Epstein-Barr virus (EBV) genome and expression in breast cancer tissue: effect of EBV infection of breast cancer cells on resistance to paclitaxel (Taxol)

Role of Epstein-Barr Virus in Breast Cancer: Correlation with Clinical Outcome and Survival Analysis

Background: Breast cancer is the most prevalent cancer among women worldwide. The potential involvement of Epstein-Barr virus (EBV) in breast cancer pathogenesis has been a subject of debate, but its correlation with clinical outcomes remains uncertain. Methods: In this study, we collected 276 pathologically confirmed breast cancer tissue samples from the tissue bank of MacKay Memorial Hospital and the National Health Research Institutes in Taiwan. DNA was extracted from frozen tissue using The QIAamp DNA Mini Kit. The Taqman quantitative PCR method was employed to assess the EBV copy number per cell in these samples, using NAMALWA cells as a reference. We performed statistical analyses, including 2 × 2 contingency tables, Cox regression analysis, and Kaplan-Meier survival curves, to explore the association between clinicopathologic factors and survival outcomes in breast cancer patients. We analyzed both relapse survival, which reflects the period patients remain free from cancer recurrence post-treatment, and overall survival, which encompasses all-cause mortality. Results: Our results revealed a significant association between EBV status and relapse survival (hazard ratio: 2.75, 95% CI: 1.30, 5.86; p = 0.008) in breast cancer patients. However, no significant association was found in overall survival outcomes. Additionally, we observed significant associations between ER status and tumor histologic grade with both overall and relapse survival. Patients with EBV-positive tumors exhibited higher recurrence rates compared to those with EBV-negative tumors. Furthermore, we noted significant correlations between EBV status and HER-2 (p = 0.0005) and histological grade (p = 0.02) in our cohort of breast cancer patients. Conclusions: The presence of EBV in breast cancer tumors appears to exert an impact on patient outcomes, particularly concerning recurrence rates. Our findings highlight the significance of considering EBV status as a potential prognostic marker in breast cancer patients. Nonetheless, further research is essential to elucidate the underlying molecular mechanisms and develop novel therapeutic approaches.

Non-Response of Epstein-Barr Virus-Associated Breast Cancer after Primary Chemotherapy: Report of Two Cases

Based on epidemiological evidence and molecular findings, a possible association of Epstein-Barr virus (EBV) with the carcinogenesis of breast cancer has been described. However, the frequency of EBV in breast cancer and the role of EBV regarding tumor progression or therapeutic results is largely unexplored. Here, we report on two cases of advanced, lymph node-positive invasive breast cancer of no special type (NST), histologically showing no clinical or histological evidence of tumor regression as an equivalent of a lack of response to primary systemic therapy. Both tumors were considered to be EBV-associated due to their positivity in EBV-encoded RNA (EBER) in situ hybridization (ISH) and their immunoreactivity against EBV Epstein-Barr nuclear antigen 1 (EBNA1). We hypothesize that the unusual non-response to chemotherapy in these cases of breast cancer classified as triple-negative and HER2-positive may be linked to the EBV co-infection of tumor cells. Therefore, EBV tumor testing should be considered in patients with breast cancer presenting with resistance to chemotherapy. This hypothesis may provide a new aspect in the context of EBV-associated mechanisms of tumor progression.

Epstein-Barr virus immediate-early protein Zta mediates the proliferation and migration of HER2-overexpressing cancer cells

Epstein-Barr virus immediate-early protein Zta plays an active role in altering cellular gene expression, which may be fundamentally linked to the viral life cycle, cell cycle, cell growth, and differentiation. HER2 is associated with a wide variety of human cancers, and its knockdown significantly reverses the malignant features of HER2-positive cancers. The aim of this study was to investigate the potential role of Zta in regulating HER2 expression and phenotype changes of MDA-MB-453 cells. Our results indicate that ectopic expression of Zta resulted in downregulation of the HER2 protein in cancer cells (MDA-MB-453, SKBR-3, BT474, and SKOV-3). The Zta protein significantly decreased HER2 mRNA and protein expression in MDA-MB-453 cells in a dose-dependent manner. Mechanistically, Zta recognized and targeted the promoter of HER2 gene, reducing the transcriptional activity of the HER2 gene. Zta induced G0/G1 arrest of MDA-MB-453 cells, inhibiting their proliferation and migration activity. These data suggest that Zta may act as a transforming suppressor of the HER2 gene.

Detection of Epstein Barr Nuclear Antigen-1 (EBNA-1), Early Antigen 1F, 2R (EA-1F, EA- 2R) along with Epstein-Barr virus Latent Membrane Protein 1 (LMP1) in Breast Cancer of Northern India: An Interim Analysis

INTRODUCTION

Worldwide, breast cancer (BC)  is a prominent cause of death, with a disproportionately high incidence in developed countries. Epstein-Barr virus (EBV) infection has been reported in up to 90% of the world's population.  Although the exact link of EBV infection and breast carcinoma is not yet determined. The present study was carried out to assess the pathological correlation of EBV infection and BC in women from Northern India.

METHODOLOGY

In this prospective observational study, 130 patients with histologically proven breast carcinoma were included. After detailed histology, the paraffin block with infiltrative tumor was selected for molecular analysis and further immunohistochemistry (IHC)- EBV PCR and Epstein-Barr virus latent membrane protein 1 (LMP1) IHC.

RESULTS

Most of the patients were diagnosed with Infiltrating Ductal Carcinoma not otherwise specified (IDC-NOS), followed by Infiltrating Ductal Carcinoma + Ductal Carcinoma in situ (IDC + DCIS). The total of 25 tissues of breast carcinoma had positive EBV PCR results (19.23%). The co-relation between the molecular and immunohistochemical results was significant in 11/25 cases that showed immunoexpression for LMP1 by IHC. Sensitivity of 44% and specificity of 100% were observed for LMP1 IHC, having a PPV value of 100% and an NPV of 88%. No significant correlation was observed between age, tumor subtype, grade, stage with respect to EBV infection; however, there was a significant association with nodal metastasis with extra nodal extension in tumors that had EBV infection.

CONCLUSION

The present study establishes an association between LMP1 and patients with EBV positive breast cancer. The authors suggest that additional multicentric studies be conducted to strengthen the reliability and generalizability of the observations of the current study.

Drosophila as a Model for Human Viral Neuroinfections

The study of human neurological infection faces many technical and ethical challenges. While not as common as mammalian models, the use of Drosophila (fruit fly) in the investigation of virus–host dynamics is a powerful research tool. In this review, we focus on the benefits and caveats of using Drosophila as a model for neurological infections and neuroimmunity. Through the examination of in vitro, in vivo and transgenic systems, we highlight select examples to illustrate the use of flies for the study of exogenous and endogenous viruses associated with neurological disease. In each case, phenotypes in Drosophila are compared to those in human conditions. In addition, we discuss antiviral drug screening in flies and how investigating virus–host interactions may lead to novel antiviral drug targets. Together, we highlight standardized and reproducible readouts of fly behaviour, motor function and neurodegeneration that permit an accurate assessment of neurological outcomes for the study of viral infection in fly models. Adoption of Drosophila as a valuable model system for neurological infections has and will continue to guide the discovery of many novel virus–host interactions.

