Analysis of human papillomavirus DNA in oral squamous cell carcinomas

Role of Physiotherapy in HPV Proven Cases of Oral Submucous Fibrosis

Background

To assess the role of physiotherapy in human papillomavirus (HPV) proven cases of oral submucous fibrosis (OSMF).

Materials and Methods

Overall, 100 patients got recruited. Only histopathologic confirmed cases of OSMF were enrolled. Purified DNA of tissue blocks was quantified by spectrophotometry. Prevalence of HPV was evaluated. The participants got randomized into 2 cohorts: HPV positive cases and HPV negative cases. Physiotherapy was done and outcome was done and outcome was assessed and compared. Assessment of results was done by SPSS software followed by statistical evaluation.

Results

HPV was seen in 80% of the patients. Mean mouth opening pretreatment and postphysiotherapy among patients with HPV positive status was 26.31 mm and 30.12 mm, respectively. Mean mouth opening pretreatment and postphysiotherapy among patients with HPV negative status was 25.11 mm and 29.74 mm, respectively. Nonsignificant results were obtained while comparing the outcome of physiotherapy among HPV positive and negative groups.

Conclusion

Outcome of physiotherapy among OSMF patients is independent of HPV status.

Prevalence of Human Papillomavirus (HPV) 16 and 18 in Oral Malignant and Potentially Malignant Disorders: A Polymerase Chain Reaction Analysis - A Comparative Study

Introduction:

Human papillomavirus (HPV) are now being increasingly associated as a cause of oral squamous cell carcinomas (OSCC). This study was designed to evaluate the prevalence of HPV in Pelizaeus-Merzbacher disease (PMD) and OSCC using polymerase chain reaction that might help in better understanding of the role played by this virus in the oncogenic process even from its evolution stage.

Materials and Methods:

Formalin-fixed paraffin-embedded tissue samples (n = 40) of OSCC and mild, moderate, and severe dysplasia were used for this study. DNA was quantified and checked for purity spectrophotometrically. Statistical analysis was performed using SPSS software and statistical significance was assessed using Fischer's exact test (p < 0.05 was considered significant).

Results:

High-risk (HR)-HPV-16 was found to be positive in 35% of OSCC cases which showed a statistically significant association of HPV 16 with OSCC. Verrucous carcinoma had predominant HPV 16 infection (60%), followed by SCC with 40%. However, this association was not statistically significant. None of the OSCC samples were infected with HPV 18. Among the PMD, we found only 5% showing HR-HPV 16 infection which was not significant.

Discussion:

Although OSCC is attributed to tobacco and alcohol consumption, a significant proportion of OSCC cases have been demonstrated to contain HPV types. The high-risk HPV type 16 tends to be the most predominant type detected in cases of OSCC.

An update on Heck's disease-a systematic review

BACKGROUND

Previous research has suggested an ethnic association of Heck's disease with a prominent genetic and familial inheritance pattern, but no systematic review has been reported, which has collected all the evidence in one paper. The aim was estimation of the updated age estimates and gender predilection of this disease and also questioning its proposed link to ethnic and geographical factors.

METHODS

Heck's disease from 1966 until present are tabulated, including various descriptive characteristics. After removal of duplicates and adhering to all the inclusion criteria, we shortlisted 95 case reports. The quality assessment of all included studies has been done following STROBE (STrengthening the Reporting of OBservational studies in Epidemiology) guidelines.

RESULTS

We found an age range of 3-92 years (mean: 23.1 years) with a male to female ratio of 3:4. Geographical distribution revealed one of the main findings of this study, which was an increased incidence of Heck's disease in the European region.

CONCLUSIONS

As already observed and established, there is a much greater prevalence of this disease in the indigenous populations of the world and more research should be encouraged to understand the correct transmission and pattern of spread of this disease.

Occupational exposure of oropharyngeal human papillomavirus amongst otolaryngologists

OBJECTIVES/HYPOTHESIS

Human papillomavirus (HPV) is a DNA virus that causes cancer in multiple sites. Although sexual activity is the primary means of oropharyngeal HPV acquisition, studies suggest HPV transmission through occupational exposure from medical instruments and surgical fumes. We assess if aerosolization of HPV16 DNA via electrocautery places otolaryngologists at risk for exposure.

STUDY DESIGN

Animal and human laboratory model.

METHODS

Plasmid (pLXSN16E6E7) expressing HPV p16 E6/E7 genes was transformed into DH5α Escherichia coli cells using the heat shock method. Miniprep and maxiprep purification of transformed DNA with subsequent restriction enzyme double digestion confirmed presence of E6E7 fragment. We injected 2 μg plasmid DNA in 20 μL TE (Tris and ethylenediaminetetraacetic acid) buffer intradermally into freshly severed mouse tail then cauterized for 5 to 10 seconds. Generated fumes were collected through a suction tube fitted with Whatman filter paper. Filter paper was placed in 100 μL TE buffer. Additionally, six patients undergoing transoral robotic surgery for resection of oropharyngeal cancer were identified, three with p16-negative tumors and three with p16-positive tumors. Intraoperatively, Whatman filter paper was exposed to electrocautery fumes, then placed in 100 uL TE buffer. Additional samples were collected from the suction tubing and filter, the surgical mask of the surgeon at head of the bed, and the robot arm.

RESULTS

Samples were analyzed via polymerase chain reaction with an assay sensitivity of 1.5 ng E6E7 DNA. None of the patient or mouse tail samples yielded detectable HPV16 DNA in the electrocautery fumes. We did not detect HPV16 DNA on the surgical masks, suction apparatus, or robot arm intraoperatively.

CONCLUSIONS

There is likely minimal risk of occupational exposure to HPV16 via electrocautery fumes.

LEVEL OF EVIDENCE

NA Laryngoscope, 130:2366-2371, 2020.

Human papillomavirus infection in oral potentially malignant disorders and cancer

Human papillomavirus (HPV) infects keratinocytes in the mucosa or skin, and persistent infection with HPV may lead to premalignant lesions and invasive cancer, especially cervical cancer. It has also been hypothesized that HPV infection is an etiological factor of oral squamous cell carcinoma and oral precancerous disorders such as lichen planus, leukoplakia, and erythroplakia. A high percentage of HPV in oral lesions supports the possible viral contribution, but an association of HPV infection with these lesions remains to be established. The current paper will update the latest progress of HPV infection in several oral potentially malignant disorders and oral squamous cell carcinoma and discuss the impact of HPV infection on the progression of oral potentially malignant disorders.

HPV in Head and Neck Cancer-30 Years of History

The interesting history of papillomavirus (PV) research has been reviewed before. The history of human papillomavirus (HPV) in head and neck region starts in 1901 when the contagious transmission of warty lesions into the mouth via oral sex was described, although the confirmation of their viral etiology had to wait until 1907. Ullman was the first to associate the human wart virus with laryngeal warts. Parsons and Kidd described the natural history of oral PV infections in rabbits already in 1942, but these findings were corroborated in humans only recently. Koilocytotic atypia described by Koss and Durfee in 1956 was recognized as a sign of HPV infection in cervical precancer lesions only in 1976-1977 (Meisels and Fortin; Purola and Savia). This prompted systematic surveys of head and neck lesions for the detection of koilocytosis since the late 1970s, and the authors of this communication were the first to propose the HPV involvement in a subgroup of head and neck cancers. Brandsma and Abramson demonstrated HPV16 DNA in tonsillar SCCs in 1989. Since the early 2000s, HPV research of head and neck squamous cell carcinomas (HNSCC) has made impressive progress, confirming that the specific anatomic site plays a key role in determining the susceptibility to HPV infection. The most likely cancer sites associated with HPV are the base of the tongue and palatine tonsils, followed by oral cavity, larynx, and sinonasal mucosa. There is substantial geographic variation in HPV association with HNSCC. Patients with HPV-associated HNSCC are younger, and survival is better than in the absence of HPV.

