Epstein-Barr virus and human malignancies

EBV as a high infection risk factor promotes RASSF10 methylation and induces cell proliferation in EBV-associated gastric cancer

Epstein-Barr virus (EBV) is the first identified human tumor-related DNA virus, and has a high infection among people worldwide. Recent studies have showed that nearly 10% of gastric cancers have shown EBV infection and this kind of gastric cancer has been identified as a new subtype: EBV associated Gastric cancer (EBVaGC). Furthermore, it has been reported that tumor related genes in the EBVaGC showed frequent methylation modifications compared to those in the EBV negative gastric cancer (EBVnGC). To fully understand the role of EBV in EBVaGC, we analyzed and found that 16.67% of gastric carcinoma samples showed positive EBER1 signals. Mechanically, EBV-encoded Latent membrane protein 1 (LMP1) inhibited the expression of RASSF10, and promoted tumorigenesis by recruiting DNMT1 and inducing the DNA methylation of RASSF10. Altogether, it allows us a better understanding of the possible mechanism of EBV-induced gene hypermethylation in gastric cancer genome. Targeting EBV-induced DNA methylation is a potential therapeutic modality of EBVaGC.

Global transcript structure resolution of high gene density genomes through multi-platform data integration

Annotation of herpesvirus genomes has traditionally been undertaken through the detection of open reading frames and other genomic motifs, supplemented with sequencing of individual cDNAs. Second generation sequencing and high-density microarray studies have revealed vastly greater herpesvirus transcriptome complexity than is captured by existing annotation. The pervasive nature of overlapping transcription throughout herpesvirus genomes, however, poses substantial problems in resolving transcript structures using these methods alone. We present an approach that combines the unique attributes of Pacific Biosciences Iso-Seq long-read, Illumina short-read and deepCAGE (Cap Analysis of Gene Expression) sequencing to globally resolve polyadenylated isoform structures in replicating Epstein-Barr virus (EBV). Our method, Transcriptome Resolution through Integration of Multi-platform Data (TRIMD), identifies nearly 300 novel EBV transcripts, quadrupling the size of the annotated viral transcriptome. These findings illustrate an array of mechanisms through which EBV achieves functional diversity in its relatively small, compact genome including programmed alternative splicing (e.g. across the IR1 repeats), alternative promoter usage by LMP2 and other latency-associated transcripts, intergenic splicing at the BZLF2 locus, and antisense transcription and pervasive readthrough transcription throughout the genome.

Epstein-Barr virus latent genes

Latent Epstein–Barr virus (EBV) infection has a substantial role in causing many human disorders. The persistence of these viral genomes in all malignant cells, yet with the expression of limited latent genes, is consistent with the notion that EBV latent genes are important for malignant cell growth. While the EBV-encoded nuclear antigen-1 (EBNA-1) and latent membrane protein-2A (LMP-2A) are critical, the EBNA-leader proteins, EBNA-2, EBNA-3A, EBNA-3C and LMP-1, are individually essential for in vitro transformation of primary B cells to lymphoblastoid cell lines. EBV-encoded RNAs and EBNA-3Bs are dispensable. In this review, the roles of EBV latent genes are summarized.

Epstein-Barr virus DNA load in tumour tissues correlates with poor differentiation status in non-muscle invasive urothelial carcinomas

OBJECTIVE

To detect the correlation between the clinical staging, grading and genomic Epstein-Barr virus (EBV) viral numbers in tumour tissues of urothelial carcinoma patients.

PATIENTS AND METHODS

From June 2004 to May 2008, 60 urothelial carcinoma patients (50 cases of bladder carcinoma and 10 of upper tract urothelial carcinoma (UTUC) were enrolled in the study. Eight patients who underwent transurethral resection of prostate for prostate hyperplasia and two patients receiving nephrectomy for non-function kidney were used as normal controls. The EBV viral copy numbers in genomic DNA were evaluated using a real-time PCR-based study. The BamHI W region of the Namalwa cell line was constructed to the plasmid clone and was used as standard curve for absolute quantitative PCR (Q-PCR).

