Human papillomavirus infection in oral potentially malignant disorders and cancer

Human Papillomavirus-Associated Oral Epithelial Dysplasia: A Practical Approach to Make the Diagnosis

Background

High-risk Human Papillomavirus (HPV) genotypes are found in malignant oral epithelial lesions, and HPV infection is proposed as a risk factor for initiating Squamous cell carcinoma (SCC) in the head and neck region. This study suggests a practical approach to detect HPV in HPV-associated oral epithelial dysplasia (HAOED).

Methods

Fifty-four oral epithelial dysplasia specimens were examined, comprising twenty-seven cases diagnosed with high-grade dysplasia and twenty-seven cases diagnosed with low-grade dysplasia using a binary grading system. To assess the cases for HPV, the specimens were examined for p16 protein using an immunohistochemical (IHC) study, and then, the Chromatin In Situ Hybridization (CISH) test was performed for all positive cases. Chromatin Immunoprecipitation-Polymerase Chain Reaction (ChIP-PCR) was performed on CISH-positive specimens to assess the outcome. This cross-sectional study was conducted in 2020 at Tehran University of Medical Science. SPSS software version 22.0 was used to perform the Chi square or Fisher's exact test to examine the relationship between variables (statistically significant level P<0.05).

Results

The expression of p16 protein was not associated with the severity of epithelial dysplasia (81.5% in low-grade and 59.2% in high-grade cases) (P=0.16). Moreover, according to the CISH test result, 9.25% of all specimens were positive (P>0.99), and in the nine cases, undergone the ChIP-PCR study, two cases (22.2%) showed positivity for HPV-16, while one case (11.1%) demonstrated positivity for HPV-51.

Conclusion

Regarding HAOED, here, we proposed a step-by-step combination approach using different diagnostic methods, including IHC for p16 protein, CISH, and ChIP-PCR based on a complementary algorithm.

The role of blood metabolites in oral cancer: insights from a Mendelian randomization approach

Aim

This research aimed to explore the causal impact of blood metabolites on oral cancer using a two-sample Mendelian randomization (MR) analysis. The study endeavored to identify potential biomarkers for oral cancer's clinical management.

Materials and methods

Based on the large individual-level datasets from UK Biobank as well as GWAS summary datasets, we first constructed genetic risk scores (GRSs) of 486 human blood metabolites and evaluated the effect on oral cancer. Various statistical methods, including inverse variance weighted (IVW), MR-Egger, and weighted median, among others, were employed to analyze the potential causal relationship between blood metabolites and oral cancer. The sensitivity analyses were conducted using Cochran's Q tests, funnel plots, leave-one-out analyses, and MR-Egger intercept tests.

Results

29 metabolites met the stringent selection criteria. Out of these, 14 metabolites demonstrated a positive association with oral cancer risk, while 15 metabolites indicated a protective effect against oral cancer. The IVW-derived estimates were significant, and the results were consistent across different statistical methodologies. Both the Cochran Q test and the MR-Egger intercept test indicated no heterogeneity and pleiotropy.

Conclusion

This MR study offers evidence of the role specific blood metabolites play in oral cancer, pinpointing several with potential risk or protective effects. These findings could be helpful for new diagnostic tools and treatments for oral cancer. While the results are promising, additional research is necessary to fully validate and refine these conclusions. This study serves as a foundational step towards more comprehensive understandings in the future.

Oral Human Papillomavirus Infection among Smokeless Tobacco-using Tribal Women in Mysuru, India

Smokeless tobacco (SLT) is consumed by more than 300 million people worldwide. Studies show high use among Indian indigenous women who are also at high risk for oral cancers. Both human papillomavirus infection (HPV) and SLT have been associated with oral cancer, this study examined the presence of high-risk HPV in oral samples collected from tribal smokeless tobacco users in Mysuru, India. Between June and August 2019, 100 tribal females (50 SLT-users and 50 non-users) from rural Mysuru District, Karnataka, were enrolled in a cross-sectional study. Following informed consent, demographic data and oral samples were collected and processed using a digene HC2 High-Risk HPV DNA test (Qiagen, USA). On average participants were 45.5 (SD: ±6.6) years. Chronic SLT users were mostly married (73%), Hindu (100%), illiterate (62%), and employed (90%). One woman was positive for high-risk HPV infection. Oral HPV infection was low in this sample and this is consistent with the literature from other low and middle-income countries. SLT use is high in this group so interventions to reduce tobacco use are warranted.

