Displaying publications 1 - 20 of 39 in total

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  1. Yeo KS, Mohidin TB, Ng CC
    C. R. Biol., 2012 Dec;335(12):713-21.
    PMID: 23312294 DOI: 10.1016/j.crvi.2012.11.002
    Epstein-Barr virus (EBV) is a ubiquitous tumor-causing virus which infects more than 90% of the world population asymptomatically. Recent studies suggest that LMP-1, -2A and -2B cooperate in the tumorigenesis of EBV-associated epithelial cancers such as nasopharygeal carcinoma, oral and gastric cancer. In this study, LMPs were expressed in the HEK293T cell line to reveal their oncogenic mechanism via investigation on their involvement in the regulation of the cell cycle and genes that are involved. LMPs were expressed in HEK293T in single and co-expression manner. The transcription of cell cycle arrest genes were examined via real-time PCR. Cell cycle progression was examined via flow cytometry. 14-3-3σ and Reprimo were upregulated in all LMP-1 expressing cells. Moreover, cell cycle arrest at G(2)/M progression was detected in all LMP-1 expressing cells. Therefore, we conclude that LMP-1 may induce cell cycle arrest at G(2)/M progression via upregulation of 14-3-3σ and Reprimo.
    Matched MeSH terms: Herpesvirus 4, Human/genetics
  2. Yee PH, Sim SP
    J Biomed Sci, 2010;17:77.
    PMID: 20858288 DOI: 10.1186/1423-0127-17-77
    Nasopharyngeal carcinoma (NPC) is commonly found in Southern China and South East Asia. Epstein-Barr virus (EBV) infection is well associated with NPC and has been implicated in its pathogenesis. Moreover, various chromosome rearrangements were reported in NPC. However, the underlying mechanism of chromosome rearrangement remains unclear. Furthermore, the relationship between EBV and chromosome rearrangement with respect to the pathogenesis of NPC has not been established. We hypothesize that during virus- or stress-induced apoptosis, chromosomes are initially cleaved at the base of the chromatin loop domain structure. Upon DNA repair, cell may survive with rearranged chromosomes.
    Matched MeSH terms: Herpesvirus 4, Human/genetics
  3. Yap YY, Hassan S, Chan M, Choo PK, Ravichandran M
    Otolaryngol Head Neck Surg, 2007 Jun;136(6):986-91.
    PMID: 17547993
    OBJECTIVES: This study examines the presence of Epstein-Barr virus (EBV) in nasopharyngeal carcinoma (NPC) by using polymerase chain reaction (PCR).

    STUDY DESIGN: Eighty-six postnasal biopsy samples and 71 fine-needle aspirate samples of neck masses were obtained from patients who were clinically suspect for NPC. Genomic DNA was extracted from the samples, and EBNA1, EBNA2, and LMP genes of EBV were detected by PCR. PCR results were compared with NPC histopathology findings.

    RESULTS: The sensitivity of PCR to detect EBNA1 (97.14%), EBNA2 (88.57%), and LMP (91.43%) genes of EBV in nasopharyngeal biopsy samples were higher than those in fine-needle aspirate samples.

    CONCLUSION: Detection of EBV by PCR in tissue obtained from nasopharyngeal biopsy and fine-needle aspirate samples of neck masses is a relatively inexpensive, reliable, and accurate method of diagnosing NPC. Detection of EBV genes is on par with histopathological examination (HPE) and superior to fine-needle aspirate cytology.

    SIGNIFICANCE: PCR is an ideal tool for suggesting NPC and guiding the diagnostic workup in occult primary tumors, facilitating earlier diagnosis and reducing morbidity and mortality.

    Matched MeSH terms: Herpesvirus 4, Human/genetics*
  4. Wah NW, Mok Y, Omar N, Chang KTE, Tay TKY, Hue SS, et al.
    Mod Pathol, 2023 Jun;36(6):100127.
