Immunohistochemical demonstration of the Epstein-Barr virus-encoded latent membrane protein in paraffin sections of Hodgkin's disease

Cancers associated with human gammaherpesviruses

Epstein-Barr virus (EBV; human herpesvirus 4; HHV-4) and Kaposi sarcoma-associated herpesvirus (KSHV; human herpesvirus 8; HHV-8) are human gammaherpesviruses that have oncogenic properties. EBV is a lymphocryptovirus, whereas HHV-8/KSHV is a rhadinovirus. As lymphotropic viruses, EBV and KSHV are associated with several lymphoproliferative diseases or plasmacytic/plasmablastic neoplasms. Interestingly, these viruses can also infect epithelial cells causing carcinomas and, in the case of KSHV, endothelial cells, causing sarcoma. EBV is associated with Burkitt lymphoma, classic Hodgkin lymphoma, nasopharyngeal carcinoma, plasmablastic lymphoma, lymphomatoid granulomatosis, leiomyosarcoma, and subsets of diffuse large B-cell lymphoma, post-transplant lymphoproliferative disorder, and gastric carcinoma. KSHV is implicated in Kaposi sarcoma, primary effusion lymphoma, multicentric Castleman disease, and KSHV-positive diffuse large B-cell lymphoma. Pathogenesis by these two herpesviruses is intrinsically linked to viral proteins expressed during the lytic and latent lifecycles. This comprehensive review intends to provide an overview of the EBV and KSHV viral cycles, viral proteins that contribute to oncogenesis, and the current understanding of the pathogenesis and clinicopathology of their related neoplastic entities.

Impact of Tumour Epstein–Barr Virus Status on Clinical Outcome in Patients with Classical Hodgkin Lymphoma (cHL): A Review of the Literature and Analysis of a Clinical Trial Cohort of Children with cHL

Simple Summary

The Epstein–Barr virus (EBV) contributes to different forms of human cancer, including a subset of classical Hodgkin lymphoma (cHL), a B-cell lymphoma with unusual histological features. Although the pathogenesis of EBV-associated cHL remains to be elucidated, biological investigations point to an important aetiological role for the virus in the development of this tumour. This is even more relevant now considering the potential opportunities that exist to treat EBV-associated disorders, for example, with immunotherapeutics or small molecule inhibitors targeting viral proteins. For this reason, we believe it is now timely to review the association between EBV and cHL and in particular to re-evaluate the impact of EBV status on clinical outcomes in cHL patients. Herein, we also report the impact of EBV on clinical outcomes in a cohort of children and adolescents with cHL.

Abstract

In this study, we have re-evaluated how EBV status influences clinical outcome. To accomplish this, we performed a literature review of all studies that have reported the effect of EBV status on patient outcome and also explored the effect of EBV positivity on outcome in a clinical trial of children with cHL from the UK. Our literature review revealed that almost all studies of older adults/elderly patients have reported an adverse effect of an EBV-positive status on outcome. In younger adults with cHL, EBV-positive status was either associated with a moderate beneficial effect or no effect, and the results in children and adolescents were conflicting. Our own analysis of a series of 166 children with cHL revealed no difference in overall survival between EBV-positive and EBV-negative groups (p = 0.942, log rank test). However, EBV-positive subjects had significantly longer event-free survival (p = 0.0026). Positive latent membrane protein 1 (LMP1) status was associated with a significantly lower risk of treatment failure in a Cox regression model (HR = 0.21, p = 0.005). In models that controlled for age, gender, and stage, EBV status had a similar effect size and statistical significance. This study highlights the age-related impact of EBV status on outcome in cHL patients and suggests different pathogenic effects of EBV at different stages of life.

Epstein-Barr-Virus infection patterns in nodular lymphocyte predominant Hodgkin-lymphoma

AIMS

We investigated 19 cases of Epstein-Barr virus (EBV)-positive nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) as information regarding latency types is currently incomplete.

METHODS & RESULTS

Immunohistochemistry (IHC) for CD20, CD79a, PAX5, OCT2 CD30, CD15, CD3, and PD1 was performed. For EBV-detection, in-situ hybridization (ISH) for EBV-encoded RNAs (EBER) was employed combined with IHC for EBV-encoded latent membrane protein (LMP)-1, -nuclear antigen (EBNA)-2 and -BZLF1. In 95% of the cases, neoplastic cells with features of Hodgkin- and Reed-Sternberg cells (HRS cells) were present, mostly showing expression of CD30. In all cases, the B-cell phenotype was largely intact, and delineation from classical HL (CHL) was further supported by MEF2A detection. All tumor cells were EBER-positive except two cases. EBV-latency type II was most frequent (89%) and type I rare. Cases with latency type I were CD30-negative. Five cases contained some BZLF1 and/or EBNA2-positive bystander lymphocytes.

CONCLUSIONS

As HRS-morphology of neoplastic cells combined with CD30 expression are frequent features of EBV-positive NLPHL, preservation of B-cell-transcription program, MEF2B expression combined with NLPHL-typical architecture and background composition facilitate distinction from CHL. EBER-ISH is the method of choice to identify these cases. The majority present with an EBV latency type II and only rarely with latency type I, which can be associated with missing CD30 expression. The presence of occasional bystander lymphocytes expressing BZLF1 and/or EBNA2 and the partial EBV-infection of neoplastic cells in some cases could indicate that EBV is either not primarily involved or only a transient driver in the pathogenesis of EBV-positive NLPHL.

MicroRNA and Other Non-Coding RNAs in Epstein-Barr Virus-Associated Cancers

EBV is a direct causative agent in around 1.5% of all cancers. The oncogenic properties of EBV are related to its ability to activate processes needed for cellular proliferation, survival, migration, and immune evasion. The EBV latency program is required for the immortalization of infected B cells and involves the expression of non-coding RNAs (ncRNAs), including viral microRNAs. These ncRNAs have different functions that contribute to virus persistence in the asymptomatic host and to the development of EBV-associated cancers. In this review, we discuss the function and potential clinical utility of EBV microRNAs and other ncRNAs in EBV-associated malignancies. This review is not intended to be comprehensive, but rather to provide examples of the importance of ncRNAs.

Relapsed and refractory classical Hodgkin lymphoma: could virotherapy help solve the equation?

Classical Hodgkin lymphoma is a neoplastic hematological disease. Standard first-line therapy, including chemotherapy and radiotherapy, is curative in >85% of early-stage patients, with a 5-year survival rate of >95%. However, approximately 15% of patients have hard-to-treat lymphoma with poor outcomes, and new treatment strategies are needed for these young adults. There are several well-documented cases in the medical literature on hematologic cancer remission following natural human viral infections. Therefore, hoping to reproduce these spontaneous tumor regressions, researchers have been investigating various viruses with oncolytic properties. There is a high rationale for using virotherapy in the treatment of Hodgkin lymphoma, in which tumor cells are often infected with the Epstein-Barr virus. Modern viral technologies and current knowledge about the relationship between viruses and cancer could accelerate the discovery of effective viral oncolytic therapies. This article reviews the use of oncolytic viruses as innovative therapies for treating Hodgkin lymphoma.

