Epstein-Barr virus specific T-cell response in nasopharyngeal carcinoma patients

There is a substantial body of evidence suggesting an association between Epstein-Barr virus (EBV) and undifferentiated nasopharyngeal carcinoma (NPC). The present study has compared a group of NPC patients (newly diagnosed and long-term survivors) and controls for EBV-specific T-cell immunity using the regression of transformation assay. Newly diagnosed patients (17 tested) when compared with either long-term survivors (20 tested) or controls (30 tested) showed a significant impairment in virus-specific T-cell immunity (p = 0.036, p = 0.043 respectively). Furthermore, donors with IgA antibody to EBV showed a significant depression in virus-specific T-cell immunity compared with donors without IgA antibody (19 IgA-positive, 48 IgA-negative; p = 0.0025). These results may be important in explaining the postulated role of EBV in the aetiology of NPC.     

Epstein-Barr virus and nasopharyngeal carcinoma

Since its discovery 50 years ago, Epstein-Barr virus (EBV) has been linked to the development of cancers originating from both lymphoid and epithelial cells. Approximately 95% of the world’s population...     

鼻咽癌患者血浆EBV DNA水平的研究进展

EB病毒与鼻咽癌的发生有密切关系。近年来,随着PCR技术的发展,在鼻咽癌患者血浆中可定量检测EBVDNA水平。大量研究表明,鼻咽癌患者血浆EBVDNA的检出率及拷贝数明显高于正常人群。放疗后转移、复发患者其EBVDNA的阳性率及拷贝数高于持续缓解患者。血浆EBVDNA水平在鼻咽癌的早期诊断、临床分期、预后判断及监测治疗后转移、复发中均有重要临床意义。     

Epstein-Barr virus and nasopharyngeal carcinoma.

Nasopharyngeal carcinoma, an epithelial tumor which is characterized by marked geographic and population differences in incidence, is consistently associated with the Epstein-Barr virus (EBV). Within the tumor, the EBV DNA is homogeneous and clonal with regard to repeat sequences suggesting that the tumor is also clonal. Expression of specific viral mRNAs or gene products are consistently detected within all of the tumor cells. These data suggest that EBV is an essential component in the development of nasopharyngeal carcinoma. Genetic or environmental co-factors may influence the ability of the virus to express these genes in infected epithelial tissue or may contribute to clonal predominance.     

Demonstration of Epstein-Barr virus antibodies in serum of patients with nasopharyngeal carcinoma

A total of eighty six blood samples (17, 19 & 50 of nasopharyngeal carcinoma, oesophageal cancer and normal healthy control respectively) were collected from Naga Hospital, Kohima, Nagaland and B. Barooah Cancer Institute, Guwahati, Assam and were processed for the detection of EBV-IgG antibody using Elisa test. The results showed that EBV positivity is higher among NPC patients as compared to oesophageal carcinoma patients and/or healthy control. The data also indicated that EBV antibody titre is significantly higher among NPC cases as compared to control.     

Salivary Epstein-Barr virus DNA level in patients with nasopharyngeal carcinoma following radiotherapy

Nasopharyngeal carcinoma (NPC) is a solid tumor closely associated with Epstein-Barr virus (EBV) infection. The purpose of this investigation was to detect and quantify the EBV DNA level in salivary samples of NPC patients following treatment using real-time PCR. A total of 175 consecutive newly diagnosed NPC patients’ whole saliva samples were collected before treatment, and the EBV DNA level was measured by real-time PCR, with the primers and probe targeting the BamHI-W region of the EBV genome. The post-treatment salivary EBV DNA level was also assessed in 46 patients. The change of EBV DNA level before and after treatment and relationship of EBV DNA level to demographic data and tumor staging were tested by Wilcoxon signed-rank test and Mann–Whitney U test, respectively with the level of significance set at 0.05. The EBV detection rate of pre-treatment saliva samples was 80%. The EBV DNA level of post-treatment saliva samples was significantly higher than the pre-treatment ones (P < 0.01). There is a trend that patients with advanced-stage showed a higher EBV DNA level than patients with early-stage. The detection of EBV DNA in saliva using real-time PCR might be a feasible and non-invasive method for early diagnosis of NPC.     

