Epstein-Barr virus strain variation and cancer

Genomic Landscapes of Epstein-Barr Virus in Pulmonary Lymphoepithelioma-like Carcinoma

Epstein-Barr virus (EBV) infection is associated with multiple malignancies, including pulmonary lymphoepithelioma-like carcinoma (pLELC), a particular subtype of primary lung cancer. However, the genomic characteristics of EBV related to pLELC remain unclear. Here, we obtained the whole-genome dataset of EBV isolated from 78 pLELC patients and 37 healthy controls using EBV-captured sequencing. Compared to the reference genome (NC_007605), a total of 3995 variations were detected across pLELC-derived EBV sequences, with the mutational hotspots located in latent genes. Combined with 180 published EBV sequences derived from healthy people in Southern China, we performed a genome-wide association study and identified 32 variations significantly related to pLELC (p < 2.56×10^-05, Bonferroni correction), with the top signal of SNP coordinate T7327C (OR = 1.22, p = 2.39×10^-15) locating in the origin of plasmid replication (OriP). The results of population structure analysis of EBV isolates in East Asian showed the EBV strains derived from pLELC were more similar to those from nasopharyngeal carcinoma (NPC) than other EBV-associated diseases. In addition, typical latency type-II infection were recognized for EBV of pLELC at both transcription and methylation levels. Taken together, we defined the global view of EBV genomic profiles in pLELC patients for the first time, providing new insights to deepening our understanding of this rare EBV-associated primary lung carcinoma. Importance Pulmonary lymphoepithelioma-like carcinoma (pLELC) is a rarely distinctive subtype of primary lung cancer closely associated with Epstein-Barr virus (EBV) infection. Here, we gave the first overview of pLELC-derived EBV at the level of genome, methylation and transcription. We obtained the EBV sequences dataset from 78 primary pLELC patients, and revealed the sequences diversity across EBV genome and detected variability in known immune epitopes. Genome-wide association analysis combining 217 healthy controls identifies significant variations related to the risk of pLELC. Meanwhile, we characterized the integration landscapes of EBV at the genome-wide level. These results provided new insight for understanding EBV's role in pLELC tumorigenesis.

Viral Causality of Human Cancer and Potential Roles of Human Endogenous Retroviruses in the Multi-Omics Era: An Evolutionary Epidemiology Review

Being responsible for almost 12% of cancers worldwide, viruses are among the oldest known and most prevalent oncogenic agents. The quality of the evidence for the in vivo tumorigenic potential of microorganisms varies, thus accordingly, viruses were classified in 4 evidence-based categories by the International Agency for Research on Cancer in 2009. Since then, our understanding of the role of viruses in cancer has significantly improved, firstly due to the emergence of high throughput sequencing technologies that allowed the “brute-force” recovery of unknown viral genomes. At the same time, multi-omics approaches unravelled novel virus-host interactions in stem-cell biology. We now know that viral elements, either exogenous or endogenous, have multiple sometimes conflicting roles in human pathophysiology and the development of cancer. Here we integrate emerging evidence on viral causality in human cancer from basic mechanisms to clinical studies. We analyze viral tumorigenesis under the scope of deep-in-time human-virus evolutionary relationships and critically comment on the evidence through the eyes of clinical epidemiology, firstly by reviewing recognized oncoviruses and their mechanisms of inducing tumorigenesis, and then by examining the potential role of integrated viruses in our genome in the process of carcinogenesis.

Prophylactic and Therapeutic EBV Vaccines: Major Scientific Obstacles, Historical Progress, and Future Direction

The Epstein-Barr virus (EBV) infects more than 95% of adults worldwide and is associated with various malignant tumors and immune diseases, imparting a huge disease burden on the human population. Available EBV vaccines are imminent. Prophylactic vaccines can effectively prevent the spread of infection, whereas therapeutic vaccines mainly stimulate cell-mediated immunity and kill infected cells, thus curbing the development of malignant tumors. Nevertheless, there are still no approved EBV vaccines after decades of effort. The complexity of the EBV life cycle, the lack of appropriate animal models, and the limited reports on adjuvant selection and immune responses are gravely impeding progress in EBV vaccines. The soluble gp350 vaccine could reduce the incidence of infectious mononucleosis (IM), which seemed to offer hope, but could not prevent EBV infection. Continuous research and vaccine trials provide deep insights into the structural biology of viruses, the designs for immunogenicity, and the evolving vaccine platforms. Moreover, the new vaccine candidates are expected to achieve further success via combined immunization to elicit both a dual protection of B cells and epithelial cells, and sustainable immunization against infected cells at several phases of infection.

Sexual Behavior Surveys Should Ask More: Covering the Diversity of Sexual Behaviors That May Contribute to the Transmission of Pathogens

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SARS-CoV-2: lessons from both the history of medicine and from the biological behavior of other well-known viruses

SARS-CoV-2 is the etiological agent of the current pandemic worldwide and its associated disease COVID-19. In this review, we have analyzed SARS-CoV-2 characteristics and those ones of other well-known RNA viruses viz. HIV, HCV and Influenza viruses, collecting their historical data, clinical manifestations and pathogenetic mechanisms. The aim of the work is obtaining useful insights and lessons for a better understanding of SARS-CoV-2. These pathogens present a distinct mode of transmission, as SARS-CoV-2 and Influenza viruses are airborne, whereas HIV and HCV are bloodborne. However, these viruses exhibit some potential similar clinical manifestations and pathogenetic mechanisms and their understanding may contribute to establishing preventive measures and new therapies against SARS-CoV-2.