Transcriptome-wide m6A methylome analysis uncovered the changes of m6A modification in oral pre-malignant cells compared with normal oral epithelial cells

As the most common post-transcriptional RNA modification, m⁶A methylation extensively regulates the structure and function of RNA. The dynamic and reversible modification of m⁶A is coordinated by m⁶A writers and erasers. m⁶A reader proteins recognize m⁶A modification on RNA, mediating different downstream biological functions. mRNA m⁶A modification and its corresponding regulators play an important role in cancers, but its characteristics in the precancerous stage are still unclear. In this study, we used oral precancerous DOK cells as a model to explore the characteristics of transcriptome-wide m⁶A modification and major m⁶A regulator expression in the precancerous stage compared with normal oral epithelial cell HOEC and oral cancer cell SCC-9 through MeRIP-seq and RT-PCR. Compared with HOEC cells, we found 1180 hyper-methylated and 1606 hypo-methylated m⁶A peaks and 354 differentially expressed mRNAs with differential m⁶A peaks in DOK cells. Although the change of m⁶A modification in DOK cells was less than that in SCC-9 cells, mRNAs with differential m⁶A in both cell lines were enriched into many identical GO terms and KEGG pathways. Among the 20 known m⁶A regulatory genes, FTO, ALKBH5, METTL3 and VIRMA were upregulated or downregulated in DOK cells, and the expression levels of 10 genes such as METTL14/16, FTO and IGF2BP2/3 were significantly changed in SCC-9 cells. Our data suggest that precancerous cells showed, to some extent, changes of m⁶A modification. Identifying some key m⁶A targets and corresponding regulators in precancerous stage may provide potential intervention targets for the prevention of cancer development through epigenetic modification in the future.

Overview of Candida albicans and Human Papillomavirus (HPV) Infection Agents and their Biomolecular Mechanisms in Promoting Oral Cancer in Pediatric Patients

Oral carcinoma represents one of the most common malignancies worldwide. Oral squamous cell carcinomas (OSCCs) account over 90% of all oral malignant tumors and are characterized by high mortality in the advanced stages. Early diagnosis is often a challenge for its ambiguous appearance in early stages. Mucosal infection by the human papillomavirus (HPV) is responsible for a growing number of malignancies, particularly cervical cancer and oropharyngeal carcinomas. In addition, Candida albicans (C. albicans), which is the principal fungi involved in the oral cancer development, may induce carcinogenesis through several mechanisms, mainly promoting inflammation. Medical knowledge and research on adolescent/pediatric patients' management and prevention are in continuous evolution. Besides, microbiota can play an important role in maintaining oral health and therefore all human health. The aim of this review is to evaluate epidemiological and pathophysiological characteristics of the several biochemical pathways involved during HPV and C. albicans infections in pediatric dentistry.

Natural Compounds for Preventing Ear, Nose, and Throat-Related Oral Infections

Oral health is an essential element in maintaining general well-being. By preserving the complex equilibrium within the oral microbial community, commensal microorganisms can protect against extrinsic pathogenic threats. However, when an imbalance occurs, the organism is susceptible to a broad range of infections. Synthetic drugs can be administered to help the body fight against the fungal, bacterial, or viral burden. Nonetheless, they may produce undesirable consequences such as toxicity, adverse effects, and drug resistance. In this respect, research has focused on finding safer and more efficient alternatives. Particularly, increasing attention has been drawn towards developing novel formulations based on natural compounds. This paper reviews the plant-based, algae-based, and beehive products investigated for their antimicrobial properties, aiming to thoroughly present the state of the art on oral infection prevention in the ear, nose, and throat (ENT) field.

