No direct role for Epstein-Barr virus in oral carcinogenesis: a study at the DNA, RNA and protein levels

Potential Role of Epstein–Barr Virus in Oral Potentially Malignant Disorders and Oral Squamous Cell Carcinoma: A Scoping Review

Though the oral cavity is anatomically proximate to the nasal cavity and acts as a key reservoir of EBV habitation and transmission, it is still unclear whether EBV plays a significant role in oral carcinogenesis. Many studies have detected EBV DNA in tissues and exfoliated cells from OSCC patients. However, very few studies have investigated the expression of functional EBV proteins implicated in its oncogenicity. The most studied are latent membrane protein 1 (LMP-1), a protein associated with the activation of signalling pathways; EBV determined nuclear antigen (EBNA)-1, a protein involved in the regulation of gene expression; and EBV-encoded small non-polyadenylated RNA (EBER)-2. LMP-1 is considered the major oncoprotein, and overexpression of LMP-1 observed in OSCC indicates that this molecule might play a significant role in oral carcinogenesis. Although numerous studies have detected EBV DNA and proteins from OSCC and oral potentially malignant disorders, heterogeneity in methodologies has led to discrepant results, hindering interpretation. Elucidating the exact functions of EBV and its proteins when expressed is vital in establishing the role of viruses in oral oncogenesis. This review summarises the current evidence on the potential role of EBV in oral oncogenesis and discusses the implications as well as recommendations for future research.

Evaluation of HPV and EBV in OSCC and the expression of p53, p16, E-cadherin, COX-2, MYC, and MLH1

OBJECTIVE

This study aimed to evaluate the presence of human papillomavirus (HPV) and Epstein-Barr virus (EBV) and the expression of p53, p16, E-cadherin, COX-2, MLH1, and MYC in oral squamous cell carcinoma (OSCC).

MATERIALS AND METHODS

One hundred OSCC specimens were submitted to in situ hybridization for HPV and EBV, and immunohistochemistry for detection of the human proteins.

RESULTS

Thirty-one cases showed HPV in tumor tissue. EBV was not detected in any case investigated. The HPV(+) group demonstrated an increase of staining scores for nuclear p16 (p = .047), cytoplasmic MYC (p = .002), while a decrease for nuclear MLH1 (p = .048), suggesting that HPV may upregulate the expression of the first two proteins and down-regulate the latter.

CONCLUSION

Our findings reinforce the hypothesis of the HPV-related oral carcinogenesis involving the expression of p16 and MYC, and MLH1 suppression. Exclusively cytoplasmic stainings for p16, MLH1, and MYC were also associated with more advanced tumors. Finally, in view of the lack of studies correlating the HPV or EBV infection to the expression of oncoproteins, more researches assessing a broader panel of markers and employing different approaches are still necessary in order to understand the role of these viruses as well as the molecular mechanisms involved in the development and progression of oral carcinomas.

The oralome and its dysbiosis: New insights into oral microbiome-host interactions

The oralome is the summary of the dynamic interactions orchestrated between the ecological community of oral microorganisms (comprised of up to approximately 1000 species of bacteria, fungi, viruses, archaea and protozoa - the oral microbiome) that live in the oral cavity and the host. These microorganisms form a complex ecosystem that thrive in the dynamic oral environment in a symbiotic relationship with the human host. However, the microbial composition is significantly affected by interspecies and host-microbial interactions, which in turn, can impact the health and disease status of the host. In this review, we discuss the composition of the oralome and inter-species and host-microbial interactions that take place in the oral cavity and examine how these interactions change from healthy (eubiotic) to disease (dysbiotic) states. We further discuss the dysbiotic signatures associated with periodontitis and caries and their sequalae, (e.g., tooth/bone loss and pulpitis), and the systemic diseases associated with these oral diseases, such as infective endocarditis, atherosclerosis, diabetes, Alzheimer's disease and head and neck/oral cancer. We then discuss current computational techniques to assess dysbiotic oral microbiome changes. Lastly, we discuss current and novel techniques for modulation of the dysbiotic oral microbiome that may help in disease prevention and treatment, including standard hygiene methods, prebiotics, probiotics, use of nano-sized drug delivery systems (nano-DDS), extracellular polymeric matrix (EPM) disruption, and host response modulators.

Prevalence of EBV, CMV, and HPV in oral squamous cell carcinoma patients in the Pakistani population

Many studies have proposed an important role of viruses in the pathogenesis of oral cancer. The present study aimed to find out the prevalence of Epstein-Barr virus (EBV), cytomegalovirus (CMV), and human papillomavirus (HPV) among patients with oral squamous cell carcinoma (OSCC) in a Pakistani cohort. We investigated tissue samples obtained from 58 patients with OSCC using the polymerase chain reaction assay. No sample was positive for HPV. EBV was identified in 15 patients (25.86%), and CMV in three patients (5.17%). Coinfection with one or more viruses was detected in two cases and was coinfection with EBV and CMV. These results suggest a low prevalence of these viruses in OSCC patients in the Pakistani population compared to most other countries where the prevalence of these viruses has been reported in the past. Nevertheless, further studies are necessary to determine the potential role of EBV and the possible importance of CMV as an infection cofactor in oral cancer.

