Epstein-Barr Virus-associated Tumors Research Articles

Epstein-Barr virus-associated post-transplant smooth muscle tumours in a kidney transplant patient.

We report on a 14-year-old girl who developed post-transplantation smooth muscle tumours (PTSMT) located in the spleen, lungs, liver, and central nervous system (CNS), 4 years after kidney transplantation. She was asymptomatic, and the disease was detected during the work-up for a urinary tract infection. Diagnosis was performed by the analysis of a tissue specimen, through the biopsy of a lung tumour, which revealed a proliferation of spindle-shaped cells which were positive for actin and vimentin. In situ hybridization studies were positive for Epstein-Barr virus, and her serologic status was negative prior to transplantation. We reduced immunosuppression by stopping mycophenolate and switching tacrolimus for sirolimus. After 18 months of follow-up, she remains asymptomatic, and the CNS tumour reduced its diameter from 24 × 21 mm to 14 × 13 mm. PTSMT should be considered in the differential diagnosis of transplanted patients who develop neoplastic complications associated with immunosuppression.

Outcomes of children treated for multiple Epstein-Barr virus-associated post-transplant tumors.

After solid organ transplantation, children are at risk for Epstein-Barr virus-associated post-transplant lymphoproliferative disorder and smooth muscle tumors. Little is known about the clinical course, Epstein-Barr viral load variations, and optimal treatment for such patients. We set forth to understand the course of repeated episodes of post-transplant lymphoproliferative disorder and smooth muscle tumors. We performed a retrospective chart review of patients up to 21 years old with solid organ transplantation and post-transplant lymphoproliferative disorder at the Children's Hospital of Philadelphia from January 2003 through June 30, 2020. Six patients had multiple episodes of Epstein-Barr virus-associated post-transplant lymphoproliferative disorder and smooth muscle tumors. When the second episode was discovered, only one patient was symptomatic. Histology differed from diagnosis in four patients. Treatment included viral-specific T-lymphocytes (2), rituximab (3), reduction in immunosuppression alone (1). Five patients had complete response, and one had stable disease, but three patients developed a subsequent tumor. Two patients developed Epstein-Barr virus-associated smooth muscle tumors. Of these six patients, four are alive. The deaths were not related to their tumors. Despite a complete response to initial therapy, children are at risk for repeated episodes of Epstein-Barr virus-associated post-transplant lymphoproliferative disorder and smooth muscle tumors. Histology and location were not typically consistent with initial diagnosis, suggesting these are second primaries rather than recurrences. Disease may be managed with individualized treatment plans but EBV-specific T cells need further study in such tumors.

Integration of Human and Viral miRNAs in Epstein-Barr Virus-Associated Tumors and Implications for Drug Repurposing.

Epstein-Barr virus (EBV) is associated with several tumors, and has substantial relevance for public health. Therapeutics innovation for EBV-related disorders is much needed. In this context, miRNAs are noncoding RNA molecules that play vital roles in EBV infection. miRNA-Seq and RNA-Seq data for EBV-associated clinical samples and cell lines have been generated, but their detailed integrative analyses, and exploitation for drug repurposing against EBV are lacking. Hence, we identified and analyzed the differentially expressed miRNAs (DEmiRs) in EBV-infected cell lines (28) and infected (28) and uninfected human tissue (20) samples using an in-house pipeline. We found significantly enriched host miRNAs like hsa-mir-3651, hsa-mir-1248, and hsa-mir-29c-3p in EBV-infected samples from EBV-associated nasopharyngeal carcinoma and Hodgkin's lymphoma, among others. Furthermore, we also identified significantly enriched novel miRNAs such as hsa-mir-29c-3p, hsa-mir-3651, and hsa-mir-98-3p, which were not previously reported in EBV-related tumors. Differentially expressed mRNAs (DEMs) were identified in EBV-infected cell lines (21) and uninfected human tissue (14) samples. We predicted and selected 1572 DEMs (upregulated) that are targeted by 547 DEmiRs (downregulated). These were further classified into essential (870) and nonessential (702) genes. Moreover, a miRNA-mRNA network was developed for the hub miRNAs. Importantly, we used the DEMs during EBV latent infection types I, II, and III to identify the candidate drugs for repurposing: Glyburide, Levodopa, Nateglinide, and Stiripentol, among others. To the best of our knowledge, this is the first integrative analyses that identified DEmiRs and DEMs as potential therapeutic targets and predicted drugs as potential candidates for repurposing against EBV-related tumors.