Epstein-Barr Virus Association with Breast Cancer: Evidence and Perspectives

Epstein-Barr virus (EBV) is an enveloped DNA virus that belongs to the gamma Herpesviridae family. The virus establishes a latent/lytic persistent infection, though it can be involved in cancer development in some subjects. Indeed, evidence supports an etiological role of EBV in undifferentiated nasopharyngeal carcinoma (NPC), a subset of gastric carcinomas and lymphomas. Additionally, EBV has been detected in breast carcinomas (BCs) although its role has not been established. In this review, we summarize epidemiological information regarding the presence of EBV in BC and we propose mechanistic models. However, additional epidemiological and experimental evidence is warranted to confirm these models.

Epstein-Barr Virus Infection in Lung Cancer: Insights and Perspectives

Lung cancer (LC) is the leading cause of cancer death worldwide. Tobacco smoke is the most frequent risk factor etiologically associated with LC, although exposures to other environmental factors such as arsenic, radon or asbestos are also involved. Additionally, the involvement of some viral infections such as high-risk human papillomaviruses (HR-HPVs), Merkel cell polyomavirus (MCPyV), Jaagsiekte Sheep Retrovirus (JSRV), John Cunningham Virus (JCV), and Epstein-Barr virus (EBV) has been suggested in LC, though an etiological relationship has not yet been established. EBV is a ubiquitous gamma herpesvirus causing persistent infections and some lymphoid and epithelial tumors. Since EBV is heterogeneously detected in LCs from different parts of the world, in this review we address the epidemiological and experimental evidence of a potential role of EBV. Considering this evidence, we propose mechanisms potentially involved in EBV-associated lung carcinogenesis. Additional studies are warranted to dissect the role of EBV in this very frequent malignancy.

Human Papillomavirus in Breast Carcinogenesis: A Passenger, a Cofactor, or a Causal Agent?

Simple Summary

Breast cancer (BC) is the most frequent tumor in women worldwide. A minority of BC patients have a family history of the disease, suggesting the importance of environmental and lifestyle factors. Human papillomavirus (HPV) infection has been detected in a subset of tumors, suggesting a potential role in BC. In this review, we summarized relevant information in respect to this topic and we propose a model of HPV-mediated breast carcinogenesis. Evidence suggests that breast tissue is accessible to HPV, which may be a causal agent of BC in a subset of cases.

Abstract

Breast cancer (BC) is the most commonly diagnosed malignancy in women worldwide as well as the leading cause of cancer-related death in this gender. Studies have identified that human papillomavirus (HPV) is a potential risk factor for BC development. While vaccines that protect against oncogenic HPVs infection have been commercially available, global disparities persist due to their high cost. Interestingly, numerous authors have detected an increased high risk (HR)-HPV infection in BC specimens when compared with non-tumor tissues. Therefore, it was suggested that HR-HPV infection could play a role in breast carcinogenesis in a subset of cases. Additional epidemiological and experimental evidence is still needed regarding the role of HR-HPV infection in the development and progression of BC.

Microbiome in human cancers

A microbiome is defined as the aggregate of all microbiota that reside in human digestive system and other tissues. This microbiota includes viruses, bacteria, fungi that live in various human organs and tissues like stomach, guts, oesophagus, mouth cavity, urinary tract, vagina, lungs, and skin. Almost 20 % of malignant cancers worldwide are related to microbial infections including bacteria, parasites, and viruses. The human body is constantly being attacked by microbes during its lifetime and microbial pathogens that have tumorigenic effects in 15-20 % of reported cancer cases. Recent scientific advances and the discovery of the effect of microbes on cancer as a pathogen or as a drug have significantly contributed to our understanding of the complex relationship between microbiome and cancer. The aim of this study is to overview some microbiomes that reside in the human body and their roles in cancer.

MiRNA-218 Is Frequently Downregulated in Malignant Breast Tumors: A Footprint of Epstein-Barr Virus Infection

BACKGROUND & OBJECTIVE

The role of Epstein-Barr Virus in development of breast cancer is frequently studied. In this regard, miRNAs are among the contributing elements in the molecular pathophysiology of EBV-related diseases. In addition, a growing number of host miRNAs are believed to be implicated in pathogenesis of breast cancer. MiR-218 is a tumor suppressive miRNA that is subjected to dysregulation in various EBV-associated cancers. We aimed to investigate the frequency of EBV and its relationship with expression status of tumor suppressive miR-218 in breast cancer and adjacent normal tissue.

METHODS

A total number of 51 fresh malignant breast cancer tissues (cases) and their adjacent normal tissues (controls) were collected. Nested-PCR and RT-qPCR were set to identify EBV frequency and miR-218 expression in cases and controls, respectively.

RESULTS

Out of all samples, 6.8% (7/102) comprising 11.6% (6/51) in malignant tissues and 1.9% (1/51) in normal control tissues were positive for EBV (P<0.05). Quantitative data showed that miR-218 was significantly downregulated in malignant tissues compared to control tissues (P<0.0001). In addition, reduced expression of miR-218 was associated with adverse clinical outcomes, metastasis, and higher grades of malignancy. Given the presence of EBV, lower expression of miR-218 was observed in breast cancer group in comparison with normal group (P<0.05).

CONCLUSION

Our results raise the possibility of the relation between EBV infection and miR-218 downregulation in breast cancer and propose further investigations in this regard.

Interplay between Epstein-Barr virus infection and environmental xenobiotic exposure in cancer

Epstein-Barr virus (EBV) is a herpesvirus associated with lymphoid and epithelial malignancies. Both B cells and epithelial cells are susceptible and permissive to EBV infection. However, considering that 90% of the human population is persistently EBV-infected, with a minority of them developing cancer, additional factors are necessary for tumor development. Xenobiotics such as tobacco smoke (TS) components, pollutants, pesticides, and food chemicals have been suggested as cofactors involved in EBV-associated cancers. In this review, the suggested mechanisms by which xenobiotics cooperate with EBV for carcinogenesis are discussed. Additionally, a model is proposed in which xenobiotics, which promote oxidative stress (OS) and DNA damage, regulate EBV replication, promoting either the maintenance of viral genomes or lytic activation, ultimately leading to cancer. Interactions between EBV and xenobiotics represent an opportunity to identify mechanisms by which this virus is involved in carcinogenesis and may, in turn, suggest both prevention and control strategies for EBV-associated cancers.

Presence of HPV, EBV and HMTV Viruses Among Egyptian Breast Cancer Women: Molecular Detection and Clinical Relevance

Background

Oncogenic viruses, their possible association with breast cancer (BC) and effect on its clinical course are interesting issue. The present study evaluates the presence of human papillomavirus (HPV), EpsteinBarr virus (EBV), and human mammary tumor virus (HMTV) in BC and their relation with clinico-pathological characteristics.

Patients and Methods

This study was conducted on 80 Egyptian women with BC and 30 control women without known oncological disease. Forty formalin-fixed paraffin-embedded (FFPE) tissues, forty fresh tissue samples, and white blood cells (WBCs) of BC patients and WBCs of controls were subjected to a qualitative polymerase chain reaction (PCR). Quantitative real-time PCR was used to measure viral loads in fresh tissues of BC. The result was correlated with clinico-pathological characteristics of BC.

Results

HPV was detected in 33 (41.25%), EBV in 30 (37.5%) and HMTV in 33 (41.25%) BC patients. None of the control women was positive for HPV or EBV while HMTV was detected in 7 (23.3%). Among 40 BC WBCs specimens, HPV/HMTV were found together in 25%, followed by EBV/HMTV in 2.5% and EBV/HPV in 2.5%. However, the three viruses (HPV/EBV/HMTV) were found together in only 5%. In the 40 fresh BC tissues, the three viruses were found together in 12 (30%), EBV/HMTV in 7 (17.5%), HPV/HMTV in 4 (10%), and HPV/EBV in 4 (10%). EBV, HMTV, or multiple viral infections were associated with younger age of BC women. HPV, EBV, and HMTV median loads in fresh tissues were 4.8×10³ copies/μL, 6.3×10³ copies/μL, and 97 copies/μL, respectively.