Conversion of Normal To Malignant Phenotype: Telomere Shortening, Telomerase Activation, and Genomic Instability During Immortalization of Human Oral Keratinocytes

Normal somatic cells terminate their replicative life span through a pathway leading to cellular senescence, which is triggered by activation of p53 and/or pRb in response to critically shortened telomere DNA. Potentially neoplastic cells must first overcome the senescence checkpoint mechanisms and subsequently activate telomerase to propagate indefinitely. Although telomerase activation is closely associated with cellular immortality, telomerase alone is not sufficient to warrant tumorigenicity. Environmental factors, including chemical carcinogens and viral infection, often contribute to aberrant changes leading to tumorigenic conversion of normal cells. Of particular importance in oral cancer development are tobacco-related chemical carcinogens and human papillomavirus (HPV) infection. To describe the molecular mechanisms by which these environmental factors facilitate the genesis of oral cancer, we first established an in vitro multistep oral carcinogenesis model by sequential exposure of normal human oral keratinocytes (NHOK) to "high risk" HPV and chemical carcinogens. Upon introduction of the HPV genome, the cells bypassed the senescence checkpoint and entered into an extended, but not immortal, life span during which telomere DNA continued to shorten. In a few immortal clones surviving beyond the crisis, we found a marked elevation of telomerase activity and stabilization of telomere length. Furthermore, the E6 and E7 oncoproteins of "high risk" HPV disrupted the cell cycle control and DNA repair in immortalized HOK, and enhanced mutation frequency resulting from genomic instability. However, HPV infection alone failed to give rise to a tumorigenic cell population, which required further exposure to chemical carcinogens in addition to HPV infection. Analysis of the data presented suggests that oral carcinogenesis is a series of discrete genetic alterations that result from a continued genotoxic challenge by environmental risk factors. Our in vitro model may be useful for investigators with interest in furthering our understanding of oral carcinogenesis.

Oncogenes and tumor suppressor genes in squamous cell carcinoma of the tongue in young patients

Objectives

The occurrence of squamous cell carcinoma of the tongue (SCCT) of young patients increased. There are still controversies about patient prognosis. The underlying molecular mechanisms remain unclear.

Methods

276 patients (66 ≤45, 210 >45 years) with SCCT were included. Clinical parameters and survival data were assessed. Oncogenes and tumor suppressors were analyzed via immunohistochemistry (p53, CXCR4, p16, EGFR) and qPCR (CDK4, CDKN2A, TP53, MDM2, AKT1, PIK3CA, NRAS, HRAS, KRAS, HGF, MET, EGF, ATM, BRCA1, E2F1, FHIT, RUNX3, STK11, BCL2, CTNNB1).

Results

The median overall survival was 142 (≤45 years) and 34 months (>45 years) (p < 0.0001; HR [95%CI]: 0.37 [0.30–0.58]). Disease specific survival in patients ≤45 years was with 181 months significantly higher than in patients >45 years (p < 0.0001; HR [95%CI]: 0.33 [0.26–0.57]). Immunhistochemistry visualized a comparable expression of analyzed proteins. QPCR demonstrated in patients ≤45 years a higher expression of genes that are associated with carcinogenesis (CTNNB1, STK11, CDKN2A, HGF, MET) as well as tumor suppressors that constitute an enhanced radio-sensitivity (ATM, BRCA1E2F1, FHIT).

Conclusion

Derogation of the WNT-CTNNB1-STK11 and CDKN2A-HGF-MET pathway can constitute the carcinogenesis, while the higher expression of radio-sensitizers ATM, BRCA1E2F1 and FHIT can explain the better OS/DSS in young patients.

Human papillomavirus and cancerous diseases of the head and neck: a systematic review and meta-analysis

The increasing incidence of head and neck cancer (HNSCC) highlights the need to better understand the role of human papillomavirus (HPV) in the development of these cancers. The aims of this study were to conduct a systematic review and a meta-analysis concerning observational studies on the association between HPV infection and HNSCC and to quantify this association, thereby obtaining a reliable estimation of the risk of HPV infection in the development of head and neck cancer. Literature searches were performed using PubMed and Scopus databases. StatsDirect 2.7.8 program was used for the analysis. We found 15 case-control studies, 63 prevalence studies, and no cohort studies. The pooled odds ratio (OR) for all the included case-control studies resulted in a value of 1.63 (95% CI 1.27-2.09; P < 0.0001). The highest pooled OR resulted from the analysis of all the studies that examined HPV 16 genotype in association oral cavity (OR 5.36; 95% CI 1.4-20). The strong evidence of association between HPV infection and HNSCC highlights the importance of the introduction of specific tests in the cancer prevention practices to evaluate the presence of the virus, especially in the oral cavity, and the possibility of an extension of the vaccine anti-HPV in the male population too.

Detection and typing of human papillomaviruses (HPV) in malignant, dysplastic, nondysplastic and normal oral epithelium by nested polymerase chain reaction, immunohistochemistry and transitional electron microscopy in patients of northern Greece

OBJECTIVES

To evaluate the role of HPV in oral carcinogenesis, we examined the prevalence of HPV in malignant, potentially malignant and normal oral epithelium and studied the relation of HPV prevalence with other factors obtained from the patient's records.

MATERIALS AND METHODS

Our material consisted of 291 tissue specimens from 258 individuals. From every individual formalin fixed and paraffin embedded tissues were examined by nested Polymerase Chain Reaction (NPCR) for the detection of HPV DNA and by immunohistochemistry (IHC) for the in situ detection of HPV L1 protein. Positive PCR products were sequenced in order to type HPVs. Also 33 fresh tissues were obtained, fixed and used to detect HPV particles by transitional electron microscopy (TEM).

RESULTS

HPV was detected in 32.9% of the tissue specimens by NPCR, in 4.7% by immunohistochemistry and in 28.1% by TEM. In detail, by nested PCR HPV L1 DNA was detected in 40% of normal tissues, 40% of fibromas, 35.8% of non-dysplastic leukoplakias, 31.6% of dysplastic leukoplakias and 22.2% of oral squamous cell carcinomas. The HPV viral load of 96.5% of the samples was very low (1 viral copy per 10(2)-10(4) cells). HPV16 prevails in all histological groups in 89-100%.

CONCLUSION

We conclude that HPV does not seem, from the specific sample examined, to play a substantial role in oral carcinogenesis. However, it cannot be excluded that HPV could be involved in oral carcinogenesis only in cases with high viral load or at early stages of carcinogenesis possibly through the hit-and-run mechanism.

The role of human papillomavirus in oral squamous cell carcinoma: myth and reality

INTRODUCTION

As the traditional risk factors for oral squamous cell carcinoma, especially tobacco, decline, new potential causative agents become the focus of research. Since the discovery of human papillomavirus (HPV) and its importance in carcinogenesis in cervical cancer, a lot of research has been undertaken to define its role in different types of cancer. In the present study, we evaluate the role of high-risk HPV types in initiation and progression of oral squamous cell carcinoma (OSCC) using a systematic review of the current literature.

MATERIAL AND METHODS

A literature research with the search term "HPV oral squamous cell carcinoma" was performed via PubMed. Results were screened systematically for relevance and classified into the following categories: molecular biology, genetics, clinical aspects, and prevalence. Articles were then further analyzed to assess quality.

RESULTS

The literature research led to 527 results, with an overall HPV prevalence of 30.1 % in OSCCs. The most frequently identified subtypes were HPV-16 and HPV-18 (25.4 and 18.1 %, respectively). Prognostic relevance of HPV was discussed controversially. HPV detection via polymerase chain reaction is the most established method today. Molecular changes according to carcinogenic pathways described for cervix carcinoma were not routinely found in OSCC. In general, no definite role of high-risk HPV is currently deducible from the literature.

