Detection of Epstein-Barr virus in oral papilloma

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.

Association between oral lichen planus and Epstein-Barr virus in Iranian patients

Background

Oral lichen planus (OLP) is a common mucocutaneous disease with malignant transformation potential. Several etiologies such as humoral, autoimmunity, and viral infections might play a role, but still there is no definite etiology for this disease. The aim of this study was to investigate the presence of Epstein-Barr virus (EBV) genome in Iranian patients with OLP as compared to people with normal mucosa.

Materials and Methods

The study was carried out on a case group including 38 tissue specimens of patients with histopathological confirmation of OLP and a control group including 38 samples of healthy mucosa. All samples were examined by nested polymerase chain reaction (PCR) method to determine the DNA of EBV.

Results

Twenty-two (57.9%) female samples and 16 (42.1%) male samples with OLP were randomly selected as the case group, and 20 (52.6%) female samples and 18 (47.4%) male samples with healthy mucosa as the control group. There was a statistically significant difference in the percentage of EBV positivity between the case (15.8%) and the control groups (P < 0.05); in the case group, three female samples (13.6%) and three male samples (18.8%) were infected with EBV; the difference between the genders was not statistically significant (P = 0.50).

Conclusion

Results emphasized that EBV genome was significantly higher among Iranian patients with OLP so antiviral therapy might be helpful.

Multifunctional non-coding Epstein-Barr virus encoded RNAs (EBERs) contribute to viral pathogenesis

Epstein-Barr Virus (EBV) is known as an oncogenic herpesvirus implicated in the pathogenesis of various malignancies. It has been reported that EBV non-coding RNAs (ncRNAs) including EBV-encoded small RNAs (EBERs) and EBV-miRNAs contribute to viral pathogenesis. EBERs that are expressed abundantly in latently EBV-infected cells have been reported to play significant roles in tumorigenesis by EBV. Furthermore, it was demonstrated that the modulation of host innate immune signals by EBERs contributes to EBV-mediated pathogenesis including oncogenesis. Recently it was demonstrated that EBERs are secreted via exosomes by EBV-infected cells. It was also demonstrated that exosomes contain a number of EBV-encoded miRNAs. Various mRNAs have been identified as targets for regulation by EBV-miRNAs in host cells, therefore, EBERs and EBV-miRNAs might function through the transfer of exosomes.

Human herpesvirus-6 and epstein-barr virus infections at different histopathological grades of oral squamous cell carcinomas

BACKGROUND

The aim of this study was to determine the prevalence and viral load of Epstein-Barr virus (EBV) and Human herpesvirus-6 (HHV-6) in different histopathologic grades of oral squamous cell carcinoma (OSCC).

METHODS

Forty-five formalin-fixed paraffin-embedded tissue section of OSCC patients were analyzed by quantitative real-time polymerase chain reaction for detection of EBV and HHV-6.

RESULTS

The mean age of the patients was 58.6 years, 69% of whom were female, and 31% were male. Overall, the positive rate for EBV and HHV-6 were 16.7% and 27.1%, respectively; and the mean viral load EBV was 27.9 × 10(3) and 38.5 × 10(3) for HHV-6. No correlation was demonstrated between the viral load of EBV DNA (P = 0.35) and HHV-6 (P = 0.38) at the different OSCC histopathologic grades.

CONCLUSIONS

These findings neither lend support to the hypothesis that EBV and HHV-6 are directly involved in OSCC nor rule out the possibility that these viruses play an indirect role in carcinogenesis in this area.