Overexpression of Epstein-Barr virus-encoded latent membrane protein-1 (LMP-1) in oral squamous cell carcinoma

Background

As oral cavity is the main location of Epstein-Barr virus (EBV) latency and shedding, and as EBV-encoded latent membrane protein-1 (LMP-1) has a crucial role in cell transformation, association between EBV infection, LMP-1 expression and oral malignancy is of interest. Although EBV DNA has been detected in oral squamous cell carcinoma (OSCC), studies on LMP-1 expression in OSCC and oral potentially malignant disorders are scarce and still controversial. This study aimed to evaluate the expression of LMP-1 in OSCC and oral leukoplakia (OL).

Methods

Biopsy specimens of 36 OSCC, 69 OL with and without dysplasia and 10 normal oral mucosa were assessed for the expression of LMP-1 using immunohistochemistry. In each case, at least 1000 cells were counted. Cells with staining were considered positive, classified by location as nuclear, cytoplasmic and nuclear plus cytoplasmic staining. Percentage of positive cells at different locations and of total positive cells were determined. For statistical analysis, SPSS version 21 was used. Statistical significance was considered at p < 0.05.

Results

LMP-1 was expressed in all studied specimens. In terms of percentage of total positive cells, LMP-1 expression was higher from normal mucosa (26.36%), OL without dysplasia (28.03%), OL with dysplasia (34.15%), to the significantly highest, (59.67%) in OSCC. In addition, cells with nuclear staining alone, cytoplasmic staining alone and cells with nuclear plus cytoplasmic staining were significantly higher in OSCC compared to those of normal mucosa, OL with and without dysplasia.

Conclusions

LMP-1 was overexpressed in OSCC. Our analysis on subcellular localization of LMP-1 in OSCC revealed prominent distinguished pattern, cytoplasmic distribution. Further studies in cell lines and animals are required to clarify the association between this EBV-encoded proteins and oral carcinogenesis.

Human papillomavirus (HPV) and Epstein-Barr virus (EBV) in keratinizing versus non- keratinizing squamous cell carcinoma of the oropharynx

Background

Oral and oropharyngeal squamous cell carcinomas (OSCC and OPSCC) represent the majority of head and neck squamous cell carcinomas (HNSCC). Human papillomavirus (HPV) is an important etiologic factor together with Epstein-Barr virus (EBV). Little is known on the prevalence of major herpesviruses [EBV, cytomegalovirus (CMV) and HHV-6, − 7 and − 8] in HNSCCs.

Methods

Fifty-one formalin-fixed paraffin-embedded (FFPE) tissue samples taken at surgery (40 oropharyngeal, 11 oral) were analyzed for 40 HPV genotypes (20 high-risk types), EBV, CMV, HHV-6, − 7 and − 8 by quantitative PCR. Expression of the HPV-induced p16^INK4A protein was also investigated by immunohistochemistry (IHC).

Results

In SCC, the prevalence of EBV was significantly higher compared to that of HPV (EBV 51% vs. HPV 19.5%; P = 0.005). HPV infection was found in 25% of OPSCC and in none of the OSCC; conversely, higher prevalence of EBV was found in OSCC (72.7%). HPV and EBV co-infection was detected only in 4 (10%) OPSCC. CMV was detected in only two cases, whereas HHV-6, − 7 and − 8 resulted negative. The prevalence of HPV but no EBV was associated with the non-keratinizing SCC type (NKSCC) compared to the keratinizing SCC type (KSCC)(HPV-DNA P < 0.005; EBV = 0.054).

Conclusions

Single HPV or EBV positivity was higher in OSCC than in OPSCC. Other potentially oncogenic herpesvirus types were minimally or not represented.

Association between epstein barr virus and tongue squamous cell carcinoma in iranian patients

Detection of Epstein-Barr virus in oral squamous cell carcinoma suggests its involvement in the carcinogenesis of oral cavity. But, there are few studies on the incidence of EBV genome in squamous cell carcinomas at specific locations in the oral cavity like tongue and with different tumor progression. In this study the presence of EBV genome in tongue Squamous Cell Carcinoma (TSCC) in Iranian patients were investigated. Accordingly, a total of 94 cases with TSCC were firstly analyzed for the presence of viral genome through Nested PCR. Patients were divided into different groups based on their gender and the size, nodal involvement, grade and stage of their tumor. Results showed the presence of EBV genome in 72.3% of TSCCs with no significant difference between two genders, although slightly higher in females. Interestingly, PCR products of EBV genome showed a statistically significant higher distribution in TSCCs at IVa stage (p=0.04), while a considerable low involvement of EBV genome was seen in T1-sized tumors. The result of this study further emphasizes the role of EBV in oral SCCs - mainly at tongue. This is the first investigation to clarify the association between EBV genome and different tumor size and stage in TSCCs; however, more studies in different regions and larger populations should be performed to be able to draw a firmed conclusion.