Calcium-dependent signalling in B-cell lymphomas

Induced waves of calcium fluxes initiate multiple signalling pathways that play an important role in the differentiation and maturation of B-cells. Finely tuned transient Ca⁺² fluxes from the endoplasmic reticulum in response to B-cell receptor (BCR) or chemokine receptor activation are followed by more sustained calcium influxes from the extracellular environment and contribute to the mechanisms responsible for the proliferation of B-cells, their migration within lymphoid organs and their differentiation. Dysregulation of these well-balanced mechanisms in B-cell lymphomas results in uncontrolled cell proliferation and resistance to apoptosis. Consequently, several cytotoxic drugs (and anti-proliferative compounds) used in standard chemotherapy regimens for the treatment of people with lymphoma target calcium-dependent pathways. Furthermore, ~10% of lymphoma associated mutations are found in genes with functions in calcium-dependent signalling, including those affecting B-cell receptor signalling pathways. In this review, we provide an overview of the Ca²⁺-dependent signalling network and outline the contribution of its key components to B cell lymphomagenesis. We also consider how the oncogenic Epstein-Barr virus, which is causally linked to the pathogenesis of a number of B-cell lymphomas, can modify Ca²⁺-dependent signalling.

Tumor-associated macrophages in classical Hodgkin lymphoma: hormetic relationship to outcome

Commonly attributed to the prevalence of M2 macrophages, tumor-associated macrophages (TAM) are linked to poor outcome in Hodgkin lymphoma (HL). MYC is supposed to control the expression of M2-specific genes in macrophages, and deficiency in MYC-positive macrophages inhibits tumor growth in mouse models. To verify this hypothesis for HL, seventy-six samples were subjected to immunohistochemical double staining using CD68 or CD163 macrophage-specific antibodies and a reagent detecting MYC. For each cell population, labelled cells were grouped according to low, intermediate and high numbers and related to disease-free survival (DFS) and overall survival (OS). MYC+ cells accounted for 21% and 18% of CD68+ and CD163+ cells, respectively. Numbers of MYC- macrophages were significantly higher in EBV+ cases while no differences were observed for MYC+ macrophages between EBV+ and EBV- cases. Cases with highest numbers of macrophages usually showed worst DFS and OS. In most scenarios, intermediate numbers of macrophages were associated with better outcome than very low or very high numbers. Our observations are reminiscent of the "hormesis hypothesis" and suggest that a relative lack of TAM may allow HL growth while macrophages display an inhibitory effect with increasing numbers. Above a certain threshold, TAM may again support tumor growth.

CTLA4 haploinsufficiency as a predisposition to classical Hodgkin lymphoma

Cytotoxic T-lymphocyte-associated protein 4 (CTLA4) haploinsufficiency (HI) is an immune dysregulation disorder characterized by T lymphocyte hyperactivation, and generalized lymphoproliferative and autoimmune disorders. Patients with CTLA4 haploinsufficiency are also prone to developing various malignancies. Due to the rare nature of this condition, the longitudinal evolution of CTLA4 haploinsufficiency clinical manifestations remains to be described. We report on over a decade-long course of a young adult men patient with known CTLA4 haploinsufficiency, who sequentially developed multiple autoimmune conditions along with two distinct episodes of classical Hodgkin Lymphoma (cHL) of unique histologies. Notably, the patient had serological and molecular evidence of Epstein Barr virus (EBV) infection at the time of diagnosis of both cHL. The allogeneic stem cell transplantation consolidated durable remission of cHL and CTLA-4 haploinsufficiency-related clinical manifestations, but failed to enable the patient to permanently suppress EBV viremia, which raises concerns for the development of other EBV infection-related conditions in the future. This case report adds on the current understanding of the natural clinical history of patients with CTLA4 haploinsufficiency, and their unique susceptibility to developing cHL.

An etiological role for the Epstein-Barr virus in the pathogenesis of classical Hodgkin lymphoma

Although a pathogenic role for the Epstein-Barr virus (EBV) is largely undisputed for tumors that are consistently EBV genome positive (eg, nasopharyngeal carcinoma, endemic Burkitt lymphoma), this is not the case for classical Hodgkin lymphoma (cHL), a tumor with only a variable EBV association. In light of recent developments in immunotherapeutics and small molecules targeting EBV, we believe it is now timely to reevaluate the role of EBV in cHL pathogenesis.

Overexpression of Epstein-Barr virus-encoded latent membrane protein-1 (LMP-1) in oral squamous cell carcinoma

Background

As oral cavity is the main location of Epstein-Barr virus (EBV) latency and shedding, and as EBV-encoded latent membrane protein-1 (LMP-1) has a crucial role in cell transformation, association between EBV infection, LMP-1 expression and oral malignancy is of interest. Although EBV DNA has been detected in oral squamous cell carcinoma (OSCC), studies on LMP-1 expression in OSCC and oral potentially malignant disorders are scarce and still controversial. This study aimed to evaluate the expression of LMP-1 in OSCC and oral leukoplakia (OL).

Methods

Biopsy specimens of 36 OSCC, 69 OL with and without dysplasia and 10 normal oral mucosa were assessed for the expression of LMP-1 using immunohistochemistry. In each case, at least 1000 cells were counted. Cells with staining were considered positive, classified by location as nuclear, cytoplasmic and nuclear plus cytoplasmic staining. Percentage of positive cells at different locations and of total positive cells were determined. For statistical analysis, SPSS version 21 was used. Statistical significance was considered at p < 0.05.

Results

LMP-1 was expressed in all studied specimens. In terms of percentage of total positive cells, LMP-1 expression was higher from normal mucosa (26.36%), OL without dysplasia (28.03%), OL with dysplasia (34.15%), to the significantly highest, (59.67%) in OSCC. In addition, cells with nuclear staining alone, cytoplasmic staining alone and cells with nuclear plus cytoplasmic staining were significantly higher in OSCC compared to those of normal mucosa, OL with and without dysplasia.

Conclusions

LMP-1 was overexpressed in OSCC. Our analysis on subcellular localization of LMP-1 in OSCC revealed prominent distinguished pattern, cytoplasmic distribution. Further studies in cell lines and animals are required to clarify the association between this EBV-encoded proteins and oral carcinogenesis.

Co-Expression of the Epstein-Barr Virus-Encoded Latent Membrane Proteins and the Pathogenesis of Classic Hodgkin Lymphoma

The Epstein-Barr virus (EBV) is present in the tumour cells of a subset of patients with classic Hodgkin lymphoma (cHL), yet the contribution of the virus to the pathogenesis of these tumours remains only poorly understood. The EBV genome in virus-associated cHL expresses a limited subset of genes, restricted to the non-coding Epstein-Barr virus-encoded RNAs (EBERs) and viral miRNA, as well as only three virus proteins; the Epstein-Barr virus nuclear antigen-1 (EBNA1), and the two latent membrane proteins, known as LMP1 and LMP2, the latter of which has two isoforms, LMP2A and LMP2B. LMP1 and LMP2A are of particular interest because they are co-expressed in tumour cells and can activate cellular signalling pathways, driving aberrant cellular transcription in infected B cells to promote lymphomagenesis. This article seeks to bring together the results of recent studies of the latent membrane proteins in different B cell systems, including experiments in animal models as well as a re-analysis of our own transcriptional data. In doing so, we summarise the potentially co-operative and antagonistic effects of the LMPs that are relevant to B cell lymphomagenesis.