    PMID: 36965331 DOI: 10.1016/j.modpat.2023.100127
    Epstein-Barr virus (EBV)-associated smooth muscle tumors (EBV-SMTs) are rare smooth muscle neoplasms exclusively associated with immunosuppression, such as in patients with HIV/AIDS, posttransplant, and congenital immunodeficiency. However, the genomic landscape of EBV-SMTs is poorly understood. Leiomyosarcomas harbor genomic instability and multiple recurrent DNA copy number alterations, whereas leiomyomas lack such changes. Thus, this study aimed to fill this knowledge gap by characterizing copy number alterations in EBV-SMTs and correlating this information with clinicopathologic characteristics. Our study investigated and compared the pathologic characteristics and copy number profiles of 9 EBV-SMTs (from 7 post-transplant and AIDS patients), 6 leiomyomas, and 7 leiomyosarcomas, using chromosomal microarray platforms. Our results showed a lower copy number alteration burden in EBV-SMTs and leiomyoma than in leiomyosarcoma. This contrast in the molecular profile between EBV-SMTs and leiomyosarcoma is concordant with the different clinical behaviors and pathologic characteristics exhibited by these tumors. Despite having an overall copy number alteration profile closer to leiomyoma, recurrent copy number gain of oncogenes, such as RUNX1, CCND2, and ETS2, was found in EBV-SMTs. Epigenetic alterations may play an important role in tumorigenesis as recurrent copy number gains were found in histone deacetylases. A gene enrichment analysis also demonstrated enrichment of genes involved in the host response to viral infection, suggesting that the tumor immune microenvironment may play an important role in EBV-SMT tumorigenesis.
    Matched MeSH terms: Herpesvirus 4, Human/genetics
  5. Vockerodt M, Vrzalikova K, Ibrahim M, Nagy E, Margielewska S, Hollows R, et al.
    J Pathol, 2019 06;248(2):142-154.
    PMID: 30666658 DOI: 10.1002/path.5237
    The Epstein-Barr virus (EBV) is found almost exclusively in the activated B-cell (ABC) subtype of diffuse large B-cell lymphoma (DLBCL), yet its contribution to this tumour remains poorly understood. We have focused on the EBV-encoded latent membrane protein-1 (LMP1), a constitutively activated CD40 homologue expressed in almost all EBV-positive DLBCLs and which can disrupt germinal centre (GC) formation and drive lymphomagenesis in mice. Comparison of the transcriptional changes that follow LMP1 expression with those that follow transient CD40 signalling in human GC B cells enabled us to define pathogenic targets of LMP1 aberrantly expressed in ABC-DLBCL. These included the down-regulation of S1PR2, a sphingosine-1-phosphate (S1P) receptor that is transcriptionally down-regulated in ABC-DLBCL, and when genetically ablated leads to DLBCL in mice. Consistent with this, we found that LMP1-expressing primary ABC-DLBCLs were significantly more likely to lack S1PR2 expression than were LMP1-negative tumours. Furthermore, we showed that the down-regulation of S1PR2 by LMP1 drives a signalling loop leading to constitutive activation of the phosphatidylinositol-3-kinase (PI3-K) pathway. Finally, core LMP1-PI3-K targets were enriched for lymphoma-related transcription factors and genes associated with shorter overall survival in patients with ABC-DLBCL. Our data identify a novel function for LMP1 in aggressive DLBCL. Copyright © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
    Matched MeSH terms: Herpesvirus 4, Human/genetics
  6. Tan LP, Tan GW, Sivanesan VM, Goh SL, Ng XJ, Lim CS, et al.
    Int J Cancer, 2020 04 15;146(8):2336-2347.
    PMID: 31469434 DOI: 10.1002/ijc.32656
    Nasopharyngeal carcinoma (NPC) is originated from the epithelial cells of nasopharynx, Epstein-Barr virus (EBV)-associated and has the highest incidence and mortality rates in Southeast Asia. Late presentation is a common issue and early detection could be the key to reduce the disease burden. Sensitivity of plasma EBV DNA, an established NPC biomarker, for Stage I NPC is controversial. Most newly reported NPC biomarkers have neither been externally validated nor compared to the established ones. This causes difficulty in planning for cost-effective early detection strategies. Our study systematically evaluated six established and four new biomarkers in NPC cases, population controls and hospital controls. We showed that BamHI-W 76 bp remains the most sensitive plasma biomarker, with 96.7% (29/30), 96.7% (58/60) and 97.4% (226/232) sensitivity to detect Stage I, early stage and all NPC, respectively. Its specificity was 94.2% (113/120) against population controls and 90.4% (113/125) against hospital controls. Diagnostic accuracy of BamHI-W 121 bp and ebv-miR-BART7-3p were validated. Hsa-miR-29a-3p and hsa-miR-103a-3p were not, possibly due to lower number of advanced stage NPC cases included in this subset. Decision tree modeling suggested that combination of BamHI-W 76 bp and VCA IgA or EA IgG may increase the specificity or sensitivity to detect NPC. EBNA1 99 bp could identify NPC patients with poor prognosis in early and advanced stage NPC. Our findings provided evidence for improvement in NPC screening strategies, covering considerations of opportunistic screening, combining biomarkers to increase sensitivity or specificity and testing biomarkers from single sampled specimen to avoid logistic problems of resampling.