Overview of Oral Potentially Malignant Disorders: From Risk Factors to Specific Therapies

Oral squamous cell carcinoma (OSCC) is a very aggressive cancer, representing one of the most common malignancies worldwide. Oral potentially malignant disorders (OPMDs) regroup a variegate set of different histological lesions, characterized by the potential capacity to transform in OSCC. Most of the risk factors associated with OSCC are present also in OPMDs' development; however, the molecular mechanisms and steps of malignant transformation are still unknown. Treatment of OSCC, including surgery, systemic therapy and radiotherapy (alone or in combination), has suffered a dramatic change in last years, especially with the introduction of immunotherapy. However, most cases are diagnosed during the advanced stage of the disease, decreasing drastically the survival rate of the patients. Hence, early diagnosis of premalignant conditions (OPMDs) is a priority in oral cancer, as well as a massive education about risk factors, the understanding of mechanisms involved in malignant progression and the development of specific and more efficient therapies. The aim of this article is to review epidemiological, clinical, morphological and molecular features of OPMDs, with the purpose to lay the foundation for an exhaustive comprehension of these lesions and their ability of malignant transformation and for the development of more effective and personalized treatments.

Human papillomavirus, Epstein-Barr virus, and Candida albicans co-infection in oral leukoplakia with different degrees of dysplasia

OBJECTIVES

To identify human papillomavirus (HPV), Epstein-Barr virus (EBV), and Candida albicans in oral leukoplakia with different degrees of dysplasia.

MATERIALS AND METHODS

An observational, cross-sectional, descriptive study was performed using 30 formalin-fixed and paraffin-embedded tissues from patients with clinical suspicion of leukoplakia and confirmed diagnosis of oral dysplasia. Histological analyses were performed by two pathologists (interobserver) and dysplasias were classified as mild, moderate, or severe. Conventional PCR was used to detect HPV and EBV viruses and C. albicans. To determine the association between each microorganism with different degrees of dysplasia a Chi-square test was employed.

RESULTS

The tongue was the most common site for leukoplakias (71.4%) in females with a mean age of 50 years (ranging between 30 to 50 years old; 57.1%). EBV was the most frequently detected (73.3%), followed by HPV (43.3%), mainly of type 16 (40%), and C. albicans (23.3%). Significant differences were observed between degrees of dysplasia and HPV presence (p = 0.005). In lesions positive for HPV, EBV, and C. albicans the most frequent histological changes were hyperkeratosis, irregular interpapillary ridges, and loss of basal stratum cell polarity.

CONCLUSION

Co-infection with human papillomavirus, Epstein Barr virus, and Candida albicans in oral leukoplakia could be associated with dysplastic changes.

Oral Potentially Malignant Disorders (OPMD): What is the clinical utility of dysplasia grade?

INTRODUCTION

Oral epithelial dysplasia is considered a potential histologic precursor of subsequent squamous cell cancer. As standard clinical practice, pathologists grade dysplasia to assess risk for progression to malignancy. Except for the most advanced grade, severe dysplasia, dysplasia grading has failed to correlate well with the risk to develop invasive cancer. The questions of what process dysplasia grading best represents and what clinical utility dysplasia grading may have are explored.

AREAS COVERED

This narrative review is based on PubMed search with emphasis on papers since 2010. Epithelial dysplasia as a precursor lesion of cancer and dysplasia grading as a risk assessment tool for progression to cancer are discussed. The close clinical association of dysplasia with known carcinogens, alcohol, and tobacco products is presented.

EXPERT OPINION

Oral epithelial dysplasia is often, associated with prolonged exposure to tobacco and alcohol products. With reduction of carcinogen exposure, dysplasia is known to regress in some cases. It is proposed that histologic dysplasia grade together with macroscopic images of dysplastic clinical lesions be used as an educational tool to incentivize patients to reduce their known carcinogen exposure. This strategy has the potential to reduce lesion progression thereby reducing the disease burden of oral cancer.