Epstein-Barr Virus-Associated Malignancies: Roles of Viral Oncoproteins in Carcinogenesis

The Epstein–Barr virus (EBV) is the first herpesvirus identified to be associated with human cancers known to infect the majority of the world population. EBV-associated malignancies are associated with a latent form of infection, and several of the EBV-encoded latent proteins are known to mediate cellular transformation. These include six nuclear antigens and three latent membrane proteins (LMPs). In lymphoid and epithelial tumors, viral latent gene expressions have distinct pattern. In both primary and metastatic tumors, the constant expression of latent membrane protein 2A (LMP2A) at the RNA level suggests that this protein is the key player in the EBV-associated tumorigenesis. While LMP2A contributing to the malignant transformation possibly by cooperating with the aberrant host genome. This can be done in part by dysregulating signaling pathways at multiple points, notably in the cell cycle and apoptotic pathways. Recent studies also have confirmed that LMP1 and LMP2 contribute to carcinoma progression and that this may reflect the combined effects of these proteins on activation of multiple signaling pathways. This review article aims to investigate the aforementioned EBV-encoded proteins that reveal established roles in tumor formation, with a greater emphasis on the oncogenic LMPs (LMP1 and LMP2A) and their roles in dysregulating signaling pathways. It also aims to provide a quick look on the six members of the EBV nuclear antigens and their roles in dysregulating apoptosis.

Epstein-Barr virus (EBV)-associated epithelial and non-epithelial lesions of the oral cavity

Epstein–Barr virus (EBV) is known to be associated with the development of malignant lymphoma and lymphoproliferative disorders (LPDs) in immunocompromised patients. EBV, a B-lymphotropic gamma-herpesvirus, causes infectious mononucleosis and oral hairy leukoplakia, as well as various pathological types of lymphoid malignancy. Furthermore, EBV is associated with epithelial malignancies such as nasopharyngeal carcinoma (NPC), salivary gland tumor, gastric carcinoma and breast carcinoma. In terms of oral disease, there have been several reports of EBV-related oral squamous cell carcinoma (OSCC) worldwide. However, the role of EBV in tumorigenesis of human oral epithelial or lymphoid tissue is unclear. This review summarizes EBV-related epithelial and non-epithelial tumors or tumor-like lesions of the oral cavity. In addition, we describe EBV latent genes and their expression in normal epithelium, inflamed gingiva, epithelial dysplasia and SCC, as well as considering LPDs (MTX- and age-related) and DLBCLs of the oral cavity.

Epstein-Barr virus: more than 50 years old and still providing surprises

It is more than 50 years since the Epstein-Barr virus (EBV), the first human tumour virus, was discovered. EBV has subsequently been found to be associated with a diverse range of tumours of both lymphoid and epithelial origin. Progress in the molecular analysis of EBV has revealed fundamental mechanisms of more general relevance to the oncogenic process. This Timeline article highlights key milestones in the 50-year history of EBV and discusses how this virus provides a paradigm for exploiting insights at the molecular level in the diagnosis, treatment and prevention of cancer.

Epstein- Barr Virus: Clinical and Epidemiological Revisits and Genetic Basis of Oncogenesis

Epstein-Barr virus (EBV) is classified as a member in the order herpesvirales, family herpesviridae, subfamily gammaherpesvirinae and the genus lymphocytovirus. The virus is an exclusively human pathogen and thus also termed as human herpesvirus 4 (HHV4). It was the first oncogenic virus recognized and has been incriminated in the causation of tumors of both lymphatic and epithelial nature. It was reported in some previous studies that 95% of the population worldwide are serologically positive to the virus. Clinically, EBV primary infection is almost silent, persisting as a life-long asymptomatic latent infection in B cells although it may be responsible for a transient clinical syndrome called infectious mononucleosis. Following reactivation of the virus from latency due to immunocompromised status, EBV was found to be associated with several tumors. EBV linked to oncogenesis as detected in lymphoid tumors such as Burkitt's lymphoma (BL), Hodgkin's disease (HD), post-transplant lymphoproliferative disorders (PTLD) and T-cell lymphomas (e.g. Peripheral T-cell lymphomas; PTCL and Anaplastic large cell lymphomas; ALCL). It is also linked to epithelial tumors such as nasopharyngeal carcinoma (NPC), gastric carcinomas and oral hairy leukoplakia (OHL). In vitro, EBV many studies have demonstrated its ability to transform B cells into lymphoblastoid cell lines (LCLs). Despite these malignancies showing different clinical and epidemiological patterns when studied, genetic studies have suggested that these EBV- associated transformations were characterized generally by low level of virus gene expression with only the latent virus proteins (LVPs) upregulated in both tumors and LCLs. In this review, we summarize some clinical and epidemiological features of EBV- associated tumors. We also discuss how EBV latent genes may lead to oncogenesis in the different clinical malignancies

DNA methylation patterns in EBV-positive and EBV-negative Hodgkin lymphomas

PURPOSE

Hodgkin lymphoma (HL) is characterized by the presence of Hodgkin and Reed-Sternberg cells. Epstein-Barr virus (EBV) infection is thought to play an important role in the development of HL. Although epigenetic alterations, such as aberrant DNA methylation, are known to contribute to the pathogenesis of various malignancies, little is known about such alterations in HL and their putative relationships with EBV infection.

METHODS

We investigated promoter methylation patterns of seven tumor-associated genes in 53 primary HL cases using methylation-specific PCR (MS-PCR). Concomitantly, the EBV infection status was assessed using PCR, in situ hybridization and immunohistochemistry.

RESULTS

The gene promoter hypermethylation frequencies observed were 77.3 % for P16, 58.5 % for RASSF1A, 50.9 % for CDH1, 45.3 % for DAPK, 43.4 % for GSTP1, 37.7 % for SHP1 and 24.3 % for MGMT. SHP1 gene promoter hypermethylation was more frequently observed in patients at extreme ages (i.e., ≤ 15 and >54 years) than in adult patients (p = 0.006) and in patients with B symptoms (p = 0.03). Interestingly, most of the analyzed gene promoters were more frequently hypermethylated in EBV-negative than in EBV-positive cases, in particular the DAPK gene promoter (58 % versus 27 %, p = 0.04). Furthermore, hypermethylation of multiple gene promoters (≥ 3) was encountered more frequently in females than in males (86 % versus 57 %, p = 0.04), whereas EBV-positive cases were more common among males than females (55 % versus 30 %, p = 0.02).

