Hybridization lasted 1. To test the sensitivity and specificity of ISH, both negative and positive controls supplied by the manufacturer were used. A case was considered positive if the nucleus of a tumor cell stained dark blue or black. Table 1 shows the study cohort characteristics. The majority of patients The male: female ratio of patients was Fifty-five patients In four of the remaining 5 patients, both the tumors and histologically normal mucosa were positive for EBV.
All four patients with positive EBV in the tumor and matching normal mucosa were male above the age of 40 years. One of them presented with metastasis to the lung and spine and received palliative chemotherapy only; his last follow up was in and the patient died few months later from his disease.
The other three patients received neoadjuvant chemotherapy followed by concurrent chemoradiotherapy, of which two are still being followed up and one is currently lost to follow-up.
The details of their follow up are summarized in Table 3. With variation and development of different modalities for the detection of EBV in NPC, ISH is a unique method because it can confirm the existence of the EBV genome in the nuclei of malignant cells, regardless of infected lymphocytes in the peripheral blood.
The presence of a viral genome in the normal nasopharyngeal epithelium in a subset of the cohort of this study is a novel finding, and positive EBV results in the absence of tumor cells may suggest recurrent disease in a previously treated patient and thus require the performance of additional biopsies. A histologically normal looking mucosa may require EBV testing and if it is positive, then the possibility of a malignant tumor may be high and a repeat biopsy is recommended.
The incidence of this cancer was higher in male than female in our series and this is not surprising, as this has been shown in a previous study in the Saudi Arabia 5. The demographics of our series are similar to other series by different groups in Saudi Arabia and South Asia We showed that all EBV-positive benign cells were found in patients with invasive carcinoma and it may be beneficial to confirm the diagnosis of recurrent NPC even in the absence of invasive carcinoma in the provided specimen.
Although our sample size was limited and most of our patients had type II and III nasopharyngeal carcinoma; future studies with a sufficient number of patients may support our findings. Our results may be limited because we excluded patients without paraffin block specimens; despite this, the majority of the WHO type carcinoma in our patients was WHO type III.
All rights reservnasopharyngeal carcinoma, which supports its role in the pathogenesis of the tumor. EBV-ISH in benign nasopharyngeal epithelium may be found in small number of patients and this finding may has a potential to be useful as a histologic tumor marker for diagnosis and screening for post-treatment recurrence. However more studies with larger number of patients including treatment failure are needed to come up with a firm conclusion in this regards.
This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
AlDhahri S Potential significance of epstein barr virus-positive mucosa in patients with nasopharyngeal carcinoma. Home Contact Us. About us About Us Providing cutting-edge scholarly communications to worldwide, enabling them to utilize available resources effectively Read More.
Open Access News and events Contact Us. For Authors We aim to bring about a change in modern scholarly communications through the effective use of editorial and publishing polices. Read More. EBV forms that exist in lymph nodes or peripheral blood. The amount of cell-associated or cell-free EBV-DNA differs among diseases, and therefore the best specimens for measuring viral loads are also different.
Table 1. The real-time PCR method measures the accumulation of amplified products with a laser scanning in a closed tube or well plate format This method is rapid, sensitive, reproducible, and is advantageous because the reaction is performed in closed tubes or wells, thereby reducing the risk of carry-over contamination 2. The main drawback of real-time PCR is that there are no standard protocols, kits, or machines.
Therefore, the comparison of values across laboratories and countries has been difficult. Consequently, the cut-off values used for the diagnosis of EBV or the initiation of treatment vary among institutions. Standardization is necessary to establish guidelines. With this standard, comparisons across institutions will become easier and lead to the establishment of guidelines for the management of EBV-associated diseases.
A recently developed droplet digital PCR utilizes water-oil emulsion droplets that form the partitions separating template DNA 14 , The advantages of this method include extremely high sensitivity and absolute quantification without standard curves.
This method is particularly useful for creating or evaluating accurate viral reference standards With different types of fluorogenic probes, multiplex PCR to detect several viruses has been developed This method is suitable in quantifying very low amount of virus or detecting mutated viruses because of the robustness to detect mismatches between mutated viruses and the primer-prove set In fact, digital PCR was successfully used for the detection of low amount of virus in the aqueous humor On the other hand, disadvantages of the method are high initial costs of equipment, relatively low throughput, and narrow dynamic ranges, compared with real time PCR 15 , Future technological improvement will doubtlessly overcome these problems.