鼻咽癌前期病变中的EB病毒感染

背景与目的：鼻咽癌中的浸润性癌细胞均感染了EB病毒（Epstein-Barr virus．EBV）。前期病变可见于早期鼻咽癌癌旁上皮。本研究旨在通过检测前期病变中的EB病毒,探讨EB病毒感染存鼻咽癌变过程中的作用,及其基因型在鼻咽癌变过程中发生的宿主内演变。方法：采用核酸原位杂交检测15例早期鼻咽癌活检组织中的EB病毒编码RNA（EBV—encoded RNA,EBER）。采用巢式PCR法检测前期病变和癌巢中的EB病毒类型和潜伏膜蛋白1（latent membrane protein 1,LMPI）EB病毒株。具有代表性的LMPI基因羧基末端PCR产物采用四色荧光终止序列技术进行DNA序列分析。结果：所有15例早期鼻咽癌中的绝大多数浸润性癌细胞均呈EBER阳性。在15例的期病变中．14例可检测到EBER阳性的异常上皮细胞和／或浸润性淋巴细胞。单个A型EB病毒可在9例癌巢（11例适用）及9例前期病变（10例通用）的DNA样本中检测到。EB病毒LMP1基因羧基末端在15例癌巢DNA样本中均可检测到,其中14例是30bp缺失型LMP1 EB病毒株,1例是野生型和30bp缺失型LMP1株的混合感染。在11例适合做EB病毒LMP1基因羧基末端扩增的前期病变的DNA样本中,5例呈野生型和30bp缺失型LMP1 EB病毒株的混合感染,4例是单个缺大型LMP1 EB病毒株感染,1例呈单个野生型LMP1 EB病毒株感染,1例呈阴性反应。野生型LMP1基因羧基末端的DNA序列与B95—8细胞的DNA序列完全一致;30bp缺大型LMP1基因羧基末端的DNA序列却其有30bp缺失（密码子：346～355）和4个错义点突变（密码子：334、335、338和366）。结论：鼻咽上皮细胞的EB病毒感染是癌变过程中侵袭前的事件;而在鼻咽癌变过程中,EB病毒基因型会产生宿主内的演变。     

Epstein-Barr virus serology in the control of nasopharyngeal carcinoma

Epstein-Barr virus (EBV) is suspected as being etiologically related to nasopharyngeal carcinoma (NPC). Antibodies to EBV antigens have been used in the early detection of NPC and serologic assays are being utilized in the mass screening of high risk populations. While areas of potential application to disease control, such as therapy, are still in the developmental phase, EBV serology has been reported to be of value in the detection of early relapse. Since the data from a series of studies provide conflicting results, however, in this report we review the current information regarding detection of early relapse and describe specific areas that require particular attention if the role of EBV serology in this aspect of NPC control is to be well defined.     

Relationship between the Epstein-Barr virus genome and nasopharyngeal carcinoma in Caucasian patients.

In order to explore whether undifferentiated nasopharyngeal carcinoma (NPC) shows a regular association with Epstein-Barr virus (EBV), regardless of the geographical and ethnic origin of the patient, a correlated histopathological and nucleic acid hybridization study was performed on biopsies from Caucasian patients with nasopharyngeal carcinomas and from various controls. Among 12 undifferentiated NPCs, 11 were positive for EBV-DNA, with multiple copies of the viral genome per cell. Serological tests showed elevated anti-VCA and anti-EA(DA) titers. Six NPCs with various degrees of squamous differentiation, four malignant lymphomas of the nasopharynx and seven carcinomas located outside the nasopharynx were EBV-DNA negative. These findings further stress the uniqueness and regularity of the association between EBV-DNA and undifferentiated NPC. Clearly, the association extends over geographical barriers and holds true not only in the previously studied, moderate-incidence African ethnic group, but also in the low-incidence Western patients.     

Rearranged Epstein-Barr virus genomes and clonal origin in nasopharyngeal carcinoma

Epstein-Barr virus (EBV) is known to be associated with two malignant diseases, nasopharyngeal carcinoma (NPC) and endemic Burkitt's lymphoma. In this study, the genomes of EBV in biopsy specimens from 4 NPC patients in Japan were analyzed using Southern blot hybridization. The NPC tissues of all examined cases contained rearranged EBV genomes whose BamHI H fragments were larger than those of prototype EBV genomes. One of them had a BamHI fragment containing contiguous sequences of BamHI Y and H. A single-sized EBV DNA terminus was observed in these NPC tissues, implying the evolution of the carcinoma from a single EBV-infected cell.     