CONCLUSIONS

Our results indicate that epigenetic changes frequently occur in both EBV-positive and EBV-negative HL. The rates of these changes were found to vary according to clinico-pathological parameters. These observations probably reflect the multitude of factors involved in HL development and the complexity of their interactions with genetic and/or hormonal factors.

Overexpression of Activation-Induced Cytidine Deaminase in MTX- and Age-Related Epstein-Barr Virus-Associated B-Cell Lymphoproliferative Disorders of the Head and Neck

Recent research has shown that activation-induced cytidine deaminase (AID) triggers somatic hypermutation and recombination, in turn contributing to lymphomagenesis. Such aberrant AID expression is seen in B-cell leukemia/lymphomas, including Burkitt lymphoma which is associated with c-myc translocation. Moreover, Epstein-Barr virus (EBV) latent membrane protein-1 (LMP-1) increases genomic instability through early growth transcription response-1 (Egr-1) mediated upregulation of AID in B-cell lymphoma. However, few clinicopathological studies have focused on AID expression in lymphoproliferative disorders (LPDs). Therefore, we conducted an immunohistochemical study to investigate the relationship between AID and LMP-1 expression in LPDs (MTX-/Age-related EBV-associated), including diffuse large B-cell lymphomas (DLBCLs). More intense AID expression was detected in LPDs (89.5%) than in DLBCLs (20.0%), and the expression of LMP-1 and EBER was more intense in LPDs (68.4% and 94.7%) than in DLBCLs (10.0% and 20.0%). Furthermore, stronger Egr-1 expression was found in MTX/Age-EBV-LPDs (83.3%) than in DLBCLs (30.0%). AID expression was significantly constitutively overexpressed in LPDs as compared with DLBCLs. These results suggest that increased AID expression in LPDs may be one of the processes involved in lymphomagenesis, thereby further increasing the survival of genetically destabilized B-cells. AID expression may be a useful indicator for differentiation between LPDs and DLBCLs.

The Epstein-Barr virus and the pathogenesis of lymphoma

Since the discovery in 1964 of the Epstein-Barr virus (EBV) in African Burkitt lymphoma, this virus has been associated with a remarkably diverse range of cancer types. Because EBV persists in the B cells of the asymptomatic host, it can easily be envisaged how it contributes to the development of B-cell lymphomas. However, EBV is also found in other cancers, including T-cell/natural killer cell lymphomas and several epithelial malignancies. Explaining the aetiological role of EBV is challenging, partly because the virus probably contributes differently to each tumour and partly because the available disease models cannot adequately recapitulate the subtle variations in the virus-host balance that exist between the different EBV-associated cancers. A further challenge is to identify the co-factors involved; because most persistently infected individuals will never develop an EBV-associated cancer, the virus cannot be working alone. This article will review what is known about the contribution of EBV to lymphoma development.

Contribution of the Epstein-Barr Virus to the Pathogenesis of Hodgkin Lymphoma

The morphology of the pathognomonic Hodgkin and Reed-Sternberg cells (HRS) of Hodgkin lymphoma was described over a century ago, yet it was only relatively recently that the B-cell origin of these cells was identified. In a proportion of cases, HRS cells harbour monoclonal forms of the B lymphotropic Epstein-Barr virus (EBV). This review summarises current knowledge of the pathogenesis of Hodgkin lymphoma with a particular emphasis on the contribution of EBV.

Epstein-Barr virus and the origin of Hodgkin lymphoma

Although Epstein-Barr virus (EBV) is present in the malignant Hodgkin/Reed-Sternberg (HRS) cells of a proportion of cases of classical Hodgkin lymphoma (cHL), how the virus contributes to the pathogenesis of this disease remains poorly defined. It is clear from the studies of other EBV-associated cancers that the virus is usually not sufficient for tumor development and that other oncogenic co-factors are required. This article reviews what is known about the contribution of EBV to the pathogenesis of cHL and focuses on emerging evidence implicating chronic inflammation as a potential oncogenic co-factor in this malignancy.

EBV may be expressed in the LP cells of nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) in both children and adults

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) and classical Hodgkin lymphoma (CHL) are classified separately because of their distinct clinical and pathologic features. Whereas Epstein-Barr virus (EBV) is detected in the neoplastic cells of 25% to 70% of CHL, NLPHL is generally considered to be EBV(-). We assessed EBV status in 302 pediatric and adult cases of NLPHL. A total of 145 pediatric (age 18 y or younger) and 157 adult cases of NLPHL were retrieved from 3 North American centers and tested for EBV by in situ hybridization (EBV-encoded small RNA). Clinical and pathologic features were analyzed. Five (3.4%) pediatric and 7 (4.5%) adult NLPHL cases contained EBV(+) lymphocyte-predominant (LP) cells. Although all 12 cases met the criteria for diagnosis of NLPHL, atypical features were present, including capsular fibrosis, atrophic germinal centers, and pleomorphic or atypical LP cells. CD20 and OCT-2 were strongly and diffusely positive in all except 1 case. However, PAX5 and CD79a were weak and/or variable in 7/8 and 6/6 cases tested, respectively. EBV(+) cases were more likely to be CD30(+) (75%) compared with EBV(-) cases (25%) (P=0.0007); CD15 was negative in all cases. Our results show that EBV(+) LP cells may occur in NLPHL. Distinguishing EBV(+) NLPHL from CHL can be challenging, as EBV(+) NLPHL can have partial expression of CD30 and weak PAX5 staining as well as pleomorphic-appearing LP cells. However, the overall appearance and maintenance of B-cell phenotype, with strong and diffuse CD20 and OCT-2 expression, support the diagnosis of NLPHL in these cases.

The EBV oncogene LMP1 protects lymphoma cells from cell death through the collagen-mediated activation of DDR1

Expression of the EBV oncogene LMP1 in primary human germinal center B cells, upregulates DDR1, a receptor tyrosine kinase activated by collagen Primary HRS cells overexpress DDR1, and its activation significantly increases lymphoma cell survival in vitro

Lack of Epstein-Barr virus infection in Chinese myasthenia gravis patients

OBJECTIVE

There are three recent contradictory reports on the incidence of Epstein-Barr virus in the pathogenesis of myasthenia gravis, with all studies carried out in Caucasian patients. The current study evaluated whether Epstein-Barr virus infection had a role in the pathogenesis of myasthenia gravis in a cohort of 30 Chinese patients.

MATERIALS AND METHODS

Serial paraffin sections of thymic hyperplasia obtained from myasthenia gravis patients were analyzed for the presence of Epstein-Barr virus-encoded small RNA -1 and Epstein-Barr virus latent membrane protein 1 by in situ hybridization and immunohistochemistry, respectively. Epstein-Barr virus(+) cervical lymph nodes from lymphoma patients and Epstein-Barr virus(-) thymus specimens obtained during cardiac surgery served as the positive and negative control groups, respectively.