RESULTS

Epstein-Barr virus DNA was detected in 56% (28/50) and 60% (6/10) of the bladder and UTUC patients, respectively. The EBV DNA could not be detected in the normal control group. By pooling the UTUC and bladder patients in stage Ta,T1, the high copy number in fixed genomic DNA amount (100 ng/20 µL) was correlated with the high grading in stage Ta,T1 urothelial carcinoma (P = 0.014). The overall grading was not statistically associated with EBV copy number (P = 0.25). Although the copy numbers between paired tumour and normal tissues were not statistically different (P= 0.169), there were more copies of EBV in the normal tissues adjacent to the tumours than in those free from urothelial carcinoma. There was no significant difference between recurrence of non-muscle invasive bladder cancer and the presence of EBV (P > 0.05).

CONCLUSIONS

Epstein-Barr virus DNA could be detected in the genome of the urothelial carcinoma specimens. The poor differentiation status was correlated with the high load of the EBV genome in non-muscle invasive urothelial carcinoma. However, recurrence-free survival was not greater in EBV-positive patients than in EBV-negative patients.

Epstein-Barr virus infection in urothelial transitional cell carcinoma tissues

OBJECTIVE

To explore a possible correlation of Epstein-Barr virus (EBV) infection with urothelial tumours, as the mutation of oncogenes, inactivation of tumour suppressor genes and viral infections may be important in the tumorigenesis of urothelial tumours, and EBV has been implicated in the pathogenesis of a variety of lymphoproliferative disorders and several epithelial neoplasms.

MATERIALS AND METHODS

In all, 104 surgical specimens of transitional cell carcinoma (TCC) were obtained from urological operating rooms, fixed in 10% buffered formalin and processed for in situ hybridization using DNA probes, to locate the signal of EBV-encoded RNAs (EBERs). Immunohistochemistry with antibodies against CD20 and EBV-encoded latent membrane protein-1 (LMP-1) was used on EBER-positive tumour specimens.

RESULTS

Thirty-one tumour specimens were positive for EBER hybridization in 100 evaluable specimens. Of these positive specimens, 21 were positive in both the infiltrating B lymphocytes and TCC tumour cells, seven only in B lymphocytes and three only in TCC cells. Of 31 EBER-positive tumour tissues, 26 (84%) had LMP-1, suggesting that EBER is more sensitive than LMP-1 for detecting EBV infection.

CONCLUSION

There is a strong association between EBV infection and a significant proportion of primary urothelial TCC tumour cells.

Salivary production of IgA and IgG to human herpes virus 8 latent and lytic antigens by patients in whom Kaposi's sarcoma has regressed

IgG and IgA antibodies with specificities to a latent and a lytic antigen of human herpes virus 8 (HHV-8) were detectable in the saliva and serum of eight patients whose Kaposi's sarcoma had regressed, seven of whom were HIV-1 infected. The measurement of antibody-specific activity and secretion rate, and the detection of secretory IgA all indicate anti-HHV-8 antibody activity in saliva. The specific humoral responses possibly influence mucosal replication of HHV-8, and in turn, that of HIV.