NK-/T-cell lymphomas

Natural killer/T-cell lymphoma (NKTL) is a sub-type of Epstein-Barr virus (EBV)-related non-Hodgkin lymphomas common in Asia and Latin America but rare elsewhere. Its pathogenesis is complex and incompletely understood. Lymphoma cells are transformed from NK- or T-cells, sometimes both. EBV-infection and subsequent genetic alterations in infected cells are central to NKTL development. Hemophagocytic syndrome is a common complication. Accurate staging is important to predict outcomes but there is controversy which system is best. More than two-thirds of NKTL lympohmas are localized at diagnosis, are frequently treated with radiation therapy only and have 5-year survival of about 70 percent. Persons with advanced NKTLs receive radiation therapy synchronously or metachronously with diverse multi-drug chemotherapy typically including L-asparginase with 5-year survival of about 40 percent. Some persons with widespread NKTL receive chemotherapy only. There are few data on safety and efficacy of high-dose therapy and a haematopoietic cell autotransplant. Immune therapies, histone deacetylase (HDAC)-inhibitors and other drugs are in early clinical trials. There are few randomized controlled clinical trials in NKTLs and no therapy strategy is clearly best; more effective therapy(ies) are needed. Some consensus recommendations are not convincingly evidence-based. Mechanisms of multi-drug resistance are considered. We discuss these issues including recent advances in our understanding of and therapy of NKTLs.

Association between variant alleles of major histocompatibility complex class II regulatory genes and nasopharyngeal carcinoma susceptibility

Major histocompatibility complex (MHC) class II regulatory genes play a paramount role in immune response that can exert a predominant influence on clinical outcome of Epstein-Barr virus infection consistently assumed as the main pathogenetic factor for nasopharyngeal carcinoma. To elucidate the relationship between allelic variants of MHC class II regulatory genes and susceptibility to nasopharyngeal carcinoma, a total of 28 polymorphic loci at MHC class II regulatory genes, involving CIITA, CREB1, RFX family genes (RFX5, RFXAP, and RFXANK), and NFY family genes (NFYA, NFYB, and NFYC), were genotyped by multiplex SNaPshot minisequencing in 137 patients with nasopharyngeal carcinoma and 107 healthy controls from the southern Chinese population. Allelic analysis disclosed that rs7404873, rs6498121, rs6498126, and rs56074043 shared correlations with nasopharyngeal carcinoma (Ptrend < 0.05). Further, rs6498126 on CIITA was independently associated with the risk of developing nasopharyngeal carcinoma (CC vs. GG, odds ratio: 7.386, 95% confidence interval: 1.934-28.207, Ptrend < 0.01). Conversely, rs7404873 on CIITA and rs56074043 on NFYB manifested epistatic interaction to decreased susceptibility of nasopharyngeal carcinoma (rs7404873, TT vs. GG, odds ratio: 0.256, 95% confidence interval: 0.088-0.740, Ptrend < 0.05; rs56074043, AA vs. AG, odds ratio: 0.341, 95% confidence interval: 0.129-0.900, Ptrend < 0.05). Additionally, bioinformatics analysis revealed that the three variants were transcriptional regulatory in function and might impact the expression of nearby genes. The findings suggested genetic variants on MHC class II regulatory genes contributed to nasopharyngeal carcinoma susceptibility and might provide new insights for screening high-risk population.

A Systematic Review of Epstein-Barr Virus Latent Membrane Protein 1 (LMP1) Gene Variants in Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is an aggressive tumor with a complex etiology. Although Epstein-Barr virus (EBV) infection is known environmental factor for NPC development, the degree to which EBV naturally infects nasopharyngeal epithelium and the moment when and why the virus actively begins to affect cell transformation remains questionable. The aim of this study was to explore the association between LMP1 gene variability and potential contribution to NPC development. A systematic review was performed through searches of PubMed, Web of Science (WoS) and SCOPUS electronic databases. Additionally, meta-analysis of the difference in the frequency of seven LMP1 gene variants in NPC and control individuals was accomplished. The results from this study give a proof of concept for the association between 30 bp deletion (OR = 3.53, 95% CI = 1.48-8.43) and Xhol loss (OR = 14.17, 95% CI = 4.99-40.20) and NPC susceptibility when comparing biopsies from NPC and healthy individuals. Otherwise, 30 bp deletion from NPC biopsies could not distinguish NPC from EBV-associated non-NPC tumors (OR = 1.74, 95% CI = 0.81-3.75). However, B95-8, China1 and North Carolina variants were uncommon for NPC individuals. Much more efforts remains to be done to verify the biological significance of the differences observed, define so-called "high-risk" EBV variants and make it available for clinical application.