    Matched MeSH terms: Herpesvirus 4, Human/genetics
  7. Tan GW, Sivanesan VM, Abdul Rahman FI, Hassan F, Hasbullah HH, Ng CC, et al.
    Int J Cancer, 2019 Oct 15;145(8):2260-2266.
    PMID: 30698824 DOI: 10.1002/ijc.32173
    Nasopharyngeal carcinoma (NPC) is an epithelial cancer of the nasopharynx which is highly associated with Epstein-Barr virus (EBV). Worldwide, most of the top 20 countries with the highest incidence and mortality rates of NPC are low- and middle-income countries. Many studies had demonstrated that EBV could be detected in the tissue, serum and plasma of NPC patients. In this study, we explored the potential of assays based on non-invasive nasal washings (NW) as a diagnostic and prognostic tool for NPC. A total of 128 patients were evaluated for NW EBV DNA loads and a subset of these samples were also tested for 27 EBV and human miRNAs shortlisted from literature. EBV DNA and seven miRNAs showed area under the receiver operating characteristic curve (AUC) values of more than 0.7, suggestive of their potential utility to detect NPC. Logistic regression analyses suggested that combination of two NW assays that test for EBNA-1 and hsa-miR-21 had the best performance in detecting NPC. The trend of NW EBV DNA load matched with clinical outcome of 71.4% (10 out of 14) NPC patients being followed-up. In summary, the non-invasive NW testing panel may be particularly useful for NPC screening in remote areas where healthcare facilities and otolaryngologists are lacking, and may encourage frequent testing of individuals in the high risk groups who are reluctant to have their blood tested. However, further validation in an independent cohort is required to strengthen the utility of this testing panel as a non-invasive detection tool for NPC.
    Matched MeSH terms: Herpesvirus 4, Human/genetics
  8. Tan EL, Selvaratnam G, Kananathan R, Sam CK
    BMC Cancer, 2006;6:227.
    PMID: 16995954
    Nasopharyngeal carcinoma (NPC) is a common epithelial neoplasm among the Chinese populations in Southern China and South East Asia. Epstein-Barr virus (EBV) is known to be an important etiologic agent of NPC and the viral gene products are frequently detected in NPC tissues along with elevated antibody titres to the viral proteins (VCA and EA) in a majority of patients. Elevated plasma EBV DNA load is regarded as an important marker for the presence of the disease and for the monitoring of disease progression. However, other serum/plasma parameters such as the levels of certain interleukins and growth factors have also been implicated in NPC. The objectives of the present study are, 1) to investigate the correlations between plasma EBV DNA load and the levels of interleukin (IL)-6, IL-10, TGF-beta1 and SCF (steel factor) and 2) to relate these parameters to the stages of NPC and the effect of treatment.
    Matched MeSH terms: Herpesvirus 4, Human/genetics
  9. Tan EL, Peh SC, Sam CK
    J Med Virol, 2003 Feb;69(2):251-7.