PTLD, a subtype of immunodeficiency-associated LPD, is defined as lymphoid or plasmacytic proliferation that develops as a consequence of immunosuppression after solid organ allografting or hematopoietic stem cell transplantation HSCT 23 , Most PTLD are associated with EBV infection, but they constitute a spectrum ranging from EBV-driven polyclonal proliferation to EBV-positive or -negative proliferation that is indistinguishable from lymphomas occurring in immunocompetent individuals.
Measuring viral loads also allows a preemptive reduction in immunosuppression if possible, as the first part of patient management. However, there are no consensus guidelines regarding the threshold of EBV DNA that warrants further work-up or preemptive therapy There is also no consensus regarding a preference for specimens. According to the European guidelines, whole blood, plasma, and serum are appropriate specimens for monitoring EBV loads These results suggest that whole blood is a better source for the diagnosis of PTLD.
On the contrary, plasma EBV-DNA declines or becomes undetectable in patients who respond to therapy, and therefore could be useful for response monitoring It should be emphasized that there is a difference between patients who have had solid organ allografting and HSCT patients Immunosuppressive treatments in solid organ allograft recipients are modest compared to HSCT recipients who receive more severe immunosuppressive treatment.
Correlations between higher EBV loads and the development of PTLD are seen in solid organ allograft recipients, but these correlations do not indicate high positive and negative predictive values In children at high risks of primary EBV infection, routine surveillance is useful for the preemptive identification of patients at high risk of PTLD Solid organ allograft recipients also sometimes carry chronic high EBV loads without symptoms consistent with PTLD 33 , 34 , but the significance of a high EBV load in terms of long-term health is unknown.
Classic HL consists of four histological subtypes, and the association with EBV varies across subtypes. ENKTL is a predominantly extranodal lymphoma of T or NK cells, which is characterized by necrosis, a cytotoxic phenotype, and vascular damage or destruction EBV-DNA levels in peripheral blood are a surrogate biomarker of tumor loads 40 and is used in making a diagnosis 41 , The quantification of EBV loads is also useful for prognostic assessment and the evaluation of treatment responses 43 — A prognostic stratification model was proposed based on an international multicenter analysis Both plasma and whole blood have been used for quantifying circulating EBV-DNA, and results from plasma and whole blood correlated with each other Since there are few direct comparisons between plasma and whole blood, the better source is unclear.
However, plasma appears to be a better biomarker for evaluating prognosis since plasma has several advantages over whole blood in terms of materials 3 , CAEBV is a systemic EBV-positive polyclonal, oligoclonal, or often monoclonal lymphoproliferative disease characterized by fever, lymphadenopathy, hepatosplenomegaly, pancytopenia, interstitial pneumonitis, and skin involvement hypersensitivity to mosquito bites or hydroa vacciniforme 4 , Since histological samples are not always obtained because of a lack of appropriate lesions for biopsies, the quantification of EBV-DNA in peripheral blood is necessary for its diagnosis.
However, there are no comparison data from large populations. On the other hand, plasma EBV loads were higher at diagnosis in patients who were deceased compared to patients that survived, suggesting that cell-free EBV-DNA has prognostic value During the past two decades, evidence regarding the monitoring of viral DNA has accumulated in a variety of EBV-associated diseases.
Determining a cut-off line to differentiate healthy individuals and those with malignancies is necessary. A lot of efforts have been devoted to establishing the cut-off value, but so far a consensus had not been reached 2 , 26 , 27 , 54 , The lack of standardization has prevented institutions from collaborating with each other and has delayed consensus on standard guidelines.
The release of the WHO standard for EBV quantification will boost collaborative studies across institutions and countries Prospective studies using the WHO international standardized assay are necessary to establish a threshold at which preemptive therapy should be started in patients who have undergone HSCT. Chronic high EBV loads in solid organ allograft recipients should also be clarified to better manage these patients.
Determining the preferred blood component for measurements is also an urgent task. Commercially available kits are now more prevalent, providing reproducible results. Fully automated DNA extraction and amplification systems should promote the accuracy and speed of the assay while saving labor costs 56 , In the future, new technologies such as digital PCR, a novel method for the absolute quantification of target nucleic acids, may replace conventional real-time PCR.
HK and Y-LK contributed to the concept development process and to the writing and review of this manuscript. They also gave final approval of the version to be published.
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Fetching data from CrossRef. This may take some time to load. Loading related content. Jump to main content. Jump to site search. You do not have JavaScript enabled. Please enable JavaScript to access the full features of the site or access our non-JavaScript page. Issue 22, From the journal: Analytical Methods.
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