CONCLUSIONS

High-risk subtypes 16 and 18 are present in the genome in approximately one third of OSCC. Its role as a causative agent is less clear than the role in oropharyngeal tumors. The infection might not be the cause of carcinogenesis in a significant number of patients but may become proportionally more important with the decrease of the classical risk factors of tobacco and alcohol.

Prognostic features, human papillomavirus status, and epidermal growth factor receptor expression in oral squamous cell carcinoma in young adults

PURPOSE

There is still debate in literature about the survival outcomes of patients who have cancer of the oral cavity when young. Hence the aims were (1) to estimate disease-free survival, overall survival, and cause-specific survival in patients who developed oral cavity squamous cell carcinoma between 18 and 40 years of age and (2) to assess the clinicopathologic factors including detection of human papillomavirus and epidermal growth factor receptor (EGFR) overexpression in primary lesions affecting recurrence.

METHODS

This is a retrospective case-note review and reevaluation of histopathologic slides of patients treated more than 25 years. Descriptive statistics, Cox proportional hazard models, and Kaplan-Meier survival curves were used for statistical analysis.

RESULTS

A total of 62 patients were treated, with mean follow-up of 11.4 years. Forty-five were oral tongue tumors and 43 had stage I or II disease. The 5-year disease-free survival was 73.5%. The 10-year overall survival and cause-specific survival rates were 81.8% and 83.4%, respectively. Smoking and alcohol intake were not seen as risk factors in this population. Multivariate modeling identified only nodal involvement as significantly associated with overall survival and only extracapsular spread as significantly associated with locoregional recurrence. At 5 years after treatment, the cause-specific survival was 100% for patients with low EGFR expression and 81.1% for patients with high EGFR expression (hazard ratio for high vs low, 3.1; 95% confidence interval, 0.4-406.9; P = .46). Human papillomavirus was not detected in all but 2 tumor specimens.

CONCLUSIONS

Survival outcomes are quite good in young patients with oral cancer.

Human papillomavirus 16 variants from Zambian women with normal pap smears

Human papillomavirus (HPV) type 16 is the most prevalent high-risk viral genotype associated with cervical cancer. Six distinct phylogenetic clusters of HPVs have been identified and are distributed differently across five continents. HPV16 DNA was extracted from cervicolavage samples from women with normal pap smears. The LCR regions were amplified in triplicate, cloned, sequenced, and analyzed from a total of 11 recovered HPV16 positive samples [Ng'andwe et al. (2007): BMC Infect Dis 7:77] were analyzed for sequence variation. The HPV16 LCR variants were assessed for promoter activity by use of a luciferase reporter gene. Six novel HPV16 variants with nucleotide exchanges in the LCR region were identified. Five clones were classified as European group HPV16 variants and one as an African group variant. Two of these variants had relatively lower promoter activity, 30% of that of the wild-type strain. The decreased promoter activity of some HPV16 variants may decrease expression of viral oncogenes and may be linked with the development, phenotype and severity of the cervical lesions in women infected with these across HPV16 variants.

p16 INK4A overexpression is frequently detected in tumour-free tonsil tissue without association with HPV

AIMS

Oncogenic human papillomavirus (HPV) type 16 has been strongly associated with tonsillar squamous cell carcinoma (TSCC) and appears to be of prognostic significance. Because HPV+ TSCC also accumulates p16(INK4A), this cyclin-dependent kinase inhibitor has been proposed as a potential biomarker for HPV in clinical diagnosis. The aim of this study was to determine the prevalence of HPV in tumour-free tonsillar tissue and the value of p16(INK4A) overexpression in predicting its presence.

METHODS AND RESULTS

p16(INK4A) overexpression was detected by immunohistochemistry in tissue sections of tumour-free tonsils of 262 patients. They were treated for non-oncological reasons (snoring or chronic/recurrent tonsillitis) consisting of tonsillectomy. Genomic DNA isolated from these tissues was subjected to HPV-specific polymerase chain reaction (PCR) analysis. p16(INK4A) immunoreactivity was detected in 28% of samples in both crypt epithelium (49/177) and lymphoid germinal centres (52/187), which correlated with each other (P < 0.0001). No reactivity was observed in superficial squamous cell epithelium. HPV16 and 18 were detected by PCR analysis in 2/195 cases (1%), which, however, were negative on fluorescence in situ hybridization analysis and discrepant on p16(INK4A) immunostaining.

CONCLUSIONS

No proof was found for the presence of HPV in tumour-free tonsil tissue, despite increased p16(INK4A) expression in a quarter of tonsil cases. Other mechanisms than HPV infection are therefore implicated in p16(INK4A) up-regulation.

Molecular biology of head and neck cancer: risks and pathways

Patients present with a differential baseline risk of cancer based on normal and expected variations in genes associated with cancer. The baseline risk of developing cancer is acted on throughout life as the genome of different cells interacts with the environment in the form of exposures (eg, toxins, infections). As genetic damage is incurred throughout a lifetime (directly to DNA sequences or to the epigenome), events are set in motion to progressively disrupt normal cellular pathways toward tumorigenesis. This article attempts to characterize broad categories of genetic aberrations and pathways in a manner that might be useful for the clinician to understand the risk of developing cancer, the pathways that are disrupted, and the potential for molecular-based diagnostics.

Human papillomavirus infection in oral verrucous carcinoma: genotyping analysis and inverse correlation with p53 expression

OBJECTIVE

Verrucous carcinoma (VC) is a rare subtype of squamous cell carcinoma, occurring mostly in oral mucosa. To clarify the role of human papillomavirus (HPV) in VC tumorigenesis, we investigated localization and genotypes of HPV and p53 expression in oral VC.

METHODS

We studied paraffin-embedded specimens of 23 VCs and 10 control non-neoplastic lesions in oral mucosa. To investigate HPV infection, HPV genotypes and p53 expression, we respectively employed in situ hybridization (ISH), sequence analysis following short PCR fragment-PCR assay and immunohistochemistry.

RESULTS

Of the 23 VC specimens, 11 (48%) had HPV-DNA (detectable by PCR), and 6 (26%) had intranuclear HPV in the upper portion of the squamous epithelium (detectable by ISH). Nine of the 11 PCR-positive specimens showed multiple infections with low- and high-risk HPVs. No HPV-16 infection was detected. Although HPV-6 and HPV-18 were frequently detected by PCR, no HPV could be found in control specimens by ISH. p53 expression was inversely correlated with HPV infection.

CONCLUSION

Thus, multiple infections with low- and high-risk HPVs and their rapid replication during hyperkeratinization may participate in the histogenesis of oral VC. Oral VC tumorigenesis may involve the inactivation of p53, which is associated with HPV infection.

Squamous cell carcinoma of the oral tongue in young patients: a matched-pair analysis

CONCLUSIONS

Young patients with squamous cell carcinoma (SCC) of the oral tongue developed fewer locoregional recurrences. The overall survival and disease-specific survival rates were better in the young patient population.

OBJECTIVES

To compare the survival rates of patients under 45 years of age and diagnosed with SCC of the oral tongue with those of patients older than 45 years.

PATIENTS AND METHODS

A retrospective review of 20 patients under 45 years of age with SCC of the oral tongue was performed. These patients were matched to an older population by sex and clinical stage. Overall survival, disease-free survival, disease-specific survival, and rates of local, regional and distant metastases were determined for both populations.

RESULTS

Stage and treatment modality were similar in the two age groups. There were significant differences in overall survival (p=0.013) and disease-specific survival (p=0.046) favoring young patients. Rates of locoregional recurrence and distant metastasis were higher in the older patients.

