Presence of Epstein-Barr virus latent membrane protein 1 gene in the nasopharyngeal swabs from patients with nasopharyngeal carcinoma

Detection of methylation status of Epstein-Barr virus DNA C promoter in the diagnosis of nasopharyngeal carcinoma

The detection of Epstein-Barr virus (EBV) DNA load in nasopharyngeal (NP) brushing samples for diagnosis of nasopharyngeal carcinoma (NPC) has attracted great attention. Further improvements that eliminate the need for clinical settings will greatly extend its application. A total of 250 participants were recruited to obtain NP brushing samples. Brush sampling both with and without the guide of endoscopy was conducted in 38 NPC patients. EBV DNA load, EBV RNA transcript and EBV DNA C promoter methylation status were, respectively, evaluated. Typical latency II transcripts were observed in brushing samples from NPC patients but not controls. Unlike in tissues, multiple lytic gene transcripts were observed not only in NPC patients but also in controls. Apart from EBV RNA transcript, samples from NPC patients also showed higher levels of EBV DNA load and C promoter methylation degree than their controls. Qualitative analysis further showed that EBV DNA C promoter was methylated in all NPC patients but in only 18.4% of the control group. Combined analysis of EBV DNA methylated degree and EBV DNA load increased the sensitivity to 100% in the detection of NPC. Using qualitative methylated type as the criteria, up to 89.5% of samples collected via blind brushing showed consistent results with samples collected via endoscopy-guided brushing from NPC patients. Detection of the methylation status of EBV DNA C promoter in NP brushing samples shows great potential in diagnosing NPC and may provide an appealing alternative for the non-invasive detection and screening of NPC without the need for clinical settings.

Epstein-Barr virus mir-bart1-5p detection via nasopharyngeal brush sampling is effective for diagnosing nasopharyngeal carcinoma

Epstein-Barr virus (EBV)-encoded microRNAs (miRNAs) are highly expressed in nasopharyngeal carcinoma (NPC) cases in high-risk areas, and may be involved in tumorigenesis. Using quantitative RT-PCR, we detected four EBV-encoded BamHI A rightward transcript (BART) miRNAs (mir-bart1-5p, mir-bart5, mir-bart6-5p and mir-bart17-5p) exclusively in 53 NPC biopsies as compared to 69 controls. In a larger patient group, that included 215 NPC cases and 209 controls, significantly higher levels of all four EBV miRNAs were detected in tumor cells harvested directly from the nasopharynx using a less invasive nasopharyngeal (NP) brush than in the controls (p < 0.001). One EBV miRNA, mir-bart1-5p, holds particular promise for use as a diagnostic indicator of NPC (with 93.5% sensitivity and 100% specificity), and its relative expression level was reflective of disease progression. Detection of this miRNA was effective for diagnosing early-stage NPC, even in cases that were falsely diagnosed as negative based on histopathological analysis, plasma EBV DNA load, and VCA-IgA and EA-IgA titers. EBV-encoded mir-bart1-5p detection via NP brush sampling could act as an efficient and less invasive method assisting clinical diagnosis of NPC.

Embelin prevents LMP1-induced TRAIL resistance via inhibition of XIAP in nasopharyngeal carcinoma cells

The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) selectively induces apoptosis in the majority of tumor cells, whilst sparing normal cells. However, the potential use of TRAIL in the treatment of cancer is limited by the inevitable emergence of drug resistance. The present study reports the upregulation of latent membrane protein 1 (LMP1)-induced TRAIL resistance via the enhanced expression of X-linked inhibitor of apoptosis protein (XIAP) in nasopharyngeal carcinoma (NPC) cells. LMP1-positive NPC cells were indicated to be more sensitive to TRAIL compared with LMP1-negative NPC cells in three NPC cell lines. CNE-1 is a LMP1-negative NPC cell line that was transfected with pGL6-LMP1; following which, sensitivity to TRAIL decreased. LMP1-induced TRAIL resistance was associated with the decreased cleavage of caspase-8,-3 and -9, BH3 interacting domain death agonist (Bid) and mitochondrial depolarization, without any effects on the expression of the death receptors, B-cell lymphoma (Bcl)-2 and Bcl-extra long. Knockdown of XIAP with small interfering RNA increased caspase-3 and -9 and Bid cleavage, and prevented LMP1-induced TRAIL resistance. Furthermore, embelin, the inhibitor of XIAP, prevented LMP1-induced TRAIL resistance in the Epstein-Barr virus (EBV)-positive CNE-1-LMP1 and C666-1 NPC cell lines. However, embelin did not enhance TRAIL-induced apoptosis in NP-69, which was used as a benign nasopharyngeal epithelial cell line. These data show that LMP1 inhibits TRAIL-mediated apoptosis by upregulation of XIAP. Embelin may be used in an efficacious and safe manner to prevent LMP1-induced TRAIL resistance. The present study may have implications for the development and validation of novel strategies to prevent TRAIL resistance in EBV-positive NPC.

Screening for nasopharyngeal cancer

BACKGROUND

Nasopharyngeal cancer is endemic in a few well-defined populations. The prognosis for advanced nasopharyngeal cancer is poor, but early-stage disease is curable and a high survival rate can be achieved. Screening for early-stage disease could lead to improved outcomes. Epstein-Barr virus (EBV) serology and nasopharyngoscopy are most commonly used for screening. The efficacy and true benefit of screening remain uncertain due to potential selection, lead-time and length-time biases.

