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

Association of Epstein-Barr virus (EBV) with nasopharyngeal carcinoma: Experience from a North Indian tertiary care hospital

INTRODUCTION

Nasopharyngeal carcinoma (NPC), arising from nasopharyngeal epithelium is caused by Epstein-Barr virus (EBV). It is common in South China, South East Asia and North East India. The aim and objectives of this study were to determine the prevalence of EBV in formalin-fixed paraffin-embedded (FFPE) tissue sections of clinically suspected NPC patients, correlate the results of polymerase chain reaction (PCR) with histopathology findings, and to determine the utility of tissue EBV DNA as a diagnostic bio-marker.

MATERIALS AND METHODS

31 FFPE tissue samples were collected from clinically suspected NPC patients from April 2018-December 2019. Histopathological diagnosis was done by examination of Hematoxylin and Eosin stained slides. Presence of EBV was detected by EBNA-1 PCR. IHC was performed using EBV Latent Membrane Protein 1.

RESULTS

Of the 31 clinically suspected NPC cases, 15 (48.4 %) were histopathological confirmed NPC. Of these15, 13 (86.6 %) were non-keratinising undifferentiated NPC, and one each were keratinising NPC and non-keratinising differentiated NPC respectively. EBV EBNA1 PCR was positive in 35.5 % (11/31) of clinically suspected NPC cases. Of the 11 PCR positive cases, 9 (81.8 %) were histopathological confirmed NPC. Of the 31 clinically suspected NPC cases, IHC was indicated in 23 biopsies. Of which, 12 (52.2 %) were positive for LMP1 in the abnormal cells. Of the 12 IHC positive samples, 10 were NPC cases.

CONCLUSION

EBV DNA as an indicator towards NPC among clinically suspected cases had a sensitivity of 60 % and specificity of 87.5 %. In this study, addition of EBV DNA detection by PCR from FFPE tissue sections could confirm EBV association in 20 % of cases where it was not detected by EBV LMP1 IHC, thus helped in increasing the detection of EBV positivity in NPC cases. Early diagnosis of NPC will improve the cure rate and hence reduce the morbidity and mortality rates.

The Promise of Circulating Tumor DNA in Head and Neck Cancer

As the seventh most common cancer globally, head and neck cancers (HNC) exert considerable disease burden, with an estimated 277,597 deaths worldwide in 2020 alone. Traditional risk factors for HNC include tobacco, alcohol, and betel nut; more recently, human papillomavirus has emerged as a distinct driver of disease. Currently, limitations of cancer screening and surveillance methods often lead to identifying HNC in more advanced stages, with associated poor outcomes. Liquid biopsies, in particular circulating tumor DNA (ctDNA), offer the potential for enhancing screening, early diagnosis, and surveillance in HNC patients, with potential improvements in HNC patient outcomes. In this review, we examine current methodologies for detecting ctDNA and highlight current research illustrating viral and non-viral ctDNA biomarker utilities in HNC screening, diagnosis, treatment response, and prognosis. We also summarize current challenges and future directions for ctDNA testing in HNC patients.

Cell-free EBV DNA as a biomarker during clinical management of nasopharyngeal carcinoma in a nonendemic region

Nasopharyngeal carcinoma (NPC) is the most common malignant tumor of the nasopharynx. Although NPC is not endemic in India, higher incidences were observed in its North-Eastern regions particularly Sikkim, Nagaland, Manipur, and Mizoram. Early detection of NPC is difficult because the nasopharynx is not readily amenable to clinical examination and symptoms of NPC are nonspecific. The development of suitable biomarkers for early diagnosis of NPC as well as accurate monitoring of treatment response is needed urgently. In this exploratory pilot study, we have investigated the clinical significance of assessing plasma Epstein-Barr virus (EBV) DNA load at diagnosis and during treatment. We found that EBV DNA is detectable at diagnosis in the majority of patients with nonendemic NPC and the absolute copy number of circulating EBV DNA per milliliter increases progressively with the stage of the disease. The viral load declined significantly with induction chemotherapy and definitive chemoradiation but showed a sharp rise at relapse. Patients with EBV DNA levels ≥1500 copies/ml had a higher risk of disease progression or relapse when compared with patients who had EBV DNA <1500 copies/ml at baseline. Estimation of plasma EBV DNA may serve as an excellent noninvasive tool to monitor disease extent, response to therapy, and for better prediction of future relapse or progression-free survival in a nonendemic NPC patient population.