    PMID: 12683415
    Nasopharyngeal carcinoma, a malignancy associated closely with Epstein-Barr virus (EBV), is prevalent among Chinese of Southern China origin. Epidemiological studies indicate a high prevalence of EBV in Asia with viral isolates having typical characteristics of the putative viral oncogene, latent membrane protein 1 (LMP-1), such as the loss of the Xho1 restriction site in Exon 1 and the 30-bp deletion in Exon 3. The EBV LMP-1 gene from throat washings of 120 nasopharyngeal carcinoma patients and 14 healthy individuals were analyzed. Similar analyses were also carried out on 30 and 12 postnasal space biopsies from nasopharyngeal carcinoma patients and healthy individuals, respectively. The 30-bp deletion was detected in 20% of nasopharyngeal carcinoma throat washes and in 100% of nasopharyngeal carcinoma postnasal space biopsies. Interestingly, 16% of the nasopharyngeal carcinoma biopsies possessed both the deleted and the undeleted variants, suggestive of dual infections. The notion of dual infections in nasopharyngeal carcinoma was further supported by the coexistence of both "F" and "f" (BamH1F region) EBV variants in 11% of the nasopharyngeal carcinoma biopsies. All of the throat washes and biopsies from the healthy controls showed the undeleted variant. The loss of the Xho1 restriction site was found with higher frequency both in throat washes and biopsies from patients with nasopharyngeal carcinoma. The discrepancy in the frequency of the 30-bp deletion between throat washes (20%) and postnasal space biopsies (100%) was an indication that this deletion is specific for viral isolates from primary tumour sites.
    Matched MeSH terms: Herpesvirus 4, Human/genetics
  10. Tan EL, Sam CK
    Exp Oncol, 2007 Sep;29(3):166-74.
    PMID: 18004239
    Epstein-Barr virus (EBV), a human gammaherpesvirus is intimately associated with nasopharyngeal carcinoma (NPC), with the incidence of the virus detected in malignant tissues being close to 100% in NPC endemic areas. The viral latent gene, latent membrane protein 1 (LMP1), has all the typical characteristics of an oncogene and extensive studies have shown beyond doubt its abilities in cellular transformation giving rise to malignant phenotypes. The present study compares the gene sequence and biological properties of LMP1 gene derived from two patients with different stages of NPC--one presented with dysplastic, pre-malignant lesion and the other with malignant lesion.
    Matched MeSH terms: Herpesvirus 4, Human/genetics*
  11. Tan EL, Looi LM, Sam CK
    Singapore Med J, 2006 Sep;47(9):803-7.
    PMID: 16924363
    Nasopharyngeal carcinoma (NPC) is an important cancer in Malaysia and is one of the major causes of cancer mortality in this country. This study evaluates the diagnostic and prognostic values in the quantitative relationship between the cell-free Epstein-Barr virus (EBV) deoxyribonucleic acid (DNA) load and the tumour burden.
    Matched MeSH terms: Herpesvirus 4, Human/genetics*
  12. See HS, Yap YY, Yip WK, Seow HF
    World J Surg Oncol, 2008;6:18.
    PMID: 18275617 DOI: 10.1186/1477-7819-6-18
    Nasopharyngeal carcinoma (NPC) is a human epithelial tumour with high prevalence amongst Chinese in Southern China and South East Asia and is associated with the Epstein-Barr virus (EBV). The viral genome harbours an oncogene, namely, the latent membrane protein 1 (LMP1) gene and known variants such as the 30-bp deletion and loss of XhoI restriction site have been found. Less is known about the relationship between these variants and the population characteristics and histological type.
    Matched MeSH terms: Herpesvirus 4, Human/genetics*
  13. Se Thoe SY, Wong KK, Pathmanathan R, Sam CK, Cheng HM, Prasad U
    Gynecol Oncol, 1993 Aug;50(2):168-72.
    PMID: 8397152
    Epstein-Barr virus (EBV) receptors (EBV/C3d receptors) were detected, using the monoclonal antibody HB5, on 23 ectocervical and 5 endocervical biopsies of the uterine cervix. Elevated IgA titers against the viral capsid antigen and early antigen of EBV were also found in the cervical secretions from cervical carcinoma patients (83%), compared with samples from patients with cervical intraepithelial neoplasia (75%), herpes simplex virus-infected patients (0%), and gynecologic patients with nonmalignant conditions (0%). EBV DNA was present in 63% of cervical carcinoma biopsies detected by in situ hybridization. These observations suggest a positive association between EBV and carcinoma of the cervix.
    Matched MeSH terms: Herpesvirus 4, Human/genetics
  14. Sandvej K, Peh SC, Andresen BS, Pallesen G
    Blood, 1994 Dec 15;84(12):4053-60.
