EBV-related Cancers Research Articles

Excess Mortality in Persons with Concurrent HIV and Cancer Diagnoses: A Retrospective Cohort Study.

With extended lifespans for people with human immunodeficiency virus (PWH), there is a corresponding increased burden of chronic illnesses, including cancer. Our objective was to estimate the excess mortality for PWH with cancer compared with people without HIV (PWoH), accounting for the higher background mortality in the general PWH population. We identified 39,000 PWH and 387,767 demographically-matched PWoH in three integrated healthcare systems from 2000-2016. We estimated excess mortality for PWH with cancer, computed as the cancer mortality rate difference-in-difference comparing PWH and PWoH. We evaluated five cancer groups: any cancer; virus-, human papillomavirus-, and Epstein-Barr virus (EBV)-related cancers; virus-unrelated cancers, and common individual cancers. We fitted a multivariable additive Poisson model to estimate excess mortality for PWH with cancer. PWH with any cancer had excess mortality compared with PWoH (41.3/1000 person-years [py], 95% Confidence Interval [CI] 34.0, 48.7). The highest excess mortality was observed for EBV-related cancers (63.2/1000 py, 95% CI 47.8, 78.7), lung cancer (147.7/1000 py, 95% CI 41.1, 254.3) and non-Hodgkin lymphoma (70.5/1000 py, 95% CI 51.4, 89.6). Excess mortality for PWH was attenuated 2009-2016, and PWH with cancer had no excess mortality 5 years after diagnosis. PWH in care may have excess mortality from certain cancer types, although disparities may have attenuated over time and do not persist beyond 5 years after diagnosis. Findings may guide improved clinical practice, and suggest further research is needed to investigate whether cancer treatment or other factors contribute to mortality disparities for PWH with cancer.

Geographic EBV variants confound disease-specific variant interpretation and predict variable immune therapy responses

AbstractEpstein-Barr virus (EBV) is a potent carcinogen linked to hematologic and solid malignancies and causes significant global morbidity and mortality. Therapy using allogeneic EBV-specific lymphocytes shows promise in certain populations, but the impact of EBV genome variation on these strategies remains unexplored. To address this, we sequenced 217 EBV genomes, including hematologic malignancies from Guatemala, Peru, Malawi, and Taiwan, and analyzed them alongside 1307 publicly available EBV genomes from cancer, nonmalignant diseases, and healthy individuals across Africa, Asia, Europe, North America, and South America. These included, to our knowledge, the first natural killer (NK)/T-cell lymphoma (NKTCL) EBV genomes reported outside of East Asia. Our findings indicate that previously proposed EBV genome variants specific to certain cancer types are more closely tied to geographic origin than to cancer histology. This included variants previously reported to be specific to NKTCL but were prevalent in EBV genomes from other cancer types and healthy individuals in East Asia. After controlling for geographic region, we did identify multiple NKTCL-specific variants associated with a 7.8-fold to 21.9-fold increased risk. We also observed frequent variations in EBV genomes that affected peptide sequences previously reported to bind common major histocompatibility complex alleles. Finally, we found several nonsynonymous variants spanning the coding sequences of current vaccine targets BALF4, BKRF2, BLLF1, BXLF2, BZLF1, and BZLF2. These results highlight the need to consider geographic variation in EBV genomes when devising strategies for exploiting adaptive immune responses against EBV-related cancers, ensuring greater global effectiveness and equity in prevention and treatment.

113 Longitudinal assessment of plasma EBV-DNA in non-endemic EBV-related nasopharyngeal cancers (NPC)

113 Longitudinal assessment of plasma EBV-DNA in non-endemic EBV-related nasopharyngeal cancers (NPC)

EBV-induced T-cell responses in EBV-specific and nonspecific cancers.

