Breast Cancer as an Epstein-Barr Virus (EBV)-Associated Malignancy

The Epstein Barr Virus is among the very first oncogenic viruses to be identified as culprits of human malignancies. Its role as an etiologic agent of breast cancer however remains debated despite mounting molecular evidence. In this chapter we address the challenge of multiple molecular etiologies of breast cancer (BC) with emphasis on the Epstein Barr Virus (EBV) as a potential causative agent within a frame work of gene/environment interaction. We also hope to contribute to a critique of the a concept of universal single agent or gene in cancer etiology. In addition to reviewing further reasons of why EBV should be considered a tumor virus, coupling molecular targets at the initiation stage, we examine evidence for the culpability of EBV as oncogenic virus in relation to the genetic and epigenetic events that leads to carcinogenesis of cancer; and the subsequent downstream interaction including genetic and epigenetic modifiers of signaling and molecular function underlying the cancerous phenotype. The TNF family is taken as an example of how the epigenetic reprogramming process, impacts molecular targets and how these combined interplay of molecular events impinges on pathogenesis and malignancy of breast cancer in humans

EBV Associated Breast Cancer Whole Methylome Analysis Reveals Viral and Developmental Enriched Pathways

Background: Breast cancer (BC) ranks among the most common cancers in Sudan and worldwide with hefty toll on female health and human resources. Recent studies have uncovered a common BC signature characterized by low frequency of oncogenic mutations and high frequency of epigenetic silencing of major BC tumor suppressor genes. Therefore, we conducted a pilot genome-wide methylome study to characterize aberrant DNA methylation in breast cancer.Results: Differential methylation analysis between primary tumor samples and normal samples from healthy adjacent tissues yielded 20,188 differentially methylated positions (DMPs), which is further divided into 13,633 hypermethylated sites corresponding to 5339 genes and 6,555 hypomethylated sites corresponding to 2811 genes. Moreover, bioinformatics analysis revealed epigenetic dysregulation of major developmental pathways including hippo signaling pathway. We also uncovered many clues to a possible role for EBV infection in BC.Conclusion: Our results clearly show the utility of epigenetic assays in interrogating breast cancer tumorigenesis, and pinpointing specific developmental and viral pathways dysregulation that might serve as potential biomarkers or targets for therapeutic interventions

Association of Epstein - Barr virus and breast cancer in Eritrea

Abstract Background The oncogenic potential of Epstein-Barr virus (EBV) in breast cancer is being increasingly recognized. Despite some controversies regarding such role, new evidence is suggesting a culpability of EBV in breast cancer, particularly in Africa where the virus has been originally associated with causation of several solid and hematological malignancies. One example is a report from Sudan implicating EBV as a prime etiologic agent for an aggressive type of breast cancer, where nearly 100% of tumor tissues were shown to carry viral signatures. To get a broader view on such association, other nearby countries should be investigated. The present study aims to determine the prevalence and possible associations of the virus in Eritrean breast cancer patients. Methods Detection of EBV genome using primers that target Epstein Barr Encoded RNA (EBER) gene and Latent Membrane Protein-1 (LMP-1) gene sequences was performed by polymerase chain reaction (PCR) on DNA samples extracted from 144 formalin fixed paraffin embedded breast cancer tissues and 63 non-cancerous breast tissue as control group. A subset of PCR positive samples was evaluated for EBER gene expression by in situ hybridization (ISH). Expression of Latent Membrane Protein-2a (LMP2a) was also assessed by immunohistochemistry in a subset of 45 samples. Results Based on PCR results, EBV genome signals were detected in a total of 40 samples (27.77%) as compared to controls (p-value = 0. 0031) with a higher sensitivity when using the EBER primers. Five out of the 14 samples stained by EBER-ISH 35.71% were positive for the virus indicating the presence of the viral genome within the tumor cells. Of those stained for IHC 7 (15.55%) were positive for LMP2a showing low viral protein frequency. Conclusions Based on these findings it can be concluded that EBV in Eritrea is associated with a smaller subset of tumors, unlike neighboring Sudan, thus pointing to possible differences in population predisposition and diseases epidemiology