Role of human papillomavirus in oral squamous cell carcinoma and oral potentially malignant disorders: A review of the literature

Salivary Chemical Barrier Proteins in Oral Squamous Cell Carcinoma-Alterations in the Defense Mechanism of the Oral Cavity

Oral squamous cell carcinoma (OSCC) is one of the most frequent types of head and neck cancer. Despite the genetic and environmental risk factors, OSCC is also associated with microbial infections and/or dysbiosis. The secreted saliva serves as the chemical barrier of the oral cavity and, since OSCC can alter the protein composition of saliva, our aim was to analyze the effect of OSCC on the salivary chemical barrier proteins. Publicly available datasets regarding the analysis of salivary proteins from patients with OSCC and controls were collected and examined in order to identify differentially expressed chemical barrier proteins. Network analysis and gene ontology (GO) classification of the differentially expressed chemical barrier proteins were performed as well. One hundred and twenty-seven proteins showing different expression pattern between the OSCC and control groups were found. Protein-protein interaction networks of up- and down-regulated proteins were constructed and analyzed. The main hub proteins (IL-6, IL-1B, IL-8, TNF, APOA1, APOA2, APOB, APOC3, APOE, and HP) were identified and the enriched GO terms were examined. Our study highlighted the importance of the chemical barrier of saliva in the development of OSCC.

Review of Disease-Specific microRNAs by Strategically Bridging Genetics and Epigenetics in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is one of the most prevalent human malignancies and a global health concern with a poor prognosis despite some therapeutic advances, highlighting the need for a better understanding of its molecular etiology. The genomic landscape of OSCC is well-established and recent research has focused on miRNAs, which regulate gene expression and may be useful non-invasive biomarkers or therapeutic targets. A plethora of findings regarding miRNA expression have been generated, posing challenges for the interpretation and identification of disease-specific molecules. Hence, we opted to identify the most important regulatory miRNAs by bridging genetics and epigenetics, focusing on the key genes implicated in OSCC development. Based on published reports, we have developed custom panels of fifteen major oncogenes and five major tumor suppressor genes. Following a miRNA/target gene interaction analysis and a comprehensive study of the literature, we selected the miRNA molecules which target the majority of these panels that have been reported to be downregulated or upregulated in OSCC, respectively. As a result, miR-34a-5p, miR-155-5p, miR-124-3p, miR-1-3p, and miR-16-5p appeared to be the most OSCC-specific. Their expression patterns, verified targets, and the signaling pathways affected by their dysregulation in OSCC are thoroughly discussed.

The correlation between human papillomavirus and oral lichen planus: A systematic review of the literature

INTRODUCTION

Oral lichen planus (OLP) is a chronic inflammatory disorder with cell-induced immunopathological responses and is considered a potential malignancy disorder in the oral cavity. Due to the high prevalence of OLP as well as the potential for malignancy, human papillomaviruses (HPVs) may play an important role in it. Although previous studies have explored the possible relationship between HPV and OLP, the findings have been conflicting and nonconclusive. This study aims to review the studies that investigated HPV-16 and HPV-18 in OLP.

METHODS AND MATERIALS

The research protocol followed the Preferred Reporting Items for Systematic Reviews (PRISMA2020) checklist. The online databases Pubmed, Scopus, Embase, Google Scholar, and Cochrane were searched using the following individual keywords: "OLP" OR "Oral Lichen Planus" OR "HPV" OR "Human Papillomavirus." The search strategy resulted in the selection of 80 articles. The articles were evaluated, and after duplication removal, 53 abstracts were reviewed, resulting in the selection of 25 studies according to inclusion and exclusion criteria. The risk of bias assessment was done by using the Modified Newcastle-Ottawa quality assessment scale. The overall prevalence of HPV in OLP lesions varied from 2.7% to 70%, depending on the type of diagnostic method used.

CONCLUSION

Despite the studies conducted on the relationship between OLP and HPV infection, there is still no conclusive evidence that HPV can play a role in the etiopathogenesis of OLP, either in clinical manifestations or in the malignant transformation of lesions.

Expression of Human Papillomavirus and the p16 Gene in Oral Potentially Malignant Disorders (OPMD): a Comparative Study With Oral Squamous Cell Carcinoma

BACKGROUND

The incidence of oral squamous cell carcinoma (OSCC) of the tongue is increasing in the younger population without traditional risk habits that lead researchers to find other related factors such as diet and viruses, especially human papillomavirus (HPV). It is noteworthy that many OSCCs develop from oral potentially malignant disorders (OPMDs). Correct diagnosis and timely management of OPMDs may help to prevent malignant transformation, and therefore it is worth seeing the involvement of HPV in OPMDs and oral cancers, as the preventive and curative measures in HPV-induced cancer types are different from the conventional types of OPMDs and OSCCs. Therefore, the main objective of this study was to identify a relationship between HPV and p16 in OPMDs and compare it with OSCC.

METHODS

This study was conducted on 83 cases of known OSCCs and OPMDs (oral submucous fibrosis, leukoplakia, and oral lichen planus). Assays, such as polymerized chain reaction (PCR) and reverse transcription-PCR, were carried out for HPV and p16 . The results were compared with clinical information and with the literature. The results were analyzed using SPSS 16.0 for windows.

RESULTS

P16 expression was mostly seen in males than in female patients. Out of 21 cases of keratosis with dysplasia, 19% expressed p16 . Of 26 oral lichen planus patients, 29% showed the p16 gene with immunohistochemistry. Interestingly, a high percentage of OSF cases expressed p16 (48.27%). Minimal expression was observed in OSCC (6.25%). HPV DNA was detected in 2.4% of the total sample. Both p16 and HPV were detected in a single case of OSCC. OPMDs expressed a significant amount of the p16 gene by immunohistochemistry and reverse transcription-PCR technique when compared with malignant lesions, suggesting a possible inactivation of the p16 gene. HPV and p16 are mostly negative in our OSCC sample, exhibiting low prevalence.

CONCLUSIONS

OPMDs expressed a significant amount of the p16 gene when compared with malignant lesions, suggesting a possible inactivation of the p16 gene. Although OSF expressed p16 , HPV was not detected, suggesting that over-expression could be independent of HPV. OSCC shows low HPV prevalence.

