Epstein-Barr virus as a marker of biological aggressiveness in breast cancer

The Role of Oncogenic Viruses in the Pathogenesis of Sporadic Breast Cancer: A Comprehensive Review of the Current Literature

Breast cancer is the most common malignancy in the female sex; although recent therapies have significantly changed the natural history of this cancer, it remains a significant challenge. In the past decade, evidence has been put forward that some oncogenic viruses may play a role in the development of sporadic breast cancer; however, data are scattered and mostly reported as sparse case series or small case-control studies. In this review, we organize and report current evidence regarding the role of high-risk human papillomavirus, mouse mammary tumor virus, Epstein-Barr virus, cytomegalovirus, bovine leukemia virus, human polyomavirus 2, and Merkel cell polyomavirus in the pathogenesis of breast cancer.

Prevalence of Hepatitis B Virus Markers among the Women with Breast Cancer

INTRODUCTION

Breast cancer represents a formidable peril to the female populace on a worldwide level. The association between breast cancer and various factors, including viral infections, has been extensively investigated. Recently, the link between HBV infection and breast cancer patients has garnered attention. The present research aims to assess the prevalence of HBV markers among women diagnosed with breast cancer in Ahvaz city, Iran.

MATERIALS AND METHODS

Serum specimens were procured from 90 patients who had been clinically diagnosed with breast cancer. The age of the patients ranged from 29 to 80 years, with a mean age of 49.42±10.7. Histological examination of biopsy specimens revealed that 75 (83.33%) were ductal, 11 (8.88%) lobular, 2 (2.22%) mucinous, 1 (1.11%) medullary, and 1 (1.11%) was metastatic. The serum samples were subjected to initial HBsAg and anti-HBc testing via ELISA. Samples that tested seropositive (HBsAg + anti-HBc) were subsequently analyzed for the S region of HBV through nested PCR and DNA sequencing. Finally, a phylogenetic tree was constructed for positive HBV DNA tests.

RESULTS

Among the 5/90 (5.55%) cancer patients, it was found that 3 (3.33%) cases of ductal carcinoma and one (1.11%) lobular carcinoma displayed positivity for HBV markers (HBsAg, anti-HBc, HBV PCR). Notably, one (1.11%) patient with ductal carcinoma solely demonstrated anti-HBc positivity. The phylogenetic tree analysis of the S region revealed that all HBV strains identified were categorized as genotype D.

CONCLUSION

The statistical analysis did not reveal any significant findings (p= 0.315) in the distribution of cancer types across different age groups. Among patients diagnosed with breast cancer, a notable prevalence of 5.5% was observed in HBV markers. The dominant HBV genotype among breast cancer patients was identified as genotype D.

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.

Exploring the link between viruses and cancer in companion animals: a comprehensive and comparative analysis

Currently, it is estimated that 15% of human neoplasms globally are caused by infectious agents, with new evidence emerging continuously. Multiple agents have been implicated in various forms of neoplasia, with viruses as the most frequent. In recent years, investigation on viral mechanisms underlying tumoral transformation in cancer development and progression are in the spotlight, both in human and veterinary oncology. Oncogenic viruses in veterinary medicine are of primary importance not only as original pathogens of pets, but also in the view of pets as models of human malignancies. Hence, this work will provide an overview of the main oncogenic viruses of companion animals, with brief notes of comparative medicine.

Prevalence of Polyomaviruses and Herpesviruses in Moroccan Breast Cancer

Breast cancer (BC) is the most frequently diagnosed cancer and the leading cause of cancer death in women worldwide, accounting for 24.5% of total new cancer cases and 15.5% of total cancer deaths. Similarly, BC is the most common cancer among Moroccan women, comprising a noteworthy percentage of 40% of all cancers in women. Globally, 15% of cancers are attributable to infections; among them, viruses play a significant role. The present study aimed to explore the presence of a wide range of viral DNA in samples recovered from 76 Moroccan patients with BC and 12 controls using Luminex technology. The explored viruses were as follows: 10 polyomaviruses (PyVs): BKV, KIV, JCV, MCV, WUV, TSV, HPyV6, HPyV7, HPyV9, and SV40; and 5 Herpesviruses (HHVs): CMV, EBV1, EBV2, HSV1, and HSV2. Our results revealed the presence of PyVs DNA in both control (16.7%) and BC tissues (18.4%). Nonetheless, HHV DNA was detected exclusively in BC tissues (23.7%), with a predominance of Epstein-Barr virus (EBV) (21%). In conclusion, our study highlights the presence of EBV in human BC tissues, which may play an important role in its development and/or progression. Further investigations are needed to confirm the presence/co-presence of these viruses in BC.