Squamous cell carcinoma of the oral cavity in young patients: a matched-pair analysis

There is an increased incidence of oral squamous cell carcinoma (SCC) in young patients. However, the literature concerning prognosis for young patients with oral SCC is conflicting. The aim of this study was to compare the survival rates of patients under 45 years of age and diagnosed with SCC of the oral cavity with those of patients older than 45 years. A retrospective review of 28 patients under 45 years of age with SCC of the oral cavity was performed. We matched each of these patients by sex, tumor site, and overall stage with two patients older than 45 years. Overall survival, disease-free survival, disease-specific survival, rates of local, regional and distant metastasis were determined for both populations. Survival analysis was performed using Cox proportional hazard models. Stage and treatment modality were similar in the two groups. There were significant differences in overall survival (P=0.024) and disease-specific survival (P=0.03) favoring young patients. Locoregional recurrence and distant metastasis were higher in the older patients. Furthermore, matched survival analysis demonstrated a difference in overall survival rate [risk ratio (RR) 2.457; P=0.033] and disease-specific survival [RR 2.475; P=0.048]. Young patients with SCC of the oral cavity developed fewer locoregional recurrences and distant metastasis. The overall survival and disease-specific survival rates were better in the young patient population.

Association between the TP53 codon72 polymorphism and oral cancer risk and prognosis

The TP53 codon72 polymorphism has recently been extensively studied to determine the risk factor for carcinogenesis. However, there are few reports about the relationship between the TP53 codon72 polymorphism and oral cancer risk or post treatment prognosis. We evaluated the genotypic distribution of the TP53 codon72 polymorphism in 100 oral cancer cases and 271 non-cancer controls. There were no significant differences in the frequencies of the three genotypes (Arg/Arg, Arg/Pro, Pro/Pro) of the TP53 codon72 polymorphism between oral cancer cases and controls. However, stratifying by smoking status, we found that the adjusted odds ratio for non-smokers with the Pro/Pro genotype was significantly increased (adjusted OR=2.70, 95% confidence interval=1.07-6.82). We also found that the cases with the Pro/Pro genotype tended to have a shorter post-treatment survival compared with those with the Arg/Pro genotype (p=0.06). Our results suggest the Pro/Pro genotype of the TP53 codon72 polymorphism increases oral cancer risk in non-smokers and worsens their prognosis.

Advances in the biology of oral cancer

The incidence of oral cancer remains high and is associated with many deaths in both Western and Asian countries. Several risk factors for the development of oral cancer are now well known, including smoking, drinking and consumption of smokeless tobacco products. Genetic predisposition to oral cancer has been found in certain cases but its components are not yet entirely clear. In accordance with the multi-step theory of carcinogenesis, the natural history of oral cancer seems to gradually evolve through transitional precursor lesions from normal epithelium to a full-blown metastatic phenotype. A number of genomic lesions accompany this transformation and a wealth of related results has appeared in recent literature and is being summarized here. Furthermore, several key genes have been implicated, especially well-known tumor suppressors like the cyclin-dependent kinase inhibitors, TP53 and RB1 and oncogenes like the cyclin family, EGFR and ras. Viral infections, particularly with oncogenic HPV subtypes and EBV, can have a tumorigenic effect on oral epithelia and their role is discussed, along with potential therapeutic interventions. A brief explanatory theoretical model of oral carcinogenesis is provided and potential avenues for further research are highlighted.

Mouthrinses containing alcohol and oral cancer: revision of epidemiological studies

The strong association between alcohol usage and the development of oral cancer (OC) has been reported in numerous papers. As some mouthrinses contain significant amounts of ethanol, a possible relationship to this pathology has been considered. The purpose of the present paper is to analyze several epidemiological studies which evaluated the association between commercial mouthrinses and the etiology of OC. Although some authors report an association, most of the studies are unclear and sometimes contradictory. The controversial aspects regarding the role of alcohol in OC may also make difficult to find a clear relationship between the use of mouthrinses containing alcohol and OC.

HPV in oral squamous cell carcinomas of a Brazilian population: amplification by PCR

Human Papilomaviruses (HPV) are a group of viruses associated with benign and malignant lesions of cutaneous and mucosal epithelia. Some "high risk" HPV types, especially HPV 16 and 18, are strongly correlated with cervical and anogenital cancers and are also related to the genesis of oral squamous cell carcinomas (OSCC). The aim of this work was to investigate the incidence of HPV infection in 40 paraffin-embedded or fresh specimens of OSCC, using PCR amplification of the viral DNA. Literature based primers (GP5+/GP6+) were used in order to amplify HPV DNA from the L1 gene, present in more than 22 types of HPV. A condyloma case with HPV 16 and 18 detected by in situ hybridization was used as a positive control. Amplification of HPV was observed only in the positive control. No squamous cell carcinoma cases showed DNA viral amplification. Absence of HPV DNA amplification by PCR in the analyzed specimens of OSCCs suggests that this virus not always plays a role in the carcinogenesis process. Discrepancy with some studies found in the literature may be related to methodology or population differences.

An Overview of Epidemiology and Common Risk Factors for Oral Squamous Cell Carcinoma

Understanding the epidemiologic picture and the risk factors for oral cancer can help identify and treat patients at risk for oral cancers. Early diagnosis of an oral cancer continues to be important to achieving a favorable prognosis. Absent a diagnosis of oral/pharyngeal cancer, there clearly can-lot be an effective treatment plan. Discovering a potentially malignant or malignant lesion and through biopsy reaching a diagnosis for the lesion begins by performing an examination with the purpose of detecting oral/pharyngeal lesions. An oral cancer screening can be performed in less than five minutes without any expensive diagnostic aids. Despite the ease with which this exam can be performed and the noninvasive nature of the examination,most patients report that they have never had an oral cancer examination. Late stage diagnosis continues to be a common situation resulting in high rates of morbidity and mortality. Without early recognition it seems that the trend of late stage diagnosis will continue. Physicians, dentists, and other health care providers should be performing the oral cancer screening examination on a routine basis for all of their patients.Note: For the interested clinician, the author highly recommends an excellent comprehensive text on the subject of oral cancer. Sol Silverman's(with multiple contributors) The American Cancer Society's Atlas of Clinical Oncology Oral Cancer: Fifth Edition by BC Decker Publishers is an excellent overview of oral cancer covering in greater detail many of the subjects that could not be covered in this brief article. Additionally, there are excellent color photographs of the common presentations of oral malignancies that can be helpful in assessing oral/pharyngeal lesions.

[The relationship between human papillomavirus and cyclin D1 gene amplification in squamous cell carcinomas of the head and neck]

INTRODUCTION

infection by oncogenic subtypes of human papillomavirus (HPV) and cyclin D1 gene (CCND1) amplification are frequent events in head and neck squamous cell carcinomas. The objective of this paper is to establish the relationship between the presence of human papillomavirus (HPV) gene sequences and the development of CCND1 gene amplification in these tumours.

MATERIALS AND METHODS

59 squamous cell carcinomas of the head and neck were studied for HPV types 6b and 16 and CCND1 gene amplification by polymerase chain reaction.

RESULTS

HPV DNA was detected in 14 tumors (24%). Ten of them were positive for the HPV type 6b and 4 for the HPV type 16. CCND1 gene amplification was found in 15 cases (25%). Although we have found a higher frequency of CCND1 amplification in the HPV-positive cases (36%, versus 22% in the HPV-negative cases), these differences were not statistically significant (P= 0,32).

CONCLUSIONS

The presence of HPV gene sequences does not seem to be related to a significative higher incidence of CCND1 gene amplification in the squamous cell carcinomas of the head and neck.