DNA Damage Response Gene Signature as Potential Treatment Markers for Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is a rapidly progressive cancer that often develops resistance against DNA damage inducers, such as radiotherapy and chemotherapy, which are still the standard of care regimens for this tumor. Thus, the identification of biomarkers capable of monitoring the clinical progression of OSCC and its responsiveness to therapy is strongly required. To meet this need, here we have employed Whole Genome Sequencing and RNA-seq data from a cohort of 316 patients retrieved from the TCGA Pan-Cancer Atlas to analyze the genomic and transcriptomic status of the DNA damage response (DDR) genes in OSCC. Then, we correlated the transcriptomic data with the clinical parameters of each patient. Finally, we relied on transcriptomic and drug sensitivity data from the CTRP v2 portal, performing Pearson's correlation analysis to identify putative vulnerabilities of OSCC cell lines correlated with DDR gene expression. Our results indicate that several DDR genes show a high frequency of genomic and transcriptomic alterations and that the expression of some of them correlates with OSCC grading and infection by the human papilloma virus. In addition, we have identified a signature of eight DDR genes (namely CCNB1, CCNB2, CDK2, CDK4, CHECK1, E2F1, FANCD2, and PRKDC) that could be predictive for OSCC response to the novel antitumor compounds sorafenib and tipifarnib-P1. Altogether, our data demonstrate that alterations in DDR genes could have an impact on the biology of OSCC. Moreover, here we propose a DDR gene signature whose expression could be predictive of OSCC responsiveness to therapy.

Molecular characterization and risk factors of oral high-risk human papillomavirus among females in Punjab, Pakistan

BACKGROUND

The development of oral and oropharyngeal cancers is associated with human papillomavirus (HPV) infection. However, debate exists about the prevalence of high-risk oral HPV (HR-HPV) and its associated risk factors. This study evaluated the distribution of genotypes and associated risk factors of oral HR-HPV infection in the normal oral mucosa of the Pakistani female population with general gynecological problems.

METHODS

A total of 200 females from a regional gynecological hospital in Pakistan were included in this cross-sectional study. A self-administered questionnaire was carried out, followed by the study participants' oral and dental examinations. Whole saliva was collected by a drooling method. The viral DNA extraction and oral HR-HPV genotyping were detected via real-time polymerase chain reaction.

RESULTS

Among the 200 females (mean age, 37.76 years), 22 females (11%) were positive for oral HR-HPV DNA. Single oral HR-HPV infection was seen in 8%, whereas co-infection was observed in 3% with HPV16 and HPV18 most common genotypes. Comparison of the risk factors like oral sex history odds ratio (OR 8.21, 95% confidence interval [CI] 1.85-28.16; p < 0.005), and open-mouth kissing (OR, 5.17; 95% CI 1.48-27.41; p = 0.005) with oral HR-HPV infection was found to be significantly associated.

CONCLUSION

In Pakistan, oral HR-HPV-positive infection is not uncommon; HPV16 and HPV18 are the most frequent genotypes. Furthermore, this study also provides data that oral HR-HPV positive infection was significantly associated with sexual behaviors. Therefore, preventive health efforts, like health education and vaccination, should be practiced.

Oral Papillomatosis: Its Relation with Human Papilloma Virus Infection and Local Immunity—An Update

Oral papilloma lesions may appear as a result of HPV infection, or not, and only special molecular methods could differentiate them. Low-risk and high-risk HPV types could induce oral HPV papillomatosis with different natural evolution, clearance and persistence mechanisms. The pathogenic mechanisms are based on the crosstalk between the oral epithelial and immune cells and this very efficient virus. HPV acts as a direct inducer in the process of transforming a benign lesion into a malignant one, the cancerization process being also debated in this paper. According to the degree of malignity, three types of papillomatous lesions can be described in the oral cavity: benign lesions, potential malign disorders and malignant lesions. The precise molecular diagnostic is important to identify the presence of various virus types and also the virus products responsible for its oncogenicity. An accurate diagnostic of oral papilloma can be established through a good knowledge of etiological and epidemiological factors, clinical examination and laboratory tests. This review intends to update the pathogenic mechanisms driving the macroscopic and histological features of oral papillomatosis having HPV infection as the main etiological factor, focusing on its interreference in the local immunity. In the absence of an accurate molecular diagnostic and knowledge of local immunological conditions, the therapeutic strategy could be difficult to decide.

Salivary detection of high-risk human papillomavirus 16 in oral squamous cell carcinoma using polymerase chain reaction in the South Indian population

Introduction

Human papilloma virus (HPV) has been associated with oral squamous cell carcinoma (OSCC) as a potential carcinogen. There are several types of HPV, of which type 16 has been strongly implicated in carcinogenesis. HPV16 in saliva can potentially facilitate early detection of subclinical cases that may warrant further diagnosis, monitoring and intervention.

Aim

The aim of this study was to evaluate the presence of HPV 16 in saliva and lesional tissue of OSCC and to determine the use of saliva as an alternative non invasive diagnostic tool in HPV16 identification.

Materials and methods

30 cases of Histopathologically confirmed OSCC with HPV positive on ELISA were taken up for the study. The tumour tissue and saliva sample of each patient were obtained to detect the presence of specific HPV16 genotype by polymerase chain reaction (PCR). The data was subjected to statistical analysis using Student t-test.

Results

In our study we found 28/30, 26/30 positive for HPV 16 in tissue and saliva samples respectively on PCR analysis. The P value was statistically significant (0.00).

Conclusion

The study revealed significant prevalence of HPV 16 among both tissue and salivary specimens of OSCC patients in south Indian population. Though, the yielded content was relatively less in saliva, it can be concluded that, saliva being a non invasive tool proved to be as useful as tissue specimen and can be used as an alternative indicator of HPV16 positivity in OSCC.

The Role of the Oral Microbiota in the Etiopathogenesis of Oral Squamous Cell Carcinoma

Dysbiosis in the oral environment may play a role in the etiopathogenesis of oral squamous cell carcinoma (OSCC). This review aims to summarize the current knowledge about the association of oral microbiota with OSCC and to describe possible etiopathogenetic mechanisms involved in processes of OSCC development and progression. Association studies included in this review were designed as case–control/case studies, analyzing the bacteriome, mycobiome, and virome from saliva, oral rinses, oral mucosal swabs, or oral mucosal tissue samples (deep and superficial) and comparing the results in healthy individuals to those with OSCC and/or with premalignant lesions. Changes in relative abundances of specific bacteria (e.g., Porphyromonas gingivalis, Fusobacterium nucleatum, Streptococcus sp.) and fungi (especially Candida sp.) were associated with OSCC. Viruses can also play a role; while the results of studies investigating the role of human papillomavirus in OSCC development are controversial, Epstein–Barr virus was positively correlated with OSCC. The oral microbiota has been linked to tumorigenesis through a variety of mechanisms, including the stimulation of cell proliferation, tumor invasiveness, angiogenesis, inhibition of cell apoptosis, induction of chronic inflammation, or production of oncometabolites. We also advocate for the necessity of performing a complex analysis of the microbiome in further studies and of standardizing the sampling procedures by establishing guidelines to support future meta-analyses.