OBJECTIVES

To determine the effectiveness of screening of asymptomatic individuals by EBV serology and/or nasopharyngoscopy in reducing the mortality of nasopharyngeal cancer compared to no screening. To assess the impact of screening for nasopharyngeal cancer on incidence, survival, adverse effects, cost-effectiveness and quality of life.

SEARCH METHODS

The Cochrane Ear, Nose and Throat Disorders Group (CENTDG) Trials Search Co-ordinator searched the CENTDG Trials Register; Central Register of Controlled Trials (CENTRAL 2015, Issue 6); PubMed; EMBASE; CINAHL; Web of Science; Clinicaltrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 6 July 2015.

SELECTION CRITERIA

Randomised controlled trials (RCT) and controlled clinical trials (CCT) evaluating screening for nasopharyngeal cancer versus no screening. Randomisation either by clusters or individuals was acceptable.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by The Cochrane Collaboration. Our primary outcome measure was nasopharyngeal cancer-specific mortality. Secondary outcomes were incidence of nasopharyngeal cancer by stage and histopathological classification at diagnosis, survival (two-year, three-year, five-year and 10-year), harms of screening (physical and psychosocial), quality of life (via validated tools such as the SF-36 and patient satisfaction), cost-effectiveness and all-cause mortality.

MAIN RESULTS

We identified no trials that met the review inclusion criteria. We retrieved 31 full-text studies for further investigation following the search. However, none met the eligibility criteria for a RCT or CCT investigation on the efficacy of screening for nasopharyngeal cancer.

AUTHORS' CONCLUSIONS

No data from RCTs or CCTs are available to allow us to determine the efficacy of screening for nasopharyngeal cancer, or the cost-effectiveness and cost-benefit of a screening strategy. High-quality studies with long-term follow-up of mortality and cost-effectiveness are needed.

Nasopharyngeal Epstein-Barr Virus Load: An Efficient Supplementary Method for Population-Based Nasopharyngeal Carcinoma Screening

Serological detection of Epstein-Barr virus (EBV) antibodies is frequently used in nasopharyngeal carcinoma (NPC) mass screening. However, the large number of seropositive subjects who require close follow-up is still a big burden. The present study aimed to detect the nasopharyngeal EBV load in a high-risk population seropositive for antibodies against EBV, as well as to examine whether assay for nasopharyngeal EBV DNA load might reduce the number of high-risk subjects for follow-up and improve early detection of NPC. A prospective and population-based cohort study was conducted in southern China from 2006 through 2013. Among 22,186 participants, 1045 subjects with serum immunoglobulin A (IgA) antibodies against viral capsid antigen (VCA) titers ≥ 1:5 were defined as high-risk group, and were then followed-up for NPC occurrence. Qualified nasopharyngeal swab specimens were available from 905 participants and used for quantitative PCR assay. Our study revealed that 89% (802/905) subjects showed positive EBV DNA in nasopharyngeal swab. The nasopharyngeal EBV load in females was higher than that in males. The nasopharyngeal EBV load increased with increasing serum VCA/IgA titers. Eight cases of newly diagnosed NPC showed an extremely elevated EBV load, and 87.5% (7 of 8 patients) were early-stage NPCs. The EBV loads of 8 NPCs were significantly higher than those of 897 NPC-free subjects (mean, 2.8 × 10(6) copies/swab [range 4.8 × 10(4)-1.1 × 10(8)] vs. 5.6 × 10(3) [range 0-3.8 × 10(6)]). Using mean EBV load in NPC-free population plus two standard deviations as cut-off value, a higher diagnostic performance was obtained for EBV load test than serum VCA/IgA test (area under ROC, 0.980 vs 0.895). In conclusion, in a prospective and population-based study we demonstrated that an additional assay of EBV load in the nasopharynx among high-risk individuals may reduce the number of subjects needed to be closely followed up and could serve as part of a NPC screening program in high-risk populations.

EA-D p45-IgG as a potential biomarker for nasopharyngeal carcinoma diagnosis

AIM

To identify new biomarkers for NPC diagnosis with an anti-EBV Western blot test kit.

METHODS

Serum samples from 64 NPC patients and healthy subjects with four specific VCA-IgA/EA-IgA profiles were tested with an anti-EBV Western blot test kit from EUROIMMUN AG. Proteins were quantified with scores of intensity visually assigned to the protein bands. The markers which showed statistical differences between the NPC and non-NPC subjects were further evaluated in another 32 NPC patients and 32 controls in comparison with established biomarkers including VCA-IgA, EA-IgA, EBV-related protein IgG, and EBV DNA.

RESULTS

Among the markers screened, EA-D p45-IgG showed a statistically significant difference (p < 0.05) between NPC and non-NPC subjects with VCA-IgA positivy. In 32 VCA-IgA positive NPC patients and 32 control subjects, the diagnostic accuracy of EA-D p45-IgG was 78.1% with a positive predictive value of 77.8% and a negative predictive value of 78.6%. In the verification experiment, the specificity and sensitivity of EA-D p45-IgG were 75.0% and 90.6 %, respectively.

CONCLUSIONS

EA-D p45-IgG might be a potential biomarker for NPC diagnosis, especially among VCA-IgA positive subjects.