The role of Epstein–Barr virus-encoded latent membrane proteins in host immune escape

Epstein–Barr virus (EBV) is a type IV herpesvirus that widely infects the vast majority of adults, and establishes a latent infection pattern in host cells to escape the clearance of immune system. The virus is intimately associated with the occurrence and progression of lymphomas and epithelial cell cancers. EBV latent membrane proteins (LMPs) can assist its immune escape by downregulating host immune response. Besides EBV, LMPs have important effects on the functions of exosomes and autophagy, which also help EBV to escape immune surveillance. These escape mechanisms may provide conditions for further development of EBV-associated tumors. In this article, we discussed the potential functions of EBV-encoded LMPs in promoting immune escape.

LncRNA TP73-AS1 promotes the development of Epstein-Barr virus associated gastric cancer by recruiting PRC2 complex to regulate WIF1 methylation

BACKGROUND

Epstein-Barr virus associated gastric cancer (EBVaGC) become a growing health problem. TP73-AS1 showed high expression in EBVaGC cells. However, the function role and underlying mechanism of TP73-AS1 need further exploration.

METHODS

The expressions of TP73-AS1, WIF1, EZH2, β-catenin and epithelial-mesenchymal transition (EMT)-related proteins were detected using qRT-PCR and Western blotting. Cell proliferation, apoptosis, migration and invasion were measured by CCK-8, colony formation, flow cytometry, wound healing and transwell assays, respectively. WIF1 promoter methylation was analyzed by MS-PCR (MSP). RNA immunoprecipitation assay (RIP) and Chromatin immunoprecipitation assay (ChIP) measured the interactions of TP73-AS1/EZH2 and EZH2/WIF1. Subcutaneous tumor growth was monitored in nude mice and immunohistochemistry (IHC) detected proliferation marker Ki-67 expression.

RESULTS

TP73-AS1 was increased while WIF1 was decreased in EBVaGC cells. Silencing of TP73-AS1 or overexpression of WIF1 repressed the growth and migration while promoted apoptosis of EBVaGC cells. Knockdown of WIF1 reversed the anticancer effect of TP73-AS1 silencing. TP73-AS1 promoted the binding of EZH2 to the WIF1 promoter by directly binding to EZH2, and thus inhibiting the expression of WIF1 by enhancing H3K27me3 level of WIF1 promoter. Moreover, TP73-AS1 activated Wnt/β-catenin signaling pathway and promoted EMT by down-regulating WIF1. TP73-AS1 silencing inhibited the progression of EBVaGC in nude mice by epigenetically regulating WIF1.

CONCLUSION

TP73-AS1 regulated the promoter methylation of WIF1 by recruiting PRC2 complex to WIF1 promoter region, thereby promoting the progression of EBVaGC. These observations provided a novel theoretical basis to investigate more effective therapies of EBVaGC.

Eukaryotic initiating factor eIF4E is targeted by EBV-encoded miR-BART11-3p and regulates cell cycle and apoptosis in EBV-associated gastric carcinoma

The eukaryotic translation initiation factor 4E (eIF4E) is a component of the eukaryotic translation initiation factor 4F, a significant complex in the protein translation process. It has been found to be closely related to many human tumors, such as gastric carcinoma. It is known that the Epstein-Barr virus (EBV) upregulates eIF4E in various ways in nasopharyngeal carcinoma. However, there are very few studies on eIF4E in EBV-associated gastric carcinoma. We found that the expression level of eIF4E in EBV-associated gastric carcinoma was lower than other types of gastric carcinoma, and the downregulation of eIF4E could lead to increased apoptosis of gastric carcinoma cells, retardation at S phase, and decreased cell migration. The dual luciferase reporter experiment showed that EBV-miR-BART11-3p could directly target the 3'-UTR region of eIF4E, and BART11-3p is the key factor leading to the downregulation of eIF4E. It could provide a new evidence for EBV-regulating host gene to affect the development of gastric carcinoma.

Investigation of Long COVID Prevalence and Its Relationship to Epstein-Barr Virus Reactivation

Coronavirus disease 2019 (COVID-19) patients sometimes experience long-term symptoms following resolution of acute disease, including fatigue, brain fog, and rashes. Collectively these have become known as long COVID. Our aim was to first determine long COVID prevalence in 185 randomly surveyed COVID-19 patients and, subsequently, to determine if there was an association between occurrence of long COVID symptoms and reactivation of Epstein–Barr virus (EBV) in 68 COVID-19 patients recruited from those surveyed. We found the prevalence of long COVID symptoms to be 30.3% (56/185), which included 4 initially asymptomatic COVID-19 patients who later developed long COVID symptoms. Next, we found that 66.7% (20/30) of long COVID subjects versus 10% (2/20) of control subjects in our primary study group were positive for EBV reactivation based on positive titers for EBV early antigen-diffuse (EA-D) IgG or EBV viral capsid antigen (VCA) IgM. The difference was significant (p < 0.001, Fisher’s exact test). A similar ratio was observed in a secondary group of 18 subjects 21–90 days after testing positive for COVID-19, indicating reactivation may occur soon after or concurrently with COVID-19 infection. These findings suggest that many long COVID symptoms may not be a direct result of the SARS-CoV-2 virus but may be the result of COVID-19 inflammation-induced EBV reactivation.