RESULTS

All the 30 myasthenia gravis specimens were negative for both Epstein-Barr virus-encoded small RNA -1 and Epstein-Barr virus latent membrane protein 1 tests. However, we obtained well-characterized membrane and cytoplasmic immunohistochemical and in situ hybridization staining for both Epstein-Barr virus latent membrane protein 1 and Epstein-Barr virus-encoded small RNA -1, respectively, in the positive control samples.

CONCLUSIONS

Our results therefore do not support a role of thymic Epstein-Barr virus infection in myasthenia gravis pathogenesis and calls for an integration of methodological and interpretation issues in detecting Epstein-Barr virus incidence in myasthenia gravis patients.

Exposures to multiple pesticides and the risk of Hodgkin lymphoma in Canadian men

Purpose

To determine the risk of Hodgkin lymphoma (HL) associated with exposures to multiple pesticides grouped by various classes, including carcinogenic classifications.

Methods

Data collected in the Cross-Canada Study of Pesticides and Health, a population-based incident case–control study in six provinces conducted between 1991 and 1994, were analyzed using unconditional logistic regression. Cases (n = 316) were identified through provincial cancer registries and hospital records. Controls (n = 1,506) were frequency-matched to cases by age (±2 years) within each province and were identified through provincial health records, telephone listings, or voter lists. The Cochran–Armitage test was used to check for trends within pesticide classes.

Results

Overall, there was an increase in the risk of HL among all subjects who reported use of five or more insecticides (OR 1.88, 95 % CI 0.92–3.87) and among subjects younger than 40 who reported use of two acetylcholinesterase inhibitors (OR 3.16, 95 % CI 1.02–9.29). There was an elevated odds ratio associated with reported use of three or more probably carcinogenic pesticides (OR 2.47, 95 % CI 1.06–5.75), but no increase in risk for use of possibly carcinogenic pesticides. The risk of HL from reported use of fungicides or any pesticides was greater for cases diagnosed before age 40 than for cases diagnosed at or after age 40. When analyses excluded proxy respondents, OR estimates strengthened in some circumstances.

Conclusions

This study found associations between HL and fungicides, insecticides, specifically acetylcholinesterase inhibitors, and pesticides previously identified as probable human carcinogens. These associations should be further evaluated, specifically in relation to age at diagnosis.

Epstein-Barr virus latent membrane protein 1 increases genomic instability through Egr-1-mediated up-regulation of activation-induced cytidine deaminase in B-cell lymphoma

Epstein-Barr virus (EBV)-encoded latent membrane protein-1 (LMP1) is a transmembrane protein essential for EBV-induced immortalization and transformation of B cells. Activation-induced cytidine deaminase (AID) triggers somatic hypermutation and recombination, in turn contributing to lymphomagenesis. Here, we report an intracellular mechanism by which LMP1 contributes to B cell lymphomagenesis via AID expression. In our experiments, LMP1 increased AID mRNA expression and promoter activity. The AID promoter region contains a binding site for Egr-1, a prominent transcription factor that is reported to be up-regulated by LMP1. In promoter activity analysis, Egr-1 enhanced the reporter activity of the wild-type AID promoter, but not that containing a mutated Egr-1 binding site. Egr-1 knockdown abrogated LMP-1-mediated up-regulation of AID promoter reporter activity in EBV-negative BJAB cells and reduced AID promoter reporter activity in EBV-positive SKW6.4 cells. AID induced down-regulation of the nuclear factor-κB (NFκB) inhibitory tumor suppressor Rassf6, suggesting that AID functions as an upstream regulator of the NFκB inhibitory Rassf6. Moreover, Egr-1 expression was associated with an increased number of genomic lesions in genome-wide analysis using single nucleotide polymorphism (SNP) microarray and copy number variation (CNV). Collectively, LMP1 induces AID up-regulation and genomic instability via Egr-1. Increased AID expression may, in turn, promote down-regulation of the NFκB inhibitor, Rassf6, thereby further increasing the survival of genetically destabilized B-cell lymphoma cells.

Increased expression of CD4+CD25 +FOXP3+ regulatory T cells correlates with Epstein-Barr virus and has no impact on survival in patients with classical Hodgkin lymphoma in Brazil

The tumor microenvironment of classical Hodgkin lymphoma (cHL) is clearly responsible for the maintenance of the malignant Hodgkin-Reed-Sternberg (HRS) cells, and Epstein-Barr virus (EBV) has been shown to play a role in this immune evasion. EBV can increase the migration of CD4(+)CD25(+)FOXP3(+) lymphocytes, named regulatory T cells (Tregs). In this study, we assessed the distribution and biological significance of Tregs in patients with cHL. Tissue microarrays were constructed using diagnostic biopsies available in 130 cHL patients and stained with CD4, CD8, CD25, and FOXP3 antibodies. For the present study, only cHL patients whose histology could be confirmed and EBV association established were studied. From the 130 cHL patients selected for this study, 56 were classified as EBV-related and 74 EBV non-related cHL. There were no association between clinical characteristics and the expression of Tregs. However, higher levels of Tregs correlated with EBV presence on HRS cells (p = 0.02), although it did not influence event-free survival (EFS) and overall survival (p = 0.98 and p = 0.59, respectively). This study demonstrates that Tregs expression correlates with EBV presence in HRS cells and has no impact on survival of patients with cHL. Further studies investigating the mechanisms in which EBV recruits Tregs to the tumor microenvironment will contribute not only to our understanding on the pathogenesis of cHL but also to the development of new therapeutic strategies.

Oropharyngeal malignant epithelial cell, lymphocyte and macrophage CD44 surface receptors for hyaluronate are expressed in sustained EBV infection: immunohistochemical data and EBV DNA tissue indices

The role of CD44 in Epstein-Barr virus (EBV)-related epithelial tumors is poorly understood. We studied the expression of CD44 in EBV infection in patients with oral squamous cell carcinoma (SCC) and nasopharyngeal carcinoma (NPC) and measured the EBV DNA. Whole blood, plasma and tissue samples from 8 male and 2 female patients with oral SCC, NPC, salivary gland lymphoepithelioma, normal salivary gland and buccal mucosa were assayed for EBV DNA. Expression of CD44, latent membrane protein (LMP), and labeling of lymphocytes, macrophages and dendritic cells were estimated by immunohistochemistry. Tissue EBV DNA was detected in 7 of 8 cases (87.5%) of oral malignant, benign and border-line lesions. LMP expression levels in tumors varied from absence and minimal to moderate - 50.3, 43.6, 6.0% and 91.1, 6.7, 2.2% for SCC and NPC, respectively. Levels of CD44 positivity in neoplasms were minimal (15.5 and 16.7%), moderate (30.3 and 47.8%), and diffuse (54.2 and 35.5%) for SCC and NPC, respectively, thus deviating from normal oral mucosa revealing heavily stained (100.0%) epithelial contours. CD19-positive B lymphocytes and S100-positive dendritic cells were intermixed with neoplastic cells. Collectively, CD44 mediated signaling may be implicated in EBV infection associated with the pathogenesis of oral SCC and NPC.