Epstein-Barr virus (EBV) is a ubiquitous human tumor virus associated with various malignancies, including B-lymphoma, NK and T-lymphoma, and epithelial carcinoma. It infects B lymphocytes and epithelial cells within the oropharynx and establishes persistent infection in memory B cells. With a balanced virus-host interaction, most individuals carry EBV asymptomatically because of the lifelong surveillance by T cell immunity against EBV. A stable anti-EBV T cell repertoire is maintained in memory at high frequency in the blood throughout persistent EBV infection. Patients with impaired T cell immunity are more likely to develop life-threatening lymphoproliferative disorders, highlighting the critical role of T cells in achieving the EBV-host balance. Recent studies reveal that the EBV protein, LMP1, triggers robust T-cell responses against multiple tumor-associated antigens (TAAs) in B cells. Additionally, EBV-specific T cells have been identified in EBV-unrelated cancers, raising questions about their role in antitumor immunity. Herein, we summarize T-cell responses in EBV-related cancers, considering latency patterns, host immune status, and factors like human leukocyte antigen (HLA) susceptibility, which may affect immune outcomes. We discuss EBV-induced TAA-specific T cell responses and explore the potential roles of EBV-specific T cell subsets in tumor microenvironments. We also describe T-cell immunotherapy strategies that harness EBV antigens, ranging from EBV-specific T cells to T cell receptor-engineered T cells. Lastly, we discuss the involvement of γδ T-cells in EBV infection and associated diseases, aiming to elucidate the comprehensive interplay between EBV and T-cell immunity.

Comparative Analysis of the Humoral Immune Response to the EBV Proteome across EBV-Related Malignancies.

Epstein-Barr virus (EBV) is linked to multiple cancers, including classical Hodgkin lymphoma (cHL), endemic Burkitt lymphoma (eBL), nasopharyngeal carcinoma (NPC), and extranodal natural killer/T-cell lymphoma (NKTCL). Anti-EBV IgG and IgA antibody responses targeting 202 sequences from 86 EBV proteins were measured using the same EBV whole proteome array across four case-control studies investigating EBV-positive cHL, eBL, NPC, and NKTCL (407 cases/620 controls). We grouped EBV-targeted antibodies into pathways by immunoglobulin type (IgA and IgG) and life-cycle stage (latent, immediate early lytic, early lytic, late lytic, and glycoprotein) and evaluated their association with each cancer type. In an additional analysis, we focused on the subset of 46 individual antibodies representing the top candidates for each cancer and compared their associations across the four cancer types using multivariable linear regression models. IgA antibody responses targeting all EBV life-cycle stages were associated with NPC but limited to anti-early lytic stage for cHL. NPC and eBL were associated with IgG antibodies across the viral life cycle; cHL with antibodies in the early lytic, late lytic and glycoprotein stages; and NKTCL with antibodies in the latent, immediate early lytic and early lytic phases. EBNA3A, BBLF1, BDLF4, and BLRF2 IgG antibodies were associated with all cancer types. Our observed similarities and differences across four EBV-associated cancers may inform EBV-related oncogenesis. Understanding the comparative humoral immune response across EBV-related cancers may aid in identifying shared etiologic roles of EBV proteins and inform unique pathogenic processes for each cancer.

The role of microRNA (miRNA) as a biomarker in HPV and EBV-related cancers

The role of microRNA (miRNA) as a biomarker in HPV and EBV-related cancers

Incidence and trend of Epstein-Barr virus-related cancer: A surveillance, epidemiology, and end results program based study.