    PMID: 7994023
    In this study, we have sequenced the C-terminal part of the Epstein-Barr virus (EBV)-BNLF-1 gene encoding for the latent membrane protein-1 from tissues of EBV-positive Danish Hodgkin's disease (HD) and of Danish and Malaysian peripheral T-cell lymphomas (PTLs) and from tonsils of Danish infectious mononucleosis (IM). Our study showed that some of the 7 single-base mutations and the 30-bp deletion previously detected between codons of amino acid 322 and 366 in the BNLF-1 gene of the nasopharyngeal carcinoma cell line CAO were present in all Malaysian PTLs and in 60% of the Danish PTLs. In HD and the IM cases, the mutations were present in about 30%. The 30-bp deletion and the single base mutations occurred independently, and mutations were detectable in the majority of EBV type B-positive cases. These findings suggest that the 30-bp deletion and the 7 single-base mutations in the C-terminal part of the CAO-BNLF-1 gene do not characterize a new EBV type A substrain. Rather, some of the positions of single base mutations and the 30-bp deletion are hot spots that may have mutated independently through the evolution of EBV strains.
    Matched MeSH terms: Herpesvirus 4, Human/genetics*
  15. Plieskatt JL, Rinaldi G, Feng Y, Levine PH, Easley S, Martinez E, et al.
    J Transl Med, 2014;12:3.
    PMID: 24393330 DOI: 10.1186/1479-5876-12-3
    Nasopharyngeal carcinoma (NPC) is a solid tumor of the head and neck. Multimodal therapy is highly effective when NPC is detected early. However, due to the location of the tumor and the absence of clinical signs, early detection is difficult, making a biomarker for the early detection of NPC a priority. The dysregulation of small non-coding RNAs (miRNAs) during carcinogenesis is the focus of much current biomarker research. Herein, we examine several miRNA discovery methods using two sample matrices to identify circulating miRNAs (c-miRNAs) associated with NPC.
    Matched MeSH terms: Herpesvirus 4, Human/genetics
  16. Permeen AM, Sam CK, Pathmanathan R, Prasad U, Wolf H
    J Virol Methods, 1990 Mar;27(3):261-7.
    PMID: 2157729
    The presence of Epstein Barr virus (EBV) DNA in biopsies from the post-nasal space (PNS) of patients suspected of nasopharyngeal carcinoma (NPC) was detected by in situ cytohybridization with an EBV DNA probe labelled with the novel labelling compound digoxigenin. The digoxigenin probe was hybridised to cryostat sections of NPC biopsies and subsequently detected by an enzyme immunoassay procedure. It was found that in situ cytohybridization using the digoxigenin probe was much more rapid and sensitive (96 h compared to five weeks) than the current method of using 3H-labelled probe. Using the digoxigenin EBV probe, it was found that in all the eighteen NPC biopsies tested, EBV DNA was detected in malignant epithelial cells and infiltrating lymphocytes. EBV DNA was also detected in some normal epithelial cells in these NPC biopsies. EBV DNA was not detected in epithelial cells of non-malignant biopsies.
    Matched MeSH terms: Herpesvirus 4, Human/genetics*
  17. Peh SC, Kim LH, Thanaletchimy N, Chai SP, Poppema S
    Malays J Pathol, 2000 Jun;22(1):13-20.
    PMID: 16329532
    Lymphoma is a relatively common group of neoplasms diagnosed in hospital practice. This study aims to elucidate the pattern of this disease encountered in a public service hospital of the Ministry of Health, Malaysia.
    Matched MeSH terms: Herpesvirus 4, Human/genetics
  18. Peh SC, Sandvej K, Pallesen G
    Int J Cancer, 1995 May 4;61(3):327-32.