Fourier Transform Infrared Spectroscopy in Oral Cancer Diagnosis

Oral cancer is one of the most common cancers worldwide. Despite easy access to the oral cavity and significant advances in treatment, the morbidity and mortality rates for oral cancer patients are still very high, mainly due to late-stage diagnosis when treatment is less successful. Oral cancer has also been found to be the most expensive cancer to treat in the United States. Early diagnosis of oral cancer can significantly improve patient survival rate and reduce medical costs. There is an urgent unmet need for an accurate and sensitive molecular-based diagnostic tool for early oral cancer detection. Fourier transform infrared spectroscopy has gained increasing attention in cancer research due to its ability to elucidate qualitative and quantitative information of biochemical content and molecular-level structural changes in complex biological systems. The diagnosis of a disease is based on biochemical changes underlying the disease pathology rather than morphological changes of the tissue. It is a versatile method that can work with tissues, cells, or body fluids. In this review article, we aim to summarize the studies of infrared spectroscopy in oral cancer research and detection. It provides early evidence to support the potential application of infrared spectroscopy as a diagnostic tool for oral potentially malignant and malignant lesions. The challenges and opportunities in clinical translation are also discussed.

Metabolomics study reveals the potential evidence of metabolic reprogramming towards the Warburg effect in precancerous lesions

Background: Most tumors have an enhanced glycolysis flux, even when oxygen is available, called the aerobic glycolysis or the Warburg effect. Metabolic reprogramming promotes cancer progression, and is even related to the tumorigenesis. However, it is not clear whether the observed metabolic changes act as a driver or a bystander in cancer development.

Methods: In this study, the metabolic characteristics of oral precancerous cells and cervical precancerous lesions were analyzed by metabolomics, and the expression of glycolytic enzymes in cervical precancerous lesions was evaluated by RT-PCR and Western blot analysis.

Results: In total, 115 and 23 metabolites with reliable signals were identified in oral cells and cervical tissues, respectively. Based on the metabolome, oral precancerous cell DOK could be clearly separated from normal human oral epithelial cells (HOEC) and oral cancer cells. Four critical differential metabolites (pyruvate, glutamine, methionine and lysine) were identified between DOK and HOEC. Metabolic profiles could clearly distinguish cervical precancerous lesions from normal cervical epithelium and cervical cancer. Compared with normal cervical epithelium, the glucose consumption and lactate production increased in cervical precancerous lesions. The expression of glycolytic enzymes LDHA, HK II and PKM2 showed an increased tendency in cervical precancerous lesions compared with normal cervical epithelium.

Conclusions: Our findings suggest that cell metabolism may be reprogrammed at the early stage of tumorigenesis, implying the contribution of metabolic reprogramming to the development of tumor.

Tissue biomarkers for predicting the risk of oral cancer in patients diagnosed with oral leukoplakia: A systematic review

OBJECTIVES

We performed a systematic review to evaluate the published biomarkers related to oral leukoplakia (OL), aiming to identify the biomarkers that indicate any future risk of cancer in patients with oral leukoplakia.

METHODS

A search strategy was developed for three main electronic databases: PubMed, Cochrane Library, and EBSCO, and also for Google Scholar, until February 28, 2020. The study selection was performed in a two-phase process aiming at studies assessing tissue biomarkers for "malignant transformation of OL." Risk of bias analysis of included studies was performed using the Quality in Prognosis Studies Tool.

RESULTS

From 3,130 articles initially identified by searching databases, a total of 46 studies were included in this systematic review, with a combined sample of 3,783 patients, of whom 1,047 presented with malignant transformation of a previously diagnosed OL as reported by the authors. The cancer incidence in the whole group was 27.6% (range: 5.4% to 54.1%). The studies were derived from different geographic areas, including Asia (n = 21), Europe (n = 15), North America (n = 9), and Oceania (n = 1). There were 49 different molecular biomarkers evaluated in the 46 included studies: p53 and podoplanin proteins were the most frequently reported, followed by abnormalities at particular chromosomal loci (e.g., LOH). Risk of bias analysis revealed concerns associated with "measurement of prognostic factor," "study confounding" and "statistical analysis and reporting."