Human papillomavirus and Chlamydia trachomatis in oral and genital mucosa of women with normal and abnormal cervical cytology

Background

HPV and C.trachomatis are the most prevalent, viral and bacterial STI worldwide. Both commonly have an asymptomatic development and can evolve into a persistent infection which, added to coinfections, may be important cofactors for the oncogenic transformation.

Objective

Evaluate the prevalence of oral and genital HPV and C.trachomatis infection in women with normal and abnormal cervical cytology.

Study design

The cross-sectional study included 200 swabs, 100 oral and 100 cervical from 50 women with normal and 50 with abnormal cervical cytology. HPV and C.trachomatis infections were detected using PCR with specific primers.

Results

HPV DNA was detected in 27% (n = 27/100) of women with normal and abnormal cytology. Out of 100 genital samples we detected HPV DNA in 18% (n = 18/100) and 14% (n = 14/100) out of 100 oral samples. HPV genotypes detected were genotype 6 of low-risk and 16, 31, 52, 58 and 16–31 coinfection of high-risk. C.trachomatis DNA was detected in 49% (n = 49/100) of patients. Out of 100 genital samples we detected C.trachomatis in 35% (n = 35/100) and 31% (n = 31) out of 100 oral samples. There is statistically significant (p < 0.05) between cytology and HPV and C.trachomatis infection but there is no statistically significant between cytology and the other characteristics.

Conclusions

Since the histology of oral mucosa resembles that of the uterine cervix, we can anticipate the presence of HPV and other STI which are detected in different lesions of genital areas and the oral mucosa. Therefore, is important C.trachomatis detection and specific treatment in asymptomatic women because this infection may increase the risk of HPV persistence and coinfection induces a pro-inflammatory environment that may promote the carcinogenesis.

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.

Dysbiosis of Oral Microbiota During Oral Squamous Cell Carcinoma Development

Infection with specific pathogens and alterations in tissue commensal microbial composition are intricately associated with the development of many human cancers. Likewise, dysbiosis of oral microbiome was also shown to play critical role in the initiation as well as progression of oral cancer. However, there are no reports portraying changes in oral microbial community in the patients of Indian subcontinent, which has the highest incidence of oral cancer per year, globally. To establish the association of bacterial dysbiosis and oral squamous cell carcinoma (OSCC) among the Indian population, malignant lesions and anatomically matched adjacent normal tissues were obtained from fifty well-differentiated OSCC patients and analyzed using 16S rRNA V3-V4 amplicon based sequencing on the MiSeq platform. Interestingly, in contrast to the previous studies, a significantly lower bacterial diversity was observed in the malignant samples as compared to the normal counterpart. Overall our study identified Prevotella, Corynebacterium, Pseudomonas, Deinococcus and Noviherbaspirillum as significantly enriched genera, whereas genera including Actinomyces, Sutterella, Stenotrophomonas, Anoxybacillus, and Serratia were notably decreased in the OSCC lesions. Moreover, we demonstrated HPV-16 but not HPV-18 was significantly associated with the OSCC development. In future, with additional validation, this panel could directly be applied into clinical diagnostic and prognostic workflows for OSCC in Indian scenario.

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.

EZB-ICR Cell Line: A New Established and Characterized Oral Squamous Cell Carcinoma Cell Line From Tongue

Background:

Tongue cancer is one of the most aggressive forms of oral squamous cell carcinoma which needs more investigations. Herein, we aimed to establish and characterize a tongue cancer cell line.

Methods:

Tumor tissue was obtained from a 70-year-old woman with tongue cancer. The established cell line named as EZB-ICR and characterized for doubling time, expression of specific markers, HPV corporation and migration status using flow cytometry, immunofluorescence staining, multiplex PCR, and migration assay.

Results:

EZB-ICR was negative for expression of mesenchymal specific markers, cytokeratin19, pan-cytokeratin, vimentin and EPCAM, but was positive for S100 and Nestin. No appearance of human papilloma virus DNA was seen. The doubling time of EZB-ICR was 31 hours and migration assay confirmed its metastatic nature.

Conclusion:

To the best of our knowledge, EZB-ICR is the first tongue human cancer cell line established in Iran, and its features make it appropriate for cancer-based in vitro studies and contribute to more studies on tongue cancer.

Detection of human papillomavirus in oropharyngeal squamous cell carcinoma

Worldwide there has been a significant increase in the incidence of oropharyngeal squamous cell carcinoma (OPSCC) etiologically attributed to oncogenic human papillomavirus (HPV). Reliable and accurate identification and detection tools are important as the incidence of HPV-related cancer is on the rise. Several HPV detection methods for OPSCC have been developed and each has its own advantages and disadvantages in regard to sensitivity, specificity, and technical difficulty. This review summarizes our current knowledge of molecular methods for detecting HPV in OPSCC, including HPV DNA/RNA polymerase chain reaction (PCR), loop-mediated isothermal amplification (LAMP), p16 immunohistochemistry (IHC), and DNA/RNA in situ hybridization (ISH) assays. This summary may facilitate the selection of a suitable method for detecting HPV infection, and therefore may help in the early diagnosis of HPV-related carcinoma to reduce its mortality, incidence, and morbidity.