10575 Background: Epstein-Barr virus (EBV) infection was highly prevalent, as was found in more than 90% of the adults globally. EBV infection has been found to be related with several types of cancer and classified as group 1 carcinogen by the International Agency for Research on Cancer. The association between EBV infection and malignancy was observed in Burkitt lymphoma (BL), Hodgkin lymphoma (HL), extranodal natural killer (NK)/T-cell lymphoma (NNKTL), gastric cancer (GC) and nasopharyngeal cancer (NPC). In this study, we aimed to analyze the incidence and the trend of incidence of these virus-related cancer and to identify whether the trend was similar between them. Methods: This was a retrospective analysis based on the data from Surveillance, Epidemiology, and End Results (18 registries, 2000-2017), which totally included 71,415 patients. EBV-related cancers were defined as BL, HL, NNKTL, GC and NPC. Age-adjusted incidence rates were displayed as per 100,000 persons. In terms of incidence trend, we calculated the average annual percent change (AAPC). AAPC was considered significantly different from 0 when the P-value was smaller than 0.05. The impact of the epidemiological and clinical characteristics on the incidence trend was estimated, with cancer type, histology, age, sex and race considered. Results: Incidence rates of EBV-related cancers were 6.68 per 100,000 persons in 2000 and 5.80 in 2017, of which the AAPC was -0.8 (95%CI, -1.1 - -0.5, P-value < 0.001). (Table) Similar with EBV-related cancer as a whole, the APCCs of BL, HL and GC were statistically significantly smaller than 0, except that the APCCs of NNKTL and NPC were statistically significantly larger than 0 and not statistically significantly different from 0 respectively. The incidence of EBV-related cancer also decreased in mixed cellularity classical HL, nodular sclerosis classical HL, adenocarcinoma of GC, signet ring cell carcinoma in GC, undifferentiated carcinoma of NPC, squamous cell carcinoma of NPC, patients diagnosed at the age of 20-39 years old and 60-79 years old, male patients and race as white, black or Asian, but increased in classical HL, NOS, nodular lymphocyte predominant HL and non-keratinizing carcinoma of NPC. Conclusions: Incidence of EBV-related cancer decreased during 2000 and 2017, which was consistent in BL, HL and GC.[Table: see text]

The Role of NK Cells in EBV Infection and EBV-Associated NPC.

A vast majority of the population worldwide are asymptomatic carriers of Epstein-Barr Virus (EBV). However, some infected individuals eventually develop EBV-related cancers, including Nasopharyngeal Carcinoma (NPC). NPC is one of the most common EBV-associated epithelial cancers, and is highly prevalent in Southern China and Southeast Asia. While NPC is highly sensitive to radiotherapy and chemotherapy, there is a lack of effective and durable treatment among the 15%–30% of patients who subsequently develop recurrent disease. Natural Killer (NK) cells are natural immune lymphocytes that are innately primed against virus-infected cells and nascent aberrant transformed cells. As EBV is found in both virally infected and cancer cells, it is of interest to examine the NK cells’ role in both EBV infection and EBV-associated NPC. Herein, we review the current understanding of how EBV-infected cells are cleared by NK cells, and how EBV can evade NK cell-mediated elimination in the context of type II latency in NPC. Next, we summarize the current literature about NPC and NK cell biology. Finally, we discuss the translational potential of NK cells in NPC. This information will deepen our understanding of host immune interactions with EBV-associated NPC and facilitate development of more effective NK-mediated therapies for NPC treatment.

EBV-miR-BART12 accelerates migration and invasion in EBV-associated cancer cells by targeting tubulin polymerization-promoting protein 1.

Epstein-Barr virus (EBV) infection leads to cancers with an epithelial origin, such as nasopharyngeal cancer and gastric cancer, as well as multiple blood cell-based malignant tumors, such as lymphoma. Interestingly, EBV is also the first virus found to carry genes encoding miRNAs. EBV encodes 25 types of pre-miRNAs which are finally processed into 44 mature miRNAs. Most EBV-encoded miRNAs were found to be involved in the occurrence and development of EBV-related tumors. However, the function of EBV-miR-BART12 remains unclear. The findings of the current study revealed that EBV-miR-BART12 binds to the 3'UTR region of Tubulin Polymerization-Promoting Protein 1 (TPPP1) mRNA and downregulates TPPP1, thereby promoting the invasion and migration of EBV-related cancers, such as nasopharyngeal cancer and gastric cancer. The mechanism underlying this process was found to be the inhibition of TPPP1 by EBV-miRNA-BART12, which, in turn, inhibits the acetylation of α-tubulin, and promotes the dynamic assembly of microtubules, remodels the cytoskeleton, and enhances the acetylation of β-catenin. β-catenin activates epithelial to mesenchymal transition (EMT). These two processes synergistically promote the invasion and metastasis of tumor cells. To the best of our knowledge, this is the first study to reveal the role of EBV-miRNA-BART12 in the development of EBV-related tumors as well as the mechanism underlying this process, and suggests potential targets and strategies for the treatment of EBV-related tumors.

