different grades of squamous cell carcinoma (SCC) and to correlate the expression of podoplanin with relevant clinical features such as age, sex, site and associated habits.

Materials and Methods:

Retrospective study was carried on formalin fixed, paraffin embedded blocks of oral SCC (OSCC) from the archives of Department of Oral and Maxillofacial Pathology, Vishnu Dental College, Bhimavaram. Thirty diagnosed cases were included, of which 10 were well-differentiated SCC (WDSCC) (n = 10), 10 moderately DSCC and 10 poorly DSCC. Demographics including age, sex, gender and associated habit history, were recorded. Immunohistochemical staining was done with podoplanin anti D2–40 antibody, for all the cases of OSCC and assessed qualitatively. The data obtained were tabulated and subjected to statistical analysis.

Results:

In the present study, 27 cases of SCC showed podoplanin expression and remaining three cases showed no expression. The scoring criterion suggested by Yuan et al. was followed for semi-quantitative assessment. OSCC, seven cases presented weak expression (Immunoreactive score [IRS] 0–3), 15 presented moderate expression (IRS Score 4–7) and 5 presented high expression (IRS Score > 8). The assessment of podoplanin expression in the cytoplasm, the membrane and the cytoplasm and membrane (both) of tumor cells showed overall high positivity in the cytoplasmic followed by both and the membrane.

Conclusion:

Podoplanin could be a potent biomarker in assessing the cytoplasm/membrane staining of tumor cells. Furthermore, a high level of podoplanin expression is suggestive of high frequency of lymph node metastasis and immature status in the differentiation process of OSCC.

Natural Compounds: DNA Methyltransferase Inhibitors in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is a multistep process which is modulated by several endogenous and environmental factors. Epigenetic changes have been found to be equally responsible for OSCC as genetic changes. A plethora of genes showing hypermethylation have been discovered in OSCC. Since these changes are reversible, a lot of emphasis is on using the natural compounds for their ability to cause demethylation which could lead to reactivation of the inactivated tumor suppressor genes. This review encompasses the promoter hypermethylation of tumor suppressor genes in OSCC and its possible reversal using natural compounds. In addition, new compounds which could be screened for their demethylating ability have also been proposed.

Epigenetic Modifications and Accumulation of DNA Double-Strand Breaks in Oral Lichen Planus Lesions Presenting Poor Response to Therapy

Epigenetics refers to changes in cell characteristics that occur independently of modifications to the deoxyribonucleic acid (DNA) sequence. Alterations mediated by epigenetic mechanisms are important factors in cancer progression. Although an exciting prospect, the identification of early epigenetic markers associated with clinical outcome in premalignant and malignant disorders remains elusive. We examined alterations in chromatin acetylation in oral lichen planus (OLP) with distinct clinical behavior and compared the alterations to the levels of DNA double-strand breaks (DSBs). We analyzed 42 OLP patients, who had different responses to therapy, for acetyl-histone H3 at lys9 (H3K9ac), which is associated with enhanced transcription and nuclear decondensation, and the presence of DSBs, as determined by accumulation of phosphorylated γH2AX foci. Patients with high levels of H3K9ac acetylation failed to respond to therapy or experienced disease recurrence shortly after therapy. Similar to H3K9ac, patients who responded poorly to therapy had increased accumulation of DNA DSB, indicating genomic instability. These findings suggest that histone modifications occur in OLP, and H3K9ac and γH2AX histones may serve as epigenetic markers for OLP recurrence.