A systematic review and recommendations on the use of plasma EBV DNA for nasopharyngeal carcinoma

INTRODUCTION

Nasopharyngeal carcinoma (NPC) is an endemic malignancy in Southeast Asia, particularly Southern China. The classical non-keratinising cell type is almost unanimously associated with latent Epstein-Barr virus (EBV) infection. Circulating plasma EBV DNA can be a useful biomarker in various clinical aspects, but comprehensive recommendations and international guidelines are still lacking. We conducted a systematic review of all original articles on the clinical application of plasma EBV DNA for NPC; we further evaluated its strengths and limitations for consideration as standard recommendations.

METHODS

The search terms 'nasopharyngeal OR nasopharynx', and 'plasma EBV DNA OR cell-free EBV OR cfEBV' were used to identify full-length articles published up to December 2020 in the English literature. Three authors independently reviewed the article titles, removed duplicates and reviewed the remaining articles for eligibility.

RESULTS

A total of 81 articles met the eligibility criteria. Based on the levels of evidence and grades of recommendation assessed, it is worth considering the inclusion of plasma EBV DNA in screening, pre-treatment work-up for enhancing prognostication and tailoring of treatment strategy, monitoring during radical treatment, post-treatment surveillance for early detection of relapse, and monitoring during salvage treatment for recurrent or metastatic NPC. One major limitation is the methodology of measurement requiring harmonisation for consistent comparability.

CONCLUSIONS

The current comprehensive review supports the inclusion of plasma EBV DNA in international guidelines in the clinical aspects listed, but methodological issues must be resolved before global application.

Beyond cancer: a reflection on the narratives of nasopharyngeal carcinoma patients in Nagaland

In the Three-year Report of the Population-Based Cancer Registries: 2012-2014 published by the Indian Council of Medical Research (ICMR 2016) [11], the incidence of nasopharyngeal carcinoma (NPC) in Nagaland has been ranked as the highest in the country and the second-highest globally next to China. With the paucity of literature and very few studies done on the high incidence of NPC among the Nagas in Nagaland, the present study was undertaken to understand and examine the experiences and perceptions of patients diagnosed with NPC and efforts were made to draw on their experiences with cancer care treatment through the thematic analysis of the ten in-depth interviews conducted. The patient's experiences with anxiety, fear, and distress due to NPC, its impact on the reconstruction of self, the coping mechanisms they develop in the form of resilience, personal attributes of hope and optimism, and the impact of religion and prayers in helping them deal with their disease are discussed in the paper.

Accuracy Evaluation and Comparison of 14 Diagnostic Markers for Nasopharyngeal Carcinoma: A Meta-Analysis

The aim of the present study was to collect published studies and compare the diagnostic accuracy of different markers for nasopharyngeal carcinoma (NPC). We systematically searched PubMed/MEDLINE, EMBASE, Cochrane Library, CNKI, and Wanfang for relevant studies until April 29, 2020. The revised Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool was used to evaluate the methodological quality of the studies. The sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under the curve (AUC) values of the diagnostic markers were combined by a bivariate mixed effect model to compare their diagnostic accuracy. We explored heterogeneity through meta-regression. In total, 244 records from 101 articles were included, with 49,432 total study subjects (13,109 cases and 36,323 controls). EA-IgG, Zta-IgG, and Epstein-Barr virus (EBV) DNA load in non-invasive nasopharyngeal brushings (EBV-DNA brushings) have both high sensitivity and specificity, EBNA1-IgG and VCA-IgG have only high sensitivity, and EBNA1-IgA, VCA-IgA, Rta-IgG, Zta-IgA, HSP70, and serum sialic acid (SA) have only high specificity. The bivariate mixed effect model of EA-IgA had a significant threshold effect. Meta-regression analysis showed that ethnicity affected EBNA1-IgA, EBNA1-IgG, VCA-IgA, and EBV DNA load in plasma, test methods affected EBNA1-IgG, publication year affected VCA-IgA, and sample size affected Rta-IgG. There was significant publication bias for VCA-IgA and Rta-IgG (P < 0.05). EA-IgG, Zta-IgG, and EBV-DNA brushings are good diagnostic markers for NPC. The diagnostic accuracy was influenced by publication year, sample size, test methods, and ethnicity.

Cell-free Epstein-Barr virus-DNA in patients with nasopharyngeal carcinoma: Plasma versus urine

BACKGROUND

The purpose of this study was to explore urinary Epstein-Barr virus (EBV)-DNA as a potential biomarker in patients with nasopharyngeal carcinoma (NPC).

METHODS

EBV-DNA copies were estimated in plasma/urine of patients with NPC (n = 76) by real-time polymerase chain reaction (PCR) at baseline, during therapy, and at follow-up. Their correlation with EBV-RNA expression in tissues (n = 53) was used to assess sensitivity and specificity of plasma/urine EBV-DNA. Correlation of urine and plasma EBV-DNA with each other and with radiological response was evaluated.