Role of viruses in gastrointestinal cancer

Gastrointestinal cancers are a global public health problem, which represent a vast majority of all cancer-caused deaths in both men and women. On the other hand, viral pathogens have been long implicated as etiological factors in the onset of certain human cancers, including gastrointestinal tumors. In this regard, Human Papilloma Virus (HPV), Epstein-Barr Virus (EBV), and John Cunningham Virus (JCV) have been more strongly suggested to be involved in gastrointestinal carcinogenesis; so that, the association of HPV with oropharyngeal and anal cancers and also the association of EBV with gastric cancer have been etiologically confirmed by epidemiological and experimental investigations. Although, the association of other viruses is less evident, but may rely on co-factors for their oncogenic roles. Therefore, to improve the prevention and treatment of these classes of cancer, their association with viral agents as potential risk factors should be investigated with care. In this respect, the present review has focused on the existing literature on the subject of viral involvement in gastrointestinal tumorgenesis, by covering and discussing various gastrointestinal cancers, corresponding viral agents and their oncogenic aspects and then summarizing evidences either supporting or rejecting a causal role of these pathogens in gastrointestinal malignancies.

No evidence for the presence of Epstein-Barr virus in squamous cell carcinoma of the mobile tongue

Squamous cell carcinoma of the head and neck (SCCHN) comprises a large group of cancers in the oral cavity and nasopharyngeal area that typically arise in older males in association with alcohol/tobacco usage. Within the oral cavity, the mobile tongue is the most common site for tumour development. The incidence of tongue squamous cell carcinoma (TSCC) is increasing in younger people, which has been suggested to associate with a viral aetiology. Two common human oncogenic viruses, human papilloma virus (HPV) and Epstein-Barr virus (EBV) are known causes of certain types of SCCHN, namely the oropharynx and nasopharynx, respectively. EBV infects most adults worldwide through oral transmission and establishes a latent infection, with sporadic productive viral replication and release of virus in the oral cavity throughout life. In view of the prevalence of EBV in the oral cavity and recent data indicating that it infects tongue epithelial cells and establishes latency, we examined 98 cases of primary squamous cell carcinoma of the mobile tongue and 15 cases of tonsillar squamous cell carcinoma for the presence of EBV-encoded RNAs (EBERs), EBV DNA and an EBV-encoded protein, EBNA-1. A commercially available in situ hybridisation kit targeting EBER transcripts (EBER-ISH) showed a positive signal in the cytoplasm and/or nuclei of tumour cells in 43% of TSCCs. However, application of control probes and RNase A digestion using in-house developed EBER-ISH showed identical EBER staining patterns, indicating non-specific signals. PCR analysis of the BamH1 W repeat sequences did not identify EBV genomes in tumour samples. Immunohistochemistry for EBNA-1 was also negative. These data exclude EBV as a potential player in TSCC in both old and young patients and highlight the importance of appropriate controls for EBER-ISH in investigating EBV in human diseases.

Epstein-Barr virus (EBV)-associated epithelial and non-epithelial lesions of the oral cavity

Epstein–Barr virus (EBV) is known to be associated with the development of malignant lymphoma and lymphoproliferative disorders (LPDs) in immunocompromised patients. EBV, a B-lymphotropic gamma-herpesvirus, causes infectious mononucleosis and oral hairy leukoplakia, as well as various pathological types of lymphoid malignancy. Furthermore, EBV is associated with epithelial malignancies such as nasopharyngeal carcinoma (NPC), salivary gland tumor, gastric carcinoma and breast carcinoma. In terms of oral disease, there have been several reports of EBV-related oral squamous cell carcinoma (OSCC) worldwide. However, the role of EBV in tumorigenesis of human oral epithelial or lymphoid tissue is unclear. This review summarizes EBV-related epithelial and non-epithelial tumors or tumor-like lesions of the oral cavity. In addition, we describe EBV latent genes and their expression in normal epithelium, inflamed gingiva, epithelial dysplasia and SCC, as well as considering LPDs (MTX- and age-related) and DLBCLs of the oral cavity.

Expression of Epstein-Barr virus among oral potentially malignant disorders and oral squamous cell carcinomas in the South Indian tobacco-chewing population

BACKGROUND

Oral cancer is the sixth most common malignancy in the world. Viruses are the causative agents of approximately 10-15% of all cancers worldwide (Cancers, 6, 2014 and 2155). The tumorigenic roles of Epstein-Barr virus in oral cancer are unclear. Literature search results are conflicting and dependent on various factors such as geographical/regional variations, sociocultural lifestyles, dietary habits, chewing/smoking tobacco habit. This study is the first original observation about frequency of Epstein-Barr virus among South Indian tobacco-chewing patients to elucidate its involvement in oral carcinogenesis and to know whether this can be a valuable diagnostic and prognostic indicator.

MATERIALS AND METHODS

A total number of 75 tobacco chewer subjects aged between 23 and 76 years with histopathologically confirmed oral potentially malignant disorders (25), oral squamous cell carcinoma (25), and age-matched healthy controls (25) formed the study group. Immunohistochemical expression of Epstein-Barr virus latent membrane protein 1 was assessed among cases and healthy controls.

RESULTS

Out of the total 75 subjects, six subjects (8%) were positive for Epstein-Barr virus antigen and 69 subjects (92%) negative. The antigen positivity was observed among two cases of moderately differentiated oral squamous cell carcinoma, two cases of leukoplakia, and two healthy controls.