Conclusion

WBCs could be a more suitable specimen instead of fresh tissue for HMTV detection in BC patients to avoid invasive procedures. The presence of HPV, EBV, and HMTV together in Egyptian women with BC was significantly associated with younger age.

Is EBV Associated with Breast Cancer in Specific Geographic Locations?

Epstein-Barr virus (EBV) is a virus that establishes a life-long infection in people, and infection with EBV is nearly ubiquitous by adulthood. EBV was identified from biopsy material from a child with Burkitt's lymphoma (BL) in sub-Saharan Africa. EBV has a well-characterised role in the development of some cancers, notably, Burkitt's lymphoma (BL), Hodgkin's disease (HD), gastric carcinoma (GC), and nasopharyngeal carcinoma (NPC). Links have also been made between EBV and breast cancer (BC), but these have been controversial. For all EBV-associated cancers, the ubiquitous nature of infection with EBV, contrasted with the relatively rare development of cancer, highlights a problem of determining whether EBV is an aetiological agent of cancer. In addition, the geographic distributions of some EBV-associated cancers point to contributions from additional co-factors. Recent meta-analyses of the incidence of EBV within BC biopsies has revealed that the diversity in the conclusions remain, however, they also show more of an association between EBV and BC biopsies in some study locations. Here, we review the evidence linking EBV with BC, and conclude that the evidence for the presence of EBV in BC biopsies is concentrated in specific geographic regions but is currently insufficient to provide a causal link. We pose some questions that could help to resolve the question of whether EBV contributes to BC and probe the contribution EBV might make to the aetiology of BC.

Association of Human Papilloma Virus and Epstein-Barr Virus with Ovarian Cancer in Shiraz, Southwestern Iran

Background & Objective:

Ovarian cancer is one of the most common cancers amongst women. The association of Human papillomavirus (HPV) and Epstein-Barr virus (EBV) with ovarian cancer is inconclusive; therefore, the aims of this study were to evaluate the frequency of HPV and EBV in malignant, borderline, benign and normal ovarian tissues.

Methods:

In this case-control study, 205 Paraffin-embedded ovarian tissue specimens including 68 malignant, 27 borderline, 65 benign, and 45 normal tissues were included from December 2014 to January 2018 and subjected to DNA extraction. The β-globin gene was amplified using PCR to confirm the quality of the extracted DNA. The genomes of HPV (genotypes 16 and 18) and EBV were identified, using specific primers by PCR.

Results:

The mean age of participants was 43.42 ± 15.4 years. The frequency of HPV was statistically significant between malignant versus benign (P=0.02) and control groups (P=0.002), but not with borderline tumor group (P=0.78). Amongst HPV infected samples, 1 (4.5%) and 14 (63.6%) samples were infected with types 16 and 18, respectively. Also 4 (18.2 %) samples were infected with both genotypes. Eleven samples including 7(10.3%) malignant, 1 (3.7%) borderline, 3 (4.6%) benign and none (0%) of normal control groups were infected with EBV, which was statistically different between malignant and the normal control group (P=0.03).

Conclusion:

The results of our study showed the possible role of high risk HPVs as well as EBV in pathogenesis of ovarian cancer, and further studies are recommended to confirm these findings.

The scope of viral causation of human cancers: interpreting virus density from an evolutionary perspective

Most known oncogenic viruses of humans use DNA as their genomic material. Research over the past quarter century has revealed that their oncogenicity results largely from direct interference with barriers to oncogenesis. In contrast to viruses that have been accepted causes of particular cancers, candidate viral causes tend to have fewer viral than cellular genomes in the tumours. These low viral loads have caused researchers to conclude that the associated viruses are not primary causes of the associated cancers. Consideration of differential survival, reproduction and infiltration of cells in a tumour suggest, however, that viral loads could be low even when viruses are primary causes of cancer. Resolution of this issue has important implications for human health because medical research tends to be effective at preventing and controlling infectious diseases. Mathematical models may clarify the problem and help guide future research by assessing whether low viral loads are likely outcomes of the differential survival, reproduction, and infiltration of cells in a tumour and, more generally, the extent to which viruses contribute to cancer. This article is part of the theme issue 'Silent cancer agents: multi-disciplinary modelling of human DNA oncoviruses'.

Epstein Barr Virus Associated Lymphomas and Epithelia Cancers in Humans

Epstein Barr virus (EBV) is a cosmopolitan oncogenic virus, infecting about 90% of the world's population and it is associated to tumors originating from both epithelia and hematopoietic cells. Transmission of the virus is mainly through oral secretions; however, transmission through organ transplantation and blood transfusion has been reported. In order to evade immune recognition, EBV establishes latent infection in B lymphocytes where it expresses limited sets of proteins called EBV transcription programs (ETPs), including six nuclear antigens (EBNAs), three latent membrane proteins (LMP), and untranslated RNA called EBV encoded RNA (EBER), shown to efficiently transform B cells into lymphoblastic cells. These programs undergo different patterns of expression which determine the occurrence of distinct types of latency in the pathogenesis of a particular tumor. Hematopoietic cell derived tumors include but not limited to Burkitt's lymphoma, Hodgkin lymphoma, post-transplant lymphoproliferative disorders, and natural killer (NK)/T cell lymphoma. EBV undergoes lytic infection in epithelia cells for amplification of the viral particle for transmission where it expresses lytic stage genes. However, for reasons yet to be unveiled, EBV switches from the expression of lytic stage genes to the expression of ETPs in epithelia cells. The expression of the ETPs lead to the transformation of epithelia cells into permanently proliferating cells, resulting in epithelia cell derived malignancies such as nasopharyngeal cancer, gastric cancer, and breast cancer. In this review, we have summarized the current updates on EBV associated epithelial and B cell-derived malignancies, and the role of EBV latency gene products in the pathogenesis of the cancers, and have suggested areas for future studies when considering therapeutic measures.

Prevalence of Epstein-Barr virus (EBV) in Iranian Breast Carcinoma Patients

Introduction:

Breast cancer (BC) is the most common malignancy affecting females worldwide. Various risk factors play a role in the developing of BC. Infectious agents like viruses have been proposed for this cancer and Epstein-Barr virus (EBV) is a widely researched candidate virus. This study detects the presence of EBV-DNA in breast cancer patients.

Methods:

The study was conducted on 59 formalin-fixed paraffin-embedded (FFPE) tissue blocks samples of women with breast carcinoma and 11 non-neoplastic breast controls. The DNA was extracted for all the samples. Then detection of EBNA1 EBV was done by polymerase chain reaction (PCR).

Results:

EBV was detected in 6.7% (4/59) of patients while all breast control samples were negative. All patients with positive EBV-DNA were high tumor grades (II, and III). Also, they had a low level of educations.

Conclusions:

According to our findings, it can be suggested that EBV may have a potential role in breast cancer development. However, this study provides substantial but not conclusive evidence for the involvement of viruses in BC disease development. Therefore, future investigations are needed to elucidate the exact role of EBV in breast cancer.