Epstein-Barr virus latent membrane protein-1 protects B-cell lymphoma from rituximab-induced apoptosis through miR-155-mediated Akt activation and up-regulation of Mcl-1

Rituximab is a CD20-targeted monoclonal antibody widely used in the treatment of B-cell lymphoma. Previously, we have shown that Epstein-Barr virus (EBV) latent membrane protein-1 (LMP1) increases chemoresistance in malignant cancer cells. In this study we examined the effects of LMP1 on the response of B-cell lymphoma cell lines to rituximab. Here we show for the first time that LMP1 activates the Akt pathway and up-regulates Mcl-1 through miR-155 expression, which contributes to the survival of rituximab-treated B-cell lymphoma cells. Furthermore, Akt inhibition or knockdown of Mcl-1 and miR-155 was found to be an efficient strategy to overcome rituximab resistance caused by LMP1 expression. Thus, we propose Akt and Mcl-1 and miR-155 as molecular targets for therapeutic intervention in the treatment of EBV-associated B-cell lymphoma with rituximab.

Polymorphisms in the Interleukin-10 and Interferon Gamma Genes in Hodgkin Lymphoma

Genetic factors are known to be important in the development of Hodgkin lymphoma (HL). Interleukin-10 (IL-10) secretion by both malignant and reactive cells is thought to be important in the pathogenesis of HL especially Epstein-Barr virus (EBV) positive cases. Polymorphisms of the IL-10 gene have been reported to be associated with susceptibility to EBV infection. The cytotoxic response to EBV is determined by a Th1 biased immune response which is characterised by interferon gamma (IFNgamma) secretion. We therefore investigated polymorphisms in the IL-10 (-1082 G/A and -592 C/A) and IFNgamma (intron 1 CA repeat) genes as predisposing factors in the development 147 cases of HL. A difference of borderline statistical significance was demonstrated for the IFNgamma gene polymorphism but significance was lost when analysis was restricted to the common genotypes. No significant differences in the distributions of genotypes were found for the IL-10 gene polymorphisms. IL-10 and IFNgamma levels were also measured on 26 patients with HL. No statistically significant differences were detected when the results were analysed by genotype. We found little evidence IL-10 and IFNgamma genotypes predispose to the development of HL or influence the inflammatory host response.

Herpesvirus-associated lymphomas: Investigations in humans and animal models

Lymphomas are solid tumors consisting of lymphoid cells; they form a heterogeneous group of less or more malignant disorders. A portion of lymphomas develop due to latent herpesvirus infections established in B and/or T-lymphocytes. The basis for latency is a lifelong presence of the circularized covalently linked viral genome within nuclei of carrier lymphocytes. In certain cases, however, the essential event leading to tumor formation is the integration of a portion(s) of viral DNA into the host cell DNA. This leads to rearrangements within the host cell genome on one hand, and, on other hand, to unregulated expression of oncoproteins encoded by the integrated fragment. Our review deals with mechanisms of lymphoma formation regarding to the role of non-structural herpesvirus oncoproteins interfering with the regulation of cell division and/or exerting anti-apoptotic effects. In addition, the authors wish to highlight the common procedures, which allowed isolation and/or identification of lymphoma-associated viruses in cell cultures derived from tumors and/or proliferating lymphatic tissues.

Impact of Epstein-Barr virus in the clinical evolution of patients with classical Hodgkin's lymphoma in Brazil

INTRODUCTION

Classical Hodgkin's Lymphoma (cHL) has been frequently associated with Epstein-Barr virus (EBV), which can be found in a latent pattern in Reed-Sternberg (RS) cells. However, the impact of the presence of EBV in RS cells and its prognosis are still controversial. We analysed the presence of EBV in RS cells and its influence in the clinical evolution of patients with cHL treated in two public hospitals in the city of São Paulo, Brazil.

MATERIALS AND METHODS

We selected 97 patients with cHL from 1994 to 2004. Patients were only included in this study if they had (1) >18 years, (2) negative HIV serology, (3) undergone similar chemotherapy protocols, (4) paraffin blocks available with enough material for systematic review and histological reclassification and for detection of EBV in RS cells by in situ hybridization and immunohistochemistry and (5) clinical, epidemiological and laboratorial parameters available after a thorough chart review.

RESULTS

EBV was identified in 52.5% of the cases. Mixed cellularity (MC) subtype was more common in EBV-related tumours (25.5%) (p=0.005). There was no difference on age, gender, stage and the presence of B symptoms between the two groups. The presence of EBV did not influence event free survival (EFS) (p=0.38) or overall survival (OS) (p=0.80) with a median follow-up of 80 months.

CONCLUSION

We demonstrate that the prevalence of EBV-related cHL in this Brazilian population is 52.5% and, that, the presence of EBV does not change the clinical evolution and OS of patients treated with similar chemotherapy protocols.

Epstein-Barr virus and Hodgkin's lymphoma in Cairo, Egypt

Fifty-five consecutive cases of Hodgkin's lymphoma (HL), collected between 1996 and 1998 from Cairo, Egypt, were histologically subtyped, phenotyped, and then studied for the presence of Epstein-Barr virus (EBV). We used immunohistochemical stains for EBV latent membrane protein 1 (LMP-1) and in situ hybridization stains for EBV-encoded small RNA (EBER-1) transcripts. Forty-five cases (82%) had classic HL (cHL), and ten cases (18%) had nodular lymphocyte predominant HL (NLPHL), with each group expressing its typical phenotype. LMP-1 stains were positive in 63% and 0% of cHL and NLPHL cases, respectively. EBER-positive Reed-Sternberg cells and variants were also present in 62% and 0% of each group, respectively. The cHL cases showed variable EBER positivity: nodular sclerosis, 58%; mixed cellularity, 100%; lymphocyte depletion, 100%; and unclassifiable, 67%. Our findings are similar to those from other developing countries and point towards a pathogenic role of EBV in cHL.

Contribution of the Epstein Barr virus to the molecular pathogenesis of Hodgkin lymphoma

Although the morphology of the pathognomonic Reed-Sternberg cells of Hodgkin lymphoma (HL) was described over a century ago, it was not until recently that their origin from B lymphocytes was recognised. The demonstration that a proportion of cases of HL harbour the Epstein-Barr virus (EBV) and that its genome is monoclonal in these tumours suggests that the virus contributes to the development of HL in some cases. This review summarises current knowledge of the pathogenesis of HL with particular emphasis on the association with EBV.

Association between Epstein-Barr virus and Hodgkin's lymphoma in Belgium: a pathological and virological study

The association between Epstein-Barr virus (EBV) and classical Hodgkin's lymphoma (cHL) varies according to the geographic location. In this work we sought to characterize EBV involvement in a series of 111 cHL cases diagnosed in Belgium. The overall prevalence of EBV infection detected by in situ hybridization in Reed-Sternberg cells was 33%. EBV positivity correlated with older age at diagnosis (>54 years; p = 0.01), mixed cellularity subtype (p = 0.000001), male gender (p = 0.004) and tended to be associated with higher clinical stage (III/IV; p = 0.02). The molecular features of the virus in EBV-positive cHL were studied by comparison with a series of reactive tonsils. A 30-bp deletion within the LMP-1 gene was in 15/28 (53.6%) EBV-positive cHL cases, and in 41.7% of reactive tonsil samples. This variant did not correlate with any clinical or pathological feature. The EBV strain was type A in all cHL and reactive samples.