Developments in Treatment Methodologies Using Dendrimers for Infectious Diseases

Dendrimers comprise a specific group of macromolecules, which combine structural properties of both single molecules and long expanded polymers. The three-dimensional form of dendrimers and the extensive possibilities for use of additional substrates for their construction creates a multivalent potential and a wide possibility for medical, diagnostic and environmental purposes. Depending on their composition and structure, dendrimers have been of interest in many fields of science, ranging from chemistry, biotechnology to biochemical applications. These compounds have found wide application from the production of catalysts for their use as antibacterial, antifungal and antiviral agents. Of particular interest are peptide dendrimers as a medium for transport of therapeutic substances: synthetic vaccines against parasites, bacteria and viruses, contrast agents used in MRI, antibodies and genetic material. This review focuses on the description of the current classes of dendrimers, the methodology for their synthesis and briefly drawbacks of their properties and their use as potential therapies against infectious diseases.

Long non-coding RNAs in nasopharyngeal carcinoma: biological functions and clinical applications

Nasopharyngeal carcinoma (NPC) is one of the most common head and neck malignancies. It has obvious ethnic and regional specificity. Long non-coding RNAs (LncRNAs) are a class of non-protein coding RNA molecules. Emerging research shows that lncRNAs play a key role in tumor development, prognosis, and treatment. With the deepening of sequence analysis, a large number of functional LncRNAs have been found in NPC, which interact with coding genes, miRNAs, and proteins to form a complex regulatory network. However, the specific role and mechanism of abnormally expressed lncRNAs in the pathogenesis of NPC is not fully understood. This article briefly introduced the concept, classification, and functional mechanism of lncRNAs and reviewed their biological functions and their clinical applications in NPC. Specifically, we described lncRNAs related to the occurrence, growth, invasion, metastasis, angiogenesis, and cancer stem cells of NPC; discussed lncRNAs related to Epstein-Barr virus infection; and summarized the role of lncRNAs in NPC treatment resistance. We have also sorted out lncRNAs related to Chinese medicine treatment. We believe that with the deepening of lncRNAs research, tumor-specific lncRNAs may become a new target for the treatment and a biomarker for predicting prognosis.

Screening and identification of key genes in EBV-associated gastric carcinoma based on bioinformatics analysis

Epstein-Barr virus (EBV) infection is closely related to gastric carcinoma (GC). In this study, we identified a set of DEGs (different expression genes) between EBVaGC (EBV-associated gastric carcinoma) and EBVnGC (EBV-negative gastric carcinoma) through multiple bioinformatics analysis using the data from GEO (Gene Expression Omnibus) dataset GSE51575, and identified ten hub genes (CXCL10, C3, CXCL9, CXCL11, SST, ICAM1, CHRM2, NPY, GBP5 and GBP1). Therefore, we performed relevant survival analysis and immune infiltration analysis, then verified the mRNA expression in GC cell lines and TCGA database. CXCL11 was finally selected to be a potential biomarker for a better prognosis and tumor infiltrating. This may provide a new view about immune therapy for EBVaGC.

EBV and the Pathogenesis of NK/T Cell Lymphoma

Epstein-Barr virus (EBV) is a ubiquitous gamma herpes virus with tropism for B cells. EBV is linked to the pathogenesis of B cell, T cell and NK cell lymphoproliferations, with extranodal NK/T cell lymphoma, nasal type (ENKTCL) being the prototype of an EBV-driven lymphoma. ENKTCL is an aggressive neoplasm, particularly widespread in East Asia and the native population of Latin America, which suggests a strong genetic predisposition. The link between ENKTCL and different populations has been partially explored. EBV genome sequencing analysis recognized two types of strains and identified variants of the latent membrane protein 1 (LMP1), which revealed different oncogenic potential. In general, most ENKTCL patients carry EBV type A with LMP1 wild type, although the LMP1 variant with a 30 base pair deletion is also common, especially in the EBV type B, where it is necessary for oncogenic transformation. Contemporary high-throughput mutational analyses have discovered recurrent gene mutations leading to activation of the JAK-STAT pathway, and mutations in other genes such as BCOR, DDX3X and TP53. The genomic landscape in ENKTCL highlights mechanisms of lymphomagenesis, such as immune response evasion, secondary to alterations in signaling pathways or epigenetics that directly or indirectly interfere with oncogenes or tumor suppressor genes. This overview discusses the most important findings of EBV pathogenesis and genetics in ENKTCL.

Heterochronic triple primary malignancies with Epstein-Barr virus infection and tumor protein 53 gene mutation: A case report and review of literature

BACKGROUND

The diagnosis and etiology of multiple primary malignant neoplasms (MPMNs) are difficult to establish. Here, we report a case of heterochronic triple primary malignancies with gastric cancer, nasopharyngeal squamous cell cancer, and then rectal cancer.