Epstein-Barr Virus Infection and Increased Sporadic Breast Carcinoma Risk: A Meta-Analysis

OBJECTIVE

An association of Epstein-Barr virus (EBV) infection with breast carcinoma (BC) risk has so far been disputed in the literature. Therefore, we performed a meta-analysis to clarify this relationship.

MATERIALS AND METHODS

An electronic database search for eligible case-control studies was performed using PubMed, Embase, Web of Science, the Cochrane Library, CNKI, and Wanfang Data until May 17, 2018. The pooled OR and 95% CI were used to estimate the relationship between EBV infection and BC risk using a fixed or random-effects model depending on heterogeneity. Subgroup analysis and meta-regression were used to explore the heterogeneity. Publication bias was assessed using Egger's and Harbord's tests.

RESULTS

A total of 16 studies with 1,279 patients and 814 controls were reviewed based on our inclusion and exclusion criteria. Compared with the control group, EBV infection had a significant association with BC risk (OR 4.75, 95% CI 2.53-8.92, p < 0.01) with significant heterogeneity observed (I2 = 65.3%). The subgroup analysis revealed that region and tissue type might explain potential sources of heterogeneity. The sensitivity analyses yielded stable results. No significant publication bias was observed.

CONCLUSION

The current results suggest that EBV infection is significantly associated with increased risk of BC.

Identification of Novel Breast Cancer Genes based on Gene Expression Profiles and PPI Data

Background:

Breast cancer is one of the most common malignancies, and a threat to female health all over the world. However, the molecular mechanism of breast cancer has not been fully discovered yet.

Objective:

It is crucial to identify breast cancer-related genes, which could provide new biomarker for breast cancer diagnosis as well as potential treatment targets.

Methods:

Here we used the minimum redundancy-maximum relevance (mRMR) method to select significant genes, then mapped the transcripts of the genes on the Protein-Protein Interaction (PPI) network and traced the shortest path between each pair of two proteins.

Results:

As a result, we identified 24 breast cancer-related genes whose betweenness were over 700. The GO enrichment analysis indicated that the transcription and oxygen level are very important in breast cancer. And the pathway analysis indicated that most of these 24 genes are enriched in prostate cancer, endocrine resistance, and pathways in cancer.

Conclusion:

We hope these 24 genes might be useful for diagnosis, prognosis and treatment for breast cancer.

No detection of EBV, BKV and JCV in breast cancer tissue samples in Iran

OBJECTIVE

The most common cancer amongst women is breast cancer. Reports on the role of EBV, BKV, and JCV in the development of breast cancer are controversial. Hence, the aim of this study was to determine the frequency of EBV, BKV, and JCV in malignant breast tumors in comparison with benign ones.

RESULTS

A total of 300 breast biopsy tissues were included, of which 150 were malignant and 150 benign. After deparaffinization, tissues were subjected to DNA extraction. β-globin gene was amplified by PCR to evaluate the quality of extracted DNA. In house PCRs assay was performed to detect EBV, JCV, and BKV genome fragment. The mean age of malignant and benign groups was 45.0 ± 9.4 and 35.2 ± 12.1 years old. Out of 150 malignant samples, 146 were ductal, two lobular and two samples both invasive ductal and lobular carcinoma. In the benign group, 96, 52 and two samples were fibroadenoma, fibrocystic, and adenosis types, respectively. Genomic DNA fragment of EBV, BKV, and JCV was not found in any of the malignant and benign breast tissues.

CONCLUSION

According to our finding, there is the possibility that EBV, BKV, and JCV are not involved in breast cancer pathogenesis.

The prevalence of EBV and CMV DNA in epithelial ovarian cancer

Background

The underlying cause of epithelial ovarian cancer (EOC) is unknown. It has been theorized that infectious agents could contribute to ovarian tumorigenesis.

Objective

To investigate the potential role of oncogenic viral infection in EOC, we examined the prevalence of Epstein-Barr Virus (EBV) DNA and cytomegalovirus (CMV) DNA in EOC tissue samples.

Methods

Formalin-fixed, paraffin-imbedded (FFPE) tumor tissue samples from 198 patients included in the Danish Pelvic Mass Study were studied: 163 with serous adenocarcinomas, 15 with endometrioid adenocarcinomas, 11 with mucinous adenocarcinomas, and nine with clear-cell carcinomas. For controls in the EBV analysis, we used 176 tissue samples from patients diagnosed with benign mucinous cystadenomas. EBV and CMV genotyping was performed by real-time polymerase chain reaction with CMV and EBV CE-IVD approved kits. In-situ hybridization (ISH) was performed on the EBV positive samples.

Results

Sufficient DNA material was obtained in 191 and 174 tissue samples from cases and controls, respectively. Ten of 191 case samples (5.2%) and one of 174 control samples (0.5%) were positive for EBV DNA (P value = 0.011). CMV DNA was detected in only one case sample (0.5%). ISH confirmed that three of the samples were of stromal origin, while the remaining seven tested negative for EBV.

Conclusions

This study is the first to demonstrate a higher prevalence of EBV DNA in tissue samples from patients with EOC than in a benign control group. However, the cellular origin of seven of the samples could not be determined by ISH analysis. Our study did not support an association between CMV and EOC.

Association of Epstein - Barr virus and breast cancer in Eritrea

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.

Breast Cancer Association with Cytomegalo Virus-A Tertiary Center Case-Control Study

PURPOSE

Cytomegalo virus is a ubiquitous virus often associated with congenital infections. Some studied have claimed an association between infection with this virus and development of breast cancer. The aim of this prospective research was to study the difference in Cytomegalo virus sero-positivity among patients with breast cancer and benign breast diseases, and thereby to prove any association.

MATERIALS AND METHODS

This was a hospital based Case-Control study conducted at the General Surgery wards of our hospital, a tertiary level public sector health care institution. This study was done on 130 patients with breast swellings who underwent surgical excision of their lumps over a 1-year period. Patients with histologically proven malignancies were selected as cases while proven benign cases were deemed to be the controls. IgG and IgM antibodies to Cytomegalo virus were checked in the patients from both groups.

RESULTS

All of the studied patients turned out to be positive for Immunoglobulin G against Cytomegalo virus while all the patients were found to be negative for Immunoglobulin M. There was no difference in the antibody titers among the benign and malignant cases in the study. Logistic regression calculation was also carried out including the study parameters and other known risk factors.

CONCLUSIONS

We conclude that there is no association between Cytomegalo virus sero-positivity and breast cancer. Another conclusion is that the studied adult population has been exposed to Cytomegalo virus in some point of their lives. Further studies of a larger magnitude are essential to confirm our results.

Types of Immune-Inflammatory Responses as a Reflection of Cell-Cell Interactions under Conditions of Tissue Regeneration and Tumor Growth

Inflammatory infiltration of tumor stroma is an integral reflection of reactions that develop in response to any damage to tumor cells including immune responses to antigens or necrosis caused by vascular disorders. In this review, we use the term "immune-inflammatory response" (IIR) that allows us to give an integral assessment of the cellular composition of the tumor microenvironment. Two main types of IIRs are discussed: type 1 and 2 T-helper reactions (Th1 and Th2), as well as their inducers: immunosuppressive responses and reactions mediated by Th22 and Th17 lymphocytes and capable of modifying the main types of IIRs. Cellular and molecular manifestations of each IIR type are analyzed and their general characteristics and roles in tissue regeneration and tumor growth are presented. Since inflammatory responses in a tumor can also be initiated by innate immunity mechanisms, special attention is given to inflammation based on them. We emphasize that processes accompanying tissue regeneration are prototypes of processes underlying cancer progression, and these processes have the same cellular and molecular substrates. We focus on evidence that tumor progression is mainly contributed by processes specific for the second phase of "wound healing" that are based on the Th2-type IIR. We emphasize that the effect of various types of immune and stroma cells on tumor progression is determined by the ability of the cells and their cytokines to promote or prevent the development of Th1- or Th2-type of IIR. Finally, we supposed that the nonspecific influence on the tumor caused by the cytokine context of the Th1- or Th2-type microenvironment should play a decisive role for suppression or stimulation of tumor growth and metastasis.