HHV-6 and EBV DNA quantitation in lymph nodes of 86 patients with Hodgkin's lymphoma

Human herpesvirus (HHV-6) and Epstein-Barr virus (EBV), are two ubiquitous human herpesviruses which share many common features although they belong to different sub-families. In particular, both viruses are found in lymph nodes of patients suffering from Hodgkin's lymphoma. The aim of this study was to detect and to quantify independently HHV-6 and EBV by a real-time PCR in lymph nodes from 86 patients with Hodgkin's lymphoma. EBV quantitative method was compared with LMP-1 protein detection among the same samples. EBV genome was detected for 61.6% of the patients (53/86) and the highest prevalence of this virus was observed in Hodgkin's lymphoma with mixed-cellularity histopathological type (80%). In contrast to that, HHV-6 genome was detected for 79.1% of the patients (68/86) and was most observed in the nodular-sclerosis group (83.6%). Among the 68 HHV-6 positive samples, 63 belonged to the B subtype. A large number of biopsies (47.7%) were positive for both viruses whereas a little number (7%) was negative for both. EBV quantitation and LMP-1 immunohistochemistry were correlated statistically but this latter technique was less sensitive. Among the nodular-sclerosis patients, HHV-6-/EBV+ patients were significatively older than HHV-6+/EBV- patients. Patients infected dually had higher values of quantitation for each virus than those positive for one virus. Data of the clinical follow-up obtained by diagnosis and during the treatment of 83 patients, were correlated with the virological findings.

Bmi-1 is induced by the Epstein-Barr virus oncogene LMP1 and regulates the expression of viral target genes in Hodgkin lymphoma cells

Polycomb group (PcG) proteins are chromatin modifiers that are necessary for the maintenance and renewal of embryonic and adult stem cells. However, overexpression of the PcG protein, Bmi-1, causes lymphoma in transgenic mice. We show that Bmi-1 is up-regulated in Hodgkin lymphoma (HL) cells by the Epstein-Barr virus (EBV) oncogene latent membrane protein-1 (LMP1) and that this up-regulation is mediated by NF-κB signaling. We also show that Bmi-1 is up-regulated by NF-κB in EBV-negative HL cells. Down-regulation of LMP1 and Bmi-1 decreased the survival of HL cells, suggesting that Bmi-1 may mediate the prosurvival effects of LMP1-induced NF-κB signaling in HL cells. Transcriptional targets of Bmi-1 were identified after its knockdown in an HL cell line. We show here that Bmi-1 and LMP1 down-regulate the ataxia telangiectasia–mutated (ATM) tumor suppressor and conclude that Bmi-1 contributes to LMP1-induced oncogenesis in HL.

Induction of autotaxin by the Epstein-Barr virus promotes the growth and survival of Hodgkin lymphoma cells

A proportion of patients with Hodgkin lymphoma carry Epstein-Barr virus (EBV), an oncogenic herpesvirus, in their tumor cells. Although it is generally assumed that EBV contributes to the malignant phenotype of Hodgkin lymphoma cells, direct evidence in support of this is lacking. Here we show that EBV infection of Hodgkin lymphoma cells results in the induction of autotaxin, a secreted tumor-associated factor with lysophospholipase-D activity. Up-regulation of autotaxin increased the generation of lysophosphatidic acid (LPA) and led to the enhanced growth and survival of Hodgkin lymphoma cells, whereas specific down-regulation of autotaxin decreased LPA levels and reduced cell growth and viability. In lymphoma tissues, autotaxin expression was mainly restricted to CD30+ anaplastic large-cell lymphomas and Hodgkin lymphoma; in the latter, high levels of autotaxin were strongly associated with EBV positivity (P = .006). Our results identify the induction of autotaxin and the subsequent generation of LPA as key molecular events that mediate the EBV-induced growth and survival of Hodgkin lymphoma cells and suggest that this pathway may provide opportunities for novel therapeutic intervention. (Blood. 2005;106:2138-2146)

Constitutive activation of phosphatidyl-inositide 3 kinase contributes to the survival of Hodgkin's lymphoma cells through a mechanism involving Akt kinase and mTOR

The molecular mechanisms underlying the pathogenesis of the malignant Hodgkin's/Reed-Sternberg (HRS) cells of Hodgkin's lymphoma (HL) are largely unknown. This study investigates the contribution of phosphatidyl-inositide 3 kinase (PI3-kinase) and demonstrates that Akt, a substrate of PI3-kinase, is constitutively activated in HL-derived cell lines. Several downstream effectors of Akt signalling, including glycogen synthase kinase 3 (GSK-3) alpha and beta and mTOR substrates 4E-BP1 and p70 S6 kinase, were also phosphorylated in HL cells. The mTOR inhibitor, rapamycin, inhibited phosphorylation of these proteins. Furthermore, LY294002 inhibited phosphorylation of p70 S6 kinase and 4E-BP1, suggesting that the phosphorylation of p70 S6 kinase and 4E-BP1 in HL cells is PI3-kinase dependent. Importantly, HRS cells of primary tumour samples not only expressed high levels of activated Akt but also displayed phosphorylation of downstream targets of Akt activation including GSK-3, 4E-BP1, and p70 S6 Kinase. Inhibition of PI3-kinase and mTOR showed only modest effects on cell survival at the lower serum concentrations. However, rapamycin and doxorubicin acted synergistically to reduce HL cell survival. A combination of rapamycin and chemotherapy should be investigated in the treatment of HL.

Frequent epigenetic inactivation of the RASSF1A tumor suppressor gene in Hodgkin's lymphoma

Epigenetic inactivation of RASSF1A, a putative tumor suppressor with proapoptotic activity, is frequently observed in a number of solid tumors, including a variety of epithelial cancers, but has not been described in hematopoietic tumors. We have analysed the expression and methylation status of RASSF1A in Hodgkin's lymphoma (HL)-derived cell lines, primary HL tumors and serum samples from HL patients. RASSF1A transcription was detectable in only 2/6 HL cell lines. Methylation-specific PCR and bisulfite genomic sequencing revealed that the RASSF1A promoter was hypermethylated in all four RASSF1A-nonexpressing cell lines. 5-aza-2'-deoxycytidine treatment resulted in demethylation of the promoter and RASSF1A expression in these lines. Hypermethylation of RASSF1A was also detected in 34/52 (65%) primary HL tumors and in 2/22 serum samples from these patients. Microdissection of Hodgkin/Reed-Sternberg (HRS) cells from several of these cases confirmed that the RASSF1A hypermethylation we detected in the analysis of whole tumor originated from the tumor cell population. Although hypermethylation of RASSF1A was detected in 5/6 non-Hodgkin's lymphoma (NHL)-derived cell lines, only rare primary NHL (1/10 of Burkitt's lymphoma, 1/12 of post-transplant lymphoma, 1/12 diffuse large B-cell lymphoma, 0/27 of nasal lymphoma, 0/8 follicular center cell lymphoma, 0/4 mantle cell lymphoma, 0/4 anaplastic large cell (Ki-1+) lymphoma, 0/2 MALT lymphoma) showed hypermethylation of the promoter. No methylation was detected in any of the 14 normal PBMC. These results point to an important role for epigenetic silencing of RASSF1A in the pathogenesis of HL. Inactivation of RASSF1A could be one mechanism by which HRS cells escape the apoptosis that should occur following nonproductive immunoglobulin gene rearrangements.