Down-regulation of miRNA-204 by LMP-1 enhances CDC42 activity and facilitates invasion of EBV-associated nasopharyngeal carcinoma cells

Nasopharayngeal carcinoma (NPC) is an Epstein-Barr virus (EBV)-associated malignancy. It is known that microRNAs are implicated in the progression of NPC. However, the role of miR-204 in NPC is poorly understood. In this study, we found that miR-204 was down-regulated in NPC cells and tissues. Low-level expression of miR-204 was significantly associated with a more aggressive and poor prognostic phenotype of NPC. We further found that EBV-encoded latent membrane protein 1 (LMP-1) suppressed miR-204 expression by activating Stat-3. Cdc42 was identified as a direct target of miR-204. Mir-204 inhibited EBV positive C666-1 cell invasion and metastasis partly through targeting cdc42.

Epstein-Barr Virus encoded LMP1 regulates cyclin D1 promoter activity by nuclear EGFR and STAT3 in CNE1 cells

The principal Epstein–Barr virus (EBV) oncoprotein, latent membrane protein 1 (LMP1) is strongly associated with nasopharyngeal carcinoma (NPC), a prevalent cancer in China. The epidermal growth factor receptor (EGFR) is important in carcinogenesis, as it is a ubiquitously expressed receptor tyrosine kinase. Signal transducer and activator of transcription 3 (STAT3) is a master transcriptional regulator in proliferation and apoptosis. Our previous study demonstrated that the nuclear EGFR could bind to the cyclin D1 promoter directly in the presence of LMP1, and the correlation between EGFR and STAT3 in NPC remains to be further explored. Here, we have shown that the interaction of EGFR and STAT3 increased in the nucleus in the presence of LMP1. LMP1 promoted both EGFR and STAT3 binding to the promoter region of cyclin D1, in turn, enhancing the promoter activity of cyclin D1. Furthermore, we demonstrated that both transcriptional activity and mRNA levels of cyclin D1 were decreased by small molecule interference of EGFR and STAT3 activity. These findings may provide a novel linkage between the EGFR and STAT3 signaling pathways and the activation of cyclin D1 by LMP1 in the carcinogenesis of NPC.

NF-κB-mediated transcriptional upregulation of TNFAIP2 by the Epstein-Barr virus oncoprotein, LMP1, promotes cell motility in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC), which is closely associated with Epstein-Barr virus (EBV), is a metastasis-prone epithelial cancer. We previously showed that tumor necrosis factor α-induced protein 2 (TNFAIP2) is highly expressed in NPC tumor tissues and is correlated with metastasis and poor survival in NPC patients. However, the underlying mechanism remains unclear. In this study, we demonstrate that the EBV oncoprotein, latent membrane protein 1 (LMP1), can transcriptionally induce TNFAIP2 expression via NF-κB. Quantitative RT-PCR and western blotting revealed that LMP1 induces TNFAIP2 expression through its C-terminal-activating region (CTAR2) domain, which is required for transduction of NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) signaling. Inhibition of NF-κB activation or depletion of p65 (a component of NF-κB) by RNA interference abolished the LMP1-induced expression of TNFAIP2, whereas ectopic expression of p65 was sufficient to induce TNFAIP2 expression. Luciferase reporter assays showed that LMP1 transcriptionally induces TNFAIP2 expression through a newly identified NF-κB-binding site within the TNFAIP2 promoter (-3,869 to -3,860 bp). Immunohistochemical analysis of NPC biopsy specimens further revealed a significant correlation between the protein levels of TNFAIP2 and activated p65 (R=0.689, P<0.001), indicating that our findings are clinically relevant. Immunofluorescence microscopy and co-immunoprecipitation assays showed that TNFAIP2 associates with actin and is involved in the formation of actin-based membrane protrusions. Furthermore, transwell migration assays demonstrated that TNFAIP2 contributes to LMP1-induced cell motility. Collectively, these findings provide novel insights into the regulation of TNFAIP2 and its role in promoting NPC tumor progression.

A large-scale study of the association between biopsy results and clinical manifestations in patients with suspicion of nasopharyngeal carcinoma

OBJECTIVES/HYPOTHESIS

This study investigated the association between the results of nasopharyngeal (NPX) biopsies and clinical manifestations in patients with suspected nasopharyngeal carcinoma (NPC).

STUDY DESIGN

Retrospective cohort study.

METHODS

Four hundred seventy-three patients with 512 NPX biopsies were enrolled. The statistical analyses were conducted to evaluate clinical significance and screening performance for suspected NPC.

RESULTS

The negative rate of all NPX biopsies was 69.7% (345/495), and the majority of the noncancerous group revealed lymphoid hyperplasias (208/345, 60.3%). The three diagnostic capabilities of NPX mass, epistaxis (EPI), neck mass (NM), EPI-NM, EPI-NPX mass, NM-NPX mass, and EPI-NM-NPX mass were 0.595, 0.557, 0.735, 0.609, 0.566, 0.748, and 0.600, respectively.

CONCLUSIONS

Although NPX mass, EPI, and NM were significant to identify suspected NPC, the diagnostic capabilities of combining EPI, NM, and NPX were still low. A large number of noncancerous biopsy results were obtained due to lymphoid hyperplasias often being mistaken as NPC.