Epstein-Barr virus infection and breast invasive ductal carcinoma in Egyptian women: A single center experience

BACKGROUND

A controversy of the role of Epstein-Barr virus (EBV) infection in breast carcinomas has been reported in the literature.

OBJECTIVES

We carried on this research to explore possible association between EBV infection and breast invasive ductal carcinoma (IDC) in Egyptian women attending our center.

STUDY DESIGN

This study carried out at Sohag university hospital on 84 paraffin embedded samples of breast tissue, of them 42 breast IDC as the case group and 42 breast fibroadenomas as the control group. Nested PCRand immunohistochemistry (IHC) done separately for all samples to identify the Epstein-Barr nuclear antigen-1 (EBNA-1) gene and EBV latent membrane protein-1 (LMP-1) respectively, in breast cancer cells and controls.

RESULTS

Specimen considered positive when both (EBNA-1) gene and LMP-1 were detected using PCR and IHC separately for the same sample, this was achieved by 10/42 (23.81%) of breast IDC (case group) and 6/42 (14.29%) of breast fibro-adenomas (control group) (P-value=0.4). Nodal involvement was the only parameter that demonstrated a significant statistical relationship with EBV presence in cancerous tissue with p-value=0.003.

CONCLUSION

Our research could not find a significant statistical association between EBV infection and breast IDC in Egyptian women attending our center, but, there might be an association between the existence of EBV and tumor aggressiveness.

Evidence for the association of Epstein-Barr Virus in breast cancer in Indian patients using in-situ hybridization technique

Epstein-Barr Virus (EBV) is etiologically linked to Burkitt lymphoma (BL), nasopharyngeal carcinoma, post-transplant lymphomas, Hodgkin disease, and possibly other tumors. However, the association of oncogenic EBV with breast carcinoma (BC) is still controversial and a matter of debate. We aimed to study the presence of EBV genome in BC cases in Indian patients and its association with the clinicopathological features. The formalin fixed paraffin embedded tissues from 83 women with primary invasive BC were studied for the presence of EBV by in-situ hybridization (ISH) technique for Epstein-Barr Virus Encoded RNA (EBER) with appropriate controls. Correlation of EBER-ISH positivity with clinicopathological features was performed using Fisher exact test and P<.05 was considered as significant. Eighty-three BC cases were comprised of 47 (56.5%) triple negative breast cancers (TNBC), 17 (20.5%) hormone positive and 19 (22.9%) HER2 positive cases. Of 83 cases, 25 cases (30.1%) were positive for EBER-ISH test. The positivity was restricted to the tumor cells and not seen in the surrounding breast lobules. EBER-ISH positivity was statistically associated with larger tumor size (52.6% in >5 cm tumors vs 19.3% in ≤5 cm; P=.014) and with TNBCs (21/47 [44.7%] in TNBCs vs 4/36 [11.1%] in non-TNBCs; P=.001). A possible causal association of EBV in BC cases in Indian patients is suggested by high frequency of EBER-ISH positivity noted in our study. This might have therapeutic significance because of the possible role of EBV specific cytotoxic T cells in targeting EBV associated tumor cells and can be considered as a potential targeted therapy. To the best of our knowledge, this is the first study from India to address this issue using EBER-ISH technique.

Epstein-Barr virus (EBV)-associated epithelial and non-epithelial lesions of the oral cavity

Epstein–Barr virus (EBV) is known to be associated with the development of malignant lymphoma and lymphoproliferative disorders (LPDs) in immunocompromised patients. EBV, a B-lymphotropic gamma-herpesvirus, causes infectious mononucleosis and oral hairy leukoplakia, as well as various pathological types of lymphoid malignancy. Furthermore, EBV is associated with epithelial malignancies such as nasopharyngeal carcinoma (NPC), salivary gland tumor, gastric carcinoma and breast carcinoma. In terms of oral disease, there have been several reports of EBV-related oral squamous cell carcinoma (OSCC) worldwide. However, the role of EBV in tumorigenesis of human oral epithelial or lymphoid tissue is unclear. This review summarizes EBV-related epithelial and non-epithelial tumors or tumor-like lesions of the oral cavity. In addition, we describe EBV latent genes and their expression in normal epithelium, inflamed gingiva, epithelial dysplasia and SCC, as well as considering LPDs (MTX- and age-related) and DLBCLs of the oral cavity.

Analysis of Viral Epigenotypes Using Bisulfite Sequencing: A Detailed Protocol for the Crucial Bisulfite Modification and PCR Amplification Steps

Characterization of viral DNA methylation patterns is essential to understand its function in viral pathogenesis. Bisulfite modification, followed by polymerase chain reaction (PCR) and sequencing is the most effective method for the high resolution methylation mapping of viral genomes. Since the bisulfite modification and PCR steps are the most critical ones, an optimized protocol for these two steps is presented, with special attention to potential pitfalls.

Evaluation Frequency of Merkel Cell Polyoma, Epstein-Barr and Mouse Mammary Tumor Viruses in Patients with Breast Cancer in Kerman, Southeast of Iran

Breast cancer is the most common cancer among women worldwide. Roles of the Epstein-Barr, Merkel cell polyoma and mouse mammary tumor viruses in breast carcinogenesis are still controversial although any relationship would clearly be important for breast cancer etiology, early detection and prevention. In the present study associations between EBV, MMTV and Merkel cell polyoma virus and breast cancer in 100 Iranian patients were evaluated using paraffin-embedded tissues. EBER RNA and expression of p53 and large T antigen were evaluated by real time PCR and CD34, p63, HER2, PR and ER markers were studied by immunohistochemistry. EBV was detected in 8/100 (8%), MMTV in 12/100 (12%), MPy in 3/100 (3%) and EBER RNA in 18/100 (18%) cases. None of the control samples demonstrated any of the viruses. p53 was suppressed in EBV, MPy and MMTV positive samples. The large T antigen rate was raised in MPy positive samples. Our results showed that EBV, MMTV and the Merkel cell polyoma virus are foundwith some proportion of breast cancers in our patients, suggesting that these viruses might have a significant role in breast cancer in Kerman, southeast of Iran.

Inflammatory and Non-inflammatory Breast Cancer: A Potential Role for Detection of Multiple Viral DNAs in Disease Progression

BACKGROUND

Inflammatory breast cancer (IBC) is the most lethal form of breast cancer. Multiple viral infections in IBC tissues were found to be associated with disease pathogenesis.

OBJECTIVE

The aim of the present study was to correlate the incidence of viral DNA with breast cancer progression.

MATERIALS AND METHODS

Overall, 135 women diagnosed with breast cancer were enrolled in this study. Using polymerase chain reaction and sequencing assays, we determined the incidence of human papillomavirus types 16 and 18 (HPV-16 and -18), human cytomegalovirus (HCMV), Epstein-Barr virus, human herpes simplex virus type 1 and 2, and human herpes virus type 8 (HHV-8) in breast carcinoma tissue biopsies. We also assessed the expression of the cell proliferation marker Ki-67 by immunohistochemistry in association with the incidence of viral DNA.