Identification of HPV16-p16INK4a mediated methylation in oral potentially malignant disorder

To evaluate the possible involvement of epigenetic modulation by HPV16-p16^INK4a in oral potentially malignant disorder (OPMD). We generated DNA-methylation profiles, according to p16^INK4a expression and HPV16 genotype (positive or negative), of OPMD samples and p16^INK4a-HPV16 negative samples (used as control), using reduced-representation bisulphite sequencing (RRBS-Seq- Illumina) technology. Twelve samples, four for each group, as follows: 1) p16^INK4a+ HPV16+; 2) p16^INK4a+ HPV16-; 3) p16^INK4a- HPV16-, were analysed in triplicate for DNA-methylation profiles. Fifty-four per cent of DMRs were hypermethylated and 46% were hypomethylated. An increase in methylation of loci in OPMD was independent of the presence of HPV. The hypermethylated genes in HPV+ samples were associated with signalling pathways such as NICD traffics to nucleus, signalling by NOTCH1 (p = 0.008), Interferon-gamma (p = 0.008) and Interleukin-6 signalling (p = 0.027). The hypomethylated genes in HPV infection were associated with TRAF3-dependent IRF activation pathway (p = 0.002), RIG-I/MDA5 mediated induction of IFN-alpha/beta pathways (p = 0.005), TRAF6 mediated IRF7 activation (p = 0.009), TRIF-mediated TLR3/TLR4 signalling (p = 0.011) and MyD88-independent cascade release of apoptotic factors (p = 0.011). Protein association analysis of DMRs in OPMD revealed 19 genes involved in the cell cycle regulation, immune system, and focal adhesion. Aberrantly methylated loci in OPMD were observed in p16^INK4a positive samples which suggests that a shift in global methylation status may be important for cancer progression. The results suggest that HPV infection in OPMD induces modulation of genes related to the immune system and regulation of the cellular cycle.

Squamous cell papilloma of the gingiva with a "garlanding a tooth" appearance: Report of an unusual case

Squamous cell papilloma of the gingiva is a benign, asymptomatic, exophytic nonplaque-associated gingival lesion caused by human papillomavirus. It affects several areas of the oral cavity with a relatively lower predilection for gingiva. The finger-like clinical presentation may be scary, misleading and may be confused with other lesions. This report presents a case of squamous cell papilloma of the gingiva. We report an unusual case of squamous papilloma of the gingiva with an unusual "garlanding a tooth" appearance.

The Potential of Phytochemicals in Oral Cancer Prevention and Therapy: A Review of the Evidence

The etiological factors of oral cancer are complex including drinking alcohol, smoking tobacco, betel quid chewing, human papillomavirus infection, and nutritional deficiencies. Understanding the molecular mechanism of oral cancer is vital. The traditional treatment for patients with oral squamous cell carcinoma (e.g., surgery, radiotherapy, and chemotherapy) and targeted molecular therapy still have numerous shortcomings. In recent years, the use of phytochemical factors to prevent or treat cancer has received increasing attention. These phytochemicals have little or no toxicity against healthy tissues and are thus ideal chemopreventive agents. However, phytochemicals usually have low water solubility, low bioavailability, and insufficient targeting which limit therapeutic use. Numerous studies have investigated the development of phytochemical delivery systems to address these problems. The present article provides an overview of oral cancer including the etiological factors, diagnosis, and traditional therapy. Furthermore, the classification, dietary sources, anticancer bioactivity, delivery system improvements, and molecular mechanisms against oral cancer of phytochemicals are also discussed in this review.

The Role of Beta HPV Types and HPV-Associated Inflammatory Processes in Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinoma (cSCC) is a common form of skin cancer with a complex but not fully understood pathogenesis. Recent research suggests the role of beta human papillomavirus (HPV) types and HPV-associated inflammatory processes in cSCC development. Beta HPV types are components of the normal flora; however, under the influence of certain cofactors, the virus may trigger a malignant process. Dysregulation of the immune system (chronic inflammation and immunosuppression), environmental factors (ultraviolet radiation), and genetic factors are the most important cofactors involved in beta HPV-related carcinogenesis. In addition, the oncoproteins E6 and E7 of beta HPV types differ biochemically from their counterparts in the structure of alpha HPV types, resulting in different mechanisms of action in carcinogenesis. The aim of our manuscript is to present an updated point of view on the involvement of beta HPV types in cSCC pathogenesis.

Oral HPV16 Prevalence in Oral Potentially Malignant Disorders and Oral Cavity Cancers

The role of human papillomavirus type 16 (HPV16) in oral potentially malignant disorders (OPMD) and oral cavity carcinoma (OC) is still under debate. We investigated HPV16 prevalence in unstimulated saliva, oral rinse samples, oral swabs and tumour biopsies collected from OPMD (n = 83) and OC (n = 106) patients. HPV16 genotype, viral load, physical status (episomal vs. integrated) and tumour p16INK4a expression were determined. Oral HPV16 prevalence was higher in OC than in OPMD, but this difference was not statistically significant (7.5% (8/106) versus 3.6% (3/83), odds ratio (OR): 2.18, 95% confidence interval (CI): 0.56, 8.48, p = 0.26). There was a significant association (p < 0.05) between oral HPV16 infection and heavy tobacco consumption. Real-time PCR results indicated that no integration events occurred in either OPMD or OC cases based on the HPV16 E2/E6 ratio. HPV16 positive OPMD and OC patients had similar HPV16 E2 and E6 viral loads. The inter-rater agreement between tumour p16INK4a expression and oral HPV16 infection was considered as fair (k = 0.361) for OC. Our data suggest that the involvement of HPV16 in oral carcinogenesis is limited.

Emerging Functions of Human IFIT Proteins in Cancer

Interferon-induced protein with tetratricopeptide repeats (IFIT) genes are prominent interferon-stimulated genes (ISGs). The human IFIT gene family consists of four genes named IFIT1, IFIT2, IFIT3, and IFIT5. The expression of IFIT genes is very low in most cell types, whereas their expression is greatly enhanced by interferon treatment, viral infection, and pathogen-associated molecular patterns (PAMPs). The proteins encoded by IFIT genes have multiple tetratricopeptide repeat (TPR) motifs. IFIT proteins do not have any known enzymatic roles. However, they execute a variety of cellular functions by mediating protein-protein interactions and forming multiprotein complexes with cellular and viral proteins through their multiple TPR motifs. The versatile tertiary structure of TPR motifs in IFIT proteins enables them to be involved in distinct biological functions, including host innate immunity, antiviral immune response, virus-induced translation initiation, replication, double-stranded RNA signaling, and PAMP recognition. The current understanding of the IFIT proteins and their role in cellular signaling mechanisms is limited to the antiviral immune response and innate immunity. However, recent studies on IFIT protein functions and their involvement in various molecular signaling mechanisms have implicated them in cancer progression and metastasis. In this article, we focused on critical molecular, biological and oncogenic functions of human IFIT proteins by reviewing their prognostic significance in health and cancer. Research suggests that IFIT proteins could be novel therapeutic targets for cancer therapy.