EB病毒感染与鼻咽癌发病机制的关系

鼻咽癌（nasopharyngeal carcinoma,NPC）是一种在中国南方、台湾、新加坡及特定地域的其它国家或地区很常见的肿瘤,其发病因素尚不明确。目前,还未发现与NPC发生过程的遗传因素有关的主要基因;而一些环境因素可能与诱发NPC有关。如食用腌鱼和长期暴露于硫酸蒸汽,研究指出EB病毒（Epstein—Barr virus,EBV）与NPC发病机理密切相关。为了探索NPC与EBV之间的关系,我们建立了10个NPC细胞株。经过广泛研究,我们认为EBV通过IgA受体（分泌组分蛋白）介导的细胞内吞作用,可能仅感染鼻咽肿瘤细胞,而不感染化生上皮细胞。我们发现EBV对于促进NPC进展起着重要作用,但并不参与启动及促进NPC的发生。     

EB病毒与鼻咽癌发生发展关系的研究进展

目的:总结国内外对鼻咽癌(nasopharyngeal carcinoma,NPC)发生发展与EB病毒关系的研究现状。方法:以"鼻咽癌、EB病毒、遗传学和表观遗传学"为关键词,应用计算机检索Medline和清华同方期刊全文数据库2003-01~2008-03的文献176篇。纳入标准:1)NPC的流行病学和组织学类型与EB病毒的关系。2)遗传学与表观遗传学改变与EB病毒致瘤的关系。3)EB病毒基因与NPC发生和发展的机制。根据纳入标准,精选35篇全文文献,最后纳入分析19篇。结果:作为肿瘤相关疱疹病毒,EB病毒感染对NPC基因表达有明显影响。遗传学改变先于EB病毒感染发生,表观遗传学改变是NPC的重要特征。LMP-1等对NPC细胞周期、细胞结构和肿瘤细胞的免疫逃逸等的作用影响NPC发生和转移。结论:EB病毒与NPC发生以及转移机制密切相关,LMP-1等是重要的病毒癌基因。     

THE INTRACELLULAR FORM OF EPSTEIN-BARR VIRUS GENOME IN NASOPHARYNGEAL CARCINOMA

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Cell-mediated immunity, Epstein-Barr virus and nasopharyngeal carcinoma.

Cellular immunity is apparently important in host defenses against cancer. A growing body of information on CMI to EBV is here reviewed, providing a strong basis for studies of such reactivity in NPC. Present work suggests that CMI responses to virus- and tumour-associated antigens may have implications for etiology, diagnosis and treatment.     

Impaired long-term T cell immunity to Epstein-Barr virus in patients with nasopharyngeal carcinoma.

The long-term T cell immunity to Epstein-Barr virus (EBV) is considered to play an important role in suppressing proliferation of EBV-infected B cells and outgrowth of EBV-associated tumors. It can be manifested and quantified by the EBV-induced focus regression assay. In the present study, we examined the strength of T cell immunity to EBV in patients with nasopharyngeal carcinoma (NPC) and other cancers originating from the head and neck region. In contrast to patients with other types of cancers, including EBV-negative NPC, patients with EBV-positive NPC were found to have a profound impairment in the long-term T cell immunity to EBV.     

Epstein-Barr virus antibodies in Sudanese patients with nasopharyngeal carcinoma: a preliminary report.

With the use of an immunofluorescence technique Epstein-Barr viral capsid antigen antibody titers were determined in the sera from 226 Sudanese: 41 with nasopharyngeal carcinoma (NPC), 77 with other head and neck cancers, 21 with malignant lymphomas, 63 with other cancers, 6 with specific granulomas, and 18 normal controls. Of the NPC patients, 87.8% had titers of 320 or greater and 43.9% had titers of 2,560 or more, whereas none had titers of less than 40. Their geometric mean titer (GMT) level was 1,855. However, compared to the NPC patients, the other patients and normal controls showed significantly higher percentages of sera with low titers and lower percentages of sera with high titers and they had a GMT that was 4--16 times lower. The high NPC titers were independent of age, sex, tribe, or locality of patients. The preliminary results indicated the importance of future immunovirologic and immunogenetic field investigations on the natural history of the Epstein-Barr virus and on the genetics of the host.     

鼻咽癌患者血浆Epstein-Barr病毒DNA定量分析

目的　探讨鼻咽癌患者血浆游离 EBV - DNA水平测定的临床应用价值。方法　采用荧光定量 PCR技术测定鼻咽癌患者治疗前 2 3例、治疗后 2 3例以及正常对照者 30例血浆 EBV- DNA水平 ,并用免疫酶法检测血清VCA - Ig A水平。结果　鼻咽癌患者血浆游离 EBV- DNA水平高于正常对照者 ,治疗后低于治疗前。结论　 (1)血浆EBV- DNA的实时定量 PCR分析对鼻咽癌的筛选检查有实用价值 ;(2 )血浆 EBV- DNA水平可能是当前反映鼻咽癌局部肿瘤负荷和治疗效果的较理想指标。     

Second malignant tumors in patients with nasopharyngeal carcinoma and their association with Epstein-Barr virus