Biomarkers for use in monitoring responses of nasopharyngeal carcinoma cells to ionizing radiation

Nasopharyngeal carcinoma (NPC) is a common head and neck cancer. The incidence rate is higher in southern China and Southeast Asia in comparison with the Western countries. Radiotherapy is the standard treatment of NPC as the cancer cells are sensitive to ionizing radiation. Radiation treatment has good local control to patients with early NPC. It is essential to monitor the response of the NPC cells to radiation treatment in advance in order to select suitable treatment choice for the patients. This review aims to discuss the potential use of biomarkers in monitoring the responsiveness of NPC cells to radiation treatment.

c-Myc and EBV-LMP1: two opposing regulators of the HLA class I antigen presentation machinery in epithelial cells

Background:

Epstein–Barr virus (EBV)-encoded latent membrane protein 1 (LMP1) up-regulates the human leukocyte antigen (HLA) class I antigen presentation machinery (APM). This appears counterintuitive with immune evasion in EBV-associated tumours like nasopharyngeal carcinoma (NPC).

Methods:

Latent membrane protein 1-transfected epithelial cell lines were used as a model system to study the impact of LMP1 and c-Myc on HLA class I components. The expression of components of the HLA class I APM, c-Myc and Ki-67 was analysed in LMP1+ and LMP1− NPC by immunohistochemistry.

Results:

In epithelial cells, LMP1 up-regulated HLA class I APM. This effect could be counteracted by c-Myc, which itself was up-regulated by LMP1 apparently through IL6 induction and Jak3/STAT3 activation. Studies of NPC biopsies revealed down-regulation of HLA class I APM expression. No difference was observed between LMP1+ and LMP1− NPC. However, expression of Ki-67 and c-Myc were up-regulated in LMP1+ tumours.

Conclusion:

These findings raise the possibility that c-Myc activation in NPC might antagonise the effect of LMP1 on HLA class I expression thus contributing to immune escape of tumour cells.

Epstein-Barr virus Latent Membrane Protein LMP1 reduces p53 protein levels independent of the PI3K-Akt pathway

Background

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy, which commonly occurs in Southern China, Taiwan, North Africa and Southeast Asia. Nasopharyngeal carcinoma is strongly associated with Epstein-Barr virus infection. The p53 tumour suppressor protein is rarely mutated in NPC suggesting that the inactivation of p53 pathway in NPC could be due to the presence of EBV proteins. The aim of this work was to determine the effects of EBV proteins namely LMP1 and LMP2A on the expression levels of p53 protein.

Findings

In this work we found that LMP1, but not LMP2A, decreased p53 protein levels. Overexpression of LMP1 resulted in increased ubiquitination of p53 suggesting that the decreased p53 protein levels by LMP1 was due to increased degradation of the protein. The reduction of p53 protein levels was independent of the PI3K-Akt pathway.

Conclusions

LMP1, but not LMP2A, reduced p53 protein levels through the increase in the polyubiquitination of p53 protein and was independent of the PI3K-Akt pathway.

A simplified tumour model established via Epstein-Barr virus-encoded, nasopharyngeal carcinoma-derived oncogene latent membrane protein 1 in immunocompetent mice

The expression and immune modulation of Epstein-Barr virus-encoded oncogene latent membrane protein 1 (N-LMP1) is essential in the pathogenesis of nasopharyngeal carcinoma. In previous studies, cell transformation has been induced by the expression of EBV-encoded N-LMP1 in non-tumour BALB/c-3T3 cells and these cells have then been used to form tumours in T-cell-deficient nude mice. However, studies using this model have been limited by the lack of a competent immune system. To facilitate the study of immune components in N-LMP1-driven oncogenesis, we herein developed a simplified N-LMP1-derived tumour model in immunocompetent mice. Cell transformation was induced by the expression of N-LMP1 in BALB/c-3T3 cells, and these transformants were used to induce oncogenesis in BALB/c mice. In contrast to the 100% successful tumour-induction rate in nude mice treated with monodispersed transformed cells, the tumour incidence in BALB/c mice was only 5-36%. However, the transplantation of tumour fragments into BALB/c mice yielded a reproducible tumour-induction rate of >85%, which is acceptable for most of the research needs. This novel model of N-LMP1-directed oncogenesis in an immunocompetent environment may serve as an important platform for the future assessment of N-LMP1-targeted tumour therapies.

Ubiquitination of MDM2 modulated by Epstein-Barr virus encoded latent membrane protein 1

Epstein-Barr virus encoded latent membrane protein 1 (LMP1), an oncogenic protein, plays an important role in the carcinogenesis of nasopharyngeal carcinoma. The MDM2 gene is a cellular pro-oncogene that is abnormally up-regulated in human tumors. MDM2 is overexpressed in nasopharyngeal carcinoma, which is associated with the presence of EBV and cervical lymph node metastasis. Because MDM2 is capable of self-ubiquitination, and the ubiquitin proteasome pathway-dependent degradation is an important mechanism for regulating MDM2 levels in cells. Here we show that LMP1 augment MDM2 protein expression in dose-dependent level, and also lead to a drastic accumulation of ubiquitinated MDM2 species, this effect is associated with the stability of MDM2 modulated by LMP1. This is the first time to explain LMP1-regulated MDM2 through a post-ubiquitination mechanism.