Prevalence of histological findings of human papillomavirus (HPV) in oral and oropharyngeal squamous cell carcinoma biopsies: preliminary study

Human papillomavirus (HPV) is considered to be an etiologic agent of cervical cancer and, recently its relation to oral and oropharyngeal cancer has also been investigated. Oral squamous cell carcinoma (SCC) represents 90% of all malignant tumors that affect the oral cavity. The prevalence of HPV in patients with SCC ranges from 0 to 100%. The most known viral cytopathic effect is koilocytosis, considered to be a major characteristic of HPV infection. Aim: The aim of this study was to verify the prevalence of some peculiar characteristics of HPV - koilocytosis - in oral and oropharyngeal SCC. Study design: transversal cohort. Material and method: Twenty slides with oral and/or oropharyngeal SCC were examined under microscopy. Results: in 15 of them, koilocytosis was found, amounting to 75%. Although we know that polymerase chain reaction (PCR) is the method with the best sensitivity for HPV detection, we began this research looking for koilocytosis, which is highly suggestive of HPV infection. Conclusion: This study is a trial project and we will continue this research with PCR measures to confirm this high prevalence of HPV infection in oral and oropharyngeal SCC.

Oral cancer; the evidence for sexual transmission

The incidence of oral cancer amongst young adults is increasing in many European and high incidence countries. Most oral cancer is aetiologically linked to the use of tobacco and/or alcohol but nearly two decades ago, we produced the first evidence for the presence of viral nucleic acids in oral squamous cell carcinoma (OSCC) tissues, hypothesising that there may be a viral involvement in at least some OSCC. Subsequently, human papillomaviruses (HPV) in particular have been implicated in OSCC. Antibody responses to HPV are seen and HPV-DNA detected in tumours by us and many others, the virus being mainly HPV-16, the genotype associated with ano-genital cancer. Recent studies have indicated that HPV may be aetiologically important particularly in some types of oropharyngeal cancer, at least in tonsillar carcinogenesis, and may represent an alternative pathway in carcinogenesis to the established factors of tobacco and alcohol. Studies of patients with OSCC have suggested possible sexual transmission of HPV.

Can HPV DNA testing on FNA material determine anogenital origin in metastatic squamous cell carcinoma?

AIMS

Currently there are no diagnostic techniques that can precisely determine the primary site of a metastatic squamous cell carcinoma (SCC). Anogenital SCC has a high prevalence of high-risk (HR) human papillomavirus (HPV) DNA, particularly in the cervix where the value approaches 100%, whereas non-anogenital SCC generally has a low prevalence. The aim of this study was to examine whether the finding of HR HPV DNA in a fine needle aspiration (FNA) of metastatic SCC could be used to determine a likely anogenital origin.

METHODS

Polymerase chain reaction (PCR) and viral sequencing were used to identify HR HPV DNA in cell block and needle rinse material derived from FNA samples in a series of metastatic SCC.

RESULTS

HPV DNA was detected in nine of 12 (75%) metastatic anogenital SCC, and type 16 was sequenced in seven. HPV DNA was detected in only one of 18 (5.6%) metastatic SCC from other sites such as lung, oral cavity and skin. The positive control case was an oral cavity tumour and type 33 was sequenced.

CONCLUSIONS

Although reservations remain, particularly in relation to the prevalence of HPV DNA in non-anogenital sites, HPV DNA testing by PCR: (1) can be successfully performed on FNA material, and (2) in the correct clinical context, can guide clinicians in assigning a site of origin. HPV DNA detection was the major indicator to the primary site in one occult tumour and several where the previous diagnosis of anogenital cancer was not known at presentation.

Tongue and tonsil carcinoma

BACKGROUND

An increasing incidence of oral carcinoma among young adults has been reported in the U.S. and Europe. Although the association between human papillomavirus infection and tonsillar carcinoma is now well established, to the authors' knowledge little is known about incidence trends in tonsillar carcinoma among younger adults. The objective of the current study was to explore the trends in both oral cavity and pharyngeal squamous cell carcinoma (SCC) in younger U.S. populations, in particular tongue and tonsillar SCC.

METHODS

Using the 1973-2001 Surveillance, Epidemiology and End Results (SEER) database, we computed age, race, and site-specific trends of oral and pharyngeal (excluding nasopharynx) carcinoma incidence rates. The percent change (PC) and annual percent change (APC) were computed to explore trends in incidence rates over time.

RESULTS

There were 2262 SCC of the oral cavity and 1251 SCC of the pharynx reported to the SEER program from 1973 to 2001 in adults aged 20-44 years. There was a statistically significant increase in the incidence of oral tongue SCC (APC = +2.1; P < 0.001), base of tongue SCC (APC = +1.7; P = 0.04), and palatine tonsil SCC (APC = +3.9; P < 0.001) among younger white individuals, whereas the incidence of SCC in all other oral and pharyngeal sites decreased or remained constant.

CONCLUSIONS

The increase in tonsil SCC incidence from 1973 to 2001 paralleled the increase in tongue SCC, whereas SCC in all other oral and pharyngeal sites remained constant or decreased. This may suggest similar etiologic factors for SCC affecting the palatine tonsils and tongue in younger populations.

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.

Human papillomavirus infections and oral tumors

In the past 20 years, there has been an increasing interest in human papillomaviruses (HPV) because of their potential role in the pathogenesis of malignant tumors. In 1983, we published the first evidence that HPV might be involved in oral squamous cell carcinomas. The identification of morphological similarities between oral and cervical mucosa lead us to this original proposal. In a recent meta-analysis, HPV was indeed confirmed as an independent risk factor for oral carcinoma. To date, totally more than 100 types of HPV have been identified. As in anogenital cancers, HPV type 16 is the most prevalent type in oral carcinomas. The benign oral lesions, associated with HPV infection, include squamous cell papilloma, condyloma acuminatum, verrucca vulgaris and focal epithelial hyperplasia (FEH). Papillomas and condylomas are mostly caused by HPV type 6 or 11, while oral verrucas are associated with the skin types 2 or 4. A family history of FEH has been suggested. The FEH lesions are caused by HPV types 13 and 32, only detected in oral epithelium. In immunocompromised patients, benign HPV-induced lesions are characterized by atypical morphology and the simultaneous detection of multiple HPV types. Oral benign HPV lesions are mostly asymptomatic, and may persist or regress spontaneously.

An AP-1 binding site mutation in HPV-16 LCR enhances E6/E7 promoter activity in human oral epithelial cells

Expression of the human papillomavirus (HPV) E6 and E7 oncoproteins is responsible for the transforming ability of the virus. The HPV long control region (LCR) and E6/E7 promoter regulate transcription of the E6 and E7 viral oncogenes. However, factors involved in the stimulation of E6/E7 promoter activity in carcinogenesis are unclear. We previously identified a point mutation in an HPV-16 immortalized human oral keratinocyte cell line subsequently exposed to a tobacco-specific carcinogen. This mutation was located in the LCR at nucleotide 7633 and contains binding sites for the transcription activator, AP-1, overlapping with putative binding regions for the transcription factor, C/EBP, which represses the E6/E7 promoter. In this study, this mutation was analyzed by both electrophoretic mobility shift analysis and luciferase assays. We found that the point mutation enhanced the binding affinity of AP-1 to the LCR, thus stimulating the E6/E7 promoter activity. Our results suggest that mutations in binding sites for crucial regulators may be the result of exposure to carcinogens and could induce expression of the E6 and E7 oncogenes.