Since previous published studies about second malignant tumors (SMTs) in nasopharyngeal carcinoma (NPC) patients usually included a limited sample size and did not attain consistent results, we conducted a large retrospective study in a cohort of 1,549 patients to assess the risk of SMT in NPC patients following radiotherapy (RT) in Taiwan. The follow-up period ranged from 2 to 16 years, with a median of 7 years. Thirty-nine patients developed SMTs during the 7,145 person-year follow-up [standardized incidence ratio (SIR): 2. 8; 95% confidence interval (CI): 2.0 to 3.9]. Increased risks of developing SMTs were observed for head and neck (H/N) cancer (SIR: 16.5; 95% CI: 10.0 to 26.8), gastric cancer (SIR: 5.5; 95% CI: 2.2 to 11.4) and leukemia (SIR: 9; 95% CI: 1.9 to 26.3). Paraffin-embedded specimens of secondary H/N cancer (11), secondary gastric cancer (6) and their corresponding NPC specimens were examined by EBER in situ hybridization to assess the association between Epstein-Barr virus (EBV) and these SMTs. Twenty-six primary H/N and 5 gastric cancer specimens were chosen as the control groups. In H/N cancer, EBV was detected in 3.8% of the primary cancers and 9.1% of the secondary cancers. All the positive specimens resulted from hypopharyngeal cancer. Of the secondary gastric cancers, only 1 case (16.6%) was associated with EBV. None of the primary gastric cancers was associated with EBV. Our results indicate an increased risk of developing SMTs, with a preference for head and neck cancer, gastric cancer and leukemia, in NPC patients after RT in Taiwan. Only a small proportion of the secondary H/N and gastric cancers was associated with EBV.     

Quantitative analysis of cell-free Epstein-Barr virus DNA in plasma of patients with nasopharyngeal carcinoma

Using real-time quantitative PCR, cell-free EBV DNA was detectable in the plasma of 96% (55 of 57) of nasopharyngeal carcinoma (NPC) patients (median concentration, 21058 copies/ml) and 7% (3 of 43) of controls (median concentration, 0 copies/ml). Advanced-stage NPC patients had higher plasma EBV DNA levels than those with early-stage disease. At 1 month after completion of radiotherapy, plasma EBV DNA was undetectable in 7 of 15 subjects (47%) but remained high in the remaining 8 subjects (53%). Clinical examination revealed that all of the former seven subjects had complete tumor regression, whereas six of the eight latter subjects exhibited evidence of disease persistence or had developed distant metastases. These results suggest that quantitative analysis of plasma EBV DNA may be a useful clinical and research tool in the screening and monitoring of NPC patients.     

Detection of cell free Epstein-Barr virus DNA in sera from patients with nasopharyngeal carcinoma

BACKGROUND: The detection of tumor-derived DNA within the circulation of patients with malignant disease using polymerase chain reaction (PCR)-based strategies has opened a new avenue for the diagnosis and monitoring of these patients. Because of the universal association of Epstein-Barr virus (EBV) with the nonsquamous type of nasopharyngeal carcinoma (NPC; World Health Organization types II and III), the detection of cell free EBV DNA in sera from patients with NPC may be a valuable tool for monitoring the progress of tumors or to provide advanced warning of tumor recurrence. METHODS: Serum samples were obtained from different patients, and cell free EBV DNA was detected with a conventional PCR approach. A total of 134 patients were sampled, including 36 patients with primary NPC, 28 control patients, 18 patients suffering from locoregional recurrence, 7 patients with distant metastasis, and 45 patients with NPC in clinical remission. A conventional PCR approach employing standard 35-cycle and 50-cycle reactions was used to detect cell free EBV genomes. Results from the two PCR cycles were compared to provide a semiquantitative picture of the relative quantity of EBV genome in each serum sample. RESULTS: The EBV DNA detection rates, i.e., the rates of positive detection, for 35-cycle and 50-cycle PCR analyses, respectively, were 38.9% and 75% for patients with primary NPC, 3.5% and 10.7% for control patients, 27.8% and 88.9% for patients with locoregional disease recurrence, 71.4% and 100% for patients with distant metastasis, and 7.1% and 36.5% for patients with disease in clinical remission. The rates of positive detection among patients with active disease all appeared to be significantly greater compared with the rates among patients with disease in clinical remission. Longitudinal data for six patients with recurrent tumors revealed a close correlation between the relative quantity of circulating cell free EBV genomes and the disease course of these patients. The sensitivity, specificity, positive predictive value, and negative predictive value of the 50-cycle PCR analysis for detecting recurrent disease were 92%, 63.5%, 42.6%, and 96.4%, respectively. CONCLUSIONS: This study demonstrated that, by using a 50-cycle PCR-based approach, high sensitivity and high negative predictive value for detecting recurrent disease can be obtained from the detection of the cell free EBV genome in sera from patients with NPC. The 50-cycle PCR analysis, therefore, may provide a simple, clinically useful adjuvant method for monitoring patients with NPC.