Epstein-Barr virus in breast carcinoma and in triple negative cases impact on clinical outcomes

BACKGROUND

The contribution of viral infection in tumors pathogenesis has currently attracted attention. Epstein-Barr virus is an infectious agent involved in numerous human malignancies, including breast cancer. Although, their prognostic impact in breast tumor is rarely investigated. Therefore, we sought in our study to evaluate the prevalence of EBV in Tunisian breast carcinoma and to examine their potential association with clinicopathological features and overall survival.

METHODS

Our retrospective study included 100 formalin fixed paraffin embedded samples from Tunisian breast carcinoma. EBV infection was evaluated by immunohistochemical analysis, using monoclonal antibody against latent membrane protein 1 (LMP-1) and polymerase chain reaction. A subset of PCR positive specimens was subjected to in situ hybridization for the detection of EBER expression. Biomarker's expression was evaluated by immunohistochemistry method. Statistical analysis was also explored.

RESULTS

The expression status of ER, PR and HER2 was 81%, 71.4% and 33.7% respectively. The triple negative profile was present in 10.84% of cases. LMP-1 expression was negative in all breast cancer specimens. PCR assay showed that 44% of patients were positive for EBV genome. None of the 15 PCR positive cases showed positive results for EBV by ISH. According to the molecular phenotype, there was a statistically significant difference in EBV DNA prevalence between breast cancer subgroups including TN (67%), Lum B (64%), HER2 + (50%) and Lum A (30%). Bivariate analysis showed that EBV DNA was significantly associated with HER2 + (p = 0.035), tumor size (p = 0.018) and high SBR grade (p = 0.009). Multiple logistic regression analysis confirms the positive correlation of EBV with tumor size (p = 0.048) and SBR grade (p = 0.042). Kaplan-Meier analysis showed that patients with EBV+ had significantly shorter overall survival than those with EBV- (p = 0.032).

CONCLUSIONS

Our study demonstrated the presence of EBV DNA in Tunisian breast carcinoma. EBV DNA was associated with aggressive features and poor overall survival. Further investigations will be required in large samples size to clarify the potential role of EBV in breast tumor progression.

DriverMP enables improved identification of cancer driver genes

BACKGROUND

Cancer is widely regarded as a complex disease primarily driven by genetic mutations. A critical concern and significant obstacle lies in discerning driver genes amid an extensive array of passenger genes.

FINDINGS

We present a new method termed DriverMP for effectively prioritizing altered genes on a cancer-type level by considering mutated gene pairs. It is designed to first apply nonsilent somatic mutation data, protein‒protein interaction network data, and differential gene expression data to prioritize mutated gene pairs, and then individual mutated genes are prioritized based on prioritized mutated gene pairs. Application of this method in 10 cancer datasets from The Cancer Genome Atlas demonstrated its great improvements over all the compared state-of-the-art methods in identifying known driver genes. Then, a comprehensive analysis demonstrated the reliability of the novel driver genes that are strongly supported by clinical experiments, disease enrichment, or biological pathway analysis.

CONCLUSIONS

The new method, DriverMP, which is able to identify driver genes by effectively integrating the advantages of multiple kinds of cancer data, is available at https://github.com/LiuYangyangSDU/DriverMP. In addition, we have developed a novel driver gene database for 10 cancer types and an online service that can be freely accessed without registration for users. The DriverMP method, the database of novel drivers, and the user-friendly online server are expected to contribute to new diagnostic and therapeutic opportunities for cancers.

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.

Association of PD-1/PD-L1 expression and Epstein--Barr virus infection in patients with invasive breast cancer

PURPOSE

Causative factors of breast cancer include infections, such as Epstein-Barr virus (EBV) infection. The aim of this study was to analyze the clinicopathological features of EBV-positive (IBC) and determine if EBV affects programmed cell death receptor 1 (PD-1)/PD ligand 1 (PD-L1) expression in IBC, similar to other EBV-infected tumors with PD-L1/PD-1 expression.