RESULTS

This study demonstrated that urine EBV-DNA has high sensitivity (96%) at diagnosis and it correlates well with plasma EBV-DNA at baseline and after neoadjuvant chemotherapy. The EBV-DNA copies reduced significantly with therapy (plasma: p < .001; urine: p = .011). Patients with low EBV-DNA copies demonstrated improved survival (plasma: p = .023; urine: p = .083).

CONCLUSION

Plasma EBV-DNA is a good prognostic marker, whereas further study on a larger cohort may help in developing urine EBV-DNA as a surrogate prognostic marker for patients with NPC. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1666-E1673, 2016.

A meta-analysis on the EBV DNA and VCA-IgA in diagnosis of Nasopharyngeal Carcinoma

OBJECTIVE

We conducted a meta-analysis to compare the EBV DNA and VCA-IgA in diagnosis of Nasopharyngeal Carcinoma, and provide important evidence for screening method of NPC.

METHODOLOGY

Three databases, Medline (from Jan. 1966 to Jan. 2012), EMBASE (from January 1988 to Jan. 2012) and Chinese Biomedical Database (from January 1980 to Jan. 2012) were used to detect the role of EBV DNA and VCA-IgA in diagnosis of NPC. Meta-DiSc statistical software was used for analysis.

RESULTS

Twenty seven case-control and cohort studies were included in final analysis. A total of 1554 cases and 2932 controls were included in our meta-analysis. The Sensitivity specificity, positive likelihood (+LR) and likelihood negative (-LR) of EBV-DNA in diagnosis of NPC were 0.75(0.72-0.76), 0.87(0.85-0.88), 6.98(4.50-10.83) and 0.18(0.11-0.29), respectively, and they were 0.83(0.81-0.85), 0.85(0.83-0.86), 10.89(5.41-21.93) and 0.20(0.14-0.29) for VCA-IgA. The SROC for EBV DNA detection was 0.939, while this was 0.936 for VCA-IgA detection. The subgroup analysis showed EBV-DNA had larger areas under the summary receiver operator curve when compared with VCA-IgA in high quality and low quality studies.

CONCLUSION

Our meta-analysis indicated the EBV DNA had higher sensitivity and specificity in diagnosis of NPC.

Clinical value of serum Epstein-Barr virus DNA assay in the diagnosis of nasopharyngeal carcinoma

Serum Epstein-Barr virus DNA has been approved for diagnosing nasopharyngeal carcinoma (NPC). The goal of this meta-analysis was to evaluate the clinical value of the serum Epstein-Barr virus DNA in the diagnosis of NPC. The PubMed, Embase, Web of Knowledge, Chinese Wanfang Med Online, and National Knowledge Infrastructure (CNKI) databases were searched to identify suitable studies. The pooled sensitivity, specificity, positive likelihood ratio (LR+), negative likelihood ratio (LR-), and diagnostic odds ratio (DOR) of the serum Epstein-Barr virus DNA for the diagnosis of NPC were calculated. Summary receiver operating characteristic curves were used to summarize overall test performances. Meta-Disc 1.4 and Stata 12.0 softwares were used to analyze the data. A total of 2,520 patients from ten trials were subjected to meta-analysis. The summary estimates of the serum Epstein-Barr virus DNA for NPC diagnosis were as follows: sensitivity 0.69 (95 % confidence interval (CI) 0.65-0.72), specificity 0.84 (95 % CI = 0.82-0.86), LR + 4.81 (95 % CI = 2.94-7.88), LR - 0.25 (95 % CI = 0.13-0.48), DOR 24.65 (95 % CI = 12.64-48.07), and area under the summary receiver operator characteristic (SROC) curve (AUC) was 0.8979. Our study demonstrates that the serum Epstein-Barr virus DNA could be a useful tumor marker for NPC diagnosis.

Application of circulating plasma/serum EBV DNA in the clinical management of nasopharyngeal carcinoma

Elevated levels of circulating cell-free Epstein-Barr virus (EBV) DNA have been detected in plasma and serum samples from nasopharyngeal cancer (NPC) patients by quantitative real time PCR (qPCR) test. This qPCR test for circulating EBV DNA was found to be useful in the clinical management of NPC patients. For instance, EBV DNA qPCR test has good sensitivity and specificity in the detection of NPC at disease onset. Increase of the viral DNA load was found in NPC patients at late stages of disease. High EBV DNA load at disease onset or detectable viral load post-treatment was associated with poor survival or frequent relapse in NPC patients. Residual EBV DNA load after primary treatment could be a useful indicator to justify adjuvant chemotherapy. The qPCR test might also be applied to define a poor prognostic group in patients at early stage (I/II) for implementing concurrent chemo-radiotherapy (chemo-RT) to improve patients' outcome. The test is also useful to monitor distant metastases or response to radiotherapy, chemo-RT or surgery. Supplementary tests, however, are needed to pick up EBV negative WHO type I NPC and test improvement is needed to increase sensitivity in detecting stage I disease and local recurrence.