Activation of the Epstein-Barr virus replicative cycle by human herpesvirus 6

One common attribute of herpesviruses is the ability to establish latent, life-long infections. The role of virus-virus interaction in viral reactivation between or among herpesviruses has not been studied. Preliminary experiments in our laboratory had indicated that infection of Epstein-Barr virus (EBV) genome-positive human lymphoid cell lines with human herpesvirus 6 (HHV-6) results in EBV reactivation in these cells. To further our knowledge of this complex phenomenon, we investigated the effect of HHV-6 infection on expression of the viral lytic cycle proteins of EBV. Our results indicate that HHV-6 upregulates, by up to 10-fold, expression of the immediate-early Zebra antigen and the diffuse and restricted (85 kDa) early antigens (EA-D and EA-R, respectively) in both EBV producer and nonproducer cell lines (i.e., P3HR1, Akata, and Raji). Maximal EA-D induction was observed at 72 h post-HHV-6 infection. Furthermore, expression of late EBV gene products, namely, the viral capsid antigen (125 kDa) and viral membrane glycoprotein gp350, was also increased in EBV producer cells (P3HR1 and Akata) following infection by HHV-6. By using dual-color membrane immunofluorescence, it was found that most of the cells expressing viral membrane glycoprotein gp350 were also positive for HHV-6 antigens, suggesting a direct effect of HHV-6 replication on induction of the EBV replicative cycle. No expression of late EBV antigens was observed in Raji cells following infection by HHV-6, implying a lack of functional complementation between the deleted form of EBV found in Raji cells and the superinfecting HHV-6. The susceptibility of the cell lines to infection by HHV-6 correlated with increased expression of various EBV proteins in that B95-8 cells, which are not susceptible to HHV-6 infection, did not show an increase in expression of EBV antigens following treatment with HHV-6. Moreover, UV light-irradiated or heat-inactivated HHV-6 had no upregulating effect on the Zebra antigen or EA-D in Raji cells, indicating that infectious virus is required for the observed effects of HHV-6 on these EBV products. These results show that HHV-6, another lymphotropic human herpesvirus, can activate EBV replication and may thus contribute to the pathogenesis of EBV-associated diseases.

Possible role of Epstein-Barr virus infection in cutaneous T-cell lymphomas

Although cutaneous T-cell lymphoma (CTCL) is a neoplastic helper T-cell disorder of unknown etiology, prolonged antigenic stimulation has been postulated to contribute to the development of this disease. Because Epstein-Barr Virus (EBV) infection has been associated with several different lymphomas, the sera of 21 CTCL patients were examined for antibodies to EBV antigens. By using complement immunofluorescence (CIF) techniques, 13 of 21 CTCL patients had detectable antibodies to Epstein-Barr Nuclear Antigens (EBNA), whereas only five of 20 control psoriatic patients were CIF positive. When immunoblot analysis was employed, all 21 of the CTCL patients had antibodies to the EBV antigens, EBNA, whereas only 12 of the control patients had detectable antibodies to these antigens. In addition, three of 21 CTCL patients had antibodies to the EBV-associated antigen, rheumatoid arthritis nuclear antigen (RANA), as determined by double immunodiffusion, whereas none of the control sera contained anti-RANA antibodies. These results indicate that antibodies against EBV antigens are found with a higher frequency and concentration in patients with CTCL when compared to controls and suggest that EBV products might serve as a possible stimulus for the development of this malignant disease.

Epstein-Barr virus antibodies in neurological diseases

Antibody titers to the Epstein-Barr virus (EBV) in the serum and cerebrospinal fluid (CSF) were determined in 57 cases of acute or subacute neurological diseases. As a result, sera from 11 cases (7 Bell's palsy, 2 encephalitis and 2 acute cerebellar ataxia) were found to be positive for antibodies to early antigen. Seven of these 11 cases either seroconverted for IgG antibodies to viral capsid antigen (VCA) or were proven positive for anti-VCA-IgM antibodies in the serum. While 4 were found positive for IgG antibodies to VCA in CSF, 3 tested by the anti-complement immunofluorescence method were all negative for EBV-associated nuclear antigen (EBNA) in CSF. Three of the 11 cases were considered to be of a primary infection with EBV because of a negative serologic test for antibodies to EBNA initially; a reinfection with the virus or a reactivation of the latent infection was suspected in some of the remaining cases.