CONCLUSIONS

Substantial heterogeneity and lack of standardized reporting of data among the studies were identified. The most promising biomarkers reported to have a significant association with the malignant transformation in OL included podoplanin and chromosomal loci abnormalities. A critical examination of the follow-up studies on OL published so far indicated that tissue biomarkers that could predict the risk of oral cancer in patients with OL are still in a discovery phase.

Association of Human Papillomavirus With Oral Lichen Planus and Oral Leukoplakia: A Meta-analysis

OBJECTIVES

To estimate the association of human papillomavirus (HPV) infection with oral lichen planus (OLP) and oral leukoplakia (OLK), and determine risk cofactors.

STUDY DESIGN

Seven databases were searched for case-control or cross-sectional studies of OLP and OLK with healthy controls, published between 1976 and 2020. The Meta package of R software was applied to calculate the pooled odds ratios (OR) and 95% confidence interval (CI).

RESULTS

Thirty-six articles were finally included. OLP and OLK cases had a higher association with HPV infection than controls (OLP: OR: 4.91, 95% CI: 2.76-8.72; OLK: OR: 2.51, 95% CI: 1.55-4.07). In subgroup analyses, the OR of HPV infection was higher with erosive lesions than with nonerosive lesions (OLP: OR: 5.36 and 3.47, respectively; OLK: OR: 3.34 and 3.21, respectively). Oral lesions were more strongly associated with HPV16/18 than with HPV6/11 (OLP: OR: 7.84 and 1.42, respectively; OLK: OR: 6.05 and 1.87, respectively) and varied by geographic region (OLP: OR: 4.01-7.02; OLK: OR: 1.46-27.13).

CONCLUSIONS

Oral HPV infection, particularly infection with HPV 16/18, was strongly associated with OLP and OLK. Risk cofactors included erosive lesions and geographic region.

High-risk human papillomavirus in patients with oral leukoplakia and oral squamous cell carcinoma-A multi-centre study in Sweden, Brazil and Romania

OBJECTIVES

Although causal associations between oral leukoplakia (OL), oral squamous cell carcinoma (OSCC) and high-risk human papillomavirus (HR-HPV) have been speculated upon in several reports, conclusive evidence has not been presented. This study investigates whether the number of cases of HR-HPV in OL has increased over time and whether the prevalence of HR-HPV-positive OL differs in various parts of the world.

PATIENTS AND METHODS

A total of 432 patients with OL from Sweden, Brazil and Romania were analysed. Patients were divided into historical (1992-2002) and contemporary (2011-2017) cohorts from the respective countries. Seventeen patients with OL developed oral squamous cell carcinoma (OSCC). A real-time PCR assay, targeting HPV sub-types 6,11,16,18,31,33,35,39,45,52,56,58 and 59, was performed to detect HR-HPV in patients with OL.

RESULTS

In the Swedish and Romanian cohorts, none of the investigated HPV sub-types were detected. In the Brazilian cohorts, five patients with OL (3%) were positive for HR-HPV, including four patients from the contemporary cohort (HPV 16, 31, 33) and one from the historical cohort (HPV 11). All the cases of OL that transformed into OSCC were HR-HPV-negative, as were the corresponding tumours.

CONCLUSIONS

In summary, the prevalence of HR-HPV in OL is low in all the tested countries, and the incidence has not changed over time. HR-HPV in OL does not seem to be a driver of oncogenesis.

Oral Human Papillomavirus: a multisite infection

Background

The Human Papillomavirus (HPV) has different strategies for persist in the cells. This characteristic has led us to consider the presence of the virus in tissues of the oral cavity that had no clinical signs of infection. The aim of this study was to detect the presence of DNA-HPV at multiple sites of the oral cavity.

Material and Methods

A case-control study was designed: Oral Squamous Carcinoma Group (OSCG), healthy n=72 and Control Group (CG), n=72, healthy volunteers paired by sex and age with OSCG. Four samples were taken from OSCG: saliva, biopsy, brush scraping of lesion and contralateral healthy side. In CG a saliva sample and a scratch of the posterior border of tongue were collected. HPV was detected by PCR using Bioneer Accuprep genomic DNA Extraction kit, and consensus primers MY09 and MY11. Chi square test was applied.