Human Papillomavirus Detection in Oropharyngeal Squamous Cell Carcinoma Using p16 Immunohistochemistry

Introduction:

Oral cancer ranks third among all cancers in the Indian population with approximately 45% of call cancer cases in India being diagnosed as oral cancer, among which 20%–50% of the cases are observed to be associated with human papillomavirus (HPV) infection.

Aim:

This study aims to detect and evaluate the presence of p16 in oropharyngeal squamous cell carcinoma (OPSCC) patients using immunohistochemistry (IHC).

Materials and Methods:

This study was based on samples collected from 21 patients with primary OPSCC who were diagnosed and treated during the period of December 2017–March 2018. Inclusion criteria were complete clinicopathologic data, adequate clinical follow-up, and availability of sufficient paraffin-embedded tumor material. HPV immunoreactivity was further investigated by means of IHC using p16 as a marker.

Results:

IHC results revealed p16 positivity in six OPSCC cases. There was no statistically significant association of the p16 positivity of HPV with the age, gender, or site.

Conclusion:

Our results suggest that IHC-based detection of p16 provides a suboptimal prognostic information if not combined with detection of HPV DNA. Although p16 expression and HPV DNA infection are correlated with HPV-associated OPSCCs, neither of the tests alone is the optimal method for HPV status detection.

p16 as an independent marker for detection of high-risk HPV in oral submucous fibrosis and oral squamous cell carcinoma

Background

An alarming increase in incidence of high-risk human papillomavirus (HPV) positive tumors in head and neck squamous cell carcinoma (HNSCC) by 25% and 70% in oropharyngeal HNSCC cannot be ignored. The early oncogenes of HPV, E6, and E7 play a key role in carcinogenesis. HPV associated tumors have a better clinical outcome and a favorable prognosis. The p16 expression has high concordance with other methods of HPV detection, ascertaining p16 as a surrogate marker for HPV.

Objective

To assess the immunohistochemical expression of p16 in oral submucous fibrosis (OSF) and oral squamous cell carcinoma (OSCC) with and without coexistent OSF as a marker for high-risk HPV detection. Materials and.

Methods

Tissue blocks of 70 cases including normal, OSF, OSCC with and without OSF were subjected to IHC staining with a p16^INK4A monoclonal antibody. (Biogenex, San Roman). The p16 expression was noted according to percent positivity and pattern. The data were tabulated, statistically analyzed using the Chi-square test and the P value was assessed.

Results

The percentage of p16 positive cells raised from normal to OSF to OSCC with and without OSF. In addition, a shift from nuclear to cytoplasmic expression from normal to OSCC was noted with a statistical significance (P < 0.001). However, no statistical significance was established with any clinicopathologic parameters except age (P = 0.012) and habits (P= 0.023).

Conclusion

The presence of HPV using p16 was not detected in OSF but was positive in OSCC. Altered pattern of expression from normal to OSF to OSCC indicates promising use of p16 as a diagnostic marker.

Is There Any Role of Arsenic Toxicity in HPV Related Oral Squamous Cell Carcinoma?

Arsenic is a potent human carcinogen affecting the rate of cancer deaths worldwide. In India, West Bengal is the worst affected state by arsenic. To our best knowledge, this is the first study relating arsenic toxicity with oral carcinoma, along with HPV infection, the latter being well established in western countries. To find out a possible correlation between arsenic toxicity and oral carcinoma in the population of West Bengal, in or without any association with human papilloma virus infection. Ethical clearance of this study was obtained from the institutional committee. One hundred and four malignant and 103 premalignant cases were selected for this study along with 200 healthy age and sex-matched individuals selected as control (100 each for malignant and premalignant) (2013-2017). On proper consent, their buccal swab and hair samples were assessed for the presence of HPV DNA by DNA extraction, followed by PCR and arsenic estimation by flow injection hydride generation atomic absorption spectrometry respectively. A very highly significant correlation has been observed between arsenic toxicity, HPV infection and the occurrence of oral carcinoma (p value = 2.18e-06; p value = 0.00100 respectively). A correlation has also been observed between these two factors simultaneously, contributing to this malignancy (phi coefficient = 0.2194839). A statistically significant correlation observed between this metal toxicity and viral infection in the occurrence of oral carcinoma in this population indicates a possible symbiotic role between these two factors in this malignancy.

Human papillomavirus genotypes and p16 expression in oral leukoplakia and squamous cell carcinoma

Several studies have shown a broad variation in the prevalence of human papillomavirus (HPV) in oral leukoplakia (OLK) and oral squamous cell carcinoma (OSCC), whereas the relationship is less well-defined and specific HPV genotypes lack examination in OLK. In the present study, the role of HPV and surrogate p16 expression was investigated to explore the correlation and pathogenesis in OLK and OSCC. Polymerase chain reaction (PCR) and flow-through hybridization technology were utilized to detect HPV genotypes in oral exfoliated cells from 30 healthy volunteers, 103 OLK and 30 OSCC patients. Expression of p16 was assessed by immunohistochemistry (IHC) in biopsies from these OLK and OSCC, in addition to 15 normal oral mucosal tissues as the control group. The healthy controls showed 3.3% (1/30) HPV presence; In OLK and OSCC, the detection rate was 4.9% (5/103), 3.3% (1/30), respectively. No significant relationship between HPV and OLK or OSCC was observed when compared with the control group (P>0.05). All 6 HPV-positive OLK and OSCC cases had p16 overexpression. But the sensitivity of p16 IHC was poor, because 88.4% (38/43) of p16 over-expressed OLK were HPV negative. There was no statistical significance between HPV and the sex, age, site, alcohol consumption, or smoking. These findings suggested HPV had a low prevalence in OLK and OSCC. This suggests the detection of HPV genotypes by PCR in exfoliated cells combined with p16 IHC may be more accurate to represent HPV infection.

Cytogenetic and micronuclei study of human papillomavirus-related oral squamous cell carcinoma

BACKGROUND

The association of human papilloma viral infection in oral squamous cell carcinoma is well studied in the Western countries, but its correlation with DNA damage in the form of micronuclei (MN) formation, ceased apoptosis or presence of chromosomal abnormalities has not yet been studied.

AIM

The aim of this study is to find any possible correlation between human papillomavirus (HPV) infection and cytogenetic damage in the oral malignant and premalignant population of West Bengal.