Activation of DNA methyltransferase 1 by EBV LMP1 Involves c-Jun NH(2)-terminal kinase signaling

EBV latent membrane protein 1 (LMP1) activates cellular DNA methyltransferases, resulting in hypermethylation and silencing of E-cadherin. However, the underlying mechanism remains to be elucidated. In this study, we show that LMP1 directly induces the dnmt1 promoter activity through its COOH-terminal activation region-2 YYD domain. Using (i) LMP1 mutants, (ii) dominant negative mutants c-jun NH(2)-terminal kinase (JNK)-DN, p38-DN, and constitutive active mutant IkappaB, as well as (iii) dsRNAs targeting c-Jun, JNK, and tumor necrosis factor receptor-associated death domain protein, and (iv) signal transduction inhibitors, we show that LMP1-mediated DNA methyltransferase-1 (DNMT1) activation involves JNK but not nuclear factor kappaB and p38/mitogen-activated protein kinase signaling. In addition, LMP1 is unable to activate dnmt1-P1 promoter with activator protein-1 (AP-1) site mutation. Chromatin immunoprecipitation assay results also confirm that LMP1 activates P1 promoter via the JNK-AP-1 pathway. Furthermore, chromatin immunoprecipitation assay data in LMP1-inducible cells disclose that LMP1 induces formation of a transcriptional repression complex, composed of DNMT1 and histone deacetylase, which locates on E-cadherin gene promoter. Treatment with JNK inhibitor, SP600125, prevents the formation of this repression complex. Statistical analyses of the immunohistochemical staining of 32 nasopharyngeal carcinoma (NPC) biopsies show LMP1 expression (18 of 32, 56.25%), DNMT1 expression (31 of 32, 97%), and phospho-c-Jun (27 of 32, 84.38%), suggesting that overexpression of these proteins is observed in NPC tumor. Overall, these results support a mechanistic link between JNK-AP-1 signaling and DNA methylation induced by the EBV oncogene product LMP1.

Noninvasive diagnosis of nasopharyngeal carcinoma: nasopharyngeal brushings reveal high Epstein-Barr virus DNA load and carcinoma-specific viral BARF1 mRNA

Nasopharyngeal carcinoma (NPC) is the most prevalent ENT-tumour in Indonesia. We investigated the primary diagnostic value of Epstein-Barr virus (EBV) DNA load and mRNA detection in noninvasive nasopharyngeal (NP) brushings, obtained prospectively from consecutive Indonesian ENT-patients with suspected NPC (N=106) and controls. A subsequent routine NP biopsy was taken for pathological examination and EBER-RISH, yielding 85 confirmed NPC and 21 non-NPC tumour patients. EBV DNA and human DNA load were quantified by real-time PCR. NP brushings from NPC patients contained extremely high EBV DNA loads compared to the 88 non-NPC controls (p<0.0001). Using mean EBV DNA load in controls plus 3 SD as cut-off value, specificity, sensitivity, positive and negative predictive values were 98, 90, 97 and 91%, respectively. Epstein-Barr nuclear antigen 1 (EBNA1) and the carcinoma-specific BARF1 mRNA were detected by nucleic acid sequence based amplification and found in 86 and 74% of NP brushings, confirming NPC tumour cell presence. EBV RNA positivity was even higher in fresh samples stored at -80 degrees C until RNA expression analyses (88% for both EBNA1 and BARF1). EBV RNA-negative NP brushings from proven NPC cases had the lowest EBV DNA loads, indicating erroneous sampling. No EBV mRNA was detected in NP brushings from healthy donors and non-NPC patients. In conclusion, EBV DNA load measurement combined with detection of BARF1 mRNA in simple NP brushings allows noninvasive NPC diagnosis. It reflects carcinoma-specific EBV involvement at the anatomical site of tumour development and reduces the need for invasive biopsies. This procedure may be useful for confirmatory diagnosis in large serological NPC screening programs and has potential as prognostic tool.

The time frame of Epstein-Barr virus latent membrane protein-1 gene to disappear in nasopharyngeal swabs after initiation of primary radiotherapy is an independently significant prognostic factor predicting local control for patients with nasopharyngeal carcinoma

PURPOSE

The presence of Epstein-Barr virus latent membrane protein-1 (LMP-1) gene in nasopharyngeal swabs indicates the presence of nasopharyngeal carcinoma (NPC) mucosal tumor cells. This study was undertaken to investigate whether the time taken for LMP-1 to disappear after initiation of primary radiotherapy (RT) was inversely associated with NPC local control.

METHODS AND MATERIALS

During July 1999 and October 2002, there were 127 nondisseminated NPC patients receiving serial examinations of nasopharyngeal swabbing with detection of LMP-1 during the RT course. The time for LMP-1 regression was defined as the number of days after initiation of RT for LMP-1 results to turn negative. The primary outcome was local control, which was represented by freedom from local recurrence.

RESULTS

The time for LMP-1 regression showed a statistically significant influence on NPC local control both univariately (p < 0.0001) and multivariately (p = 0.004). In multivariate analysis, the administration of chemotherapy conferred a significantly more favorable local control (p = 0.03). Advanced T status (> or = T2b), overall treatment time of external photon radiotherapy longer than 55 days, and older age showed trends toward being poor prognosticators. The time for LMP-1 regression was very heterogeneous. According to the quartiles of the time for LMP-1 regression, we defined the pattern of LMP-1 regression as late regression if it required 40 days or more. Kaplan-Meier plots indicated that the patients with late regression had a significantly worse local control than those with intermediate or early regression (p = 0.0129).

CONCLUSION

Among the potential prognostic factors examined in this study, the time for LMP-1 regression was the most independently significant factor that was inversely associated with NPC local control.

Monitoring tumor recurrence with nasopharyngeal swab and latent membrane protein-1 and epstein-barr nuclear antigen-1 gene detection in treated patients with nasopharyngeal carcinoma

OBJECTIVES

Epstein-Barr virus (EBV) is closely related to nasopharyngeal carcinoma (NPC). Detection of EBV genomic DNA in a nasopharyngeal swab specimen may indicate the presence of NPC, and the EBV genomic DNA is only detected in patients with NPC and not in other head and neck cancers. This study aims to prove that detection of EBV genomic DNA by means of the latent membrane protein (LMP)-1 gene and the Epstein-Barr nuclear antigen (EBNA)-1 gene in the nasopharynx in NPC patients after radiation therapy indicates local recurrence of NPC.

