Human Papillomavirus in the Oral Cavity

Reviewing the role of human papillomavirus in oral cancer using the Bradford Hill criteria of causation

Human papillomavirus is a well-established risk factor for oropharyngeal cancer, although its role in oral cancer is still debated. Inconclusive evidence of its role in oral cancer is due to conflicting data arising from methodological differences, mostly due to the use of diagnostic tests with varying sensitivity and specificity. In addition, there is a lack of experimental data linking HPV to oral cancer. Recent epidemiological studies provide data on HPV prevalence in oral squamous cell carcinoma and other potentially malignant oral disorders. Further, molecular data from in vivo and in vitro models have led to new insights into the role of human papillomavirus in oral cancer. The clinical significance of identifying HPV as an etiology for oral squamous cell carcinoma is that if proven, vaccination could be an effective prevention tool. Further, like oropharyngeal squamous cell carcinoma, prognostic differences may exist between human papillomavirus positive and negative oral squamous cell carcinoma. This manuscript reviews data from the published literature using Bradford Hill criteria of causation to assess the role of human papillomavirus in oral cancer. Due to the advancement in molecular biology, the requirements of each of the Bradford Hill criteria of causation are modified to include integrated data from both epidemiological studies and experimental studies exploring molecular carcinogenesis.

Verrucous papillary lesions: dilemmas in diagnosis and terminology

Verrucous papillary lesions (VPLs) of oral cavity are diagnostically challenging as they include a spectrum of benign, potentially malignant, and frankly malignant lesions. A majority of the benign VPLs have viral aetiology and include commonly occurring squamous papilloma along with verruca vulgaris, focal epithelial hyperplasia, and condyloma. Current understanding of potentially malignant VPLs is perplexing and is primarily attributed to the use of confusing and unsatisfactory terminology. Clinically and histologically oral verrucous hyperplasia, a potentially malignant disorder, resembles oral verrucous carcinoma and may be indistinguishable from one another. The most reliable way to separate these entities on routine haematoxylin-eosin stained tissue sections is to recognize the exophytic growth patterns of oral verrucous hyperplasia from the combined exophytic and endophytic growth patterns associated with verrucous carcinoma. A review of the literature showed that there is a lot of confusion regarding the current clinical and histopathological guidelines to diagnose this potentially malignant entity. The criteria elaborated by different authors in establishing the diagnosis of oral verrucous hyperplasia are discussed in detail. A brief overview of the treatment modalities adopted is also discussed. The need for establishing a clear understanding of this potentially malignant entity is stressed as it may have far reaching implications on its management.

HPV detection in the oral and genital mucosa of women with positive histopathological exam for genital HPV, by means of the PCR

Infection by the Human Papilloma Virus (HPV) is one of the most frequent sexually transmitted diseases all over the world. The relationship between oral and genital HPV remains uncertain, as it is with its role on oral carcinogenesis. The goal of the present investigation was to check for the presence of HPV DNA in the oral and genital mucosas of women with HPV genital infection, using the polymerase chain reaction (PCR).

Study method

Cross-sectional cohort.

Materials and Methods

this is a pilot and prospective study involving 30 women, aged between 14 and 51 years, with HPV genital infection, confirmed by histopathology. All the patients were submitted to the exam and sample collection by swabbing the oral and genital mucosas in order to test for HPV DNA through the PCR technique.

Results

none of the oral cavity samples were positive for HPV, while in the genital tract, HPV was detected in 17 (57%) of the 30 patients, especially HPVs 6b and 16.

Conclusion

Results show a higher percentage of genital HPV in comparison to the oral cavity, and suggest that genital HPV does not seem to be a predisposing factor for the oral infection in the same patient.

HPV in oral squamous cell carcinoma vs head and neck squamous cell carcinoma biopsies: a meta-analysis (1988-2007)

INTRODUCTION

In the literature, there exists a wide range of human papillomavirus (HPV) DNA prevalence for head and neck squamous cell carcinoma (HNSCC), especially in relation to methods of viral detection and the lesion site. We estimated the pooled prevalence of HPV DNA in biopsies of HNSCC generically grouped versus oral squamous cell carcinoma (OSCC) in relation to the method of viral DNA detection, with the primary end point of verifying if these two variables (specification of tumour site and method of HPV DNA identification) influence the datum on HPV assay.

METHODS

By means of MEDLINE/PubMED/Ovid databases, we selected studies examining paraffin-embedded (PE) biopsies of HNSCC and OSCC. According to the inclusion criteria, 62 studies were analyzed. The following data were abstracted: sample size, HPV DNA prevalence, methods of detection [PCR and in situ hybridization (ISH)] and HPV genotypes. After testing the heterogeneity of the studies by the Cochran Q test, metanalysis was performed using the random effects model.