CASE SUMMARY

The patient was first diagnosed with gastric cancer at the age of 33 in 2014 and underwent distal gastrectomy and gastrojejunostomy and six cycles of adjuvant chemotherapy. Three years later, he was diagnosed with nasopharyngeal cancer and treated with radical chemoradiotherapy in 2017. Recently, a mass in the middle of the rectum was resected and reported as ulcerative, moderately to poorly differentiated adenocarcinoma. Research on the etiology of MPMNs showed that Epstein-Barr virus (EBV) infection may be the cause of gastric cancer and nasopharyngeal squamous cell cancer since these two primary lesions were positive for transcripts of EBV-encoded ribonucleic acid using an in situ hybridization EBV-encoded ribonucleic acid probe in formalin-fixed, paraffin-embedded tissue. The cause of rectal cancer may be due to a somatic mutation of tumor protein 53 gene in exon 8 (c.844C>T, p.Arg282Trp) through high-throughput sequencing for the rectal cancer. Appropriate standard therapy for each primary cancer was administered, and the patient has no evidence of cancer disease to date.

CONCLUSION

To our knowledge, this is the first report on heterochronic triple primary malignancies whose cause may be associated with EBV infection and tumor protein 53 genetic mutations. The etiological research may not only elucidate the cause of MPMN but also has implications in clinical management.

A global phylogenetic analysis of Japanese tonsil-derived Epstein-Barr virus strains using viral whole-genome cloning and long-read sequencing

Epstein-Barr virus (EBV) establishes lifelong latent infection in the majority of healthy individuals, while it is a causative agent for various diseases, including some malignancies. Recent high-throughput sequencing results indicate that there are substantial levels of viral genome heterogeneity among different EBV strains. However, the extent of EBV strain variation among asymptomatically infected individuals remains elusive. Here, we present a streamlined experimental strategy to clone and sequence EBV genomes derived from human tonsillar tissues, which are the reservoirs of asymptomatic EBV infection. Complete EBV genome sequences, including those of repetitive regions, were determined for seven tonsil-derived EBV strains. Phylogenetic analyses based on the whole viral genome sequences of worldwide non-tumour-derived EBV strains revealed that Asian EBV strains could be divided into several distinct subgroups. EBV strains derived from nasopharyngeal carcinoma-endemic areas constitute different subgroups from a subgroup of EBV strains from non-endemic areas, including Japan. The results could be consistent with biased regional distribution of EBV-associated diseases depending on the different EBV strains colonizing different regions in Asian countries.

Epstein-Barr Virus and Systemic Autoimmune Diseases

Epstein-Barr Virus (EBV) is an extremely successful human herpes virus, which infects essentially all human beings at some time during their life span. EBV infection and the associated immune response results in production of antibodies (seroconversion), which occurs mainly during the first years of life, but may also happen during adolescence or later in life. Infection of adolescents can result in infectious mononucleosis, an acute serious condition characterized by massive lymphocytosis. Transmission of EBV mainly occurs through saliva but can rarely be spread through semen or blood, e.g. through organ transplantations and blood transfusions. EBV transmission through oral secretions results in infection of epithelial cells of the oropharynx. From the epithelial cells EBV can infect B cells, which are the major reservoir for the virus, but other cell types may also become infected. As a result, EBV can shuttle between different cell types, mainly B cells and epithelial cells. Moreover, since the virus can switch between a latent and a lytic life cycle, EBV has the ability to cause chronic relapsing/reactivating infections. Chronic or recurrent EBV infection of epithelial cells has been linked to systemic lupus erythematosus and Sjögren’s syndrome, whereas chronic/recurrent infection of B cells has been associated with rheumatoid arthritis, multiple sclerosis and other diseases. Accordingly, since EBV can shuttle between epithelial cells and B cells, the systemic autoimmune diseases often occur as overlapping syndromes with symptoms and characteristic autoantibodies (e.g. antinuclear antibodies and rheumatoid factors) reflecting epithelial and/or B cell infection.

An Introduction to Virus Infections and Human Cancer

Approximately, 1.4 million virus-induced cancers occur annually, representing roughly 10% of the worldwide cancer burden, with the majority (> 85%) occurring in the lower- and middle-income countries. The viruses associated with the greatest number of cancer cases are human papillomaviruses (HPVs), which cause cervical cancer and several other epithelial malignancies, and hepatitis viruses HBV and HCV, which are responsible for the majority of hepatocellular cancer. Other oncoviruses include Epstein-Barr virus (EBV), Kaposi's sarcoma herpesvirus (KSHV), human T-cell leukemia virus (HTLV-I), and Merkel cell polyoma virus (MCPyV). These oncoviruses include various classes of DNA and RNA viruses and induce cancer by a variety of mechanisms. However, cancers develop in a minority of infected individuals and almost always after chronic infection of many year's duration. Identification of the oncoviruses has provided critical insights in human carcinogenesis and led to several interventions that may reduce the risk of developing the tumors they induce. These interventions include preventive vaccines against HBV and HPV, screening for persistent HPV and HCV infections, antivirals for the treatment of chronic HBV and HCV infection, and screening the blood supply for the presence of HBV and HCV. Further efforts to identify additional oncogenic viruses in human cancers and new insights into etiology and pathogenesis of virally induced cancers would likely lead to new approaches for prophylactic and therapeutic interventions.