RESULTS

HCMV and HPV-16 were the most detected viral DNAs in breast carcinoma tissues; however, the frequency of HCMV and HHV-8 DNA were significantly higher in IBC than non-IBC tissues. Moreover, the prevalence of multiple viral DNAs was higher in IBC than non-IBC tissues. The incidence of multiple viral DNAs positively correlates with tumor size and number of metastatic lymph nodes in both non-IBC and IBC patients. The expression of Ki-67 was found to be significantly higher in both non-IBC and IBC tissues in which multiple viral DNAs were detected.

CONCLUSIONS

The incidence of multiple viral DNAs in IBC tissues was higher compared with non-IBC tissues. The present results suggest the possibility of a functional relationship between the presence of multiple viral DNAs and disease pathogenesis.

Detection of Epstein-Barr virus genome and latent infection gene expression in normal epithelia, epithelial dysplasia, and squamous cell carcinoma of the oral cavity

A relationship between Epstein-Barr virus (EBV) infection and cancer of lymphoid and epithelial tissues such as Burkitt's lymphoma, Hodgkin's disease, nasopharyngeal carcinoma (NPC), gastric carcinoma, and oral cancer has been reported. EBV is transmitted orally and infects B cells and epithelial cells. However, it has remained uncertain whether EBV plays a role in carcinogenesis of oral mucosal tissue. In the present study, we detected the EBV genome and latent EBV gene expression in normal mucosal epithelia, epithelial dysplasia, and oral squamous cell carcinoma (OSCC) to clarify whether EBV is involved in carcinogenesis of the oral cavity. We examined 333 formalin-fixed, paraffin-embedded tissue samples (morphologically normal oral mucosa 30 samples, gingivitis 32, tonsillitis 17, oral epithelial dysplasia 83, OSCC 150, and NPC 21). EBV latent infection genes (EBNA-2, LMP-1) were detected not only in OSCC (50.2 %, 10.7 %) but also in severe epithelial dysplasia (66.7 %, 44.4 %), mild to moderate epithelial dysplasia (43.1 %, 18.5 %), gingivitis (78.1 %, 21.9 %), and normal mucosa (83.3 %, 23.3 %). Furthermore, the intensity of EBV latent infection gene expression (EBER, LMP-1) was significantly higher in severe epithelial dysplasia (94.4 %, 72.2 %) than in OSCC (34.7 %, 38.7 %). These results suggest that EBV latent infection genes and their increased expression in severe epithelial dysplasia might play an important role in the dysplasia-carcinoma sequence in the oral cavity.

Chimerically fused antigen rich of overlapped epitopes from latent membrane protein 2 (LMP2) of Epstein-Barr virus as a potential vaccine and diagnostic agent

Epstein-Barr virus (EBV) is prevalent throughout the world and is associated with several malignant diseases in humans. Latent membrane protein 2 (LMP2) of EBV plays a crucial role in the pathogenesis of EBV-associated tumors; therefore, LMP2 has been considered to be a potential immunodiagnostic and immunotherapeutic target. A multi-epitope-based antigen is a promising option for therapeutic vaccines and diagnoses of such malignancies. In this study, we systematically screened cytotoxic T lymphocyte (CTL), helper T cell (Th) and B-cell epitopes within EBV-LMP2 using bioinformatics. Based on the screen, two peptides rich in overlapping epitopes of both T cells and B cells were selected to construct a plasmid containing the sequence for a chimeric multi-epitope protein referred to as EBV-LMP2m, which is composed of LMP2aa195∼232 and LMP2aa419∼436. The EBV-LMP2m protein was expressed in E. coli BL21 (DE3) after prokaryotic codon optimization. Inoculation of the purified chimeric antigen in BALB/c mice induced not only high levels of specific IgG in the serum and secretory IgA in the vaginal mucus but also a specific CTL response. By using purified EBV-LMP2m as an antigen, the presence of specific IgG in the serum specimens of 202 nasopharyngeal carcinoma (NPC) patients was effectively detected with 52.84% sensitivity and 95.40% specificity, which represents an improvement over the traditional detection method based on VCA-IgA (60.53% sensitivity and 76.86% specificity). The above results indicate that EBV-LMP2m may be used not only as a potential target antigen for EBV-associated tumors but also a diagnostic agent for NPC patients.

No significant viral transcription detected in whole breast cancer transcriptomes

Background

Studies evaluating the presence of viral sequences in breast cancer (BC), including various strains of human papillomavirus and human herpes virus, have yielded conflicting results. Most were based on RT-PCR and in situ hybridization.

Methods

In this report we searched for expressed viral sequences in 58 BC transcriptomes using five distinct in silico methods. In addition, we complemented our RNA sequencing results with exome sequencing, PCR and immunohistochemistry (IHC) analyses. A control sample was used to test our in silico methods.

Results

All of the computational methods correctly detected viral sequences in the control sample. We identified a small number of viral sequences belonging to human herpesvirus 4 and 6 and Merkel cell polyomavirus. The extremely low expression levels—two orders of magnitude lower than in a typical hepatitis B virus infection in hepatocellular carcinoma—did not suggest active infections. The presence of viral elements was confirmed in sample-matched exome sequences, but could not be confirmed by PCR or IHC.

Conclusions

Our results show that no viral sequences are expressed in significant amounts in the BC investigated. The presence of non-transcribed viral DNA cannot be excluded.

Cytomegalovirus and Epstein-Barr virus in breast cancer

Findings of polymerase chain reaction (PCR) studies of cytomegalovirus (CMV) and Epstein-Barr virus (EBV) and breast cancer vary, making it difficult to determine whether either, both, or neither virus is causally associated with breast cancer. We investigated CMV and EBV in paired samples of breast cancer and normal breast tissue from 70 women using quantitative PCR. A serum sample from each woman was tested for CMV and EBV IgG. To place our results in context, we reviewed the existing literature and performed a meta-analysis of our results together with previous PCR studies of EBV, CMV, and breast cancer. Of the serology samples, 67 of 70 (96%) were EBV IgG positive and 49 of 70 (70%) were CMV IgG positive. QPCR detected EBV in 24 (34%) of the tumour and 9 (13%) of the paired normal specimens and CMV in 0 (0%) of the tumour and 2 (3%) of the paired normal specimens. Our findings, together with earlier results summarised in the meta-analysis, suggest several possibilities: variable findings may be due to limitations of molecular analyses; 'hit and run' oncogenesis may lead to inconsistent results; one or both viruses has a role at a later stage in breast cancer development; infection with multiple viruses increases breast cancer risk; or neither virus has a role. Future studies should focus on ways to investigate these possibilities, and should include comparisons of breast cancer tissue samples with appropriate normal tissue samples.

Epstein-Barr virus infection and clinical outcome in breast cancer patients correlate with immune cell TNF-α/IFN-γ response

BACKGROUND

For nearly two decades now, various studies have reported detecting the Epstein-Barr virus (EBV) in breast cancer (BC) cases. Yet the results are unconvincing, and their interpretation has remained a matter of debate. We have now presented prospective data on the effect of EBV infection combined with survival in patients enrolled in a prospective study.