RESULTS

The pooled prevalence of HPV DNA in the overall samples (Sigma: 4852) was 34.5%, in OSCC it was 38.1% and in the not site-specific HNSCC was 24.1%. With regard to the detection method, PCR-based studies reported a higher prevalence rate than ISH-based rates (34.8, versus 32.9%) especially in the OSCC subgroup (OSCC PCR based: 39.9%).

CONCLUSION

These findings support the assumption that a correct distinction of HNSCC by site, together with the use of more sensitive HPV DNA detection methods, should be considered as essential prerogatives in designing future investigations into viral prevalence in head and neck tumors.

Prevalência do papilomavírus humano (HPV) na cavidade oral e na orofaringe

A prevalência do papilomavírus humano (HPV) na cavidade oral e na orofaringe ainda não está bem esclarecida como nos estudos do trato genital, na qual é bem definida. Entretanto, novas pesquisas estão surgindo após o aparecimento dos exames de biologia molecular. Neste estudo foi realizada uma revisão da literatura com o objetivo de verificar a prevalência do papilomavírus humano na cavidade oral e na orofaringe. Os resultados desta pesquisa mostraram uma prevalência do HPV 16 na mucosa oral normal (infecção latente). Já nas lesões benignas orais associadas ao HPV mostraram uma prevalência do HPV 6 e 11 em papilomas de células escamosas e condilomas, e, nas verrugas, uma prevalência do HPV 2 e 57, enquanto na hiperplasia epitelial focal prevaleceram os HPVs 13 e 32, e no câncer oral, principalmente, no carcinoma de células escamosas (CCE), foi evidenciada uma alta prevalência do HPV 16, o que sugere sua participação na carcinogênese oral, apesar de ser um assunto controverso. Constatou-se também uma enorme discrepância nos resultados da prevalência do papilomavírus humano (HPV) na mucosa oral normal (infecção latente) e no câncer oral, enquanto nas lesões benignas associadas ao vírus, os resultados foram confirmatórios.

Prevalence of human papillomavirus (HPV) in oral cavity and oropharynx

The prevalence of human papillomavirus (HPV) in the oral cavity and oropharynx has not yet been as well studied as its infection of the vaginal tract. However, new study are emerge after the development of molecular biology techniques. The objective of this study is to show the prevalence of HPV in the oral cavity and the oropharynx. An ample bibliographic review was done showing a prevalence of HPV 6, 11 in a normal oral mucous membrane (latent infection). In oral benign lesions associated with HPV, a prevalence of HPV 6 and 11 was observed in squamous cell papilloma (SCP) and condylomas acuminatum, while HPV 2 and 57 were more prevalent in verruca vulgaris lesions. As for focal epithelial hyperplasia (FEH) and oral cancer, especially squamous cell carcinoma (SCC), the prevalence was of HPV 13 and 32, and HPV 16, respectively. The last findings are, nonetheless, controversial. The last findings are, nonetheless, controversial. Showed also discrepancy result the prevalence of human papillomavirus (HPV) in normal oral mucous (latent infection) and in oral cancer, however evidenced confirmatory result in oral benign lesions associated with virus.

HPV e carcinogênese oral: revisão bibliográfica

O Papilomavírus humano (HPV) é um vírus ubíquo de DNA, epiteliotrópico, que tem a pele e as mucosas como principais sítios de infecção. Ultimamente, a sua associação com neoplasias benignas e malignas da cavidade oral, principalmente o carcinoma epidermóide, tem sido mais evidente. O seu achado comum em epitélio de mucosa oral normal, amplamente divulgado na literatura, não permite inferências mais precisas quanto ao seu papel na carcinogênese (se agente etiológico principal, coadjuvante ou simples habitante do epitélio de revestimento da mucosa oral). São mais de 100 tipos já identificados, dos quais 24 já foram localizados na cavidade oral. Desses, 4 são particularmente importantes, os tipos 6 e 11 (que estão envolvidos nas lesões benignas do epitélio oral) e 16 e 18 (comprovadamente carcinogênicos e possivelmente envolvidos na etiologia de determinados carcinomas epidermóides orais). A ação desses dois últimos tipos está principalmente associada às oncoproteínas E6 e E7 produzidas pelos mesmos. A E6 liga-se, seqüestra e degrada a p53, importante proteína supressora de tumor. A segunda liga-se e seqüestra a pRb, também supressora de tumor, facilitando a liberação de E2F. Apesar do aprimoramento das técnicas de detecção do HPV nas lesões de mucosa oral, o seu envolvimento direto com os carcinomas orais não foi ainda devidamente comprovado, todavia a sua ação sinérgica com outros carcinógenos químicos e físicos, tais como o fumo e o álcool, em determinados carcinomas epidermóides nos parece o caminho mais correto para explicar a ação do papilomavírus humano na carcinogênese oral.