The use of nested polymerase chain reaction and restriction fragment length polymorphism for the detection and typing of mucosal human papillomaviruses in samples containing low copy numbers of viral DNA

Mucosal human papillomaviruses (HPVs) that infect the genital area have also been shown to infect the oral cavity. In this study a restriction fragment length polymorphism (RFLP) method was developed on a nested polymerase chain reaction (PCR) product to identify ten high risk HPV types 16, 18, 31, 33, 35, 45, 51, 52, 58 and 59 as well as the low risk HPV 11. HPV DNA was detected in 23/31 (74%) of buccal specimens using a sensitive nested PCR employing degenerate consensus primers (Williamson and Rybicki, 1991). Consensus PCR using the PGMy09/11 primers. was able to detect HPV in only 29% of the specimens that had tested positive using the nested HPV PCR primers. HPV 11 type specific primers detected HPV 11 DNA in only 66% of the specimens showing HPV 11 DNA by means of nested PCR and RFLP. A Genbank search revealed that the PCR primers could detect a wide range of mucosal HPV types including types HPV 70, 72 and 73 which have all been isolated from immunocompromised patients. Of the 23 buccal specimens that were positive for HPV DNA, 13 were single infections, five were dual infections and three were triple infections. The HPV types identified by RFLP were: HPV 11 (18/23), HPV 18 (8/23), HPV 16 (3/23), and HPV 33 (1/23). HPV 13 (2/23) was identified by direct sequencing of the inner amplicon of the PCR product.

Risk of oral cancer associated with human papillomavirus infection, betel quid chewing, and cigarette smoking in Taiwan--an integrated molecular and epidemiological study of 58 cases

BACKGROUND

The association between oral squamous cell carcinoma (OSCC) and human papillomavirus (HPV) 6, 11, 16 and 18 is uncertain. Past reports varied in the methodology and results. We conducted this study using in situ PCR in situ hybridization (ISH) assay which was considered as the most sensitive method for detection of viral DNA. We undertook an epidemiologic survey about the history of betel quid chewing and cigarette smoking, since these habits are common in Taiwan.

METHODS

In situ PCR ISH was performed on the tumor specimens from 29 patients with OSCC and the oral mucosal specimens from 29 patients without OSCC. Their betel quid chewing and cigarette smoking histories were also reviewed.

RESULTS

HPV16, HPV18, betel quid chewing and cigarette smoking were statistically significant risk factors in univariate analysis. HPV6 and 11 were not. Multivariate analysis showed that HPV16 infection (adjusted Odds ratio = 11.20) and betel quid chewing (adjusted Odds ratio = 17.06) remained to be independent factors for OSCC.

CONCLUSIONS

Our results showed that HPV16 and betel quid chewing were two major risk factors for OSCC in Taiwan, indicating that they act through different mechanisms in the pathogenesis of OSCC.

Oral squamous cell carcinoma; from an hypothesis about a virus, to concern about possible sexual transmission

Nearly two decades ago, we produced the first evidence for the presence of viral nucleic acids in oral squamous cell carcinoma (OSCC) tissues, hypothesising that there may be a viral involvement in at least some OSCC. Subsequently, human papillomaviruses (HPV) in particular have been implicated in OSCC. Antibody responses to HPV are seen and HPV-DNA detected in tumors by us and many others, the virus being mainly HPV-16, the genotype associated with ano-genital cancer. HPV are seen by in situ hybridisation only in tumour and premalignant tissue but not in surrounding normal mucosa suggesting HPV has a causal relationship. HPV may also be integrated in the host genome, further suggesting a causal role. Studies of patients with OSCC have suggested possible sexual transmission of HPV. Recent studies have indicated that HPV may be aetiologically important particularly in some types of oropharyngeal cancer, at least in tonsillar carcinogenesis, and may represent an alternative pathway in carcinogenesis to the established factors of tobacco and alcohol. We have come a very long way in the two decades since our first suggestion of a viral aetiopathogenesis was greeted with incredulity, and data from on-going studies by the International Agency for Research on Cancer, Johns Hopkins Oncology Center and others are eagerly awaited.

Human papillomavirus as a risk factor for oral squamous cell carcinoma: a meta-analysis, 1982-1997

OBJECTIVE

Human papillomavirus (HPV) infection is a significant risk factor for uterine cervical carcinoma. However, the role of HPV infection in oral squamous cell carcinoma (OSCC) is less well defined. To determine the significance of the relationship of this virus in the progressive development of oral cancer, we estimated the risk of HPV detection in normal oral mucosa, precancerous oral tissue, and oral carcinoma using meta-analysis.

STUDY DESIGN

Case reports and clinical series published in English-language journals were retrieved by searching MEDLINE (January 1980-August 1998). Review articles were also examined to identify additional studies. Studies that used biochemical, immunologic, microscopic, or molecular analyses to detect HPV in tissue or cells derived from normal oral mucosa (n = 25), benign leukoplakia (n = 21), intraepithelial neoplasia (ie, dysplasia and carcinoma in situ; n = 27), and oral cancer (n = 94) were included in the meta-analysis. Information on sample size, age, sex, method of tissue preservation (ie, fresh, frozen, paraffin-embedded), assay, primer amplification region (early, late), high-risk versus low-risk genotype, and use of tobacco or alcohol was abstracted by one author (C.S.M.).

RESULTS

Data from 94 reports that analyzed 4680 samples were included in the meta-analysis. Analyses made by means of a random-effects model with and without adjustments for assay sensitivity showed increased probability of HPV detection in tissue with precancerous and cancerous features compared with normal mucosa. The likelihood of detecting HPV in normal oral mucosa (10.0%; 95% confidence interval [CI], 6.1%-14.6%) was significantly less than of detecting benign leukoplakia (22.2%; 95% CI, 15.7%-29.9%), intraepithelial neoplasia (26.2%; 95% CI, 19.6%-33.6%), verrucous carcinoma (29.5%; 95% CI, 23%-36.8%), and OSCC (46.5%; 95% CI, 37.6%-55.5%). Adjustment of findings for differences in assay sensitivity indicated that these estimates may be conservative. Overall, HPV was between 2 and 3 times more likely to be detected in precancerous oral mucosa and 4.7 times more likely to be detected in oral carcinoma than in normal mucosa. The pooled odds ratio for the subset of studies directly comparing the prevalence of HPV in normal mucosa and OSCC was 5.37, confirming the trend observed in the overall sample. The probability of detecting high-risk HPVs in OSCCs was 2.8 times greater than that of low-risk HPVs.

CONCLUSION

This meta-analysis indicates that HPV is detected with increased frequency in oral dysplastic and carcinomatous epithelium in comparison with normal oral mucosa. The findings provide further quantitative evidence that oral infection with HPV, particularly with high-risk genotypes, is a significant independent risk factor for OSCC.

Human papillomavirus in the oral cavities of children and adolescents

OBJECTIVE

The purpose of this pilot study was to determine the frequency of human papillomavirus (HPV) in the oral cavities of children and adolescents and to identify potential risk factors for HPV infection.

STUDY DESIGN

Sociodemographic information was obtained on 268 healthy infants, children, and adolescents who were < or = 20 years old. Oral squamous cells were collected from swabs with young children and from oral saline solution rinses with older children and adolescents. Extracted DNA was evaluated for HPV by polymerase chain reaction, dot blot hybridization, and DNA sequencing. Factors associated with the presence of HPV were tested by using chi(2), Fisher's exact test, and logistic regression tests.

RESULTS

HPV was detected in 6.0% of the participants. HPV frequency among young children (<7 years old) was 8.7% (11/127), and among adolescents (13-20 years old) it was 5.2% (5/97). HPV was not detected in children aged 7 to 12 years old (0/44). Fifty-four percent (6/11) of HPV-positive children were 1 year of age or less; 3 of the HPV-positive children (<7 years old) were delivered by cesarean section. No statistically significant association was found between the detection of HPV in the oral cavity and method of delivery or gender; parent's race, education, HPV-related conditions, smoking history, or number of sex partners; or adolescent's smoking history or history of sexual activity.