METHODS

We collected 140 samples of IBC tissues and 25 samples of adjacent tissues. All patients were followed-up by telephone from the day of surgery to December 2020. Chromogenic in-situ hybridization was performed to evaluate EBV-encoded RNA (EBER). Immunohistochemistry was performed to evaluate PD-L1 and PD-1 expressions. The correlation between PD1/PDL1 expression and clinicopathological features was also analyzed.

RESULTS

EBER was detected in 57 of 140 (40.7%) IBC tissues and not detected in any adjacent tissue (P < 0.05). Clinicopathologic features of patients were consistent with EBV-associated IBC. EBV infection was correlated with the mass size, menopausal status, axillary lymph node metastasis, vascular invasion, Ki-67 index, clinical stage, and estrogen receptor and progesterone receptor expressions (all P < 0.05), but not with the histological type, invasive ductal carcinoma histological grade, or human epidermal growth factor receptor 2 (HER2) expression (all P > 0.05). The positive rate of PD-1/PD-L1 expression was higher in the EBV-positive group than in the EBV-negative group (P < 0.05). The Kaplan-Meier univariate survival analysis showed that EBV was associated with poor disease-free survival and overall survival in patients with IBC. PD-L1/PD-1 expression could predict a poor prognosis.

CONCLUSIONS

In this study, clinicopathologic characteristics of patients were consistent with EBV-infected IBC. Patients with EBV-positive breast cancer were more likely to have elevated PD-1/PDL-1 expression compared to those with EBV-negative breast cancer. This finding could serve as a basis to explore therapeutic targets, particularly immunotherapy, for patients with IBC.

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

Simple Summary

Epstein–Barr virus (EBV) is a very ubiquitous and persistent virus present in ~90% of the world population. The infection is generally asymptomatic during the lifetime, though it can cause lymphoid tumors and carcinomas in some subjects. The role of EBV in breast cancer (BC) has yet to be determined. In this review, we present the historical background and scientific evidence regarding the presence and potential role of EBV in this malignancy and we propose possible molecular mechanisms. Knowledge of EBV´s role in BC will contribute to establishing prevention strategies, early detection, and control of this highly aggressive and prevalent malignancy.

Abstract

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.

Incidence of Epstein-Barr Virus Among Women With Breast Cancer Using Monoclonal Antibodies for Latent Membrane Protein 1 (LMP1)

BACKGROUND/AIM

Breast cancer is a common type of cancer in Sudan. Numerous studies propose viral oncogenesis as an etiological factor for breast cancer. The aim of the study was to analyze the presence of the Epstein-Barr virus (EBV) using monoclonal antibodies against latent membrane protein 1 (LAMP1) and determine the correlation between the presence of EBV and clinicopathological characteristics.

PATIENTS AND METHODS

This study used immunohistochemistry to analyze the presence of EBV in 202 samples from Sudanese women diagnosed with breast cancer. Clinicopathological data were collected from patient records from the Radiation and Isotopes Centre in Khartoum State, Republic of Sudan.

RESULTS

This study included 202 patients 168 (83.2%), 16 (7.9%), and 18 (8.9%), diagnosed with invasive ductal carcinoma, invasive lobular carcinoma, and papillary carcinoma, respectively. Axillary lymph node metastasis was present in 57 (28.2%) of cases, while 11 patients (5.4%) tested positive for EBV. The mean age of patients was 48.14±14.4 years. EBV infection was more frequently detected in invasive ductal carcinoma cases, and EBV positivity was not associated with cancer type, grade, progesterone levels, and HER2 expression. On the other hand, a statistically significant association was found between EBV presence and lymph node involvement, estrogen receptor status, and age group.

CONCLUSION

EBV may not play a vital role in the pathogenesis of breast carcinoma in Sudanese women.