STUDY DESIGN

Prospective.

METHODS

Nasopharyngeal swab with polymerase chain reaction (PCR)-based LMP-1 and EBNA-1 gene detection was used to monitor local recurrence in 84 NPC patients who completed radiation therapy.

RESULTS

Of the 12 patients demonstrating positive LMP-1 and EBNA-1 gene, 11 had local recurrence, and 10 of them had early rT1 mucosal recurrence. Subsequent salvage nasopharyngectomy controlled local disease in nine. Only one local recurrence in the skull base failed to show LMP-1 gene initially. Detection of LMP-1 gene and later verification with EBNA-1 gene from nasopharyngeal swabs in NPC patients after radiation therapy predicted local recurrence with a sensitivity of 91.7% and a specificity of 98.6%.

CONCLUSIONS

Nasopharyngeal swab with LMP-1 and EBNA-1 gene detection is a useful and reliable method to monitor local recurrence in NPC patients. It helps to detect recurrence early and may improve local control and enhance survival.

Molecular diagnosis of nasopharyngeal carcinoma: detecting LMP-1 and EBNA by nasopharyngeal swab

OBJECTIVES

The aim of this study was to investigate the feasibility of molecular diagnosis of nasopharyngeal carcinoma (NPC) by combining nasopharyngeal swab and polymerase chain reaction (PCR) to detect Epstein-Barr virus (EBV) derived latent membrane protein-1 gene (LMP-1) and Epstein-Barr nuclear antigen gene (EBNA).

METHODS

437 adults underwent nasopharyngoscopy, possible biopsy, and nasopharyngeal swab to obtain nasopharyngeal cells for the detection of LMP-1 and EBNA by PCR.

RESULTS

By detecting LMP-1 and EBNA in the nasopharyngeal swabs, NPC could be diagnosed with a false-positive rate of 1.7% (6/354), a false-negative rate of 8.6% (6/70), a sensitivity of 91.4% (64/70), a specificity of 98.3% (348/354), positive predictive value of 91.4% (64/70), and negative predictive value of 98.3% (348/354).

CONCLUSION

Detecting EBV genomic LMP-1 and EBNA by nasopharyngeal swab verifies NPC with a sensitivity of 91.4% and specificity of 98.3%. The nasopharyngeal swab coupled with PCR based EBV LMP-1 and EBNA detection could serve as a good supplement to pathological diagnosis of NPC.

Descriptive epidemiology and risk factors for head and neck cancer

Although more common in developing countries, over 11,000 deaths will occur in the United States from head and neck cancer in 2004. Squamous cell carcinomas account for the vast majority of cases in the United States and the majority of these are related to exposure to tobacco and alcohol. Newer data suggest a genetic contribution. This group is the focus of primary and secondary preventative efforts.

Prevalence of LMP-1 gene in tonsils and non-neoplastic nasopharynxes by nest-polymerase chain reaction in Taiwan

BACKGROUND

The purpose of this study was to investigate the frequency of Epstein-Barr virus (EBV) latent membrane protein-1 (LMP-1) in tonsils and non-neoplastic nasopharynxes in Taiwan.

METHODS

Nest-polymerase chain reaction (nest-PCR) was used to examine the presence of LMP-1 gene in lymphoid hyperplasia from non-neoplastic tonsillar and nasopharyngeal tissues and in tonsillar cancers.

RESULTS

In 152 cases, 64 biopsy tissues were obtained from lymphoid hyperplasia of nasopharynxes, 57 from tonsillectomy of non-neoplastic tonsils, and 31 from tonsillar cancers. LMP-1 was detected in 43.4% of the study group. Nineteen (29.7%) and 29 (50.9%) lymphoid hyperplasias from normal nasopharynxes and tonsils, respectively, and 18 (58.1%) biopsies from tonsillar cancers had positive LMP-1. The 30-base pair (bp) deleted variant was detected in 89.5% and 82.8% of normal nasopharynxes and tonsils, respectively, and in 66.7% of biopsies from tonsillar cancers (p =.198).

CONCLUSION

This study found that the 30-bp variant was the predominant type of LMP-1 from a healthy population in Taiwan.

Serum EBV DNA as a Biomarker in Primary Nasopharyngeal Carcinoma of Indian Origin

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a unique tumor due to its etiology and endemic distribution. Ethnic and regional factors are found to strongly influence the risk of disease; however, there have been no well-conducted studies on Indian patients. The present study assesses the relationship between Epstein-Barr Virus (EBV) and sporadic Indian NPC and the role of serum EBV DNA in NPC detection.

METHODS

Primers directed against non-polymorphic Epstein-Barr nuclear antigen-1 (EBNA-1) gene were used to detect the presence of EBV DNA from fresh tissue and serum in NPC, using PCR.

RESULTS

EBV DNA was detected in 69% of the biopsies and 58% of the serum of the NPC patients. With respect to histology, WHO Type III NPC, WHO Type II tumors and WHO I tumors showed 100%, 72.2% and 33% EBV positivity, respectively. EBV positivity was also observed in 23% (6/26) of benign samples. All biopsies of patients with positive serum samples were positive for EBV DNA.