CONCLUSION

No significant association between Epstein-Barr virus positivity was observed among oral potentially malignant disorders and oral squamous cell carcinoma among South Indian tobacco-chewing patients. This can be partially explained by the methodology employed, by the patient population analyzed and different habits in various geographical regions.

Detection of Epstein-Barr virus in different sources of materials from patients with oral lichen planus: a case-control study

AIMS

To detect the presence of Epstein-Barr virus (EBV) DNA in different sources of materials from a matched group of patients with oral lichen planus (OLP) and a group of people without OLP lesions, and to correlate the presence of virus with epidemiological variables of the groups studied.

METHODS

Fresh tissue samples, saliva, exfoliated cells and plasma of 24 patients with OLP lesions (cases) and 17 patients without OLP lesions (controls) were collected. EBV was detected by nested PCR.

RESULTS

Viral positivity was obtained in 62.5% of tissue samples; in 70.8% of exfoliated cell samples; in 33.3% of blood plasma samples and in 75% of saliva samples in the cases; and in 35.3% of tissue samples; 82.4% of exfoliated cell samples; in 47.1% of blood plasma samples and in 64.7% of saliva samples in the controls. There was a predominance of women in both groups. Variables not atrophic-erosive were most affected by EBV.

CONCLUSIONS

No relationship between EBV and OLP was found. However, all sources tested in this study were considered suitable for the detection of viruses.

Epstein-Barr virus and its association with rheumatoid arthritis and oral lichen planus

CONTEXT

Pathogenesis of autoimmune diseases (AD) is one of a multifactorial milieu. A genetic predisposition, an immune system failure, hormonal imbalance and environmental factors play important roles. Among the many environmental factors, the role of infection is gaining importance in the pathogenesis of various autoimmune disorders; among them, Epstein-Barr virus (EBV) plays a pivotal role. Literature states an association of various AD with EBV namely multiple sclerosis, autoimmune thyroiditis, systemic lupus erythematous, oral lichen planus (OLP), rheumatoid arthritis (RA), autoimmune hepatitis, Sjögren's syndrome and Kawasaki disease; among these, the most commonly occurring are OLP and RA.

AIM

Considering the frequency of occurrences, our aim was to perform a qualitative analysis of EBV viral capsid antigen (EBV VCA) IgG in the sera of patients with RA, OLP and establish a comparison with normal.

SETTINGS AND DESIGN

In-vitro experiment in a research laboratory.

SUBJECTS AND METHODS

Five-milliliter blood sample was collected from 25 patients diagnosed with RA and OLP. Serum was separated and EBV VCA IgG antibody titer was detected using NovaTec EBV VCA IgG ELISA kit.

STATISTICAL ANALYSIS USED

Chi-square test.

RESULTS

Six out of 25 subjects with RA and 4 out of 25 subjects with OLP tested positive for EBV VCA IgG.

CONCLUSIONS

Both environmental and genetic factors are important contributory components for autoimmune conditions. Screening for viral etiology would improve the efficacy of conventional treatment and reduce the risk of relapses.

A novel gammaherpesvirus found in oral squamous cell carcinomas in sun bears (Helarctos malayanus)

A novel herpesvirus was detected in sun bears ( Helarctos malayanus) with oral squamous cell carcinoma. Five captive sun bears from 4 institutions in the United States presented with oral lesions ranging from erythema and mild erosions to nodular, ulcerated masses. All 5 were diagnosed with squamous cell carcinoma. The tumors were treated with surgical resection but recurrence, local extension, or appearance of new lesions was noted in all cases. Intralesional chemotherapy was administered in 2 cases, and the nonsteroidal anti-inflammatory drug piroxicam was administered in 3 cases. Virus was detected in 4 of the 5 bears’ tissue samples using a consensus herpesvirus polymerase chain reaction. Nucleotide sequencing and phylogenetic analysis showed that this herpesvirus is in the subfamily Gammaherpesvirinae and distinct from other known herpesviruses. The association between the herpesvirus and squamous cell carcinoma is unknown. The current study presents a novel gammaherpesvirus within the order Ursidae, with the name Ursid herpesvirus 1 proposed.

Are oral and dental diseases linked to cancer?

OBJECTIVE

Infection and inflammation play a role in carcinogenesis, and highly prevalent oral and dental diseases have been significantly linked to some types of cancer. This article reviews current literature in this area.

MATERIALS AND METHODS

Open literature review using the PubMed database and focused on publications from 2000 to 2010.

RESULTS

Numerous potential mechanisms are implicated in the oral disease/carcinogenesis paradigm, including infection- and inflammation-associated cell pathology and microbial carcinogen metabolism. Poor oral hygiene is associated with oral cancer, but there is also evidence of a possible link between oral or dental infections and malignancies in general.

CONCLUSION

Oral infections may trigger malignant transformation in tissues of the mouth and other organs. However, scientific evidence to date remains weak and further well-conducted studies are warranted before cancer can be properly added to the list of oral infection-related systemic diseases.