Epstein-Barr virus-associated inflammatory pseudotumor variant of follicular dendritic cell sarcoma of the liver: a case report and review of the literature.

Follicular dendritic cell sarcoma is a rare stromal tumor with no standard treatment. However, some reports have revealed that follicular dendritic cell sarcoma has an inflammatory pseudotumor variant associated with Epstein-Barr virus infection that has a relatively good prognosis. In this report, we present a case of a resected inflammatory pseudotumor variant of follicular dendritic cell sarcoma of the liver, and have reviewed the literature on the clinicopathological, molecular, and genomic features of this tumor. The inflammatory pseudotumor variant of follicular dendritic cell sarcoma originates only in the liver or spleen, causes no symptoms, and is more common in middle-aged Asian women. It has no characteristic imaging features, which partially explains why the inflammatory pseudotumor variant of follicular dendritic cell sarcoma is difficult to diagnose. Pathologically, the inflammatory pseudotumor variant of follicular dendritic cell sarcoma has spindle cells mixed with inflammatory cells and is variably positive for follicular dendritic cell markers (CD21, CD23, and CD35) and Epstein-Barr virus-encoded RNA. On genetic analysis, patients with this tumor high levels of latent membrane protein1 gene expression and extremely low levels of host C-X-C Chemokine Receptor type 7 gene expression, indicating that the inflammatory pseudotumor variant of follicular dendritic cell sarcoma has a latent Epstein-Barr virus type 2 infection. The inflammatory pseudotumor variant of follicular dendritic cell sarcoma is an Epstein-Barr virus-associated tumor and a favorable prognosis by surgical resection, similar to Epstein-Barr virus-associated gastric cancer.

Designing a vaccine-based therapy against Epstein-Barr virus-associated tumors using immunoinformatics approach

Epstein-Barr virus (EBV) is widely known due to its role in the etiology of infectious mononucleosis. However, it is the first oncovirus that was identified and has been implicated in the etiology of several types of cancers. Globally, EBV infection is associated with more than 200, 000 new cancer cases and 150, 000 deaths yearly. A prophylactic or therapeutic vaccine targeting tumors associated with EBV infection is currently lacking. Therefore, this study aimed to develop a multiepitope-based polyvalent vaccine against EBV-associated tumors using immunoinformatics approach. The latency-associated proteins (LAP) of three strains of the virus were used in this study. Potential epitopes predicted from the proteins were analyzed and selected based on several predicted properties. Thirty viable B-cell and T-cell epitopes were selected and conjugated using various linkers alongside beta-defensin 3 as an adjuvant and pan HLA DR-binding epitope (PADRE) sequence to improve the immunogenicity of the vaccine construct. Molecular docking studies of the vaccine construct against toll-like receptors (TLRs) showed it is capable of inducing immune response via recognition by TLRs while immune simulation studies showed it could induce both cellular and humoral immune responses. Furthermore, molecular dynamics study of the complex formed by the vaccine candidate and TLR-4 showed that the complex was stable. Ultimately, the designed vaccine showed desirable properties based on in silico evaluation; however, experimental studies are needed to validate the efficacy of the vaccine against EBV-associated tumors.

Letter to the Editor: Epstein-Barr Virus-Associated Liver Smooth Muscle Tumor Treated by Radiofrequency Ablation.