The relation between Epstein-Barr virus antibodies and clinical symptomatology and immunodeficiency in patients with Hodgkin's disease

Anti-Epstein-Barr virus (EBV) titers were measured in the sera of 37 patients with Hodgkin's disease and in 40 normal controls. The patients were grouped according to histologic type, clinical symptomatology (relapse or remission), and their immune state (immunodeficient or non-immunodeficient). Anti-Epstein-Barr nuclear antigens (EBNA) and antiviral capside antigens (VCA) titers were higher in patients with Hodgkin's disease than in the controls. Anti-EBNA titers were significantly higher in patients with lymphocyte predominance, and anti-VCA titers were significantly higher in patients with mixed cellularity. Patients in clinical relapse had higher anti-EBV antibody titers than patients in remission or those in the control group. Immunodeficent pateints had significantly higher anti-VCA titers than either the non-immuno-deficient or the control cases. We believe high anti-EBV titers are related to immunodeficiencies. The relationship between Hodgkin's disease and EBV is discussed.

[Viruses, virus-like and virus-related structures in nasopharyngeal carcinoma (author's transl)]

Five cases of nasopharyngeal carcinoma with typically elevated EB-virus-antigen-titer were studied by light- and electron microscopic methods. Within the cytoplasm corona viruses in different forms, regular capsid-like particles with a diameter of 60 nm, tubuloreticular aggregates, and pathologic alterations of the membranes of the endoplasmatic reticulum could be found. The nuclei of the tumour cells often showed particles within the nucleoplasm with an average diameter of 100 nm containing a central core; the appearance of the particles is similar to that of herpes viruses as shown in the literature concerning EB-viruses. Atypic mitoses are common as well as free nucleoplasma-like condensates within the ground cytoplasm. Multiple doubling of the membranes of the endoplasmatic reticulum are characteristic for the tumor cell cytoplasm. Myelin figures are often situated within the enlarged tubules of the E. R., within mitochondria and within the nuclei. The results are discussed concerning the possible viral etiology of nasopharyngeal carcinoma. We do not believe that the particles found within the nucleoplasm have a relation to nuclear pores. The arguments are discussed.

Serum immunoglobulin levels and malaria antibodies in Burkitt's lymphoma

Data are presented to support a relationship between malaria infection and Burkitt's lymphoma in African children. IgG, IgM and IgA levels were measured in sera from Burkitt's lymphoma patients and from sex- and age-matched, nearest-neighbour controls. All three classes of immunoglobulins were present in significantly lower amounts in the sera from Burkitt's lymphoma patients than in the sera from controls. The mechanism of this apparent B-cell suppression is not yet clear. Malaria-specific IgG and IgM antibody titres were determined in the indirect immunofluorescence test. No significant difference in the IgG malaria-specific antibodies was detected between the two groups of sera. Malaria antibody levels measured using IgM specific conjugates were significantly lower in the sera from Burkitt's lymphoma patients in reactions with Plasmodium falciparum antigen. No significant difference was observed when P. malariae was used. Confirmation of this finding would serve as a positive link between Burkitt's lymphoma and P. falciparum infection.

Light and electron microscopic investigations of nasopharyngeal carcinomas with regard to the viral etiology of these tumors

Five carcinomata of the nasopharynx (four lymphoepithelial carcinomata of the Regaud type and one squamous cell carcinoma) were examined light and electron microscopically. In addition to the familiar histological and cytological features of these tumors, and because of an increased antibody titer against Epstein-Barr virus in all five patients, all those cytoplasmic and nuclear inclusions were examined which could be interpreted as indicative of a virus contact. The following structures were found: 1. Particles and microtubules which correspond in diameter, shape, and location to Corona viruses. 2. Particles surrounded by a double membrane and resembling in form and diameter Oncorna viruses. 3. Tubulo-reticular, coil-shaped cytoplasmic inclusions interpreted as an unspecific reaction of the host cell to viral attack. 4. Spherical nuclear bodies, which are frequently observed in tumors and in viral infections. 5. Intranuclear particles which correspond in diameter, structure, and distribution to viruses of the herpes type such as have been described in cell cultures of Burkitt lymphoma and nasopharyngeal carcinoma. The fifth group particularly was discussed in detail with regard to differentiation between those particles and other structures which could simulate a virus structure. Together with the appearance of increased ribosomes and of particular chromatin distribution within the tumor cell nuclei, the particles we discussed have been interpreted as morphological indications of a virus etiology of the examined tumors.