Detection of EBV infection and gene expression in oral cancer from patients in Taiwan by microarray analysis

Epstein-Barr virus is known to cause nasopharyngeal carcinoma. Although oral cavity is located close to the nasal pharynx, the pathogenetic role of Epstein-Barr virus (EBV) in oral cancers is unclear. This molecular epidemiology study uses EBV genomic microarray (EBV-chip) to simultaneously detect the prevalent rate and viral gene expression patterns in 57 oral squamous cell carcinoma biopsies (OSCC) collected from patients in Taiwan. The majority of the specimens (82.5%) were EBV-positive that probably expressed coincidently the genes for EBNAs, LMP2A and 2B, and certain structural proteins. Importantly, the genes fabricated at the spots 61 (BBRF1, BBRF2, and BBRF3) and 68 (BDLF4 and BDRF1) on EBV-chip were actively expressed in a significantly greater number of OSCC exhibiting exophytic morphology or ulceration than those tissues with deep invasive lesions (P = .0265 and .0141, resp.). The results may thus provide the lead information for understanding the role of EBV in oral cancer pathogenesis.

Epstein-Barr virus prevalence in oral squamous cell cancer and in potentially malignant oral disorders in an eastern Hungarian population

We tested 65, 44, and 116 patients with oral squamous cell cancer (OSCC), oral leukoplakia (OL), and oral lichen planus (OLP) against 68 age-matched controls for the presence of Epstein-Barr virus (EBV). Apparently healthy mucosa was simultaneously sampled and examined in all patients. Paraffin-embedded tissue sections of all EBV-positive patients with OSCC were examined for latent membrane protein-1 (LMP-1) expression (demonstrable in most EBV-associated malignancies) using immunohistochemistry. The prevalence of EBV in the controls and in OSCC, OL, and OLP lesions was 19.1%, 73.8%, 29.5%, and 46.6%, respectively, and 66.2%, 22.7%, and 31.9% in the healthy mucosa of patients, respectively. The prevalence of EBV in OSCC patients was significantly higher than in controls or in respective samples of the other two patient groups both in the lesion and in the healthy mucosa. Comparisons including only patients with EBV-negative lesions yielded similar results. Lesions of patients with OLP, but not of patients with OL, differed significantly from controls in EBV prevalence. In OSCC, LMP-1 expression was not detected, and EBV carriage was not significantly associated with any risk factors and did not influence the outcome. Although a high prevalence of EBV was found in OSCC, comparable carriage rates on healthy mucosa of patients indicated that an aetiological role of EBV is unlikely.

The role of viruses in squamous cell carcinoma of the oropharyngeal mucosa

The development of squamous cell carcinomas of the oropharyngeal mucosa may involve many factors, including viruses. This review examines the evidence that viruses could be involved in the etiology of oral cancer, and shows that the evidence for a role of different viruses varies from very weak to very persuasive. Papillomaviruses are probably involved in the etiology of some carcinomas, particularly those of the oropharynx, and some herpes viruses may be involved as well. On the other hand some viruses can cause cancer in experimental situations but not in humans. Thus the importance of viruses in oral cancer is not always clear and must be evaluated with care. Those viruses that are associated with the disease provide targets for therapy and for diagnostic assays.

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.

Epstein-Barr virus in oral diseases

Epstein-Barr virus (EBV), a B-lymphotropic gamma-herpesvirus, causes infectious mononucleosis and oral hairy leukoplakia, and is associated with various types of lymphoid and epithelial malignancies. Saliva is the main vehicle for EBV transmission from individual to individual. Recent studies have also implicated EBV in the pathogenesis of advanced types of periodontal disease. EBV DNA is detected in 60-80% of aggressive periodontitis lesions and in 15-20% of gingivitis lesions or normal periodontal sites. The periodontal presence of EBV is associated with an elevated occurrence of periodontopathic anaerobic bacteria. Moreover, EBV active infection occurs in approximately 70% of symptomatic and large-size periapical lesions. EBV and cytomegalovirus often co-exist in marginal and apical periodontitis. Periodontal therapy can markedly suppress the EBV load in periodontal pockets as well as in saliva, which has the potential to reduce the risk of viral transmission between close individuals. EBV proteins up-regulate cytokines and growth factors, which seem to play a central role in the proliferative response of tongue epithelial cells in oral hairy leukoplakia and in the cell-transformation process of EBV-associated malignancies. Further research is needed to identify the full range of EBV-related diseases in the human oral cavity.

Quantitative analysis of cell-free Epstein-Barr virus DNA in plasma of patients with nonnasopharyngeal head and neck carcinomas

PURPOSE

We investigated the detectability of EBV DNA in the plasma of patients with non-nasopharyngeal head and neck carcinomas (NNHNC). Previous studies have shown that EBV is present in the tumor tissue of some NNHNC.

EXPERIMENTAL DESIGN

We recruited 101 patients with NNHNC and 48 healthy controls. Blood samples were taken from controls and patients before treatment. Tumor tissue samples were tested for the presence of EBV in the first 69 patients by in situ hybridization for small EBV-encoded RNA (EBER). Plasma EBV DNA was measured by real-time quantitative PCR in patients and controls.