METHODS

We assessed 85 BC patients over an 87-month follow-up period to determine whether EBV infection, evaluated by qPCR in both peripheral blood mononuclear cells (PBMCs) and tumor biopsies, interacted with host cell components that modulate the evolution parameters of BC. We also examined the EBV replicating form by the titration of serum anti-ZEBRA antibodies. Immunological studies were performed on a series of 35 patients randomly selected from the second half of the survey, involving IFN-γ and TNF-α intracellular immunostaining tests performed via flow cytometry analysis in peripheral NK and T cells, in parallel with EBV signature. The effect of the EBV load in the blood or tumor tissue on patient survival was analyzed using univariate and multivariate analyses, combined with an analysis of covariance.

RESULTS

Our study represents the first ever report of the impact of EBV on the clinical outcome of BC patients, regardless of tumor histology or treatment regimen. No correlation was found between: (i) EBV detection in tumor or PBMCs and tumor characteristics; (ii) EBV and other prognostic factors. Notably, patients exhibiting anti-ZEBRA antibodies at high titers experienced poorer overall survival (p = 0.002). Those who recovered from their disease were found to have a measurable EBV DNA load, together with a high frequency of IFN-γ and TNF-α producing PBMCs (p = 0.04), which indicates the existence of a Th1-type polarized immune response in both the tumor and its surrounding tissue.

CONCLUSIONS

The replicative form of EBV, as investigated using anti-ZEBRA titers, correlated with poorer outcomes, whereas the latent form of the virus that was measured and quantified using the EBV tumor DNA conferred a survival advantage to BC patients, which could occur through the activation of non-specific anti-tumoral immune responses.

Carcinogenic viruses and solid cancers without sufficient evidence of causal association

Viral infections are important risk factors for tumor development in humans. Selected types of cancers, either lymphomas or carcinomas, for which there is sufficient evidence in humans of a causal association with specific viruses, have been identified. Experimental and clinical data on the possible association of other tumor types and carcinogenic viruses are presently controversial. In this article, we review the current evidence on the relationship between breast, colorectal and lung cancers and carcinogenic viruses. The majority of the publications reviewed do not provide definitive evidence that the viruses studied are associated with breast, colon and lung cancers. However, since this association may be clinically relevant for some tumor subtypes (i.e., lung cancer and papillomaviruses), there is an urgent need for further investigation on this topic. Using innovative laboratory techniques for viral detection on well-defined tumor types, National and International networks against cancer should encourage and organize concerted research programs on viruses and solid cancer association.

BamHI-A rightward frame 1, an Epstein-Barr virus-encoded oncogene and immune modulator

Epstein–Barr virus (EBV) causes several benign and malignant disorders of lymphoid and epithelial origin. EBV-related tumors display distinct patterns of viral latent gene expression, of which the BamHI-A rightward frame 1 (BARF1) is selectively expressed in carcinomas, regulated by cellular differentiation factors including ΔNp63α. BARF1 functions as a viral oncogene, immortalizing and transforming epithelial cells of different origin by acting as a mitogenic growth factor, inducing cyclin-D expression, and up-regulating antiapoptotic Bcl-2, stimulating host cell growth and survival. In addition, secreted hexameric BARF1 has immune evasive properties, functionally corrupting macrophage colony stimulating factor, as supported by recent functional and structural data. Therefore, BARF1, an intracellular and secreted protein, not only has multiple pathogenic functions but also can function as a target for immune responses. Deciphering the role of BARF1 in EBV biology will contribute to novel diagnostic and treatment options for EBV-driven carcinomas. Herein, we discuss recent insights on the regulation of BARF1 expression and aspects of structure-function relating to its oncogenic and immune suppressive properties. © 2013 The Authors. Reviews in Medical Virology published by John Wiley & Sons, Ltd.

Association of Epstein-Barr virus infection and breast carcinoma

INTRODUCTION

A controversy regarding the association of Epstein-Barr virus (EBV) with breast carcinomas has recently been reported in the literature. The present study was carried out in an attempt to determine whether there is a relationship between latent infection with EBV and breast carcinomas in Jordanian females.

MATERIAL AND METHODS

Extraction of DNA from the archive samples of breast carcinoma cases embedded in paraffin wax was performed and the extracted DNA was subjected to polymerase chain reaction amplification to detect the EBV genome using four sets of primers for EBER 2, BNLF-1, EBNA 2, and Gp220. Immunohistochemistry study was performed on sections of 4 µm which were cut from paraffin blocks of tumor and control groups. Monoclonal antibody against EBNA-1 was applied to all slides to identify the EBV-infected tumor cells. Detection was performed using the Dako envision dual link system.

RESULTS

DNA was successfully extracted from 92 paraffin embedded samples of breast carcinoma patients, and from 49 normal samples. The extracted DNA was confirmed by using glyceraldehyde-3-phosphate-dehydrogenase (GAPDH) primers. Twenty-four out of 92 breast carcinoma specimens was found to be infected with EBV as compared to 3 out of 49 control group specimens, which represented a statistically significant difference (p-value using χ(2) = 0.008). Immunohistochemically, 24 (26%) of the 92 studied samples were found to be positive, showing EBNA-1 granular nuclear staining in tumor epithelial cells.

CONCLUSIONS

These findings suggest an association between EBV infection and breast carcinoma development.

Upregulation of special AT-rich-binding protein 1 by Epstein-Barr virus latent membrane protein 1 in human nasopharyngeal cells and nasopharyngeal cancer

A global regulator of chromatin remodelling and gene expression, special AT-rich-binding protein 1 (SATB1) has been implicated in promotion of growth and metastasis of a number of cancers. Here, we demonstrate that the principal oncogene of Epstein-Barr virus (EBV), latent membrane protein 1 (LMP1) upregulates SATB1 RNA and protein expression in human nasopharyngeal cell lines. Silencing of endogenously expressed SATB1 with specific short hairpin RNA decreases cell proliferation and resistance to apoptosis induced by growth factor withdrawal. Additionally, we provide evidence that LMP1-mediated expression of Survivin, a multifunctional protein involved in promoting cell growth and survival, is mediated at least in part by SATB1 in human nasopharyngeal cells. Finally, we show that SATB1 protein levels are elevated in tissue samples from patients with nasopharyngeal carcinoma (NPC), and are directly correlated with the expression of LMP1. Taken together, our results suggest that SATB1 functions as a pro-metastatic effector of LMP1 signalling in EBV-positive NPC.

An expanded myeloid derived suppressor cell population does not play a role in gammaherpesvirus-exacerbated breast cancer metastases

Background

Mice latently infected with murine gammaherpesvirus 68 (HV-68) and transplanted with 4 T1 breast cancer cells developed exacerbated metastatic lesions when compared to controls. The mechanisms responsible for this viral-exacerbated disease were not clear. The ability of HV-68 infection to induce S100A8 and S100A9 production and to expand a population of CD11b+Gr-1+ cells suggested that increased numbers, or activity, of viral-expanded myeloid derived suppressor cells (MDSCs) might contribute to HV-68-associated metastatic breast cancer in this model. We questioned whether mock or HV-68 infected mice with significant breast cancer might have differences in the number and/or activity of MDSCs.

Methods

Myeloid-derived macrophages and dendritic cells were isolated from normal mice and cultured in vitro with HV-68 to assess S100A8 and S100A9 mRNA and protein expression. In vivo studies were performed using groups of mice that were mock treated or infected with HV-68. After viral latency was established, 4 T1 breast cancer cells were transplanted in mice. When primary breast tumors were present mice were euthanized and cells isolated for phenotyping of myeloid cell populations using FACS, and for ex vivo analysis of suppressor activity. Serum from these animals was also collected to quantify S100A8 and S100A9 levels.