SETTINGS AND DESIGN

A total of 104 malignant and 103 premalignant cases were selected along with 200 controls.

METHODS

The buccal smear samples were Pap stained for the detection of MN, apoptosis frequency and koilocytes. The buccal swab samples were processed for DNA extraction followed by polymerase chain reaction for the detection of HPV DNA. The peripheral venous blood samples were processed for the detection of any chromosomal abnormality, by the method of human leukocyte culture followed by Giemsa staining.

STATISTICAL ANALYSIS USED

Correlation analysis using GraphPad Prism software was used in this study.

RESULTS

About 34.6%, 42.3% and 6.73% of malignant and 6.79%, 3.88% and 20.38% of premalignant cases showed the presence of HPV DNA, koilocytes and apoptosis, respectively. The difference between the MN frequencies of premalignant and malignant oral lesions with the control group is significant with respect to various risk factors (P < 0.05). One percentage of malignant cases showed the presence of chromosomal break.

CONCLUSION

A considerable percentage of malignant cases showing the presence of koilocytes and viral DNA may indicate the effect of HPV infection leading to the malignancy, which can be correlated with the MN and apoptosis frequency.

Association of DFNA5, SYK, and NELL1 variants along with HPV infection in oral cancer among the prolonged tobacco-chewers

Southeast Asia, especially India, is well known for the highest use of smokeless tobacco. These products are known to induce oral squamous cell carcinoma. However, not all long-term tobacco-chewers develop oral squamous cell carcinoma. In addition, germline variants play a crucial role in susceptibility, prognosis, development, and progression of the disease. These prompted us to study the genetic susceptibility to oral squamous cell carcinoma among the long-term tobacco-chewers. Here, we presented a retrospective study on prolonged tobacco-chewers of Northeast India to identify the potential protective or risk-associated germline variants in tobacco-related oral squamous cell carcinoma along with HPV infection. Targeted re-sequencing (n = 60) of 170 genetic regions from 75 genes was carried out in Ion-PGM™ and validation (n = 116) of the observed variants was done using Sequenom iPLEX MassARRAY™ platform followed by polymerase chain reaction-based HPV genotyping and p16-immunohistochemistry study. Subsequently, estimation of population structure, different statistical and in silico approaches were undertaken. We identified one nonsense-mediated mRNA decay transcript variant in the DFNA5 region (rs2237306), associated with Benzo(a)pyrene, as a protective factor (odds ratio = 0.33; p = 0.009) and four harmful (odds ratio > 2.5; p < 0.05) intronic variants, rs182361, rs290974, and rs169724 in SYK and rs1670661 in NELL1 region, involved in genetic susceptibility to tobacco- and HPV-mediated oral oncogenesis. Among the oral squamous cell carcinoma patients, 12.6% (11/87) were HPV positive, out of which 45.5% (5/11) were HPV16-infected, 27.3% (3/11) were HPV18-infected, and 27.3% (3/11) had an infection of both subtypes. Multifactor dimensionality reduction analysis showed that the interactions among HPV and NELL1 variant rs1670661 with age and gender augmented the risk of both non-tobacco- and tobacco-related oral squamous cell carcinoma, respectively. These suggest that HPV infection may be one of the important risk factors for oral squamous cell carcinoma in this population. Finally, we newly report a DFNA5 variant probably conferring protection via nonsense-mediated mRNA decay pathway against tobacco-related oral squamous cell carcinoma. Thus, the analytical approach used here can be useful in predicting the population-specific significant variants associated with oral squamous cell carcinoma in any heterogeneous population.

The prevalence and genotyping of human papillomavirus in patients with oral tumors in health centers and clinics of Mazandaran in Iran

Oral cancer is one of the most prevalent cancers in the world which contains many kinds of malignant neoplasms in the oral cavity. Due to the carcinogenicity of human papillomavirus (HPV) and its prevalence in cancer, including the oral cancer, this study was aimed at investigate the prevalence of HPV and its genotypes in patients suffering from oral tumors using PCR method. In this study, 83 samples of oral lesions were collected in the form of paraffin-embedded tissue. After extracting the DNA using DNA extraction kits, high-risk HPV positive samples were examined using special kits for genotyping, and low-risk types were sequenced after nested PCR. The results showed that 13.2% of samples was HPV positive. The result of PCR using genotyping kit indicated that high-risk types of 18, 31, 16, and 33 appeared in samples with prevalence rate of 27.2, 18.1, 9.09 and 9.09%, respectively. In this manner, the result of sequence indicated that the prevalence of HPV-6 genotype was 36.3% in the samples. The results of this study indicated that both low-risk and high-risk types of HPV are associated with the risk of oral tumors, so that Types 6 and 18 were reported as the most prevalent types in the samples.

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.

ASC contributes to metastasis of oral cavity squamous cell carcinoma

ASC (Apoptosis-associated Speck-like protein containing a CARD) acts as a platform protein in the inflammasome cascade of some cancer types. However, its potential involvement in OSCC (oral cavity squamous cell carcinoma) has not yet been determined. Here, we investigated the potential role of ASC in OSCC. RT-qPCR analysis of 20 paired tumor and adjacent normal tissue samples revealed that the mRNA levels of ASC, along with IL-1β, CASP1, and NLRP3 in ASC-associated NLRP3 inflammasome were significantly elevated in OSCC tissues. Immunohistochemical staining of these four proteins in 111 clinical specimens revealed that high-level expression of ASC was significantly associated with tumor stage, node stage (p=0.001), overall stage (p<0.001), extracapsular spread (p<0.001), perineural invasion (p=0.004) and tumor depth (p<0.001). Kaplan-Meier survival analysis further revealed that high-level ASC expression was correlated with poorer overall survival (p=0.001), disease-specific survival (p<0.001) and disease-free survival (p<0.001). Studies using OSCC cell lines indicated that high-level ASC expression enhanced cell migration and invasion, and experiments using an orthotropic nude mouse model confirmed that ASC overexpression induced metastasis of OSCC cells. This is the first report to show that ASC contributes to OSCC metastasis, and that high-level ASC expression is a marker for poor prognosis in OSCC patients.