Results

432 samples were obtained from 144 individuals. DNA-HPV was detected in 30 (42%) of OSCG subjects and 3(4%) of CG. Two or more positive samples were obtained in 67% of the OSCG, 67% in saliva and 60% in biopsy; in CG 100% of the individuals were positive in the two samples.

Conclusions

HPV is frequently present in oral cavity as a multifocal infection, even without the presence of clinical lesions.

Key words:HPV, Oral cavity, Saliva, Oral cancer.

Human papilloma virus genotypes in dysplasia and epithelial hyperplasia of oral cavity using the luminex xmap technology. A multicenter study

Background

Oral cancer associated with high risk (HPV-HR) human papilloma virus (HPV) has been increasing. HPV-HR has been associated with epithelial dysplasia, however, little information exists on its frequency in epithelial hyperplasia lesions. The aim of this study is to compare HPV genotypes in dysplastic and hyperplastic lesions of oral cavity.

Material and Methods

Two hundred and fifty oral lesions: 131 dysplasia and 119 hyperplasia from two regions of Colombia were evaluated. One hundred seventy-four coming from urban area and 104 from a high risk population to oral cancer from a rural area. HPV was identified by qPCR and Twenty-four HPVs genotypes were evaluated by Luminex® technology. Logistic regressions were performed to establish the associations between HPV infections with oral dysplasia.

Results

Twenty-eight percent (70/250) of the samples were positives for any HPV and HPV-HRs were more frequently than low risk HPVs. HPV-16 was the most detected genotype (16%) followed by HPV-31, 53, 18 and 45. HPV, HPV-HRs and HPV-16 were only associated with dysplasia in urban area; OR 3.28 (CI 95% 1.49-7.17), OR 7.94 (CI 95% 2.97-21.2) and OR 5.90 (CI 95% 2.05-17). Individuals in rural area showed more HPV and HPV-HRs infection in hyperplasic lesions than urban population. The majority of HPV+ lesions had multi-type of HPV (52/70) and the urban individuals showed more genotypes than rural population.

Conclusions

HPV-.HRs are frequently found in hyperplastic and dysplastic epithelial lesions. HPV-HRs and HPV-16 were associated with dysplasia in urban population. Rural high risk population and urban population differ in the frequency and variety of HPV genotypes.

Key words:Human papilloma virus, epithelial dysplasia, epithelial hyperplasia, HPV-genotypes.

Evaluation of the Accuracy of Liquid-Based Oral Brush Cytology in Screening for Oral Squamous Cell Carcinoma

This study evaluates the accuracy of the results of liquid-based oral brush cytology and compares it to the histology and/or the clinical follow-ups of the respective patients. A total of 1352 exfoliated specimens were collected with an Orcellex brush from an identical number of oral lesions, then cytological diagnoses were made using liquid-based cytology. The final diagnoses in the study were 105 histologically proven squamous cell carcinomas (SCCs), 744 potentially malignant lesions and 503 cases of traumatic, inflammatory or benign hyperplastic oral lesions. The sensitivity and specificity of the liquid-based brush biopsy were 95.6% (95% CI 94.5–96.7%) and 84.9% (95% CI 83.0–86.8%), respectively. This led to the conclusion that brush biopsy is potentially a highly sensitive and reliable method to make cytological diagnoses of oral neoplasia. The main advantage of a brush biopsy over a scalpel biopsy is that it is less invasive and is more tolerated by the patients. Therefore, more lesions can be screened and more cancers can be detected at an early stage.

Oral mucosal mesenchymal stem cell‑derived exosomes: A potential therapeutic target in oral premalignant lesions