The roles of miRNAs and lncRNAs in Epstein-Barr virus associated epithelial cell tumors

Epstein-Barr virus (EBV) infection is highly prevalent in the population and is known to be associated with a variety of human tumors, such as nasopharyngeal carcinoma, gastric cancer, and lymphoma; however, the mechanisms of EBV carcinogenesis remain unclear. Recent studies have revealed that many non-coding RNAs participate in the regulation of proliferation, migration, invasion, and other processes in EBV-associated tumor, and the interaction between ncRNAs and the potential target genes has gradually become a research hotspot. Therefore, here, we discuss the expression and roles of ncRNAs in EBV-associated epithelial tumors.

Epstein-Barr Virus and Human Adenovirus Viremia in Renal Tumors Is Associated with Histological Features of Malignancy

Background: There is growing evidence that viral infections may impact the risk and clinical course of malignancies, including solid tumors. The aim of this study was to assess the possible association of selected chronic/latent viral infections with the clinical course of renal cell carcinoma (RCC). Methods: In this prospective study we enrolled 27 patients undergoing partial or radical nephrectomy due to the histologically confirmed RCC and followed them up for one year post-operation. Isolation of the nucleic acids was performed using the NucleoSpin Tissue Kit (Macherey-Nagel, Düren, Germany) from tumor tissue and using the EZ1 Virus Mini Kit v2.0 from plasma. The number of viral copies of human adenovirus (ADV), herpes simplex virus HSV-1 and HSV-2, Epstein-Barr virus (EBV), cytomegalovirus (CMV), BK virus (BKV) and John Cunningham virus (JCV) in the tissue and plasma was assessed with real-time PCR. Results: Viral infections were diagnosed in ten patients (37.0%), including three ADV cases (11.1%) and eight EBV cases (29.6%). Infected patients tended to be significantly older (71.3 vs. 57.6 years, p < 0.05), more commonly presented with chronic renal disease (OR 2.4, p < 0.05), diabetes (OR 4.2, p < 0.05) and overweight (OR 2.0, p < 0.05). Regarding oncological data, infected patients were found to have a higher rate of high-grade cancers (OR 5.0, p < 0.05) and a higher rate of papillary RCCs (OR 8.3, p < 0.05). Status of viral infections had no influence on the clinical cancer stage, surgical procedure or survival. Conclusions: EBV and ADV infections are common in renal cancer patients and increase the risk of high-grade RCC presence. While there is no significant impact on short term survival, further studies are needed to assess the relevance of these findings in a long run.

[Epstein-Barr virus (Herpesviridae: Gammaherpesvirinae: Lymphocryptovirus: Human gammaherpesvirus 4): replication strategies]

The Epstein-Barr virus (EBV), one of the most common in the human population, is capable of lifelong persistence in resting memory B-cells, in T-cells in case of type 2 EBV, and in some undifferentiated epithelial cells. In most people, EBV persistence is not accompanied by significant symptoms, but frequent virus activations are associated with the increased risks of severe diseases, such as chronic active Epstein-Barr virus infection, hemophagocytic lymphohistiocytosis, multiple sclerosis, systemic lupus erythematosus, gastric and nasopharyngeal carcinomas, and a variety of T- and B-cell lymphomas. Therefore, the molecular viral and host cell processes during asymptomatic or low-symptom EBV persistence are of great interest. This review describes the behavior of the viral DNA in an infected cell and the forms of its existence (linear, circular episome, chromosomally integrated forms), as well as methods of EBV genome copying. Two closely related cycles of viral reproduction are considered. Lytic activation is unfavorable for the survival of a particular viral genome in the cell, and may be a result of differentiation of a latently infected cell, or the arrival of stress signals due to adverse extracellular conditions. The EBV has a large number of adaptive mechanisms for limiting lytic reactivation and reducing hostility of host immune cells. Understanding the molecular aspects of EBV persistence will help in the future develop more effective targeted drugs for the treatment of both viral infection and associated diseases.

Epstein-Barr Virus Mediated Signaling in Nasopharyngeal Carcinoma Carcinogenesis

Simple Summary

Epstein-Barr virus (EBV) infection is known to contribute in nasopharyngeal carcinoma (NPC) carcinogenesis. The oncogenic roles of the EBV proteins and non-coding RNAs in NPC are becoming evident with the aid of current advances in genome-wide and in-depth molecular analyses. This current work provides a comprehensive overview, which covers recent understandings of the pathogenic role of EBV infection in NPC. Perspectives on molecular mechanisms, which are involved in the pathogenesis of NPC, focusing on the connection between EBV and NPC cells and the corresponding signaling pathways are highlighted. Cancer hallmarks associated with EBV in NPC development are also discussed herein.

Abstract

Nasopharyngeal carcinoma (NPC) is one of the most common tumors occurring in China and Southeast Asia. Etiology of NPC seems to be complex and involves many determinants, one of which is Epstein-Barr virus (EBV) infection. Although evidence demonstrates that EBV infection plays a key role in NPC carcinogenesis, the exact relationship between EBV and dysregulation of signaling pathways in NPC needs to be clarified. This review focuses on the interplay between EBV and NPC cells and the corresponding signaling pathways, which are modulated by EBV oncoproteins and non-coding RNAs. These altered signaling pathways could be critical for the initiation and progression of NPC.