Ex corpore linguae: A cohort analysis after a unique surgical technique in oral cancer resection

OBJECTIVE

Resection of posteriorly located oral squamous cell carcinomas (OSCCs) remains challenging for head and neck surgeons. However, several surgical techniques, such as lip and mandibular splitting, as well as submental "visor drop-down" of intraoral soft tissues, have been proposed for this purpose. Merrick et al. suggested that a pedicled genial drop-down surgical approach should be used to resect dorsally located OSCCs. Our study investigated patient outcomes following this surgical procedure, as no previous study has analyzed long-term follow-up data.

MATERIAL AND METHODS

All patients who underwent surgery using the pedicled genial "visor drop-down" approach at the Maxillofacial Department of the University Hospital Giessen in Germany between 1995 and 2010 were included in this study. In addition, our study required that patients diagnosed with OSCC had no history of other intraoral malignancy or any other form of malignancy. A preliminary questionnaire was completed for each patient based on retrospective analysis of available data from medical reports.

RESULTS

A total of 51 patients fulfilled all inclusion and exclusion criteria and were evaluated retrospectively. In total, 32 patients were excluded from the study due to OSCC recurrence or acquisition of a different type of malignancy. The male to female distribution of patients in our study was 30 to 21 (58.8%-41.2%), and the mean ages of female and male patients were 57.7 (SD 14.3) and 55.7 (SD 14.4) years, respectively. Approximately 76.5% of tumors were located along the dorsal aspect of the tongue, 17.6% were along the floor of the mouth, 3.9% were in the dorsal mandibular region, and 1.9% were in the dorsal palatal region. The mean overall operation time was 6.25 h, and 28 patients received microvascular flaps for reconstruction. Results of final histopathological examination suggested primary in-sano resection of the tumor in 84.3% of patients. Overall, the 5-year postoperative survival rate was 52.9%; 31.3% of the patient cohort was not followed up for the full 5-year period. In addition, 15.7% of the patients included in our study died during the study period. Unimpaired functional outcomes in terms of swallowing and speech were observed in 86.3% of patients.

CONCLUSION

The pedicled genial "visor drop-down" approach, also known as the ex corpore linguae, is a suitable method for the radical resection of dorsally located OSCCs, with a promising 5-year survival rate and satisfactory postoperative oral function.

Microenvironmental regulation of the progression of oral potentially malignant disorders towards malignancy

Oral potentially malignant disorders (OPMD) develop in a complex tissue microenvironment where they grow sustainably, acquiring oral squamous cell carcinoma (OSCC) characteristics. The malignant tumor depends on interactions with the surrounding microenvironment to achieve loco-regional invasion and distant metastases. Unlike abnormal cells, the multiple cell types in the tissue microenvironment are relatively stable at the genomic level and, thus, become therapeutic targets with lower risk of resistance, decreasing the risk of OPMD acquiring cancer characteristics and carcinoma recurrence. However, deciding how to disrupt the OPMD and OSCC microenvironments is itself a daunting challenge, since their microenvironments present opposite capacities, resulting in diverse consequences. Furthermore, recent studies revealed that tumor-associated immune cells also participate in the process of differentiation from OPMD to OSCC, suggesting that reeducating stromal cells may be a new strategy to prevent OPMD from acquiring OSCC characteristics and to treat OSCC. In this review, we discuss the characteristics of the microenvironment of OPMD and OSCC as well as new therapeutic strategies.

[Analysis of the current status of research on human papillomavirus-associated head and neck cancers based on recent Chinese literature]

OBJECTIVE

To analyze the current status of research on human papillomavirus (HPV)-associated head and neck cancers in China using national and international references.

METHODS

We searched for bibliographies in the electronic databases of Sichuan University, including Chinese Biological and Medical Database (CBM), China Science and Technology Journal Database (VIP), and Wanfang Journal Database. Then, data was selected and extracted to analyze the basic characteristics of HPV-related head and neck cancers, the general prevalence of HPV, and the effects of various clinic pathological indicators on HPV patients.

RESULTS

The general prevalence of HPV was 34.05% among civil patients with head and neck cancers. Our analysis of different clinical and pathological indices that affect HPV-associated oral squamous cell carcinomas revealed that non-smoking and non-drinking groups had higher HPV infection rates compared with smoking (P=0.002) and drinking (P<
0.005) groups. In addition, N2-N3 stage patients had higher detectable rates than N0-N1 stage patients (P=0.027).

CONCLUSIONS

The majority of civil research studies on HPV-associated head and neck cancers are concentrated on clinical studies. Thus, the molecular neuropathology and signaling pathway of HPV should be further explored in the future to advance prognostic methods. Moreover, the perspective view of therapeutic vaccines and molecular-targeting treatments should receive close attention. 
.

Detection of human papillomavirus infection by molecular tests and its relation to colonic polyps and colorectal cancer

Objectives:

To prospectively examine the association between human papilloma virus (HPV) colonization of the colonic mucosa and the development of colorectal polyps (CRPs), and colorectal cancer (CRC) in Saudi Arabia.

Methods:

A case control study was performed between January 2013 and December 2014. All eligible patients underwent standard diagnostic colonoscopy. Patients with polyps or colorectal cancer were considered cases, while those with any other endoscopic findings were controls. Biopsy samples from polyps and tumors, and/or from normal colonic mucosa were acquired. Human papilloma virus colonization was detected using a hybrid capture technique of samples taken from both normal tissue, and CRPs and CRC. The association between HPV and CRPs/CRC was evaluated.

Results:

A total of 132 patients were recruited. The mean age was 53 (±15.9) years. Sixty patients had endoscopically detectable CRPs/CRC, and 72 had either inflammation or normal endoscopic evaluations. Only 4 (0.8%) of the 132 samples that were collected and analyzed were positive for the HPV gene. Statistical analysis did not identify any significant association between HPV colonization and the presence of CRPs/CRC. The only significant predictor of detecting CRPs/CRC on colonoscopy was symptomatic presentation (odds ratio=11.072, 95% confidence interval 4.7-26.2, p<0.001).

Conclusion:

Human papilloma virus colonic colonization is rare in Saudi Arabia. An association between HPV colonization and CRP/CRC development could not be identified in this cohort of patients.