Abstract 3791: Understanding the function of LMP1 CTAR3 in EBV-associated cancers

Abstract Background: Over 90% of the human population is infected with Epstein-Barr virus (EBV), which has been linked to cancers such as Hodgkin’s lymphoma and nasopharyngeal carcinoma. The principal oncoprotein responsible for cellular proliferation, increased cell invasion, evasion of apoptosis, and metastasis observed in EBV-associated cancers is latent membrane protein-1 (LMP-1). LMP-1 constitutively activates multiple signal transduction pathways via its cytoplasmic C-terminal activating regions (CTARs). Although, the functions of CTAR1 and CTAR2 regions have been extensively defined, the functions of a third regulatory region, CTAR3, are less understood. CTAR3 participates in protein sumoylation, which regulates evasion of immune responses and oncogenesis. The CTAR3 region is composed of 11-amino acid repeats and JAK binding motifs that contribute to the sumoylating activity of LMP-1. Variation in the number of repetitive elements has been noted in clinical isolates, but the exact function of these elements in oncogenesis is unknown. Therefore, the present study aims to generate EBV LMP-1 CTAR3 mutations within the repetitive elements to study their role in oncogenesis. Methods: Recombineering using an EBV-containing bacterial artificial chromosomes (BACs) was utilized to prepare mutant CTAR3 constructs with a N-terminal hemagglutinin (HA) epitope tag. Mutant BACs were transfected into HEK 293 cells and clones selected using hygromycin. Expression of mutant CTAR3 proteins was detected by immunoblot using HA antibody. Results: Preliminary results indicate the successful generation of infectious EBV clones containing the following LMP-1 CTAR3 mutations: (1) HA - Wild Type, (2) HA - JAK Only, (3) HA - No JAK, and (4) HA - ΔCTAR3. Clones for each mutant were selected after transfection into HEK 293 cells. Expression of mutant CTAR3 proteins was confirmed via immunoblot. The ability of the mutants to produce infectious virus was determined after induction of HEK CTAR3 clones and infection of B cells (RAJI) with culture supernatant. All CTAR3 mutants produced infectious virus and expressed CTAR3 mutant proteins of the expected molecular weight. Conclusions: An EBV-BAC was recombineered to create EBV strains with targeted mutations in CTAR3. The novel BAC mutants will be used to assess the function of CTAR3 domains in EBV replication and oncogenesis. The role that CTAR3 plays in envelopment and egress during lytic replication will be determined. Additionally, the role of CTAR3 during EBV-mediated immortalization of naïve B-cells will be examined. Ultimately, mutant EBV strains will be studied in a SCID mouse model to determine the role of CTAR3 sumoylation in cell migration and metastasis in vivo. Overall, further appreciation of the role of LMP-1 in tumorigenesis will identify potential targets for therapeutic intervention in patients with EBV-related cancers. *Analise McGreal and Aimee Minko contributed equally to this work. Citation Format: Analise McGreal, Aimee Minko, Melissa A. Visalli, Robert J. Visalli, Gretchen L. Bentz. Understanding the function of LMP1 CTAR3 in EBV-associated cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3791.

Modelling the dynamics of EBV transmission to inform a vaccine target product profile and future vaccination strategy

Epstein-Barr virus (EBV) is one of the most common human viruses and the cause of pathologies such as infectious mononucleosis (IM) and certain cancers. No vaccine against EBV infection currently exists, but such vaccines are in development. Knowledge of how EBV is transmitted at the population level is critical to the development of target product profiles (TPPs) for such vaccines and future vaccination strategies. We present the first mathematical model of EBV transmission, parameterised using data from England, and use it to compare hypothetical prophylactic vaccines with different characteristics and the impact of vaccinating different age groups. We found that vaccine duration had more impact than vaccine efficacy on modelled EBV and IM prevalence. The age group vaccinated also had an important effect: vaccinating at a younger age led to a greater reduction in seroprevalence but an increase in IM cases associated with delayed infection. Vaccination had impact on cancer incidence only in the long run, because in England most EBV-related cancers arise in later life. Durability of protection should be a key factor to prioritise in EBV vaccine development and included in vaccine TPPs. These findings are timely and important for vaccine developers and policy-makers alike.