Surgical InfectionsVol. 23, No. 9 Letters to the EditorLetter to the Editor: Epstein-Barr Virus-Associated Liver Smooth Muscle Tumor Treated by Radiofrequency AblationAw Liang Cheng, Brian Lee Juin Hsien, and Vishal G. ShelatAw Liang ChengMinistry of Health Holdings, Singapore.Search for more papers by this author, Brian Lee Juin HsienLee Kong Chian School of Medicine, Nanyang Technological University, Singapore.Search for more papers by this author, and Vishal G. ShelatAddress correspondence to: Dr. Vishal G. Shelat, Department of General Surgery, Tan Tock Seng Hospital, Annex 1, Level 4, 308433, Singapore E-mail Address: vgshelat@gmail.comLee Kong Chian School of Medicine, Nanyang Technological University, Singapore.Department of General Surgery, Tan Tock Seng Hospital, Singapore.Search for more papers by this authorPublished Online:8 Nov 2022https://doi.org/10.1089/sur.2022.221AboutSectionsView articleView Full TextPDF/EPUB Permissions & CitationsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail View article"Letter to the Editor: Epstein-Barr Virus-Associated Liver Smooth Muscle Tumor Treated by Radiofrequency Ablation." Surgical Infections, 23(9), pp. 858–859FiguresReferencesRelatedDetails Volume 23Issue 9Nov 2022 InformationCopyright 2022, Mary Ann Liebert, Inc., publishersTo cite this article:Aw Liang Cheng, Brian Lee Juin Hsien, and Vishal G. Shelat.Letter to the Editor: Epstein-Barr Virus-Associated Liver Smooth Muscle Tumor Treated by Radiofrequency Ablation.Surgical Infections.Nov 2022.858-859.http://doi.org/10.1089/sur.2022.221Published in Volume: 23 Issue 9: November 8, 2022Online Ahead of Print:August 4, 2022PDF download

Defining Novel DNA Virus-Tumor Associations and Genomic Correlates Using Prospective Clinical Tumor/Normal Matched Sequencing Data

This study is the largest analysis of DNA viruses in solid tumors with associated genomics. To achieve this, a novel method for discovery of DNA viruses from matched tumor/normal next-generation sequencing samples was developed and validated. This method performed comparably to reference methods for the detection of high-risk (HR) human papilloma virus (HPV) (area under the receiver operating characteristic curve=0.953). After virus identification in 48,148 consecutives samples from 42,846 unique patients, novel virus tumor associations were established by segregating tumor types to determine whether each DNA virus was enriched in each of the tumor types compared with the remaining cohort. All firmly established solid tumor-virus associations (eg, HR HPV in cervical cancer) were confirmed, and the novel associations discovered included: human herpes virus 6 in neuroblastoma, human herpes virus 7 in esophagogastric cancer, and HPV42 in digital papillary adenocarcinoma. Theseassociations were confirmed in an independent validation cohort. HR HPV- and Epstein-Barr virus-associated tumors showed newly discovered genomic associations, including a lower tumor mutation burden. The study demonstrated the ability to study the role of DNA viruses in human cancer from clinical genomics data and established the largest cohort that can be utilized as a validation set for future discovery efforts.

Advances on the mechanism of exosome-mediated microRNA delivery in Epstein-Barr virus associated tumors

Advances on the mechanism of exosome-mediated microRNA delivery in Epstein-Barr virus associated tumors

The Role of Lytic Infection for Lymphomagenesis of Human γ-Herpesviruses.

Epstein Barr virus (EBV) and Kaposi sarcoma associated herpesvirus (KSHV) are two oncogenic human γ-herpesviruses that are each associated with 1-2% of human tumors. They encode bona fide oncogenes that they express during latent infection to amplify their host cells and themselves within these. In contrast, lytic virus particle producing infection has been considered to destroy host cells and might be even induced to therapeutically eliminate EBV and KSHV associated tumors. However, it has become apparent in recent years that early lytic replication supports tumorigenesis by these two human oncogenic viruses. This review will discuss the evidence for this paradigm change and how lytic gene products might condition the microenvironment to facilitate EBV and KSHV associated tumorigenesis.

Exosomes derived from Vδ2-T cells control Epstein-Barr virus-associated tumors and induce T cell antitumor immunity.