Thyroid Autoimmunity and Lichen

Lichen planus (LP) and lichen sclerosus (LS) are cutaneous-mucous diseases with uncertain epidemiology. Current data, which are likely to be underestimated, suggest a prevalence in the general population of 0.1-4% for cutaneous LP, 1.27-2.0% for oral LP, and 0.1-3.3% for LS. While etiology of lichen is still unknown, clinical and histological evidence show an (auto)immune pathogenesis. Association of lichen with autoimmune thyroid disease (AITD) has been investigated in few studies. This association appears better defined in the case of LS, while is more controversial for LP. In both situations, the frequency of the association is higher in females. We review the available literature on the correlation between the different types of lichen and AITD, and the literature on the genetic risk factors which are shared by both conditions. Such data suggest that a common pathogenic mechanism could be the cause for co-occurrence of lichen and AITD, at least in some patients. Additionally, analyzing literature data and in continuity with our previous work on other autoimmune diseases, we suggest that molecular mimicry could trigger both diseases, and thus explain their co-occurrence.

Prevalence of human papillomavirus16 DNA and p16INK4a protein in oral squamous cell carcinoma: A systematic review and meta-analysis

BACKGROUND AND AIM

Indian patients with oral squamous cell carcinoma (OSCC) are etiologically associated with the use of tobacco and alcohol; yet, a proportion of tumors that may harbor human papillomavirus (HPV) infections cannot be neglected. The following meta-analysis was conducted to address the association of p16INK4a and HPV DNA with OSCC. In addition, the study also provides the updated prevalence of HPV-induced OSCC.

MATERIALS AND METHODS

Literature survey was performed using databases such as PubMed with the help of the following keywords - "HPV infection," "oral squamous cell carcinoma," "p16INK4a," "HPV DNA," "E6," "E7," "L1," "L2" and "LCR." Proportion method was performed to derive the forest plot using MedCalc statistical software version 16.4.3.

RESULTS

Among 145 research articles, 33 articles were selected for further analysis, in which 13 articles were related to HPV DNA detection in tissues, 11 articles detected the overexpression of p16INK4a and nine articles reported the detection of both HPV DNA and p16INK4a expression. Meta-analysis revealed significant heterogeneity (P < 0.0001) among the articles. Overall, the study consisted of 3339 patients with OSCC, among which 559 patients were diagnosed with the presence of HPV16 DNA with a random proportion of 20.1% at 95% confidence interval (CI) (13.9-27.1, P < 0.0001). Overexpression of p16INK4a protein was observed in 709 patients with a random proportion of 25.4% at 95% CI (14.3-38.3, P < 0.0001).

CONCLUSION

HPV DNA and expression of p16INK4a was suggested as gold standard for the detection of HPV infection in many cases of cancers. Frequency of HPV infection is significantly higher in patients with OSCC as identified through the detection of HPV DNA and p16INK4a expression. Even though the association of HPV infection has been established in head and neck cancer, this review could further the establishment of molecular level interaction of HPV in patients with oral cancer.

[Precancerous lesions of the buccal epithelium]

Squamous cell carcinomas of the oral cavity and lips consistently have a high incidence (they constitute the fifth most common form of cancer in France) and carry a heavy prognosis, particularly if diagnosed late. According to different studies, between 10 and 80% of such carcinomas occur in a pre-existing or precancerous lesion. The World Health Organisation (WHO) recommends the use of two terms for such lesions: precursor lesions, i.e. histological lesions associated with intraepithelial neoplasia (IEN) and verrucous hyperplasia (VH), frequently resulting clinically in leukoplakia or erythroplakia; "at risk" lesions, which include lichen planus, submucosal oral fibrosis and certain forms of genodermatosis.

[HPV infection in oral, pharyngeal and laryngeal papillomas]

BACKGROUND

HPV infections play a major role in the pathogenesis of squamous cell carcinomas of the head and neck. Regarding benign papillomas, the role of HPV is still uncertain.

MATERIALS AND METHODS

To clarify this issue, 100 exophytic papillomas of the oral cavity, pharynx and larynx were subjected to histopathological and molecular pathological examination. Excision biopsies were taken from 62 male and 38 female patients with an age range of 18 to 87 years. Biopsies were tested for p16 expression by immunohistochemistry and analyzed for HPV subtypes 6/11 (low-risk), 16/18 and 31/33/53 (high-risk) by chromogenic in situ hybridization.

RESULTS

HPV infections were verified molecularly in 34 % of biopsies; in all cases with the low-risk HPV subtypes 6/11. Only one case showed infection with both 6/11 and 31/33/53 subtypes, but not subtype 16/18; whereas expression of p16 was found in 67 %. The rate of positive molecular verification of HPV infection (in situ hybridization) was highest in the laryngeal lesions with 61.1 %, followed by the oral cavity with 52.9 %, and lowest in pharyngeal lesions (21.5 %). Recurrent papillomas were seen in 18 cases (18 %), of which 14 were molecularly positive for HPV (in situ hybridization). A correlation between inflammatory infiltration and HPV infection could be verified in 82 %.

CONCLUSION

Our data demonstrate an important role of HPV infection for the development of benign papillomas of the head and neck region. Furthermore, there is a positive correlation between HPV infection and recurrent papillomas. Therefore, a molecular morphological HPV analysis of papillomas could provide important prognostic data.

Absence of high-risk HPV 16 and 18 in Chinese patients with oral squamous cell carcinoma and oral potentially malignant disorders

BACKGROUND

The critical role of human papillomavirus (HPV) in cancer has been recognized, but the involvement of HPV in oral squamous cell carcinoma (OSCC) and oral potentially malignant disorders (OPMD) is still controversial. The aim of this study was to identify and verify the prevalence of high-risk HPV infection (HPV16 and 18) in Chinese patients with OSCC or OPMD using real-time PCR and DNA sequencing.

METHODS

Paired tissue and serum DNA samples were extracted from 40 Chinese patients with OSCC and 59 with OPMD. A SYBR Green-based real-time PCR assay was developed to detect the E6 gene of HPV16 and HPV18. Suspicious positive samples were then sequenced to eliminate false positives.

RESULTS

We found that none of the tissue and serum samples of OSCCs and OPMDs were positive for HPV16 E6 or 18 E6, using both real-time PCR and DNA sequencing. Overall, 3 of 198 (1.52 %) and 7 of 198 (3.54 %) samples were false-positive for HPV16 E6 and HPV18 E6, respectively, using real-time PCR.

CONCLUSION

The lack of HPV16 and HPV18 detected in this study indicates that high-risk HPV 16 and 18 infections are uncommon in Chinese patients with OSCC and OPMD. Real-time PCR followed by DNA sequencing for HPV DNA detection is an effective strategy to rule out false positives.