CONCLUSION

EBV infection was found in sporadic NPC of South Indian origin, which confirms the etiological role of EBV in NPC. Detection of EBNA-1 in the serum and corresponding tissues of NPC patients suggests that the serum EBV DNA originates from NPC and also indicates the benefit of circulating viral DNA as an early marker in the diagnosis of NPC. Serum DNA-PCR methods can be extrapolated to follow-up studies involving tumor regression or to assess the response to various therapies.

Improved Accuracy of Detection of Nasopharyngeal Carcinoma by Combined Application of Circulating Epstein–Barr Virus DNA and Anti-Epstein–Barr Viral Capsid Antigen IgA Antibody

Background: Circulating Epstein–Barr viral (EBV) DNA and anti-EBV capsid antigen IgA (IgA VCA) represent two of the most sensitive peripheral blood markers of nasopharyngeal carcinoma (NPC), but direct comparative studies of these two markers are lacking.

Methods: The sensitivities and specificities of IgA-VCA and EBV DNA for diagnosis of NPC were determined in 139 new cases of NPC and 178 healthy individuals, respectively. EBV DNA was also assessed in 36 healthy family members identified as having false-positive IgA-VCA results at a screening clinic. EBV DNA was measured by a real-time quantitative PCR assay with a detection limit of 60 copies/mL. IgA-VCA was measured by semiquantitative indirect immunofluorescent method; a titer ≥1/10 was taken as positive.

Results: The sensitivities of EBV DNA and IgA-VCA for diagnosis of NPC were 95% (95% confidence interval, 91–98%) and 81% (73–87%), respectively. The combined marker panel had an overall sensitivity (positive result by either marker) of 99%. The concentrations of both markers showed dependence on cancer stage. The specificities of EBV DNA and IgA-VCA were 98% (96–99%) and 96% (91–98%), respectively. Among 36 healthy family members with false-positive IgA-VCA results, three-fourths had undetectable EBV DNA, whereas the others had increased EBV DNA concentrations that were significantly lower than in NPC patients.

Conclusions: For diagnosis of NPC, EBV DNA identifies almost all false-negative IgA-VCA cases and gives a 99% diagnostic sensitivity when combined with IgA-VCA. In the screening setting, EBV DNA identifies three-fourths of false-positive IgA-VCA cases. The selective application of EBV DNA in an IgA-VCA-based screening protocol could improve screening accuracy with only moderate increases in cost.

Presence of the latent membrane protein 1 gene in nasopharyngeal swabs from patients with mucosal recurrent nasopharyngeal carcinoma

BACKGROUND

Nasopharyngeal carcinoma (NPC) is the most common head and neck malignancy in southeastern China and Taiwan. Early detection of the local disease followed by timely and appropriate treatment is essential to increasing cure and survival rates. Detection of Epstein-Barr virus (EBV) genomic DNA, such as the latent membrane protein 1 gene (LMP-1), in patients postirradiation during follow-up may indicate mucosal recurrence.

METHODS

Seventy-one patients with NPC underwent serial nasopharyngeal swabs for LMP-1 polymerase chain reaction assay before, during, and after irradiation. All of patients achieved a complete disease remission of the LMP-1 gene after irradiation that lasted for at least 6 months.

RESULTS

The median LMP-1 disease remission time after the beginning of irradiation was 4.3 weeks. Patients with early LMP-1 disease remission (</= 4 weeks after the beginning of irradiation) and delayed LMP-1 disease remission (> 4 weeks) had 3-year local control rates of 93.5% and 76.9%, respectively (P = 0.0529). The LMP-1 gene was detected again (reexpression of LMP-1 [re-LMP-1]) in 10 patients after irradiation with at least 6 months of follow-up. Nine of 10 patients (90%) in the re-LMP-1 positive group and 2 of 61 patients (3.3%) in the re-LMP-1 negative group developed local recurrence. Mucosal recurrence developed in nine patients, and all displayed re-LMP-1. By detecting re-LMP-1 using nasopharyngeal swabs, mucosal recurrence was diagnosed with a sensitivity of 100% (9 of 9 patients) and a specificity of 98.4% (61 of 62 patients). The 3-year overall survival rate, the disease free survival rate for the entire group, and the estimated local mucosal control rates in the re-LMP-1 positive and re-LMP-1 negative groups were 86.5%, 76.5%, 19.4%, and 96.7%, respectively.

CONCLUSIONS

Expression of EBV LMP-1 in nasopharyngeal swab specimens from patients with irradiated/treated NPC can provide a highly sensitive and specific method of forecasting mucosal recurrence. This investigation confirmed the reliability and feasibility of nasopharyngeal swabs in screening for mucosal recurrences in patients with NPC.

Detection of Epstein-Barr virus-derived latent membrane protein-1 gene in various head and neck cancers: is it specific for nasopharyngeal carcinoma?

OBJECTIVE

The object of the study was to determine the incidence of the presence of Epstein-Barr virus-derived latent membrane protein-1 (LMP-1) gene in various head and neck cancers by polymerase chain reaction method.

STUDY DESIGN

Prospective study.

METHODS

During a 5-year period, polymerase chain reaction was used to investigate the presence of LMP-1 gene in various head and neck cancers from different locations and histopathological types, noncancerous nasopharyngeal biopsy samples, and tonsillectomy specimens from patients with chronic hypertrophic tonsillitis.