Treatment of life-threatening Epstein-Barr virus (EBV)-associated tumors remains a great challenge, especially for patients with relapsed or refractory disease. Here, we found that exosomes derived from phosphoantigen-expanded Vδ2-T cells (Vδ2-T-Exos) contained death-inducing ligands (FasL and TRAIL), an activating receptor for natural killer (NK) cells (NKG2D), immunostimulatory ligands (CD80 and CD86), and antigen-presenting molecules (MHC class I and II). Vδ2-T-Exos targeted and efficiently killed EBV-associated tumor cells through FasL and TRAIL pathways and promoted EBV antigen-specific CD4 and CD8 T cell expansion. Administration of Vδ2-T-Exos effectively controlled EBV-associated tumors in Rag2-/-γc-/- and humanized mice. Because expanding Vδ2-T cells and preparing autologous Vδ2-T-Exos from cancer patients ex vivo in large scale is challenging, we explored the antitumor activity of allogeneic Vδ2-T-Exos in humanized mouse cancer models. Here, we found that allogeneic Vδ2-T-Exos had more effective antitumor activity than autologous Vδ2-T-Exos in humanized mice; the allogeneic Vδ2-T-Exos increased the infiltration of T cells into tumor tissues and induced more robust CD4 and CD8 T cell-mediated antitumor immunity. Compared with exosomes derived from NK cells (NK-Exos) with direct cytotoxic antitumor activity or dendritic cells (DC-Exos) that induced T cell antitumor responses, Vδ2-T-Exos directly killed tumor cells and induced T cell-mediated antitumor response, thus resulting in more effective control of EBV-associated tumors. This study provided proof of concept for the strategy of using Vδ2-T-Exos, especially allogeneic Vδ2-T-Exos, to treat EBV-associated tumors.

IL-10 knockdown with siRNA enhances the efficacy of Doxorubicin chemotherapy in EBV-positive tumors by inducing lytic cycle via PI3K/p38 MAPK/NF-kB pathway.

High levels of IL-10 expression in Epstein-Barr virus (EBV) associated tumors have been reported and it is likely to be important for maintaining EBV latency and EBV-associated tumors. The switch from the latent form of EBV to the lytic form in tumor cells can lead to tumor cell lysis. Here, we found that knockdown of IL-10 induced EBV lytic replication. Subsequently, we demonstrated that IL-10 knockdown activated BZLF1 promoter through PI3K-p38 MAPK-NF-κB signaling pathway. Interestingly, we verified that VEGF-A was required for IL-10 knockdown to activate PI3K signaling and the accompanying EBV lytic induction. Exogenous recombinant human VEGF-A induced PI3K activation and EBV lytic infection, and inhibition of VEGF-A signaling prevented the PI3K/AKT phosphorylation and EBV reactivation responded to IL-10 knockdown. Most importantly, IL-10 knockdown synergized with chemotherapeutic agent Doxorubicin to kill EBV associated tumor cells in vitro and repress EBV-positive tumor growth in vivo. Our results suggest that inhibition of IL-10 has the potential to serve as a new supplemental strategy for the treatment of EBV-associated tumors.

Abstract 4752: EBV associated tumors have increased regulatory T cell recruitment and are therefore a potential indication for treatment with potent and selective small molecule CCR4 antagonists