CONCLUSIONS

This study suggests that HPV is present in the oral cavity primarily in children 2 years old and younger and in adolescents 13 years and older. Cesarean delivery was not protective against oral HPV infection; in fact, half of the HPV-positive infants were born by cesarean delivery.

Synchronous oral leiomyosarcoma and squamous cell carcinoma

An unusual case of synchronous squamous cell carcinoma and leiomyosarcoma of the oral cavity is reported in a patient without any identified environmental risk or predisposing factors. The invasive squamous cell carcinoma involved the tongue, whereas the leiomyosarcoma was located in the soft palate. No immunostaining was found for human papillomavirus or Epstein-Barr virus, and in situ hybridization showed negativity for human papillomavirus DNA within the tumor cells. Alterations of bcl -2, c-erb -b2 and Rb oncoproteins were not found immunohistochemically. Overexpression of p53 was detected by immunohistochemistry in both tumors, but p53 gene mutations were not found by polymerase chain reaction. Neither loss of heterozygosity of p53 nor microsatellite instability was detected in this patient. The smooth muscle nature of the leiomyosarcoma was confirmed by immunohistochemical methods. To our knowledge, synchronous smooth muscle and epithelial oral tumors have not previously been reported.

p53 polymorphism, human papillomavirus infection in the oral cavity, and oral cancer

OBJECTIVES

Human papillomavirus (HPV) infection has emerged as a risk factor in oral carcinogenesis. An arginine-coding polymorphism of the tumor suppressor protein p53 at codon 72 is more readily degraded by the HPV oncoprotein E6. Our objective was to evaluate the association between p53 polymorphism at codon 72 and HPV infection in the oral cavity, as well as its association with oral cancer.

STUDY DESIGN

Oral squamous cells from 202 patients with oral cancer and 333 age-sex frequency matched controls were evaluated by polymerase chain reaction for the presence and type of HPV and for alleles of codon 72 in p53. Fisher exact test and chi(2) tests were used to evaluate the data.

RESULTS

The p53 codon 72 polymorphism is not associated with HPV infection, whether comparing HPV-negative controls with HPV-positive controls or comparing HPV-negative cases with HPV-positive cases. Additionally, we found no association with the codon 72 polymorphism and oral cancer, whether comparing HPV-negative controls with HPV-negative cases or comparing HPV-positive controls with HPV-positive cases.

CONCLUSIONS

There is no association between p53 codon 72 polymorphism and HPV infection or between the p53 polymorphism and the risk of oral cancer.

"High risk" HPV types are frequently detected in potentially malignant and malignant oral lesions, but not in normal oral mucosa

Studies on the involvement of the human papillomavirus (HPV) in initiation and progression of oral neoplasia have generated conflicting results. The observed discrepancy is attributable mainly to the varying sensitivity of the applied methodologies and to epidemiologic factors of the examined patient groups. To evaluate the role of HPV in oral carcinogenesis, we analyzed 53 potentially neoplastic and neoplastic oral lesions consisting of 29 cases of hyperplasia, 5 cases of dysplasia, and 19 cases of squamous cell carcinomas, as well as 16 oral specimens derived from healthy individuals. A highly sensitive nested polymerase chain reaction (PCR) assay was used, along with type-specific PCR, restriction fragment length polymorphism analysis, dot blotting, and nonisotopic in situ hybridization. Nested PCR revealed the presence of HPV DNA in 48 of the 53 (91%) pathologic samples analyzed, whereas none (0%) of the normal specimens was found to be infected. Positivity for HPV was independent of histology and the smoking habits of the analyzed group of patients. At least one "high risk" type, such as HPV 16, 18, and 33, was detected by type-specific PCR in 47 (98%) infected specimens, whereas only 1 (2%) squamous cell carcinoma was solely infected by a "low risk" type (HPV 6). HPV 16 was the prevailing viral type, being present in 71% of infected cases. Single HPV 16 and HPV 18 infections were confirmed by restriction fragment length polymorphism. HPV 58 was detected by dot blotting in three hyperplastic lesions. HPV positivity and genotyping were further confirmed, and the physical status of this virus was evaluated by nonisotopic in situ hybridization. Diffuse and punctate signals, indicative of the episomal and integrative pattern of HPV infection, were observed for low- and high-risk types, respectively. Our findings are suggestive of an early involvement of high-risk HPV types in oral carcinogenesis.

Relationship of human papillomavirus to ploidy in squamous cell carcinomas of the head and neck

To establish the relationship between the presence of human papillomavirus (HPV) gene sequences and the development of genetic abnormalities, 31 squamous cell carcinomas of the head and neck were studied for the presence of HPV types 6b and 16 and the DNA content by flow cytometry. Eighteen (58%) cases were aneuploid. HPV DNA was present in seven (22.5%) tumors. Five of them were positive for the HPV type 6b and two for the HPV type 16. Aneuploidy was correlated with poorly differentiated tumors. No correlation was found between the presence of HPV, DNA content, or tumor differentiation. Consequently, the presence of HPV gene sequences does not seem to be related to a higher incidence of genetic abnormalities in squamous cell carcinomas of the head and neck.

Expression of human papillomavirus E7 mRNA in human oral and cervical neoplasia and cell lines

Human papillomaviruses (HPVs) have been strongly linked to progression of human cancers, such as cervical and oral cancers. Two HPV oncoproteins, E6 and E7, can inhibit the tumor suppressor proteins, p53 and pRB, respectively, resulting in a deregulation of the cell cycle. In order to further test the significance of HPV expression in oral and cervical carcinogenesis, we analyzed HPV E7 mRNA in oral and cervical neoplasia and cell lines by reverse transcriptase-polymerase chain reaction (RT-PCR). We found that HPV E7 mRNA was present in 90% of patients with oral neoplasia and 100% of patients with cervical neoplasia. Quantitative RT-PCR and western blot analysis on both transformed cervical and oral epithelial cell lines demonstrated that the mRNA level of HPV-16 E7 corresponded to E7 protein level, suggesting that HPV oncogene expression is primarily regulated at the transcriptional or post-transcription level. The potential clinical application of quantitative RT-PCR for HPV E7 mRNA expression in cancer screening and treatment evaluation requires further investigation.

Oral and oropharyngeal squamous cell carcinoma in young adults: a report on 13 cases and review of the literature

OBJECTIVE

Squamous cell carcinoma (SCC) of the head and neck is rare in patients younger than 45 years. Patients aged 18 to 45 years with SCC of the oral cavity (OC) and oropharynx (OP) were retrospectively compared with older control subjects.

METHODS

Twenty of 127 patients with OC/OP SCC were young adults. Thirteen patients (10 men) comprise the present series; 9 had OC lesions. Seven case controls were identified.

RESULTS

Overall, 15.75% of patients with OC/OP SCC were 18 to 45 years old. Seven OC lesions were early stage, and 2 were late stage; OP lesions were evenly divided. Eleven of 13 patients were disease free at the time of their last visit; 2 died of disease. Thirty-one percent of young patients were heavy drinkers; 77% of them smoked.

CONCLUSIONS

Young adults' survival rate resembles that reported for all patients with head and neck cancer stage for stage. Tobacco and alcohol abuse prevention among young people is imperative. Health care providers who encounter a young patient with a suspicious head or neck lesion must include malignancy in their differential diagnosis.

Oral cancer risk in relation to sexual history and evidence of human papillomavirus infection

BACKGROUND

Experimental models and analyses of human tumors suggest that oncogenic, sexually transmittable human papillomaviruses (HPVs) are etiologic factors in the development of oral squamous cell carcinoma (SCC). We conducted a population-based, case-control study to determine whether the risk of this cancer is related to HPV infection and sexual history factors.