Seasonal differences in the onset of the EBV-positive and -negative forms of paediatric Hodgkin's lymphoma

In this study, we have shown that there are seasonal differences in the onset of the (Epstein–Barr virus) EBV-positive and -negative forms of paediatric Hodgkin's lymphoma (HL). This suggests aetiological differences between the two forms of this disease. EBV-positive HL might be a rare consequence of primary EBV infection.

Epstein-Barr virus and oncogenesis: from latent genes to tumours

Epstein-Barr virus (EBV) is a ubiquitous human herpesvirus associated with the development of both lymphoid and epithelial tumours. As a common virus infection, EBV appears to have evolved to exploit the process of B cell development to persist as a life-long asymptomatic infection. However, the virus can contribute to oncogenesis as evidenced by its frequent detection in certain tumours, namely Burkitt's lymphoma (BL), post-transplant B cell lymphomas, Hodgkin's disease (HD) and nasopharyngeal carcinoma (NPC), and by its unique ability to efficiently transform resting B cells in vitro into permanently growing lymphoblastoid cell lines (LCLs). These transforming effects are associated with the restricted expression of EBV genes such that only a subset of so-called latent virus proteins are expressed in virus infected tumours and in LCLs. Distinct forms of EBV latency are manifest in the different tumours and these appear to be a vestige of the pattern of latent gene expression used by the virus during the establishment of persistent infection within the B cell pool. This review summarises our current knowledge of EBV latent gene function and how this relates to the role of the virus in the aetiology of different tumours.

The effect of Epstein-Barr virus status on outcome in age- and sex-defined subgroups of patients with advanced Hodgkin's disease

BACKGROUND

Conflicting data on the effect of the Epstein-Barr virus (EBV) on outcome in Hodgkin's disease (HD) might be due to the heterogeneous nature of this disease. In this study we have investigated whether the effect of EBV status on outcome is different between aetiologically defined age groups (15-34, 35-44, 45+ years) and also between males and females.

PATIENTS AND METHODS

Paraffin-embedded sections from 273 patients with advanced HD from two related clinical trials were analysed for the presence of EBV using in situ hybridisation.

RESULTS

EBV was detected in 78 (29%) of cases. For all patients, after a median follow-up of 5 years, there were no significant differences in survival by EBV status although there was a trend towards longer failure-free survival times for EBV-positive patients. Multivariate analyses suggested that EBV and sex, when in combination, were prognostic factors for failure-free survival (P = 0.06 for both). For subgroups, the effect of EBV on failure-free survival was significant for males and 15-34 years age group (P = 0.05 and P = 0.03, respectively).

CONCLUSION

This study suggests that with a median follow-up of 5 years, EBV status does not affect survival but being EBV-positive may be beneficial in terms of failure-free survival, particularly for males and younger adults.

An unbalanced translocation involving chromosome 14 is the probable cause for loss of potentially functional rearranged immunoglobulin heavy chain genes in the Epstein-Barr virus-positive Hodgkin's lymphoma-derived cell line L591

In the vast majority of cases, Hodgkin-Reed Sternberg (H-RS) cells, the malignant cells in Hodgkin's lymphoma (HL), are derived from germinal centre B cells. In some cases, somatic mutations within the rearranged immunoglobulin heavy (IgH) chain genes were detected, rendering potentially functional gene rearrangements non-functional. In these H-RS cells the expression of high-affinity B-cell receptors (BCR) was prevented. As in other cases only one non-productive IgH chain gene rearrangement was amplified from H-RS cells, it was speculated whether, in these cases, the functionally rearranged IgH chain genes were lost. An alternative explanation might be that the rearranged genes could not be amplified owing to a high load of somatic mutations within the primer binding sites. Here, we showed that, in the HL-derived Epstein-Barr virus (EBV)-positive cell line L591, only one non-functional somatically mutated IgH gene rearrangement could be detected. The other potentially functional IgH gene rearrangement was lost as a result of an unbalanced translocation affecting the long arm of chromosome 14. Moreover, L591 cells express the EBV latent membrane proteins LMP1 and LMP2A, which might have contributed to the 'escape' of these cells from apoptosis within the germinal centre. We conclude that, apart from the introduction of 'crippling mutations' into the rearranged VDJ genes rearrangement, deletions of the IGH locus may be regarded as another mechanism to prevent the expression of a BCR in H-RS cells.

Diagnosis of Epstein-Barr virus-associated diseases

Epstein-Barr virus (EBV) is a common DNA virus distributed worldwide. Usually the initial infection involves the upper respiratory tract without any problems and almost the entire population more than 25 years old test positive for anti-EBV antibodies. However, EBV often causes not only acute lytic infection but also chronic active infection with B cells and even T cells. In addition the EBV genome has been detected in tumors of hematopoietic or epithelial cell origin such as Burkitt's lymphomas, Hodgkin's disease, NK/T cell lymphomas, nasopharyngeal carcinomas (NPCs) and gastric adenocarcinomas. It is clearly important to make a correct diagnosis for EBV associated diseases and monitor the EBV load in individual patients for an appropriate therapy. In this paper recent advances in serological, immunological and molecular approaches for detection of EBV associated disease are described.

Epstein-Barr virus latent membrane protein-1 (LMP-1) expression in oral squamous cell carcinoma

OBJECTIVES

Epstein-Barr virus (EBV) is frequently associated with malignant cell transformation through the action of the oncoprotein latent membrane protein-1 (LMP-1). The present study aimed to determine the presence of EBV in oral squamous cell carcinomas (OSCCs) and the expression of LMP-1 in neoplastic cells of EBV-positive OSCCs.

STUDY DESIGN/METHODS

In a retrospective study of 78 OSCCs, we investigated the presence of the DNA of EBV by polymerase chain reaction, the expression of the oncoprotein LMP-1 by immunohistochemistry, and the presence of EBV-encoded RNA (EBER) by in situ hybridization.

RESULTS

EBV DNA was detected in 19.2% of the cases. Expression of LMP-1 in neoplastic cells was found in 85.7% of the EBV-positive OSCCs. EBV presence was significantly more frequent (P <.05) in OSCCs localized on the lateral tongue. EBV-positive OSCCs more frequently presented (P <.05) greater nuclear atypia.

CONCLUSION

EBV can appear in latent form in OSCC and express its main oncoprotein, LMP-1.