Abstract B166: Mass spectrometric characterization of MHC peptides on therapeutic EBV transformed primary lymphoblastoid cells from HLA A*11 patients

Abstract EBV transformed lymphoblastoid cell lines (LCL) derived from patients with Epstein Barr virus (EBV)-related cancer have been used as "feeder cells" after terminally irradiation in multiple cell therapy protocols targeting EBV-related cancers. These cells are subsequently co-cultured with patient peripheral blood mononuclear cells (PBMC) and are sufficient expansion of autologous cell product, given therapeutically back to patients. LCL are known to present both host genome derived cancer-associated antigens relevant for cancer, alongside EBV antigens. PBMC that are co-cultured with LCL have been used in multiple small studies across multiple EBV related cancers. This study was performed in the context of LCL used as feeder cells in the context of EBV-related nasopharyngeal cancer that was treated with autologous cell product after co-culture with LCL as part of a phase II clinical trial in Singapore. The aims of this study were, firstly, to perform unbiased identification of MHC peptides using mass spectrometry; secondly, to map the peptides to respective HLA alleles using publicly available HLA peptide binding prediction algorithms; and thirdly, to look specifically at HLA A*11 allele specific EBV-derived peptides. 6 patients with HLA A*11 were identified and LCL from these patients were grown in cell culture for 1-3 months each, until 5E8 cells were available. Cells were treated in suspension with acidification in order to enable acid elution of MHC peptides. Mass spectrometric analysis was performed for unbiased evaluation of MHC peptides. Based on the consensus peptide sequences derived from 8-mer and 9-mer peptides, HLA A*11:01 appeared to be a dominant allele with at least 20% of peptides having basic end residues that are typical for binding to HLA allele. Between 3,000 to 5,000 distinct peptide sequences across lengths characteristic for both class I and II MHC alleles were identified for each sample, including multiple peptides derived host genome DNA, and some from EBV proteins including LMP1, BARF1, EBNA6, and TTK. There was some overlap of peptides seen across the samples. For example, 2 patient samples, with 3,636 and 4,033 distinct peptides identified respectively, had 1,025 overlapping peptides. 2 patient samples with HLA A*11:01 and HLA A*11:02 respectively, had 1 overlapping EBV protein derived set of peptides that demonstrated differences in trimming of peptides derived from the same epitope across these 2 HLA classes. Only 1 EBV protein was found to be consistently represented in the MHC peptidome across the patient samples, with the same epitope represented across all the samples within the scope of this study. This small study demonstrates that mass spectrometric analysis of large numbers of cells is able to directly deconvolute the MHC peptide, and this is relevant in the context of adoptive cell therapies that utilize "feeder cells" that are required to reliably present clinically relevant antigens to generate autologous cell product. Furthermore, in the absence of reliable peptide prediction algorithms for HLA alleles that are more prevalent in Asia, such as HLA A*11:02, this approach is useful for direct characterization of peptides that bind. Citation Format: Amit Jain. Mass spectrometric characterization of MHC peptides on therapeutic EBV transformed primary lymphoblastoid cells from HLA A*11 patients [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B166.

An integrated automated multispectral imaging technique that simultaneously detects and quantitates viral RNA and immune cell protein markers in fixed sections from Epstein-Barr virus-related tumours

Background/aimEpstein-Barr virus (EBV) is an oncovirus that is commonly associated with the development of lymphomas and epithelial carcinomas. In the era of immunotherapy, histological evaluation of EBV-related cancers is currently a multi-sample, multi-technique process requiring separate time-consuming detection of EBV-encoded small RNAs by in situ hybridisation (ISH), and parallel labelling of sections for cancer-associated protein markers. MethodsUsing EBV-associated tumours as proof-of-concept for feasibility, here we developed an approach that allows simultaneous detection of EBV RNAs and multiple protein markers such as PD-L1, EBV-LMP, CD8, CD4, CD20, CD30 and CD15on a single tissue section based on our recently reported automated staining protocol. ResultsWe successfully combined multiplex immunofluorescence (mIF) to detect 3 abovementioned protein markers involved in cancer, with ISH, and applied the protocol to f tissue samples from patients diagnosed with EBV-associated pulmonary lymphoepithelioma-like carcinoma (LELC), gastric carcinoma and Hodgkin's Lymphoma. Empowered by the Vectra 3 Automated Quantitative Pathology Imaging System, we demonstrate the utility and potential of this integrated approach to concurrently detect and quantitate viral RNA and protein biomarkers of immune and tumour cells. ConclusionThis study represents an important step forward in the research and diagnosis of EBV-associated cancers, and could be readily modified to include other proteins and RNA markers to apply to other malignancies. More importantly, the novel automated ISH-mIF protocol that we detailly described here could also be readily reproduced by most of the diagnostic and research lab to future projects that aim to look at both RNA and protein markers.