Does cyclophosphamide induce bladder cancer?

An increasing incidence of bladder neoplasms temporally associated with chemotherapy, usually cyclophosphamide, is being reported. These secondary primary bladder malignancies are characteristically found in two groups of patients: those with lymphoproliferative or myeloproliferative tumors, and those with immunosuppression after organ transplantation. A case of adenocarcinoma of the bladder associated with malignant lymphoma is reported, and the known cases of second primary bladder malignancies after cyclophosphamide therapy as reported in the literature are reviewed. Studies relating to the enhanced occurrence of second primary cancers in lymphoproliferative disorders are presented. The recognized urologic toxicities of cyclophosphamide, including cytopathologic changes in animals and humans, are discussed. The observed association between immunosuppression and second primary malignancies is explored, as supported by studies on congenital immunodeficiency in humans, viral oncogenesis in experimental animals, and neoplasia after organ transplantation. Possible mechanisms of carcinogenesis associated with cyclophosphamide are reviewed, including suppression of humoral and cell-mediated immune defense mechanisms, direct carcinogenesis, or cocarcinogenesis. A plea is made for the orderly reporting and careful documentation of bladder tumors in patients receiving cyclophosphamide. It is suggested that prospective studies in these patients and in patients receiving cyclophosphamide for nonmalignant disorders would be of value in assessing the culpability of cyclophosphamide as a carcinogen.

Ocular granulocytic sarcoma (chloroma) with acute myelomonocytic leukemia in Turkish children

In a series of 166 leukemic children from Turkey, 56 had acute myelomonocytic leukemia (AMML). Seventeen boys and 3 girls presented with chloroma-like deposits (granulocytic or myeloid sarcomas) in the eye and orbit, all showing AMML on initial study of blood and marrow. The ocular lesions responded rapidly to antileukemic therapy. Laboratory studies of AMML cases revealed no cytogenetic or immune defects, and Epstein-Barr virus titers were normal. A group-specific (GS-3) antigen (type-C virus?) was identified in one patient by radioimmunoassay of orbital tumor extracts. It is not clear what factors contribute toward the myelomoncytic differentiation of leukemia and its localization in the eye and orbit, but opportunities for further study are enhanced by reports of a predisposition to ocular chloroma among leukemic children in Africa, Egypt, and Japan.

Viral particles in nasopharyngeal carcinoma

Lymphoepithelioma of the nasopharynx was identified in a 17-year-old Chinese male. The Epstein-Barr virus titer was 1:3200. Tissue from the tumor mass was prepared for electron microscopy. Particles consistent with the morphological characteristics of herpes virus were found within the cytoplasm of malignant epithelial cells. This finding is discussed in relation to other data suggesting an oncogenic role of herpes virus in human malignancy.

Marker chromosome 14q+ in non-endemic Burkitt's lymphoma

The chromosomal aberrations in tumor cells obtained by bone marrow aspiration from a patient with non-endemic Burkitt's lymphoma (BL) are reported. Twenty percent of the cells contained the marker chromosome 14q+ earlier described in endemic Burkitt's tumors. Other marker chromosomes were dound only in mitoses which did not contain the 14q+.