Epstein-Barr Virus-Encoded RNAs: Key Molecules in Viral Pathogenesis

The Epstein-Barr virus (EBV) is known as an oncogenic herpesvirus that has been implicated in the pathogenesis of various malignancies. EBV-encoded RNAs (EBERs) are non-coding RNAs expressed abundantly in latently EBV-infected cells. Herein, I summarize the current understanding of the functions of EBERs, including the interactions with cellular factors through which EBERs contribute to EBV-mediated pathogenesis. Previous studies have demonstrated that EBERs are responsible for malignant phenotypes in lymphoid cells, and can induce several cytokines that can promote the growth of various EBV-infected cancer cells. EBERs were also found to bind retinoic acid-inducible gene I (RIG-I) and thus activate its downstream signaling. Furthermore, EBERs induce interleukin-10, an autocrine growth factor for Burkitt’s lymphoma cells, by activating RIG-I/interferon regulatory factor 3 pathway, suggesting that EBER-mediated innate immune signaling modulation contributes to EBV-mediated oncogenesis. Recently, EBV-infected cells were reported to secret EBERs, which were then recognized by toll-like receptor 3 (TLR3), leading to the induction of type I interferon and inflammatory cytokines, and subsequent immune activation. Furthermore, EBER1 was detected in the sera of patients with active EBV-infectious diseases, suggesting that EBER1-meidated TLR3 signaling activation could account for the pathogenesis of active EBV-infectious diseases.

Middle ear squamous papilloma: A report of four cases analyzed by HPV and EBV in situ hybridization

Squamous papilloma involving the middle ear as a primary lesion is an extremely rare occurrence. The aims of the present study were to investigate the presence of human papilloma virus (HPV) and Epstein-Barr virus (EBV) infections in primary middle ear squamous papilloma and to describe the clinical and pathological features of the disease along with therapeutic strategies. A retrospective review was conducted of four patients with clinical and pathological diagnoses of middle ear squamous papilloma. In situ hybridization (ISH) for a wide range of HPV DNA subtypes and EBV-encoded RNA was performed in the tissue samples obtained from these patients. Only two cases of primary squamous papilloma in the middle ear have been previously reported in the English literature. These papillomas developed in males of ~60-years of age and otorrhea was the most frequent complaint. Premalignant changes were observed in two of the present cases and ISH of HPV and EBV was negative in all four cases. The results of the present study indicated that chronic inflammatory stimulation, not HPV and EBV infection, is involved in the occurrence of middle ear squamous papilloma and its malignant transformation. Radical surgery and long-term postoperative follow-up are recommended due to its malignant and recurrent potential. Further genetic investigations with additional new cases are required to clarify the pathogenesis of squamous papilloma involving the middle ear.

Modulation of innate immunity system by Epstein-Barr virus-encoded non-coding RNA and oncogenesis

Epstein-Barr virus (EBV)-encoded small RNAs (EBERs) are polyA-, non-coding RNAs that are expressed abundantly in all forms of cells latently infected with EBV. EBERs (EBER1 and EBER2) contribute to the clonal proliferation of EBV-negative Burkitt's lymphoma (BL) cells in soft agar, tumorigenicity in SCID mice, up-regulation of the bcl-2 oncoprotein, resistance to apoptosis, and maintenance of malignant phenotypes in BL cells. EBERs induce the expression of interleukin (IL)-10 in BL cells, insulin-like growth factor 1 (IGF-I) in gastric and nasopharyngeal carcinoma cells, IL-9 in T cells, and IL-6 in lymphoblastoid cell lines. Additionally, each of these cytokines acts as an autocrine growth factor. In BL cells, EBERs bind the double-stranded RNA-activated protein kinase PKR, inhibit its phosphorylation, and thereby prevent IFN-alpha-mediated apoptosis. In epithelial cells, EBERs confer resistance to Fas-mediated apoptosis by blocking PKR activity. EBERs form complexes with PKR, ribosomal protein L22, lupus erythematosis-associated antigen (La), and retinoic acid-inducible gene I (RIG-I). In BL cells, EBERs activate RIG-I signaling and induce the expression of type-I IFNs and interferon stimulated genes (ISGs) through the activation of RIG-I substrates, nuclear factor-kappa B (NF-kappaB), and IFN regulatory factor 3 (IRF-3), and anti-inflamatory cytokine IL-10 through IRF-3 but not NF-kappaB signaling. EBERs also play critical roles in the growth transformation of B lymphocytes. Although EBER1 and EBER2 exhibit similarities in their primary (54%) and secondary structures, recent findings have shown that recombinant EBVs carrying only the EBER2 gene play a greater role in the growth transformation of B lymphocytes than EBVs carrying only the EBER1 gene. Thus, EBERs play multiple roles in various cell types, and we present a model that highlights the functions of EBERs in EBV-mediated oncogenesis in BL cells.