RESULTS

Squamous cell carcinoma (SCC) was the commonest histology (78 patients) followed by lymphoepithelial carcinoma (8 patients). EBER was detected in tumor cells in 7 of 69 patients tested. All of the EBER-positive tumors were lymphoepithelial carcinoma. Two controls (2 of 48; 4.2%) had detectable plasma EBV DNA. Plasma EBV DNA was detected in all of the patients with EBER-positive tumors, and in 23 of 94 (24.5%) patients with tumors of EBER-negative or unknown status. The proportion of plasma EBV DNA-positive cases in either group was significantly higher than that in the control group (P < 0.0027). Plasma EBV DNA concentrations in patients with EBER-positive tumors (median, 3827 copies/ml) were significantly higher than those in the controls (median, 0 copy/ml; P = 0.0001). Of patients with SCC, 21 (26.9%) had detectable plasma EBV DNA (median concentration, 34 copies/ml). Plasma EBV DNA concentrations in the whole group of patients with SCC (median, 0 copy/ml; interquartile range, 0-4 copies/ml) were also significantly higher than those in the controls (P = 0.001).

CONCLUSIONS

Our data indicate that plasma EBV DNA reflects tumoral EBER status, and it may be of use as a tumor marker for EBER-positive NNHNC. The biological and clinical significance of low levels of circulating EBV DNA in the minority of patients with EBER-negative tumors remain to be elucidated.

Presence of human papillomavirus-18 and Epstein–Barr virus in a squamous cell carcinoma of the tongue in a 20-year-old patient. Case report and review of the current literature

We report on a squamous cell carcinoma of the tongue in a 20-year-old woman with co-infection of the tumor with human papilloma virus type 18 and Epstein-Barr virus. To our knowledge, this is the first case of co-infection in carcinoma of the tongue to be reported. We review the present data and theories concerning viral oncogenesis of oral carcinomas.

Epstein-Barr virus in head and neck cancer assessed by quantitative polymerase chain reaction

OBJECTIVES/HYPOTHESIS

Epstein-Barr virus (EBV) has classically been associated with nasopharyngeal carcinoma and Burkitt's lymphoma. Recently, multiple studies have been published linking EBV with oral squamous cell carcinoma and, to a lesser extent, hypopharyngeal and laryngeal tumors. Using a sensitive method of detection, the authors sought to analyze the presence and quantity of EBV DNA in a large cohort of head and neck cancers.

STUDY DESIGN

: Retrospective cohort study.

METHODS

Three hundred head and neck cancer samples exclusive of nasopharyngeal carcinoma were examined for the presence of EBV using quantitative polymerase chain reaction. Eighty-four tumor samples from the larynx, 30 from the hypopharynx, 73 from the oropharynx, and 113 from the oral cavity were analyzed for EBV quantity, which was expressed as the number of viral copies per cell genome. Representative samples, which contained the highest EBV DNA levels, were examined using in situ hybridization. Results were correlated with tumor grade and site and tobacco and alcohol exposure.

RESULTS

Three of 300 (1%) tumor samples were overtly positive for EBV DNA (defined as >0.1 copies of viral DNA/cell genome). Five of 300 (2%) tumor samples showed low levels (defined as >0.01 and <0.1 copies of viral DNA/cell genome), and 68 of 300 tumor samples (23%) showed trace levels (defined as < 0.01 copies of viral DNA/cell genome) of EBV DNA. No correlation was found between EBV positivity and tobacco exposure, alcohol exposure, or tumor grade.

CONCLUSION

In the overwhelming majority of head and neck cancers in this North American cohort, EBV did not appear to contribute to growth of a dominant clonal population with integrated EBV genome and was unlikely to be a genetic etiological agent in tumor development. The low quantities of EBV detected in a minority of head and neck cancers may be related to the presence of EBV genome in rare lymphoid or epithelial cells adjacent to the primary head and neck cancer.

Epstein-Barr virus in gastric carcinomas and gastric stump carcinomas: a late event in gastric carcinogenesis

BACKGROUND

To determine at what stage during gastric carcinogenesis Epstein-Barr virus (EBV) enters the gastric epithelial cells, the presence of EBV was investigated in two pathogenetically related but distinct forms of adenocarcinoma of the stomach-gastric carcinoma of the intact stomach (GCIS) and gastric stump carcinoma (GSC)-and their presumed precursor lesions.

PATIENTS AND METHODS

Eleven patients with EBV positive GCIS and eight patients with EBV positive GSC, demonstrated by the highly sensitive EBV encoded RNA 1/2 (EBER1/2) RNA in situ hybridisation (RISH) technique, were studied. Paraffin wax embedded tissue available from preoperative gastric biopsies and tumour adjacent tissue from the resection specimens containing normal gastric mucosa, inflamed gastric mucosa, and preneoplastic lesions (intestinal metaplasia and dysplasia) was investigated by EBER1/2 RISH, in addition to EBV nuclear antigen 1 (EBNA-1) and latent membrane protein 1 (LMP-1) immunohistochemistry (IHC).

RESULTS

In both GCIS and GSC and their precursor lesions EBER1/2 transcripts were restricted to the carcinoma cells. In addition, positivity of EBNA-1 IHC was also restricted to the tumour cells. IHC for LMP-1 was negative in all cases tested.

CONCLUSIONS

The absence of EBER1/2 transcripts in preneoplastic gastric lesions (intestinal metaplasia and dysplasia) and their presence in two distinct types of gastric carcinoma strongly suggest that EBV can only infect neoplastic gastric cells and thus is a late event in gastric carcinogenesis.