The ocular manifestations of herpes zoster, varicella, infectious mononucleosis, and cytomegalovirus disease

Herpes zoster, caused by varicella-zoster (V-Z) virus which also causes varicella (chickenpox), is usually a benign self-limited disease. However, when the ophthalmic division of the trigeminal nerve is affected, the ocular disease (ophthalmic zoster), although also usually mild and self-limited, may have severe complications (corneal scarring, glaucoma, iris atrophy, posterior synechiae, scleritis, motor disturbances, optic neuritis, retinitis, anterior segment necrosis, and phthisis bulbi and servere postherpetic neuralgia). Varicella affects the eye rarely (except for the typical lid lesions), but associated conjunctival and corneal lesions, iridocyclitis, glaucoma, chorioretinitis, and optic nerve lesions have been described. Infectious mononucleosis may involve the eye either by direct involvement or from a remote focus such as the central nervous system. Ocular manifestations of cytomegalovirus disease is usually limited to the choroid and retina unless involvement of the developing embryo occurs prior to the development of the eye.

The nephrotic syndrome associated with neoplasia: an unusual paraneoplastic syndrome. Report of a case and review of the literature

The nephrotic syndrome complicating malignancy in the absence of renal vein thrombosis, amyloid or neoplastic infiltration of the kidney is an unusual occurrence. A case of diffuse, well differentiated, lymphocytic lymphoma and lipoid nephrosis documented by light microscopy, electron microscopy and immunofluorescent studies is reported. A review of the literature revealed 76 case reports in which the nephrotic syndrome was associated with neoplasia. The most frequently associated neoplasms are Hodgkin's disease, various carcinomas, nonHodgkin's lymphoma and leukemia in descending order. The most frequent renal lesion in patients with the nephrotic syndrome associated with various carcinomas is membranous glomerulonephritis (81 per cent) as opposed to patients with lymphomas or leukemias who have predominantly lipoid nephrosis (60 per cent). The evidence is reviewed suggesting that the lesions in membranous nephropathy are immunologically mediated by tumor or viral antigen-antibody complexes and in lipoid nephrosis perhaps by a defect in t-lymphocyte function.

Activation in vitro by BUdR of a productive EB virus infection in the epithelial cells of nasopharyngeal carcinoma

Material from a nasopharyngeal carcinoma (NCP) has been passaged in athymic (nude) mice to eliminate non-malignant infiltrating cells. The human origin and derivation from NPC malignant epithelial cells of the nude mouse tumours have been confirmed by chromosome examination, electron microscopy showing desmosomes and keratin fibrils, and postive EB virus nuclear antigen (EBNA) testing. Samples of the mouse-grown tumours were cultured and pure monolayers of epithelial cells were obtained which still expressed EBNA and contained desmosomes and keratin; these cultures grew well for about 3 weeks. Extensive electron microscope searches failed to reveal herpes virus particles. In contrast, cultures treated with BUdR showed typical immature and mature herpes virus particles in epithelial, keratin-containing cells, and immunofluorescence tests for virus capsid antigen with a battery of human sera identified this agent as EB virus. EB virus has thus, for the first time, been activated in NPC epithelial cells and shown to be capable of replication in a cell type other than a primate B-lymphocyte.

Karyotypes in infectious mononucleosis

Using a trypsin-Giemsa banding procedure, chromosome analysis was performed on blood from 21 consecutive patients hospitalized for infectious mononucleosis. Mitoses were harvested after 2 and 24 h in vitro incubation without PHA and after 48 h with PHA. No abnormalities were seen.

Chromosome abnormalities identified by banding technique in a patient with acute myeloid leukaemia complicating Hodgkin's disease

Chromosome analyses using the Giemsa banding technique were performed on bone marrow cells in a patient with the association of Hodgkin's disease and acute myeloid leukaemia. All cells had an abnormal karyotype showing an extra chromosome No. 14, loss of one chromosome No. 17 and gain of one chromosome No. 18. These abnormalities are in many respects similar to the karyotype changes of lymphoid cells in malignant lymphomas, suggesting a pathogenetic relationship between the two disorders.