Signaling by the Epstein–Barr virus LMP1 protein induces potent cytotoxic CD4+ and CD8+ T cell responses

The B-lymphotropic Epstein-Barr virus (EBV), pandemic in humans, is rapidly controlled on initial infection by T cell surveillance; thereafter, the virus establishes a lifelong latent infection in the host. If surveillance fails, fatal lymphoproliferation and lymphomagenesis ensue. The initial T cell response consists of predominantly CD8+ cytotoxic T cells and a smaller expansion of CD4+ cells. A major approach to treating EBV-associated lymphomas is adoptive transfer of autologous or allogeneic T cells that are stimulated/expanded on EBV-transformed B cells. Strikingly, the clinical response correlates with the frequency of CD4 cells in the infused T cells. Although in vitro studies suggested that EBV-specific CD4 cells develop cytotoxicity, they have not been comprehensively characterized and the molecular mechanism underlying their formation remains unknown. Our recent work, using a transgenic approach in mice, has revealed a central role for the EBV signaling molecule LMP1 in immune surveillance and transformation of EBV-infected B cells. The mouse model offers a unique tool for uncovering basic features of EBV immunity. Here, we show that LMP1 expression in B cells induces potent cytotoxic CD4 and CD8 T cell responses, by enhancing antigen presentation and costimulation by CD70, OX40 ligand, and 4-1BB ligand. Our data further suggest that cytotoxic CD4 cells hold superior therapeutic value for LMP1 (EBV)-driven lymphomas. These findings provide insights into EBV immunity, demonstrating that LMP1 signaling alone is sufficient to induce a prominent cytotoxic CD4 response, and suggest strategies for immunotherapy in EBV-related and other cancers.

The role of oxidative stress in EBV lytic reactivation, radioresistance and the potential preventive and therapeutic implications.

Epstein-Barr virus (EBV) is an important cancer causing virus. Cancer associated with EBV account for approximately 1.5% of all cancers, and represent 1.8% of all cancer deaths worldwide. EBV reactivation plays an important role in the development of EBV-related diseases and is closely related with patients' survival and clinical stages of EBV-related cancers. The therapy regarding to EBV-related cancers is very urgent, especially in endemic areas. Generating oxidative stress is a critical mechanism by which host cells defend against infection by virus. In addition, ROS-mediated oxidative stress plays a significant but paradoxical role acting as a "double-edged sword" to regulate cellular response to radiation, which is the main therapy strategy for EBV-related cancers, especially nasopharyngeal carcinoma. Therefore, in this review we primarily discuss the possible interplay among the oxidative stress, EBV lytic reactivation and radioresistance. Understanding the role of oxidative stress in EBV lytic reactivation and radioresistance will assist in the development of effective strategies for prevention and treatment of EBV-related cancers.

Pathogenic Role of Exosomes in Epstein-Barr Virus (EBV)-Associated Cancers.