Prolonged siRNA expression in mammalian cells using an Epstein-Barr virus-based plasmid expression system

RNA interference (RNAi) is a powerful tool in gene function analysis and disease treatment, especially diseases that are 'undruggable' by classical small molecules. However, the RNAi applications are limited due to some defects, such as short duration and toxic side effects. New strategies are still needed to improve RNAi applications. Previous studies have illustrated that Epstein-Barr virus nuclear antigen 1 (EBNA-1) and the origin of plasmid replication (oriP) are critical factors for EBV latent gene expression, which can keep the replication of the EBV genome as an extrachromosomal element for a relatively long time. Here we report a plasmid expression system on the base of oriP and EBNA-1, which could produce protein as well as short interfering RNAs(siRNAs) for a long time in mammalian cells. siRNA expression mediated by this system causes efficient and specific down-regulation of gene expression. Except for analyzing gene function, this study also provided a new optional and practical way for protein and/or RNAi-based therapies that require enduring effect.

DNA methylation biomarkers for nasopharyngeal carcinoma

Background

Aberrant methylation of DNA plays an important role in the pathogenesis of nasopharyngeal carcinoma (NPC). In the current study, we aimed to integrate three cohorts profile datasets to identify abnormally methylated-differentially expressed genes and pathways associated with NPC.

Methods

Data of gene expression microarrays (GSE53819, GSE412452) and gene methylation microarrays (GSE52068) obtained from the GEO database. Aberrantly methylated differentially expressed genes (DEGs) were obtained by GEO2R. The David database was utilized to perform enrichment and functional analysis regarding selected genes. To create a protein-protein interaction (PPI), STRING and Cytoscape software were utilized. The MCODE was used for module analysis of the PPI network.

Results

In total, 181 hypomethylation-high expression genes were identified, which were enriched in the biological mechanisms involved in the differentiation of endodermal cell, mitotic nuclear division, mitotic cell cycle process, chromosome segregation and cell cycle phase transition, etc. Pathway enrichment showed ECM-receptor interaction, PI3K-Akt signaling pathway, Focal adhesion, Protein digestion and absorption and Amoebiasis, etc. The top 3 hub genes of PPI network were FANCI, POSTN, and IFIH1. Additionally, 210 hypermethylation-low expression genes were identified, and our data revealed enrichment in biological processes including axoneme assembly, micro tubular formation, assembly of axonemal dynein complex, cilium movement and cilium organization, etc. Pathway analysis indicated enrichment in B cell receptor signaling pathway, Hematopoietic cell lineage, Leukocyte transendothelial migration, Complement and coagulation cascades and Fc gamma R-mediated phagocytosis, etc. The ZMYND10, PACRG and POU2AF1 were identified as the top three hub genes of PPI network. After validation in TCGA and GEPIA database, most hub genes remained significant. Patients with high expression of POSTN found to have shorter overall survival, while in patients with high expression of ZMYND10 and POU2AF1 longer overall survival was identified.

Conclusions

The data revealed novel aberrantly methylated-differentially expressed genes and pathways in NPC by bioinformatics analysis, potentially providing novel insights for the molecular mechanisms governing NPC progression. Hub genes including FANCI, POSTN, IFIH1, ZMYND10, PACRG and POU2AF1 might serve as novel biomarkers for precision diagnosis and providing medical treatment for patient with NPC.

Epstein-Barr Virus Infection in the Development of Neurological Disorders

Epstein-Barr Virus (EBV) is a ubiquitous human herpesvirus that contributes to the etiology of diverse human cancers and auto-immune diseases. EBV establishes a relatively benign, long-term latent infection in over 90 percent of the adult population. Yet, it also increases risk for certain cancers and auto-immune disorders depending on complex viral, host, and environmental factors that are only partly understood. EBV latent infection is found predominantly in memory B-cells, but the natural infection cycle and pathological aberrations enable EBV to infect numerous other cell types, including oral, nasopharyngeal, and gastric epithelia, B-, T-, and NK-lymphoid cells, myocytes, adipocytes, astrocytes, and neurons. EBV infected cells, free virus, and gene products can also be found in the CNS. In addition to the direct effects of EBV on infected cells and tissue, the effect of chronic EBV infection on the immune system is also thought to contribute to pathogenesis, especially auto-immune disease. Here, we review properties of EBV infection that may shed light on its potential pathogenic role in neurological disorders.

Herpesviruses in Head and Neck Cancers

Head and neck cancers arise in the mucosa lining the oral cavity, oropharynx, hypopharynx, larynx, sinonasal tract, and nasopharynx. The etiology of head and neck cancers is complex and involves many factors, including the presence of oncogenic viruses. These types of cancers are among the most common cancers in the world. Thorough knowledge of the pathogenesis of viral infections is needed to fully understand their impact on cancer development.