Results

In vitro studies demonstrated that direct exposure of myeloid cells to HV-68 did not induce increased expression of S100A8 or S100A9 mRNAs or secreted protein. HV-68 infected mice with metastatic breast cancer disease had no increases in S100A8/A9 levels and no significant increases in the numbers or activation of CD11b+Gr-1+MDSCs when compared to mock treated mice with breast cancer.

Conclusions

Together these studies are consistent with the notion that expanded myeloid derived suppressor cells do not play a role in gammaherpesvirus-exacerbated breast cancer metastases. The mechanisms responsible for HV-68 induced exacerbation of metastatic breast cancer remain unclear.

Exacerbated metastatic disease in a mouse mammary tumor model following latent gammaherpesvirus infection

Background

Controversy exists as to the ability of human gammaherpesviruses to cause or exacerbate breast cancer disease in patients. The difficulty in conducting definitive human studies can be overcome by investigating developing breast cancer in a mouse model. In this study, we utilized mice latently infected with murine gammaherpesvirus 68 (HV-68) to question whether such a viral burden could exacerbate metastatic breast cancer disease using a mouse mammary tumor model.

Results

Mice latently infected with HV-68 had a similar primary tumor burden, but much greater metastatic disease, when compared to mock treated mice given the transplantable tumor, 4 T1. This was true for lung lesions, as well as secondary tumor masses. Increased expression of pan-cytokeratin and VEGF-A in tumors from HV-68 infected mice was consistent with increased metastatic disease in these animals. Surprisingly, no viral particles could be cultured from tumor tissues, and the presence of viral DNA or RNA transcripts could not be detected in primary or secondary tumor tissues.

Conclusions

Latent HV-68 infection had no significant effect on the size of primary 4 T1 mammary tumors, but exacerbated the number of metastatic lung lesions and secondary tumors when compared to mock treated mice. Increased expression of the tumor marker, pan-cytokeratin, and VEGF-A in tumors of mice harboring latent virus was consistent with an exacerbated metastatic disease. Mechanisms responsible for this exacerbation are indirect, since no virus could be detected in cancerous tissues.

Advances in Virus-Directed Therapeutics against Epstein-Barr Virus-Associated Malignancies

Epstein-Barr virus (EBV) is the causal agent in the etiology of Burkitt's lymphoma and nasopharyngeal carcinoma and is also associated with multiple human malignancies, including Hodgkin's and non-Hodgkin's lymphoma, and posttransplantation lymphoproliferative disease, as well as sporadic cancers of other tissues. A causal relationship of EBV to these latter malignancies remains controversial, although the episomic EBV genome in most of these cancers is clonal, suggesting infection very early in the development of the tumor and a possible role for EBV in the genesis of these diseases. Furthermore, the prognosis of these tumors is invariably poor when EBV is present, compared to their EBV-negative counterparts. The physical presence of EBV in these tumors represents a potential "tumor-specific" target for therapeutic approaches. While treatment options for other types of herpesvirus infections have evolved and improved over the last two decades, however, therapies directed at EBV have lagged. A major constraint to pharmacological intervention is the shift from lytic infection to a latent pattern of gene expression, which persists in those tumors associated with the virus. In this paper we provide a brief account of new virus-targeted therapeutic approaches against EBV-associated malignancies.

Epstein-Barr virus infection and sporadic breast cancer risk: a meta-analysis

Background

A large number of epidemiological studies have evaluated the association between Epstein-Barr virus infection and breast carcinoma risk but results have been inconsistent.

Methodology

Research using the polymerase chain reaction technique for detecting the Epstein-Barr virus was selected; 24 studies and 1535 cases were reviewed. Information on the study populations, sample types, publication calendar period and histological types of breast carcinoma were collected. An unconditional logistic regression model was used to analyze potential parameters related to the Epstein-Barr virus prevalence. A Kappa test was used to evaluate the consistency in detecting different Epstein-Barr virus DNA regions. Nine studies that included control groups and 1045 breast cancer cases were adopted in this meta-analysis.

Conclusions

We found that 29.32% of the patients with breast carcinoma were infected with the Epstein-Barr virus. The prevalence of Epstein-Barr was highest in Asia (35.25%) and lowest in the USA (18.27%). Statistical analysis revealed a trend that showed lobular breast carcinoma might have the strongest association with Epstein-Barr virus infection. This meta-analysis showed a significant increase in breast malignancy risk in patients testing positive for the Epstein-Barr virus (OR = 6.29, 95% CI = 2.13–18.59). This result suggests that an Epstein-Barr virus infection is statistically associated with increased breast carcinoma risk.

Epstein-Barr virus is seldom found in mammary epithelium of breast cancer tissue using in situ molecular methods

Epstein-Barr virus (EBV) has been proposed as a possible etiological agent of breast cancer based on 21 reports of EBV in malignant breast tissues. Most of these studies used standard and nested solution polymerase chain reaction (PCR) techniques, both disadvantaged by susceptibility to contamination from laboratory EBV, and the inability to localize the signal to a specific cell type. To avoid these issues, we used in situ molecular methods of viral detection to reassess the frequency of EBV in malignant breast tissue. We used a commercial in situ hybridization (ISH) system with an EBER genome target, and a non-commercial in situ PCR (IS-PCR) method using primers specific for the BamH1 region. The assays were performed on malignant breast tissue sections from 70 breast cancer patients at the M. D. Anderson Cancer Center, Houston, TX. EBV was found in mammary epithelial cells, the cell type from which most breast cancers arise, in 2/70 (2.9%) of specimens using IS-PCR and in none of the specimens using ISH. Based on these findings that EBV was present in human mammary epithelial cells so infrequently, it is unlikely to play a causative role in most types of breast cancer.

Are viruses associated with human breast cancer? Scrutinizing the molecular evidence

The three viruses most studied as possible causes of human breast cancer are mouse mammary tumor virus-like sequences (MMTV-LS), Epstein-Barr virus (EBV), and oncogenic (high risk) types of human papilloma virus (HPV). The first step in fulfilling traditional criteria for inferring that a cancer is caused by a virus is to demonstrate the virus in the affected tissue. Molecular techniques, compared to host antibody assessment and immunohistochemistry, are the most definitive in establishing viral presence. Results of 85 original molecular research investigations to detect one or more of the three viruses have been extremely divergent with no consensus reached. We evaluated the methodology of these studies for the following: type of molecular assay, DNA/RNA quality control, positive and negative assay controls, type of fixation, genome targets, methods for preventing and detecting molecular contamination, pathology of specimens processed, sample size, and proportion of specimens positive for the viral genome region targeted. Only seven of the studies convincingly demonstrated the presence of an oncogenic virus biomarker (EBV: 4/30 studies (13%); HPV 3/29 studies (10%), whereas 25 convincingly demonstrated absence of the virus studied (MMTV-LS: 4/25 (16%); EBV: 15/30 (50%); 6/29 (21%). The remainder of the studies suffered shortcomings, which, in our opinion, prevented a definitive conclusion. Only one of the studies compared frequency of the virus in breast tissue of breast cancer patients versus appropriate normal control subjects with no history of breast cancer. None of the studies were designed as epidemiologic studies to determine if the presence of the virus was significantly associated with breast cancer. Based on our evaluation, the data in the publications reviewed here remain preliminary, and do not justify a conclusion that MMTV-LS, HPV, or EBV are causally associated with breast cancer. However, they form a valuable basis for redirecting future studies.