Characterization of a Suppressive Cis-acting Element in the Epstein-Barr Virus LMP1 Promoter

Clinicopathologic study of mantle cell lymphoma with epstein-barr virus infection: A case series and literature review

Background

Mantle cell lymphoma (MCL) with Epstein–Barr virus (EBV) infection is rarely reported. The objective of this study was to analyze the prevalence and clinicopathological features of MCL with EBV infection in the largest series thus far.

Methods

After screening 138 cases of MCL, we identified eight cases of MCL with EBV infection.

Results

Most of them (7/8) had non-neoplastic bystander cells with positivity for EBV and no expression of latent membrane protein 1 (LMP1) and EBV nuclear antigen 2 (EBNA2). The cases of MCL with EBER positivity did not have abnormal immune function or other lymphomas. Moreover, their histopathological morphology was indicative of classical MCL. Cases of MCL with EBER positivity exhibited statistically significant differences in lactate dehydrogenase, anemia status, and MCL international prognostic index grouping (P=0.008, P=0.02, P=0.001, and P=0.011, respectively). The differences between the two groups in age, sex ratio, clinical manifestations, and immunohistochemical phenotypes were not statistically significant.

Conclusions

The incidence of MCL with EBV infection was low (5.8%). Clinicopathologically, cases of MCL with EBER positivity were similar to their EBV-negative counterparts. Our findings revealed that most cells infected by EBV in MCL are background cells rather than tumor cells. This is inconsistent with data from previous studies, indicating that tumor cells in MCL may not be prone to EBV infection.

Molecular Basis of Epstein-Barr Virus Latency Establishment and Lytic Reactivation

Epstein–Barr virus (EBV) is a causative agent of infectious mononucleosis and several types of cancer. Like other herpesviruses, it establishes an asymptomatic, life-long latent infection, with occasional reactivation and shedding of progeny viruses. During latency, EBV expresses a small number of viral genes, and exists as an episome in the host–cell nucleus. Expression patterns of latency genes are dependent on the cell type, time after infection, and milieu of the cell (e.g., germinal center or peripheral blood). Upon lytic induction, expression of the viral immediate-early genes, BZLF1 and BRLF1, are induced, followed by early gene expression, viral DNA replication, late gene expression, and maturation and egress of progeny virions. Furthermore, EBV reactivation involves more than just progeny production. The EBV life cycle is regulated by signal transduction, transcription factors, promoter sequences, epigenetics, and the 3D structure of the genome. In this article, the molecular basis of EBV latency establishment and reactivation is summarized.

Expression and clinical significance of neuropilin-1 in Epstein-Barr virus-associated lymphomas

BACKGROUND

The expression of neuropilin-1 (NRP-1) in Epstein-Barr virus (EBV)-associated lymphomas and its relationships with clinicopathological parameters was investigated.

METHODS

The researchers compared 111 cases of patients with lymphoma to 20 cases of reactive lymphoid hyperplasia. In situ hybridization was applied to observe the expression of EBV-encoded RNA (EBER) in lymphomas, and immunohistochemistry was used to detect the NRP-1 expression in lymphoma tissues and lymph node tissues with reactive hyperplasia.

RESULTS

In these 111 cases, the EBER of 62 cases (55.9%) appeared positive. NRP-1 was relatively highly expressed in lymphomas (P= 0.019). Further, NRP-1 showed higher expression in lymphomas with positive EBER than in negative ones. A comprehensive analysis revealed that NRP-1 was differently expressed in NK/T-cell lymphoma, Hodgkin's lymphoma, diffuse large B-cell lymphoma, and anaplastic large cell lymphoma (P= 0.027). Moreover, highly expressed NRP-1 was found to be a useful independent prognostic factor in assessing overall survival and progression-free survival rates in cases of non-Hodgkin's lymphoma (NHL).

CONCLUSIONS

NRP-1 exhibited higher expression in lymphomas, and it was positively expressed in EBV-positive lymphomas. Moreover, highly expressed NRP-1 can be used as an undesirable independent prognostic factor in NHL.