The rapidly changing landscape in mature T-cell lymphoma (MTCL) biology and management

Historical advances in the care of patients with non-Hodgkin lymphoma (NHL) have been restricted largely to patients with B-cell lymphoma. The peripheral T-cell lymphomas (PTCLs), which are rare and heterogeneous in nature, have yet to experience the same degree of improvement in outcome over the past 20 to 30 years. It is estimated that there are approximately 80,000 and 14,000 cases, respectively, of NHL and Hodgkin lymphoma per year in the United States. As a subgroup of NHL, the PTCLs account for 6% to 10% of all cases of NHL, making them exceedingly rare. In addition, the World Health Organization 2017 classification describes 29 distinct subtypes of PTCL. This intrinsic diversity, coupled with its rarity, has stymied progress in the disease. In addition, most subtypes carry an inferior prognosis compared with their B-cell counterparts, an outcome largely attributed to the fact that most treatment paradigms for patients with PTCL have been derived from B-cell neoplasms, a radically different disease. In fact, the first drug ever approved for patients with PTCL was approved only a decade ago. The plethora of recent drug approvals in PTCL, coupled with a deeper understanding of the molecular pathogenesis of the disease, has stimulated the field to pursue new avenues of research that are now largely predicated on the development of novel, targeted small molecules, which include a host of epigenetic modifiers and biologics. There is an expectation these advances may begin to favorably challenge the chemotherapy paradigms that have been used in the T-cell malignancies.

Thirty years of Epstein-Barr virus-associated gastric carcinoma

Thirty years have passed since a possible association of Epstein-Barr virus (EBV) with gastric carcinoma was reported. We now know EBV-associated gastric carcinoma to be a specific subtype of gastric carcinoma. Global epigenetic methylation and counteraction of the antitumour microenvironment are two major characteristics of this subtype of gastric carcinoma. Recent development of therapeutic modalities for gastric carcinoma, such as endoscopic mucosal dissection and immune checkpoint inhibitor therapy, has made the presence of EBV infection a biomarker for the treatment of gastric carcinoma. This review presents a portrait of EBV-associated gastric carcinoma from initiation to maturity that we define as the 'gastritis-infection-cancer sequence', followed by its molecular abnormalities and interactions with immune checkpoint molecules and the microenvironment. EBV non-coding RNAs (microRNA and circular RNA) and exosomes derived from EBV-infected cells that were previously behind the scenes are now recognized for their roles in EBV-associated gastric carcinoma. The virus utilizes cellular machinery skilfully to control infected cells and their microenvironment. We should thus strive to understand virus-host interactions more fully in the following years to overcome this virus-driven subtype of gastric carcinoma.

Educational Case: Extranodal NK/T-Cell Lymphoma, Nasal Type

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, seehttp://journals.sagepub.com/doi/10.1177/2374289517715040.¹

The Global Landscape of EBV-Associated Tumors

Epstein-Barr virus (EBV), a gamma-1 herpesvirus, is carried as a life-long asymptomatic infection by the great majority of individuals in all human populations. Yet this seemingly innocent virus is aetiologically linked to two pre-malignant lymphoproliferative diseases (LPDs) and up to nine distinct human tumors; collectively these have a huge global impact, being responsible for some 200,000 new cases of cancer arising worldwide each year. EBV replicates in oral epithelium but persists as a latent infection within the B cell system and several of its diseases are indeed of B cell origin; these include B-LPD of the immunocompromised, Hodgkin Lymphoma (HL), Burkitt Lymphoma (BL), Diffuse Large B cell Lymphoma (DLBCL) and two rarer tumors associated with profound immune impairment, plasmablastic lymphoma (PBL) and primary effusion lymphoma (PEL). Surprisingly, the virus is also linked to tumors arising in other cellular niches which, rather than being essential reservoirs of virus persistence in vivo, appear to represent rare cul-de-sacs of latent infection. These non-B cell tumors include LPDs and malignant lymphomas of T or NK cells, nasopharyngeal carcinoma (NPC) and gastric carcinoma of epithelial origin, and leiomyosarcoma, a rare smooth muscle cell tumor of the immunocompromised. Here we describe the main characteristics of these tumors, their distinct epidemiologies, histological features and degrees of EBV association, then consider how their different patterns of EBV latency may reflect the alternative latency programmes through which the virus first colonizes and then persists in immunocompetent host. For each tumor, we discuss current understanding of EBV's role in the oncogenic process, the identity (where known) of host genetic and environmental factors predisposing tumor development, and the recent evidence from cancer genomics identifying somatic changes that either complement or in some cases replace the contribution of the virus. Thereafter we look for possible connections between the pathogenesis of these apparently different malignancies and point to new research areas where insights may be gained.

Epstein-Barr virus strain variation and cancer

Epstein-Barr virus (EBV) is a human tumor virus and is etiologically linked to various malignancies. Certain EBV-associated diseases, such as Burkitt lymphomas and nasopharyngeal carcinomas, are endemic and exhibit biased geographic distribution worldwide. Recent advances in deep sequencing technology enabled high-throughput sequencing of the EBV genome from clinical samples. Rapid cloning and sequencing of cancer-derived EBV genomes, followed by reconstitution of infectious virus, have also become possible. These developments have revealed that various EBV strains are differentially distributed throughout the world, and that the behavior of cancer-derived EBV strains is different from that of the prototype EBV strain of non-cancerous origin. In this review, we summarize recent progress and future perspectives regarding the association between EBV strain variation and cancer.