Emerging evidence indicates that mesenchymal stem cells (MSCs) serve an indispensable role in the tumor microenvironment. However, whether MSCs participate in the development of oral carcinogenesis remains unclear. The present study isolated MSCs from clinical tissues and investigated the differences of MSCs derived from normal oral mucosa (N-MSC), oral leukoplakia with dysplasia (LK-MSC) and oral carcinoma (Ca-MSC). The results revealed that the LK-MSCs exhibited reduced proliferation and migration, compared with the N-MSCs and Ca-MSCs. Furthermore, it was demonstrated that the exosomes secreted by LK-MSCs have significant roles in promoting proliferation, migration and invasion in vitro, which was similar to the Ca-MSC-derived exosomes. The promoting effect was also demonstrated in a 3D coculture model. When the secretion of exosomes was blocked, the promoting effect of LK-MSCs was reversed. Based on a microarray analysis of MSC-derived exosomes, microRNA-8485 (miR-8485) was identified to be ectopically expressed. The exosomal miR-8485 was capable of promoting the proliferation, migration and invasion of tumor cells. Therefore, the present study highlights the significance of MSC-derived exosomes and exosomal miR-8485 in premalignant lesions and carcinogenesis. Intervention with the secretion of MSC-derived-exosomes may be an innovative strategy to retard the carcinogenesis.

Metabolomics study of oral cancers

BACKGROUND

Oral cancer is one of the most frequently occurring cancers. Metabolic reprogramming is an important hallmark of cancer. Metabolomics characterizes all the small molecules in a biological sample, and a complete set of small molecules in such sample is referred as metabolome. Nuclear magnetic resonance spectroscopy and mass spectrometry are two widely used techniques in metabolomics studies. Increasing evidence demonstrates that metabolomics techniques can be used to explore the metabolic signatures in oral cancer. Elucidation of metabolic alterations in oral cancer is also important for the understanding of its pathological mechanisms.

AIM OF REVIEW

In this paper, we summarize the latest progress of metabolomics study in oral cancer and provide the suggestions for the future studies.

KEY SCIENTIFIC CONCEPTS OF REVIEW

The metabolomics studies in saliva, serum, and tumor tissues revealed the existence of metabolic signatures in bio-fluids and tissues of oral cancer, and several tumor-specific metabolites identified in individual study could discriminate oral cancer from healthy controls or precancerous lesions, which are potential biomarkers for the screening or early diagnosis of oral cancer. Metabolomics study of oral cancers in the future should aim to establish a routine procedure with high sensitivity, profile intracellular metabolites to find out the metabolic characteristics of tumor cells, and investigate the mechanism behind metabolomic alterations and the metabolic response of cancer cells to chemotherapy.

Risk factors and etiopathogenesis of potentially premalignant oral epithelial lesions

Potentially malignant oral mucosal disease has some ability to give rise to malignancy of the oral epithelium, that is, oral squamous cell carcinoma (OSCC). The present article provides a succinct review of the possible or probable causes of potentially premalignant oral epithelial lesions. There is a focus upon studies that examined the causes or etiologic associations with clinically likely or histopathologically detectable oral epithelial dysplasia.

Intraoral Potentially Malignant Disorders in a Brazilian Oral Pathology Service: Epidemiological, Clinical, and Histopathological Findings

The aim of this study was to investigate the characteristics of individuals with intraoral potentially malignant disorders (IOPMD) in an oral pathology service in Brazil. Cases were screened based on clinical diagnosis of leukoplakia (LKP), erythroleukoplakia (ELKP), and erythroplakia (EP). Clinical data and information regarding associated factors were gathered from biopsy reports. Histological diagnoses were collected from histopathological records. Among 208 IOPMD cases, 84.13% involved LKP; 11.1%, ELKP; and 4.8%, EP. The most affected sites were the gingiva and buccal mucosa. Histologically, epithelial dysplasia was present in 66.8% of the lesions, acanthosis and hyperkeratosis without epithelial dysplasia were present in 27.9%, and squamous cell carcinoma was present in 2.9%. Most patients were males, fair-skinned, with mean age of 53.4 years. Chronic smokers represented 73% of subjects, of which 30% also consumed alcohol. Smokers and drinkers were mostly males (p < 0.001). EP and ELKP represented histologically more severe degrees of epithelial dysplasia than LKP (p < 0.001). In conclusion, individuals with IOPMD were more frequently fair-skinned men in the sixth decade of life, with smoking habit. Special attention is required to clinical diagnoses of ELKP and EP since the prevalence of severe epithelial dysplasia, in situ carcinoma, and squamous cell carcinoma is higher than in LKP.