Abstract We have performed experiments to test whether Epstein Barr Virus (EBV)-infected tumors are enhanced for regulatory T cell (Treg) infiltration and whether selective and potent CCR4 antagonists would be a particularly effective therapeutic in this class of indications. Treg cells, which contribute to an immune-suppressive tumor microenvironment (TME), are attracted to tumors via the recognition of CCL17 and CCL22 ligands by the CCR4 receptor. These chemokines have been shown to be expressed in cells infected by the Epstein Barr Virus (EBV) via the viral LMP1 gene. Tumor types which are frequently associated with EBV-infection include gastric adenocarcinoma (~10% positive), classical Hodgkin's Lymphoma (~50%), and nasopharyngeal carcinoma (~100%). Analyzing RNA expression in EBV-associated tumors, we found strong expression of CCL17, CCL22, and FOXP3, a marker of Treg, when compared to EBV-negative tumors. In fact, NPC tumors show extremely high FOXP3 levels. To further test this link, we obtained EBV-associated tumor samples and performed RNA in situ hybridization (ISH) to measure co-expression of these genes. Strong co-localization, was indeed found, further supporting a link between EBV and Treg recruitment. To directly test whether EBV-positive tumors recruit Treg into tumors via CCL22/17 upregulation, we developed models in which mice were inoculated subcutaneously with EBV-positive cancer cell lines. These EBV-positive cancer cells were assessed for chemokine production in vitro and in vivo by ELISA. We assessed tumor-infiltrating lymphocytes (TILs) in established tumors, including Treg, CD4+ and CD8+ T cells as well as T cell activation markers. Treating these tumor-bearing mice with selective and potent CCR4 small-molecule antagonists alone or in combination with checkpoint-targeting antibodies allowed us to demonstrate meaningful antitumor responses in EBV-positive tumors. Together, these data suggest that EBV-positive tumors, such as gastric adenocarcinomas, Hodgkin's lymphomas, and nasopharyngeal carcinomas, are a class of indications of particular interest and potentially increased responsiveness to small-molecule CCR4 antagonists. These results are helping to inform the ongoing FLX475 trials currently in the clinic. Citation Format: Oezcan Talay, Aparna Jorapur, Scott Jacobson, Sachie Marubayashi, Lisa Marshall, Silpa Suthram, Omar Robles, John Ketcham, Maureen K. Reilly, Ashkaan Younai, Berenger Biannic, Dennis Hu, Minna Bui, Jacob Schwarz, Paul Kassner, Gene Cutler. EBV associated tumors have increased regulatory T cell recruitment and are therefore a potential indication for treatment with potent and selective small molecule CCR4 antagonists [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4752.

Single nucleotide polymorphism rs2274084 of gap junction protein beta 2 gene among Epstein-Barr virus-associated tumors.

Gap junction protein beta 2 gene (GJB2) encodes one of connexins- Connexin 26 (Cx26), which mainly expressed in epithelial cells. Cx26 is usually considered a channel to exchange information between cells, which plays a critical role in tumor cell proliferation. We investigated GJB2 rs2274084 polymorphism in three types of tumors, including nasophoryngeal carcinoma (NPC), gastric cancer (GC) and lymphoma. Proteinase K digestion and phenolchloroform purification and QIAamp DNA FFPE tissue kit was used for DNA extraction. The genotype of GJB2 gene rs2274084 was detected through Sequenom MassARRAY SNP technique. The Chi-square test and Fisher's exact test were used to compare the differences between two groups. The genotype frequency of GJB2 gene rs2274084 was significantly different between EBV-positive NPC and normal control (P< 0.05). However, for EBV-associated gastric cancer (EBVaGC), EBV-negative gastric cancer (EBVnGC) and lymphoma, no significant differences were found in comparison with the normal control. The mutation rate of TT genotype was a risk factor to the occurrence of EBV-positive NPC.

Small molecule perturbation of the CAND1-Cullin1-ubiquitin cycle stabilizes p53 and triggers Epstein-Barr virus reactivation.

The chemical probe C60 efficiently triggers Epstein-Barr Virus (EBV) reactivation from latency through an unknown mechanism. Here, we identify the Cullin exchange factor CAND1 as a biochemical target of C60. We also identified CAND1 in an shRNA library screen for EBV lytic reactivation. Gene expression profiling revealed that C60 activates the p53 pathway and protein analysis revealed a strong stabilization and S15 phosphorylation of p53. C60 reduced Cullin1 association with CAND1 and led to a global accumulation of ubiquitylated substrates. C60 also stabilized the EBV immediate early protein ZTA through a Cullin-CAND1-interaction motif in the ZTA transcription activation domain. We propose that C60 perturbs the normal interaction and function of CAND1 with Cullins to promote the stabilization of substrates like ZTA and p53, leading to EBV reactivation from latency. Understanding the mechanism of action of C60 may provide new approaches for treatment of EBV associated tumors, as well as new tools to stabilize p53.

Filaggrin gene polymorphism associated with Epstein-Barr virus-associated tumors in China.