No role for Epstein-Barr virus in Dutch hepatocellular carcinoma: a study at the DNA, RNA and protein levels

Epstein-Barr virus (EBV) has been suggested to play a role in hepatocellular carcinoma (HCC). However, reports on detailed EBV transcript analyses in HCCs are limited. It was shown recently that expression of the transforming BARF1 (BamHI A rightward open reading frame 1) gene of EBV is restricted to latently EBV-infected epithelial malignancies, i.e. nasopharyngeal carcinoma and gastric carcinoma. The aim of this study was to test the presence of EBV in Dutch HCCs. A semiquantitative DNA PCR-enzyme immunoassay (PCR-EIA) for the BamHI W fragment of EBV was used to assess the presence of EBV in frozen and paraffin-embedded tissues of 16 HCCs. In addition, several RNA detection techniques, i.e. nucleic acid sequence-based amplification (NASBA), RT-PCR, RNA in situ hybridization (RISH) and immunohistochemistry (IHC), were applied. Five of 16 HCCs and two of four hepatitis C virus hepatitis samples were weakly positive for EBV DNA by PCR-EIA. Using sensitive RNA transcription techniques, no transcripts were found for BARF1, EBNA-1 and BARTs (BamHI A rightward transcripts) in any of the liver tissues tested. In addition, RISH for EBER1/2 and BARTs and IHC for EBNA-1, LMP-1 and ZEBRA, performed on the paraffin-embedded tissue of the PCR-EIA-positive cases and on adjacent non-neoplastic liver tissues, were negative. The absence of epithelial-specific BARF1 transcripts and other EBV transcripts and proteins in the EBV DNA PCR-positive cases argues strongly against a role for EBV in HCC.

Evaluation of the NucliSens Basic Kit assay for detection of Norwalk virus RNA in stool specimens

Norwalk-like viruses (NLVs) are a genetically diverse group of human caliciviruses that are the most common cause of epidemic gastroenteritis and are detected typically in stool by reverse transcription (RT)-PCR or electron microscopy (EM). The application of a rapid nucleic acid sequence-based amplification (NASBA) assay for the detection of NLV RNA in stool is described using the NucliSens Basic Kit. Primers and probes for the NLV Basic Kit assay were based on the RNA polymerase region of the prototype NLV, Norwalk virus (NV) genome and could consistently detect 10(4) RT-PCR detectable units of NV RNA in a stool filtrate. When compared directly with RT-PCR on a dilution series of NV stool filtrate, the NucliSens Basic Kit assay was equally sensitive. Cross-reactivity studies with a representative panel of other enteric pathogens were negative. When applied to 15 stool specimens from NV-challenged volunteers, the NASBA Basic Kit application for NV detection yielded 100% sensitivity, 50% specificity, and 67% concordance, using RT-PCR as the 'gold standard'. Despite the specificity of the NASBA primer/probe sequences for NV, other representatives from both NLV genogroups I and II could be detected by the Basic Kit assay in outbreak stool specimens, although the results were inconsistent. Our results suggest that the NucliSens Basic Kit assay provides a rapid and sensitive alternative to RT-PCR for detecting NV RNA in stool specimens. However, improvements in test specificity and primer design will be needed before the assay can be used routinely in the clinical setting.

Pathogenic roles for Epstein-Barr virus (EBV) gene products in EBV-associated proliferative disorders

Epstein-Barr virus (EBV) is associated with a still growing spectrum of clinical disorders, ranging from acute and chronic inflammatory diseases to lymphoid and epithelial malignancies. Based on a combination of in vitro and in vivo findings, EBV is thought to contribute in the pathogenesis of these diseases. The different EBV gene expression patterns in the various disorders, suggest different EBV-mediated pathogenic mechanisms. In the following pages, an overview of the biology of EBV-infection is given and functional aspects of EBV-proteins are discussed and their putative role in the various EBV-associated disorders is described. EBV gene expression patterns and possible pathogenic mechanisms are discussed. In addition, expression of the cellular genes upregulated by EBV in vitro is discussed, and a comparison with the in vivo situation is made.

Prevalence of Epstein-Barr virus in oral squamous cell carcinoma, oral lichen planus, and normal oral mucosa

OBJECTIVE

The Epstein-Barr virus (EBV) is associated with both malignant and benign diseases in the head and neck region. In several studies it has also been associated with oral squamous cell carcinoma (OSCC). Oral lichen planus (OLP) is a disease with unknown origin, and viral antigens have been proposed as etiologic agents. Smoking and alcohol habits are known risk factors for oral cancer development. In this study, the prevalence of EBV in OSCC and OLP was investigated, along with the effect of smoking, alcohol use, and age on EBV prevalence.

STUDY DESIGN

We examined 29 patients with OSCC, 23 with OLP, and 67 with clinically healthy oral mucosa. For EBV DNA analysis, a nested polymerase chain reaction method was used.

RESULTS

The overall EBV prevalence in patients with oral disease was 32.1%. Of the OSCC patients, 37.9% were EBV positive; and of the OLP patients, 26.1% were EBV positive. Both percentages were statistically significant compared with that of control patients (7.3%). The difference in EBV prevalence between the smoking control group and the nonsmoking control group was insignificant. Increased age did not enhance EBV prevalence.