    PMID: 7729943
    Epstein-Barr virus (EBV) type B, a less potent transformer of B lymphocytes than type A, has rarely been detected in EBV-associated neoplasms except in AIDS-related lymphomas, in which about 50% of the cases contained this sub-type. In this study we analyzed the association of EBV and the distribution of virus sub-types in Asian non-Hodgkin's lymphoma (NHL) of the upper aerodigestive tract. We studied archival material of 29 NHL cases from Malaysia. B- and T-cell associated antigens were demonstrated by immunohistochemistry, and EBV early RNA EBER-1 was demonstrated using the RNA in situ hybridization technique. EBV was detected in the majority of tumour cells in 11/13 T-NHL but in only 1/16 B-NHL. EBV was sub-typed by single-step polymerase chain reaction of the EBNA-2 gene. This was successful in 9/10 cases of EBER-1-positive tumours and all contained type-A virus only. Our results showed a preponderance of T-cell lymphoma of the upper aerodigestive tract in the ethnic Chinese group of Malaysian patients, and EBV was strongly associated with T-NHL but not with B-NHL. Our results suggest that type-A EBV is the prevalent sub-type in Asian NHL of the upper aerodigestive tract, similarly to findings in Asian nasopharyngeal carcinoma.
    Matched MeSH terms: Herpesvirus 4, Human/genetics
  19. Peh SC, Danielle Quen QW
    Med J Malaysia, 2003 Jun;58(2):196-204.
    PMID: 14569739
    Epstein-Barr virus (EBV) is believed to have a pathogenic role in lymphomas of the upper-aerodigestive tract. This study aims to elucidate the virus association pattern in nasal and nasal-type NK/T-cell lymphomas, and in sequential biopsies of these tumours. A total of 31 cases of previously diagnosed as lethal midline granuloma. Stewart's granuloma, nasal T-cell non-Hodgkin's lymphoma (T-NHL) and NK/T-cell lymphomas from all anatomical sites were retrieved from the files for the study. Reviews of these cases confirm 8 nasal T-NHL, 19 nasal and 4 extranasal lymphomas of NK/T-cell phenotype from 10 Malays, 18 Chinese, 2 Indian and 1 Kadazan. The male: female ratio was 2.4: 1. All T- and NK/T-cell lymphomas strongly expressed TIA-1 and 63% expressed CD2. The majority of NK/T-cell lymphoma occurred in Chinese (13/23), of which 12/13 (92%) of these cases were associated with EBV. Of the 15 nasal and 9 tonsillar B-cell lymphomas included for a comparison study, only 3 (20%) of the nasal cases were associated with EBV (1 male Chinese, 1 female Chinese and 1 male of other ethnic group). Eight cases of NK/T-cell tumours with sequential biopsies show persistence of EBV, irrespective of the interval and sites of subsequent presentations. This study confirms the cytotoxic nature of NK/T-cell tumour and that EBV is strongly associated with the disease regardless of the anatomical site of presentation and ethnicity. However, nasal and paranasal lymphomas of all phenotypes appear to show higher predilection of EBV association in the ethnic Chinese when compared to non-Chinese.
    Matched MeSH terms: Herpesvirus 4, Human/genetics
  20. Peh SC, Kim LH, Poppema S
    Pathology, 2002 Oct;34(5):446-50.
    PMID: 12408344
    AIMS: Epstein-Barr virus (EBV) is associated with many human malignancies. It is implicated in a pathogenetic role in some of these tumours. Two subtypes, type A and B have been identified on the basis of DNA sequence divergence in the nuclear protein genes (EBNA) 2, 3, 4 and 6. They differ in their transforming efficiency and prevalence pattern in different geographical locations. We aimed to identify the virus subtype infection pattern in our EBV-associated diseases.

    METHODS: Paraffin-embedded tissue from 38 lymphomas (17 Hodgkin's, 14 Burkitt's, four T cell and 3 B cell non-Hodgkin's lymphomas) and 14 nasopharyngeal carcinomas (NPC) were studied, with 12 reactive lymph nodes and tonsils as normal control. EBER in situ hybridisation was performed to confirm EBV association in the tumour cells. A nested polymerase chain reaction (PCR) protocol was employed using two pairs of consensus primers which flanked a 105-bp deletion in the type A virus. U2 region encoding for EBNA-2 was chosen as the target of amplification, with cell lines B95.8 and AG876 serving as positive controls for types A and B virus, respectively.

    RESULTS: All cases showed presence of type A virus, consistently detected with nested PCR protocol but not with single step PCR. There was no type B virus or mix infections detected.

    CONCLUSIONS: Nested PCR technique has successfully increased the sensitivity of EBV subtype detection, and type A virus is the prevalent strain associated with human diseases in Malaysia.

    Matched MeSH terms: Herpesvirus 4, Human/genetics
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