Exosomes are 40- to 100-nm membrane-bound small vesicles that carry a great variety of cellular cargoes including proteins, DNA, messenger RNAs (mRNAs), and microRNAs (miRNAs). These nanovesicles are detected in various biological fluids such as serum, urine, saliva, and seminal fluids. Exosomes serve as key mediators in intercellular communication by facilitating the transfer and exchange of cellular components from cells to cells. They contain various pathogenic factors whereby their adverse effects have been implicated in multiple viral infections and cancers. Interestingly, accumulating evidences showed that exosomes derived from tumour viruses or oncoviruses, exacerbate virus-associated cancers by remodelling the tumour microenvironment. In this review, we summarize the contributing factors of Epstein-Barr virus (EBV) products-containing exosomes in viral pathogenesis and their potential implications in EBV-driven malignancies. Understanding the biological role of these exosomes in the disease would undoubtedly boost the development of a more comprehensive strategy to combat EBV-associated cancers and to better predict the therapeutic outcomes. Furthermore, we also highlight the potentials and challenges of EBV products-containing exosomes being employed as diagnostic markers and therapeutic targets for EBV-related cancers. Since these aspects are rather underexplored, we attempt to underline interesting areas that warrant further investigations in the future.

Highlights of This Issue

Martens and colleagues describe changes in circulating immune cells in metastatic melanoma patients treated with ipilimumab, a CTLA-4 inhibitor, and the impact on clinical outcome. Routine blood counts of T cells, Tregs, and MDSCs were performed in an international cohort of 82 melanoma patients. Changes in absolute lymphocyte counts, CD4+ T cells, and CD8+ T cells were associated with overall survival and clinical response. Increases in all three cell populations identified patients with excellent outcome. These changes reflect the positive mode of action of ipilimumab, underline the importance of the specific T cell response for immunologic tumor control, and represent surrogate marker candidates for outcome.Somatic mutations in the tyrosine kinase domain of HER2 may be an alternative mechanism to HER2 activation and affect breast cancer sensitivity toward HER2-targeted therapies. In this study by Zuo and colleagues, 1,248 primary tumors and 18 paired metastatic samples were sequenced for HER2 mutations. Functional analysis found that HER2 negative breast cancer with novel activating mutations may benefit from HER2-targeted therapies, while HER2-positive tumors harboring novel resistance mutations did not. These findings will help illustrate the potential clinical implications of HER2 somatic mutations and assist in identifying patients who would benefit from HER2-targeted therapies in choosing the most beneficial treatment.Lenalidomide, thalidomide and pomalidomide (LTP) are immunomodulatory agents for the treatment of multiple myeloma; however, they may increase the incidence of secondary primary malignancies, particularly with lenalidomide use in the maintenance setting. Jones and colleagues show that LTP are able to stimulate the Epstein-Barr virus (EBV) lytic cycle, both in vitro and in vivo, primarily by activating phosphoinositide 3-kinase signaling. This provides a potential mechanism through which use of LTP in immunocompromised patients could promote the development of EBV-associated malignancies, such as Hodgkin disease, through immune suppression, and could also provide a new approach for EBV-related cancers in combination with ganciclovir.Lumican is an extracellular matrix protein whose presence with primary pancreatic ductal adenocarcinoma (PDAC) tumors is associated with improved patient outcome. Kang and colleagues find that activated pancreatic stellate cells isolated from primary PDAC tumors secrete large amounts of lumican that augment adhesion and migration of activated pancreatic stellate cells in a collagen-rich environment. TGF-β inhibits lumican transcription and secretion in activated stellate cells through its canonical signaling pathway and binding of SMAD4 to novel SMAD-binding elements. These findings underscore the influential role of lumican within the stroma of localized PDAC and its impact on tumor biology and patient outcome.

Epstein-Barr virus-encoded miR-BART6-3p inhibits cancer cell metastasis and invasion by targeting long non-coding RNA LOC553103.

Epstein-Barr virus (EBV) infection is causatively related to a variety of human cancers, including nasopharyngeal carcinoma (NPC) and gastric cancer (GC). EBV encodes 44 mature miRNAs, a number of which have been proven to promote carcinogenesis by targeting host genes or self-viral genes. However, in this study, we found that an EBV-encoded microRNA, termed EBV-miR-BART6-3p, inhibited EBV-associated cancer cell migration and invasion including NPC and GC by reversing the epithelial–mesenchymal transition (EMT) process. Using microarray analysis, we identified and validated that a novel long non-coding RNA (lncRNA) LOC553103 was downregulated by EBV-miR-BART6-3p, and LOC553103 knockdown by specific siRNAs phenocopied the effect of EBV-miR-BART6-3p, while LOC553103 overexpression promoted cancer cell migration and invasion to facilitate EMT. In conclusion, we determined that EBV-miR-BART6-3p, a microRNA encoded by oncogenic EBV, inhibited EBV-associated cancer cell migration and invasion by targeting and downregulating a novel lncRNA LOC553103. Thus, our study presents an unreported mechanism underlying EBV infection in EBV-associated cancer carcinogenesis, and provides a potential novel diagnosis and treatment biomarker for NPC and other EBV-related cancers.