CONCLUSIONS

This investigation shows that EBV is present in oral diseases such as OSCC and OLP. Smoking, alcohol use, or age does not seem to be a risk factor for EBV infection. The etiologic role of EBV in OSCC and OLP needs to be examined in a prospective follow-up study.

Epstein-Barr virus latent membrane protein-1 (LMP-1) expression in oral squamous cell carcinoma

OBJECTIVES

Epstein-Barr virus (EBV) is frequently associated with malignant cell transformation through the action of the oncoprotein latent membrane protein-1 (LMP-1). The present study aimed to determine the presence of EBV in oral squamous cell carcinomas (OSCCs) and the expression of LMP-1 in neoplastic cells of EBV-positive OSCCs.

STUDY DESIGN/METHODS

In a retrospective study of 78 OSCCs, we investigated the presence of the DNA of EBV by polymerase chain reaction, the expression of the oncoprotein LMP-1 by immunohistochemistry, and the presence of EBV-encoded RNA (EBER) by in situ hybridization.

RESULTS

EBV DNA was detected in 19.2% of the cases. Expression of LMP-1 in neoplastic cells was found in 85.7% of the EBV-positive OSCCs. EBV presence was significantly more frequent (P <.05) in OSCCs localized on the lateral tongue. EBV-positive OSCCs more frequently presented (P <.05) greater nuclear atypia.

CONCLUSION

EBV can appear in latent form in OSCC and express its main oncoprotein, LMP-1.

No direct role for Epstein-Barr virus in American hepatocellular carcinoma

Epstein-Barr virus (EBV) was recently linked to hepatocellular carcinogenesis in Japanese patients. It is not clear whether EBV infection is also associated with hepatocellular carcinoma (HCC) occurring in American patients. We studied 41 cases of HCC from the Los Angeles area for evidence of EBV infection by in situ hybridization, immunohistochemistry, and polymerase chain reaction methods. Of 41 cases, 16 were seropositive for hepatitis B virus surface antigen (39%), 9 of 29 tested were seropositive for hepatitis C virus antibody (31%); in total, 22 cases were seropositive for hepatitis B virus and/or hepatitis C virus (53%). Of 41 cases, 1 was positive for EBV-encoded small nonpolyadenylated RNA (EBER)-1 (2%) by in situ hybridization. By immunohistochemistry, two cases were positive for EBV nuclear antigen (EBNA)-1 (5%), one was positive for the transactivating immediate early BZLF1 (ZEBRA) (2%), and none was positive for latent membrane protein-1. None of the 41 cases was positive for latent membrane protein-1 and EBV nuclear antigen (EBNA)-4 DNAs by polymerase chain reaction assay. All four positive cases showed rare EBER-1-, ZEBRA-, or EBNA-1- positive cells (<0.1%); in none of these cases was there expression of any other EBV viral genes. In the one case each that was positive for EBER-1 and ZEBRA, both of which occurred in patients of non-Asian ethnicity, the staining was limited to infiltrating small lymphocytes, and tumor cells were negative. In the two cases that were positive for EBNA-1, both of which occurred in patients of Asian ethnicity, the staining was limited to tumor cells, and infiltrating small lymphocytes were negative. Our study indicates that rare cases of American HCC may contain EBV-infected cells, but it is unlikely that EBV plays a major role in the carcinogenesis of HCC.

No significant association of Epstein-Barr virus infection with invasive breast carcinoma

We studied 48 cases of invasive breast carcinoma for evidence of Epstein-Barr virus (EBV), which is associated with many human malignancies. In situ hybridization studies to detect the presence of EBV-encoded small nonpolyadenylated RNA (EBER)-1 were performed in paraffin sections. Immunohistochemical studies to detect EBV nuclear antigen (EBNA)-1, latent membrane protein (LMP)-1, and the transactivating immediate-early BZLF1 (ZEBRA) protein were also performed in paraffin sections. The presence of EBV genomic DNA was studied by polymerase chain reaction (PCR) amplification using sets of primers flanking the EBNA-4 and the EBV-LMP-1 genes in frozen tissues. Southern blot analysis using a probe flanking the EBV terminal repeat region was then attempted in cases that were PCR-positive. Five of 48 cases (10%) of breast carcinoma showed focal EBER-positive tumor cells. Twelve cases (25%) were positive for EBNA-1 by immunohistochemistry, all but one different from the EBER-positive cases. None of the cases were positive for LMP-1 or ZEBRA protein by immunohistochemistry. PCR studies for EBNA-4 and LMP-1 were each positive in five cases (including three cases in common). However, Southern blot studies successfully performed in all but one of the PCR-positive cases were completely negative. The identification of EBV by any methodology was not correlated with tumor size, grade, or lymph node status. This study demonstrated evidence of EBV infection in tissues involved by invasive breast carcinomas in a significant subset of cases. However, the lack of localization of EBV infection to a significant population of the tumor cells in any case, the negativity by Southern blot hybridization, and the lack of expression of multiple antigens in any case strongly argue against a significant role for EBV in the pathogenesis of breast carcinoma.