Detection of Epstein-Barr virus DNA in serum or plasma for nasopharyngeal cancer: a meta-analysis

BACKGROUND

Studies have shown that the plasma or serum cell-free Epstein-Barr virus (EBV) DNA level might be a tumor marker for the diagnosis of nasopharyngeal carcinoma (NPC).

OBJECTIVE

The objective of this study was to evaluate the diagnostic value of the detection of EBV DNA in plasma or serum for NPC.

METHODS

Articles related to the diagnosis of NPC by the detection of EBV DNA in plasma or serum were retrieved from different databases. Sensitivity, specificity, summary receiver operator curves, and likelihood ratios were pooled to assess the diagnostic value of individual diagnostic tests.

RESULTS

Fifteen studies were included in the meta-analysis. The pooled sensitivity and specificity were 89.1% (95% confidence interval [CI], 87.0%-90.9%) and 85.0% (95% CI, 83.0%-86.9%). The subgroup analysis regarding sample type found that the pooled sensitivity and specificity were 91.4% (95% CI, 89.0%-93.4%) and 93.2% (95% CI, 91.2%-95.0%) for the plasma group and 84.4% (95% CI, 79.9%-88.3%) and 76.0% (95% CI, 72.1%-79.6%) for the serum group.

CONCLUSION

The detection of EBV DNA for the diagnosis of NPC has good sensitivity and specificity and might be helpful for the screening of NPC.

The progress on genetic analysis of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a rare malignancy in most parts of the world, but is one of the most common cancers in Southeast Asia. Both genetic and environmental factors contribute to the tumorigenesis of NPC, most notably the consumption of certain salted food items and Epstein-Barr virus infection. This review will focus on the current progress of the genetic analysis of NPC (genetic susceptibilities and somatic alterations). We will review the current advances in genomic technologies and their shaping of the future direction of NPC research.

The tumor supressor function of STGC3 and its reduced expression in nasopharyngeal carcinoma

STGC3 is a novel candidate tumor suppressor gene that was found to be associated with nasopharyngeal carcinoma (NPC) via the cDNA cloning and RACE processes. The biological function of the STGC3 protein and its expression level in nasopharyngeal carcinoma remain unknown. This study aimed to evaluate the STGC3 protein expression level in NPC and to investigate the inhibitory function of STGC3 as a candidate tumor suppressor gene. We assessed the expression of the STGC3 protein in NPC biopsies and normal control specimens via Western blot and immunohistochemical analysis. The expression of STGC3 as induced by doxycycline (Dox) via a tetracycline (Tet)-regulated system in human nasopharyngeal carcinoma cell line CNE2 was also established, and the effect of STGC3 restoration on the biological behavior of CNE2 was observed. A reduced level of STGC3 expression (0.978 ± 0.213 versus 0.324 ± 0.185, P < 0.05) was detected in NPC versus normal nasopharyngeal tissue by Western blot assay. Immunohistochemical assays for STGC3 detected positive staining in the nuclei and cytoplasm of epithelial cells, and the positive expression rate in NPC, 8 of 21 (38%), was lower than that in normal nasopharynx samples, 16 of 22 (72%). After STGC3 expression was restored, the growth capacity and clone formation potential of CNE2 cells in soft agar were significantly suppressed, and the cell percentage in G₀/G₁ phase increased, while the percentage of cells entering the S and G₂ phases decreased. This indicates that an abnormality in STGC3 expression is associated with nasopharyngeal carcinogenesis and that it may play an important role in controlling cell growth and regulating the cell cycle.

Circulating nucleic acids (CNAs) and cancer--a survey

It has been known for decades that it is possible to detect small amounts of extracellular nucleic acids in plasma and serum of healthy and diseased human beings. The unequivocal proof that part of these circulating nucleic acids (CNAs) is of tumor origin, initiated a surge of studies which confirmed and extended the original observations. In the past few years many experiments showed that tumor-associated alterations can be detected at the DNA and RNA level. At the DNA level the detection of point mutations, microsatellite alterations, chromosomal alterations, i.e. inversion and deletion, and hypermethylation of promoter sequences were demonstrated. At the RNA level the overexpression of tumor-associated genes was shown. These observations laid the foundation for the development of assays for an early detection of cancer as well as for other clinical means.