Role of EBERs in the pathogenesis of EBV infection

Epstein-Barr virus (EBV)-encoded small RNAs (EBERs) are noncoding RNAs that are expressed abundantly in latently EBV-infected cells. Previous studies demonstrated that EBERs (EBER1 and EBER2) play significant roles in various EBV-infected cancer cells. EBERs are responsible for malignant phenotypes of Burkitt's lymphoma (BL) cells including resistance to apoptosis. In addition, EBERs induce the expression of interleukin (IL)-10 in BL cells, insulin-like growth factor (IGF)-1 in gastric carcinoma and nasopharyngeal carcinoma cells, IL-9 in T cells that act as an autocrine growth factor. It was also reported that EBERs play critical roles in the B cell growth transformation including IL-6 induction by EBER2. EBERs have been discovered to interact with cellular proteins that play a key role in antiviral innate immunity. They bind the protein kinase RNA-dependent (PKR) and inhibit its activation, leading to resistance to PKR-mediated apoptosis. Recently, it was demonstrated that EBERs bind RIG-I and activate its downstream signaling, which induces expression of type-I interferon (IFN)s. Furthermore, EBERs induce IL-10 through IRF3 but not NF-kappaB activation in BL cells, suggesting that modulation of innate immune signaling by EBERs contribute to EBV-mediated oncogenesis. Most recently, it was reported that EBERs are secreted from EBV-infected cells and are recognized by toll-like receptor (TLR)3, leading to induction of type-I IFNs and inflammatory cytokines, and subsequent immune activation. Furthermore, EBER1 could be detected in the sera of patients with active EBV infectious diseases, suggesting that activation of TLR3 signaling by EBER1 would be account for the pathogenesis of active EBV infectious diseases.

Molecular diagnosis of nasopharyngeal carcinoma using detection of Epstein-Barr virus latent membrane protein-1 gene in cervical metastatic lymph nodes

BACKGROUND

Cervical lymphadenopathy could be a manifestation of occult nasopharyngeal carcinoma (NPC). Epstein-Barr virus (EBV) is frequently detected in NPC, and its malignant transformation is associated through the action of the oncoprotein latent membrane protein-1 (LMP-1).

PURPOSE

The aim of this study was to investigate whether a primary nasopharyngeal origin could be localized by detection of EBV LMP-1 gene in cervical metastatic lymph nodes.

MATERIALS AND METHODS

In this prospective study, 32 paraffin-embedded tissues of various head and neck carcinomas and 20 normal tonsil specimens were examined for the presence of LMP-1 gene, using polymerase chain reaction.

RESULTS

Ten of 12 nasopharyngeal biopsies and 8 of 10 metastatic lymph nodes of the same NPC were positive for LMP-1 gene. The LMP-1 gene was detected in metastatic lymph nodes of NPC, with a sensitivity of 80%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 91%. On the contrary, the LMP-1 gene was not detected in any of the samples of other head and neck carcinomas and their metastatic nodes as well as in tonsillar specimens. There was a significant association between the presence of LMP-1 gene and tumor location in the nasopharynx (P < .0001).

CONCLUSION

The presence of LMP-1 gene in metastatic cervical lymph nodes is significantly associated with nasopharyngeal origin of the carcinoma. Meanwhile, EBV has no role in the tumorigenesis of carcinomas arising from other head and neck regions.

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.

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.

The role of EBERs in oncogenesis

Epstein-Barr virus (EBV)-encoded small non-polyadenylated RNAs (EBERs) are the most abundant viral transcripts in latently EBV-infected cells. However, until recently, their roles in viral infection were totally unknown. It now appears that EBERs play a key role in maintaining the malignant phenotypes of Burkitt's lymphoma (BL) cells. The EBERs confer clonability in soft agarose, tumourigenicity in mice, and resistance to apoptosis against various stimuli in BL. Furthermore, EBERs induce transcription of interleukin-10, which acts as an autocrine growth factor of BL. These studies open the way toward the new concept that RNA molecules can act in oncogenesis.