Mutations of filaggrin gene (FLG) have been identified as the cause of ichthyosis vulgaris, while recently FLG mutations were found to be associated with gastric cancer. This study aimed to investigate the association of filaggrin polymorphism with Epstein-Barr virus-associated tumors in China. A total of 200 patients with three types of tumors and 117 normal control samples were genotyped at three common FLG mutation loci (rs3126085, K4671X, R501X) by using Sequenom MassARRAY technique. The χ 2 test was used to evaluate the relationship between the mutation and the three kinds of tumors. A two-sided P value of <0.05 was considered statistically significant. The results showed that two single-nucleotide polymorphism (SNP) loci (rs3126085, K4671X) were significantly associated with nasopharyngeal carcinoma in genetic model. In addition, the two SNPs K4671X and rs3126085 were related to Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC) and EBV-negative gastric carcinoma (EBVnGC), respectively. Furthermore, allele distributions in EBVaGC and EBVnGC were verified to be different in both SNP loci.

Relationship between PPP1R15A gene polymorphism (rs611251) and Epstein-Barr virus-associated tumors.

Protein phosphatase 1, regulatory subunit 15A (PPP1R15A), also known as growth arrest and DNA damage-inducible protein GADD34, plays a vital role in promoting cell death and the unfolded protein response (UPR). In order to explore whether the SNP (rs611251) of PPP1R15A gene has a role in different types of Epstein-Barr virus (EBV) - associated tumors, we detected the PPP1R15A gene rs611251 polymorphism in 195 cases of EBV positive tumors (93 lymphomas, 48 gastric carcinomas, 54 nasopharyngeal carcinomas), 208 cases of EBV-negative tumors (136 gastric carcinoma, 19 nasopharyngeal carcinomas, 53 lymphomas) and 113 peripheral blood samples from healthy individuals. Compared with normal controls, the wild type TT and allele T of rs611251 showed higher frequency in gastric carcinoma (GCs), nasopharyngeal carcinomas (NPCs) and lymphomas. However, there was no significant difference between EBV-associated gastric (EBVaGC) and EBVnGC, EBV-positive NPCs and EBV-negative NPCs, EBV-related lymphomas and EBV-negative lymphomas in rs611251 of PPP1R15A. In conclusion, the PPP1R15A rs611251 polymorphism was significantly related to three kinds of tumors. Nevertheless, EBV has no obvious effect on PPP1R15A rs611251 polymorphism of NPC, GC and lymphoma. What's more, the genotype TT and allele T could be risk factors for NPC, GC and lymphoma. Our study explores the relationship between PPP1R15A gene polymorphism (rs611251) and Epstein-Barr virus-associated tumors for the first time. PPP1R15A gene SNP (rs611251) have association with multiple tumor types, which may provide some new clues to the detection and treatment of tumors.

Emerging molecular classifications and therapeutic implications for gastric cancer

Gastric cancer (GC) is a highly aggressive and life-threatening malignancy. Even with radical surgical removal and front-line chemotherapy, more than half of GCs locally relapse and metastasize at a distant site. The dismal outcomes reflect the ineffectiveness of a one-size-fits-all approach for a highly heterogeneous disease with diverse etiological causes and complex molecular underpinnings. The recent comprehensive genomic and molecular profiling has led to our deepened understanding of GC. The emerging molecular classification schemes based on the genetic, epigenetic, and molecular signatures are providing great promise for the development of more effective therapeutic strategies in a more personalized and precise manner. To this end, the Cancer Genome Atlas (TCGA) research network conducted a comprehensive molecular evaluation of primary GCs and proposed a new molecular classification dividing GCs into four subtypes: Epstein-Barr virus-associated tumors, microsatellite unstable tumors, genomically stable tumors, and tumors with chromosomal instability. This review primarily focuses on the TCGA molecular classification of GCs and discusses the implications on novel targeted therapy strategies. We believe that these fundamental findings will support the future application of targeted therapies and will guide our efforts to develop more efficacious drugs to treat human GCs.

Sequence analysis of EBV immune evasion gene BNLF2a in EBV associated tumors and healthy individuals from nasopharyngeal carcinoma endemic and non-endemic regions of China.