METHODS

Case subjects (n = 284) were 18-65-year-old residents of three counties in western Washington State who were newly diagnosed with oral SCC from 1990 through 1995. Control subjects (n = 477) similar in age and sex were selected from the general population. Serum samples were tested for HPV type 16 capsid antibodies. Exfoliated oral tissue collected from case and control subjects and tumor tissue from case subjects were tested for HPV DNA. Odds ratios (ORs) were calculated after adjusting for age, sex, cigarette smoking, and alcohol consumption.

RESULTS

Among males only, oral SCC risk increased with self-reported decreasing age at first intercourse, increasing number of sex partners, and a history of genital warts. Approximately 26% of the tumors in case subjects contained HPV DNA; 16.5% of the tumors contained HPV type 16 DNA. The prevalence of oncogenic HPV types in exfoliated oral tissue was similar in case and control subjects. The ORs for HPV type 16 capsid seropositivity were 2.3 (95% confidence interval [CI] = 1.6-3.3) for all oral SCCs and 6.8 (95% CI = 3.0-15.2) for oral SCCs containing HPV type 16 DNA. The joint association of cigarette smoking and HPV type 16 capsid seropositivity with oral SCC (OR = 8.5; 95% CI = 5.1-14.4) was stronger than predicted from the sum of individual associations with current smoking (OR = 3.2; 95% CI = 2.0-5.2) and seropositivity (OR = 1.7; 95% CI = 1.1-2.6).

CONCLUSIONS

HPV type 16 infection may contribute to the development of a small proportion of oral SCCs in this population, most likely in combination with cigarette smoking.

Expression of keratin 13, 14 and 19 in oral squamous cell carcinomas from Sudanese snuff dippers: lack of association with human papillomavirus infection

In stratified squamous epithelia, altered expression of keratins (Ks) is one possible marker of malignant potential. In the epithelium of the uterine cervix, presence of human papillomaviruses (HPVs) is increasingly regarded as a marker of risk for cervical cancer. However, a similar role in oral cancer and precancer remains controversial. To address these questions, formalin-fixed, paraffin-embedded oral carcinomas from Sudanese snuff dippers (n=14) and oral carcinomas from Sudanese (n=14), Swedish (n=19) and Norwegian (n=41) non-snuff dippers were examined by immunohistochemistry for expression of K types 13, 14 and 19 using monoclonal antibodies. HPV infection was searched for in all the carcinomas by in situ hybridization (ISH) using the cocktail HPV OmniProbe and the ViraType probe. Carcinomas from Sudanese (snuff dippers/non-snuff dippers) were also examined for HPV infection by polymerase chain reaction (PCR) using the general HPV primers GP5+/GP6+. For the oral carcinomas from snuff dippers, moderate to intense expression of K13 (71%; 10/14), K14 (86%; 12/14) and K19 (93%; 13/14) was found. For the oral carcinomas from non-snuff dippers, weak to moderate expression of K13 (64%; 47/74), K14 (43%; 32/74) and K19 (45%; 33/74) was found. HPV DNA was not detected in any of the carcinomas from three countries when examined by ISH. The Sudanese (from snuff dippers/non-snuff dippers) oral carcinomas were also negative for HPV DNA with the PCR. The present study shows that (i) there is a high level of expression of K13, K14 and K19 in oral carcinomas from snuff dippers compared to those from non-snuff dippers, (ii) this high level of expression may arise from dysregulation of keratinocyte proliferation and maturation caused by damaging effects of snuff, (iii) the HPV genome is not found in Sudanese (snuff dippers/non-snuff dippers), Swedish or Norwegian oral carcinomas, and (iv) this may suggest that these viruses do not play a prominent role in the aetiology of oral carcinomas from these countries.

Detection of HPV-16 genome in human oral cancers and potentially malignant lesions from India

The presence of high risk human papilloma virus (HPV) 16 and 18 was examined in 100 oral cancer patients of Indian descent, 80 patients with potentially malignant oral lesions and corresponding clinically normal mucosa from 48 of these patients. Additionally, presence of HPV-33, -6 and -11 was also studied in 86 oral cancers, 50 potentially malignant oral lesions and 30 corresponding normal oral mucosa. All the patients with oral cancer and oral lesions, were long term tobacco-chewers, and a majority of the patients were in Advanced Stages III and IV. The DNA samples were amplified by polymerase chain reaction (PCR) using HPV L1 consensus primers. Typing of HPV was performed by Southern hybridization analysis of the PCR products using HPV-16, -18, -33, -6 and -11 type specific oligonucleotide probes. HPV-16 was detected in 15 out of 100 (15%) oral tumours, 27 out of 80 (34%) potentially malignant lesions and 15 out of 48 (31%) of the corresponding normal mucosa in the patients with oral lesions. HPV-18 was not detected in any of the oral cancers, oral lesions and normal mucosa. HPV-33 and the low-risk HPV-6 and -11 were also not detected in the oral cancers, oral lesions and corresponding normal mucosa. A significantly higher prevalence of HPV-16 was observed in oral lesions (27 out of 80, 34%) as compared to oral cancers (15 out of 100, 15%). The observed difference of 19% (95% confidence interval [CI]: 6%, 31%), between these two proportions was statistically significant at the 5% level of significance. Our data indicates that HPV-16 may play a direct role in a certain proportion of oral cancers; whereas in a subpopulation of oral cancers HPV-16 infection may be vital in the early events associated with development of potentially malignant oral lesions, and the presence of the virus not essential in the progression of the oral lesion to frank malignancy.

Human papillomavirus and head and neck cancer: epidemiology and molecular biology

BACKGROUND

Human papillomaviruses (HPV) are known to cause cancers of the cervix and other anogenital tract sites. Molecular biology has provided some evidence as to the specific mechanisms involved in the HPV-related carcinogenesis. Epidemiologic and molecular biology studies have also suggested that HPV infection may be associated with cancers of the head and neck.

METHODS

This review summarizes the biology of HPV and its potential etiologic role in head and neck cancer. Published reports were used to determine the prevalence of HPV in benign, precancerous, and neoplastic lesions of the oral cavity, pharynx, and larynx. The prevalence was also examined by head and neck site, HPV type, and method of HPV detection. In addition, the occurrence of HPV in normal head and neck tissue, epidemiologic factors related to HPV infection, and clinical implications are discussed.

RESULTS

Overall, the frequency of HPV in benign and precancerous lesions ranged from 18.5% to 35.9%, depending upon the detection methodology. Based upon the most sensitive method of detection, polymerase chain reaction (PCR), the overall prevalence of HPV in head and neck tumors was 34.5% (416 of 1205 tumors). The majority of HPV-positive tumors contained the "high risk" HPV types 16 (40.0%) and 18 (11.9%). Among head and neck sites, HPV was most often detected in tumors of the oral cavity (59%), followed by the pharynx (43%), and larynx (33%). The frequency of HPV positivity in oral samples from healthy individuals ranged from 1% to 60%. A limited number of descriptive and analytic epidemiologic studies have indicated that age (<60 years) and sex (male) were associated with the presence of HPV in the tumor, whereas tobacco and alcohol use were not. The relationship between HPV and survival is unclear, with few comprehensive studies currently available.

CONCLUSIONS

The prevalence of HPV, particularly the high-risk types, suggests a potential etiologic role for the virus in head and neck cancer. Molecular biology has provided important data on the interaction of the HPV oncoproteins with genes important in cell cycle control. Nonetheless, more basic research is needed to describe the physical state of the virus in a variety of cell types and the interaction with other genes. In addition, epidemiologic research is required to further understand the association between HPV and demographic and other risk factors as well as possible routes of transmission. Finally, much work is warranted to provide a definitive assessment of the prognostic significance of HPV in head and neck cancer.