High Levels of Antibody that Neutralize B-cell Infection of Epstein-Barr Virus and that Bind EBV gp350 Are Associated with a Lower Risk of Nasopharyngeal Carcinoma.

Elevated IgA antibodies indicative of ongoing exposure to Epstein-Barr virus (EBV) are high-risk biomarkers for nasopharyngeal carcinoma (NPC), an EBV-related epithelial tumor. However, protective biomarkers that limit exposure to the virus have not been defined. We evaluated whether antibodies that can neutralize EBV infection by targeting glycoproteins involved in viral cell entry, including EBV vaccine candidate glycoprotein 350 (gp350), were associated with lower NPC risk. In a prospective cohort of 2,557 individuals from 358 high-risk NPC multiplex families in Taiwan, we identified 21 incident NPC cases and 50 disease-free controls. To complement data from high-risk families, we further identified 30 prevalent NPC cases and 50 healthy controls from the general Taiwanese population. We quantified EBV-neutralizing antibody, antibodies against EBV glycoproteins involved in B-cell and epithelial cell entry, and anti-EBNA1 IgA, a high-risk NPC biomarker. EBV-neutralizing antibodies blocking B-cell infection and anti-gp350 antibodies were present at significantly higher levels in disease-free controls compared with incident NPC cases (P < 0.03). Family members with both low EBV-neutralizing potential and elevated EBNA1 IgA had a 7-fold increased risk of NPC (95% CI, 1.9-28.7). Neutralizing antibodies against epithelial cell infection did not differ between incident cases and disease-free controls. Anti-glycoprotein antibody levels measured at diagnosis (prevalent NPC) were significantly higher than levels measured prior to diagnosis (P < 0.01). Elevated titers of EBV-neutralizing antibody and anti-gp350 antibody were low-risk biomarkers for NPC. These data suggest that a vaccine that induces potent EBV gp350 and B-cell-neutralizing antibodies could reduce the risk of EBV-related cancers such as NPC. Clin Cancer Res; 22(14); 3451-7. ©2016 AACR.

Murine Models of Epstein-Barr Virus-Associated Lymphomagenesis.

The Epstein-Barr virus (EBV) is a B-lymphotropic gamma herpes virus associated with a number of malignancies. Most EBV-related cancers present complex medical management challenges; thus it has been essential to develop preclinical in vivo models allowing for the study of pathogenesis, prevention, and treatment of these diseases. Early in vivo models used nonhuman primates; however, such models were limited by the inability of EBV to achieve viral latency, availability, and cost. Immunodeficient mouse strains emerged as efficient models that allow for engraftment of human mononuclear cells and controlled evaluation of EBV-driven lymphoproliferative disease (EBV-LPD). By using highly immunodeficient strains of mice such as severe combined immune deficiency (SCID) and NOD/LtSz-scid ILrg(-/-)(NOG) mice, investigators have developed efficient platforms for evaluating pathogenesis of benign (HLH) and malignant (EBV-LPD) diseases associated with EBV. Humanized murine chimeric models have been essential tools for evaluating preventive strategies with vaccine and adoptive cellular approaches, as well as development of experimental therapeutic strategies. Manipulation of the human immune cells before engraftment or mutation of viral lytic and latent genes has enhanced our understanding of the oncogenic nature of EBV and the complexity of human immune responses to EBV. In this review, we discuss how the EBV murine models have evolved to become essential tools for studying the virology of EBV as it relates to human EBV-LPD pathogenesis, the immunobiology of innate and adaptive responses, and limitations of these models.