BNLF2a is an Epstein-Barr virus (EBV) immune evasion gene. Its protein is located in the endoplasmic reticulum (ER) membrane, and can inhibit the antigen transporting function of TAP, thereby perturbing the immune response to EBV in lytic and prelatent phase. In order to explore whether the polymorphism of BNLF2a gene has a role in different types of EBV associated tumors, we conducted complete sequencing of the gene BNLF2a in 408 cases of EBV positive tumors (76 lymphomas, 45 gastric carcinomas, and 85 nasopharyngeal carcinomas in northern China and 27 lymphomas, 30 gastric carcinomas, and 57 nasopharyngeal carcinomas in southern China) and throat washings from healthy individuals (39 in northern China and 49 in southern China). Two main variant types of BNLF2a were identified. Type BNLF2a-A, which was similar to B95-8, was dominant in all sub-populations (66.7-100%) in this study. Type BNLF2a-B was characterized by the mutations at position 8 and 40. The variation patterns of BNLF2a were significantly different between samples from northern and southern China (P < 0.05), and between the tumors and healthy donor samples from the northern China (P < 0.0167). Type BNLF2a-B was more frequent in healthy donors of northern China (33.3%), and the proportion of this type was higher in the northern than in the southern NPCs. These data demonstrate that the BNLF2a gene is highly conserved, and its polymorphism is geographically restricted. Type BNLF2a-B is more prevalent in northern China and may be less tumor transformative.

Updates on Epstein-Barr virus-encoded microRNAs in Epstein-Barr virus-associated tumors

EB病毒(Epstein-Barr virus,EBV)又称人类疱疹病毒4,是一种线性双链DNA病毒,在人群中广泛感染,与淋巴瘤、鼻咽癌、胃癌等多种恶性肿瘤的发生发展密切相关.微小RNA(microRNA,miRNA)是一类存在于多种真核生物和DNA病毒中的非编码RNA,长度为19 ～ 25 nt,以碱基互补的方式和靶标mRNA的3'端非翻译区(3'UTR)结合,导致靶标mRNA的翻译抑制或降解[1-2].EBV是首个被发现可以编码miRNA的病毒.2013年6月 miRbase数据库(www.mirbase.org)公布的数据显示,至今已经发现EBV编码的25个前体miRNA和44个成熟miRNA。

Tumour angiogenesis in Epstein-Barr virus-associated post-transplant smooth muscle tumours

Epstein-Barr virus (EBV)-associated post-transplant smooth muscle tumours (PTSMT), are rare complications following organ/stem cell transplantation. Despite the mainly benign behaviour of PTSMT, alternative therapies are needed for those patients with progressive tumours. In tumours not approachable by surgery or reduction of immunosuppression, the angiogenic microenvironment might be a potential target of therapy, an approach that is well utilised in other soft tissue neoplasms. In a previous study, we evaluated the expression of EBV-related genes and the microRNA profile in PTSMT, but so far the characteristics of angiogenesis in PTSMT are not known. Therefore, the aim of this study was to evaluate the expression pattern of angiogenesis-related genes in PTSMT, in order to identify potential target molecules for anti-angiogenic therapy.PTSMT (n = 5 tumours) were compared with uterine leiomyomas (n = 7). Analyses included real-time PCR of 45 angiogenesis-associated genes, immunohistochemistry (CD31, prostaglandin endoperoxide synthase 1/PTGS1) and assessment of tumour vascularisation by conventional histopathology.PTSMT showed similar or fewer vessels than leiomyomas. Of the genes under investigation, 23 were down-deregulated (pro-angiogenic and some anti-angiogenic factors) and five were up-regulated (e.g. PTGS1 which is expressed at very low levels in leiomyomas but moderately higher levels in PTSMT).In summary, no particular target molecule could be identified, because tumour angiogenesis in PTSMT is characterised by low levels of major pro-angiogenic factors and there is no prominent increase in tumour vascularisation. EBV can induce angiogenesis via its viral late membrane protein 1 (LMP1) but PTSMT frequently do not express LMP1, which could be an explanation why, despite EBV infection, PTSMT show no exaggerated tumour angiogenesis.