RESULTS

Of 202 patients enrolled in the study, 53 were diagnosed by pathological study with oropharyngeal carcinoma, 45 with nasopharyngeal carcinoma, 26 with oral cavity carcinoma, 26 with laryngohypopharyngeal carcinoma, 31 with nasopharyngeal lymphoid hyperplasia, and 21 with tonsils with lymphoid hyperplasia. After the application of polymerase chain reaction, the LMP-1 gene was not detected in any sample from oral cavity carcinoma, laryngohypopharyngeal carcinoma, or nasopharyngeal lymphoid hyperplasia or from tonsillectomy specimens but was detected in only one case of tonsillar carcinoma. On the contrary, the LMP-1 gene was detected in 43 (95.6%) of 45 samples from patients with nasopharyngeal carcinoma. The statistical analysis shows a significant association (P <.001) between the presence of LMP-1 gene and tumor localization in the nasopharynx.

CONCLUSIONS

The study shows that the presence of LMP-1 gene detected by polymerase chain reaction in the tumor cell is only significantly associated with tumor located in the nasopharynx, implying that Epstein-Barr virus plays a trifling role in the tumorigenesis of carcinomas arising from other head and neck locations. The polymerase chain reaction method that was used is a potential tool for screening nasopharyngeal carcinoma.

Detection of LMP-1 gene in middle ear effusion of NPC

Nasopharyngeal carcinoma (NPC) is closely related with Epstein-Barr virus (EBV). Almost every NPC tumor cells carries clonal EBV genomes. Detection of EBV derived latent membrane protein-1 gene (LMP-1) indicate the presence of NPC. Middle ear effusion (MEE) is a frequent sign of NPC. There have been no reports on LMP-1 in MEE. Tympanocentesis of 88 ears with MEE of 66 patients were done in three groups of patients, group (I) NPC, 31 patients, 50 ears, (II) other head and neck cancers, five patients, six ears and (III) no cancer history, 30 patients, 32 ears. The middle ear aspirate and nasopharyngeal swab specimen were collected to detect LMP-1 with a PCR-based method. Sixty aspirates (68%) out of 88 ears with MEE had enough DNA for PCR amplification. LMP-1 was detected in six middle ear aspirate specimen from three patients in group I who had petrous apex invasion. LMP-1 was detected in 30 swab specimen (93.8%) out of 32 nasopharyngeal swabs in group I. LMP-1 was not detected in middle ear aspirates or nasopharyngeal swab in group II and III patients. LMP-1 was not detected in MEE in patients without NPC. In NPC patients, the detection of LMP-1 may indicate petrous apex invasion.

Detección del virus herpes simplex y del virus de epstein-barr en los carcinomas de células escamosas de vías aerodigestivas superiores

OBJECTIVE

Previous studies have investigated the role of viruses in tumor origin of head and neck cancer. Despite this, mechanis of viral carcinogenesis remain unclear. The aim of this study is to determine the prevalence of herpes simplex virus (HSV) and Epstein-Barr virus (EBV) in malignant laryngeal and oropharyngeal lesions.

MATERIAL AND METHODS

Fresh frozen specimens of 28 laryngeal and oropharyngeal squamous cell carcinomas were studied. The presence or absence of HSV and EBV was determined with polymerase chain reaction (PCR) assays.

RESULTS

None of the samples showed evidence for EBV DNA. One tonsilar carcinoma case (3.5%) was positive for HSV DNA detection.

CONCLUSIONS

These results do not support HSV and EBV as etiological factors in head and neck cancer.

The significance of LMP1 expression in nasopharyngeal carcinoma

The Epstein-Barr virus (EBV)-encoded latent membrane protein 1 (LMP1) is a key effector of EBV-mediated B cell transformation. LMP1 displays potent oncogenic properties in rodent fibroblasts, and induces a wide range of effects in B cells and epithelial cells. LMP1 functions as a constitutively active tumor necrosis factor receptor (TNFR) engaging a multitude of signaling pathways that include NF-kappaB, the mitogen-activated protein kinases (MAPKs), JNK, p38, the JAK/STAT pathway and, more recently, the small Rho GTPases. The constitutive activation of these signaling cascades explains LMP1's ability to induce such a diverse array of morphological and phenotypic effects in cells and provides an insight into how LMP1 may induce cell transformation. The frequent expression of LMP1 in undifferentiated nasopharyngeal carcinoma (NPC) points to a role for this viral oncoprotein as a key effector molecule in NPC pathogenesis.

Induction of chemosensitivity in nasopharyngeal carcinoma cells using a human papillomavirus regulatory sequence and the thymidine kinase gene

Nasopharyngeal carcinoma (NPC) is a human cancer of epithelial cell origin. Infection by Epstein-Barr virus has been shown to be closely associated with this tumor. Recent studies have indicated that another common epitheliotropic virus, human papillomavirus (HPV), is also found in a significant number of NPC cases. In this study, we evaluated the feasibility of using the HPV regulatory long control region (LCR) to drive the expression of the thymidine kinase (tk) gene to achieve chemosensitivity for gene therapeutic treatment of NPC. Testing HPV-11-LCR-tk constructs in NPC cell lines in the presence of ganciclovir (GCV) led to 50-60% cell death of transfected cells. The therapeutic efficacy was further tested in an in vivo model using nude mice transplanted with tumors derived from transfected NPC cells. Injection of 50 mg/kg body weight GCV twice daily for 14 days resulted in visually complete regression of the transplanted NPC tumor loads within 20 days after GCV treatment. Taken together, results from this pilot study indicate the feasibility of the development of a gene therapeutic protocol based on the chemosensitive gene constructs described in this paper.