Interrelated Oncogenic Viruses and Breast Cancer

Breast Cancer is a multifactorial disease and recent evidence that viruses have a greater role in its aetiology and pathophysiology than previously hypothesized, has garnered a lot of attention in the past couple of years. After the role of Mouse Mammary Tumour Virus (MMTV) in the oncogenesis of breast cancer has been proved in mice, search for similar viruses found quite a plausible relation of Human Papilloma Virus (HPV), Epstein–Barr virus (EBV), and Bovine Leukaemia Virus (BLV) with breast cancer. However, despite practical efforts to provide some clarity in this issue, the evidence that viruses cause breast cancer still remains inconclusive. Therefore, this article aims to clarify some ambiguity and elucidate the correlation of breast cancer and those particular viruses which are found to bring about the development of tumorigenesis by a previous infection or by their own oncogenic ability to manipulate the molecular mechanisms and bypass the immune system of the human body. Although many studies have reported, both, the individual and co-existing presence of HPV, EBV, MMTV, and BLV in patient sample tissues, particularly in Western women, and proposed oncogenic mechanisms, majority of the collective survey of literature fails to provide a delineated and strong conclusive evidence that viruses do, in fact, cause breast cancer. Measures to prevent these viral infections may curb breast cancer cases, especially in the West. More studies are needed to provide a definite conclusion.

Human Mammary Tumor Virus, Human Papilloma Virus, and Epstein-Barr Virus Infection Are Associated With Sporadic Breast Cancer Metastasis

Background

Viral cause of sporadic breast cancer (SBC) has been suggested based on the experimental murine model of mammary tumor caused by mouse mammary tumor virus (MMTV), Epstein-Barr virus (EBV), and human papillomavirus (HPV). While some studies have demonstrated the presence of viral sequences of MMTV, HPV, and EBV in breast cancer cells, others failed. These contradictions may be attributed to the geographical distribution of breast cancer incidence and/or technical variations. In the current study, we aimed to investigate the correlation of MMTV, HPV, and EBV infections with the development of breast cancer in Jordanian patients.

Methods

One hundred SBC tissue samples were subjected to laser capture microdissection for the selection of tumor cells populations. Fluorescence polymerase chain reaction (PCR) was used to detect the presence of the MMTV env-like sequences. Real-time PCR was used for HPV and EBV detection, and EBV was further confirmed by chromogen in situ hybridization (CISH).

Results

Mouse mammary tumor virus, HPV, and EBV were detected in SBC in 11%, 21%, and 23%, respectively. Only 3 of 52 (5.7%) positive cases demonstrated multiple virus infections. However, 49 of 52 (94%) of the positive cases revealed the presence of 1 type of viral sequences. Consequently, 52% of the studied breast cancer cases were infected with at least 1 type of the aforementioned viruses.

Conclusions

The current cohort suggests that MMTV, HPV, and EBV have a potential role in the development of breast cancer and adding more reasons to proceed with the quest of a possible viral origin of breast cancer.

Human Mammary Tumor Virus, Human Papilloma Virus, and Epstein-Barr Virus Infection Are Associated With Sporadic Breast Cancer Metastasis

Background:

Viral cause of sporadic breast cancer (SBC) has been suggested based on the experimental murine model of mammary tumor caused by mouse mammary tumor virus (MMTV), Epstein-Barr virus (EBV), and human papillomavirus (HPV). While some studies have demonstrated the presence of viral sequences of MMTV, HPV, and EBV in breast cancer cells, others failed. These contradictions may be attributed to the geographical distribution of breast cancer incidence and/or technical variations. In the current study, we aimed to investigate the correlation of MMTV, HPV, and EBV infections with the development of breast cancer in Jordanian patients.

Methods:

One hundred SBC tissue samples were subjected to laser capture microdissection for the selection of tumor cells populations. Fluorescence polymerase chain reaction (PCR) was used to detect the presence of the MMTV env-like sequences. Real-time PCR was used for HPV and EBV detection, and EBV was further confirmed by chromogen in situ hybridization (CISH).

Results:

Mouse mammary tumor virus, HPV, and EBV were detected in SBC in 11%, 21%, and 23%, respectively. Only 3 of 52 (5.7%) positive cases demonstrated multiple virus infections. However, 49 of 52 (94%) of the positive cases revealed the presence of 1 type of viral sequences. Consequently, 52% of the studied breast cancer cases were infected with at least 1 type of the aforementioned viruses.

Conclusions:

The current cohort suggests that MMTV, HPV, and EBV have a potential role in the development of breast cancer and adding more reasons to proceed with the quest of a possible viral origin of breast cancer.

Co-Expression of Androgen Receptor and Cathepsin D Defines a Triple-Negative Breast Cancer Subgroup with Poorer Overall Survival

Background: In the triple-negative breast cancer (TNBC) group, the luminal androgen receptor subtype is characterized by expression of androgen receptor (AR) and lack of estrogen receptor and cytokeratin 5/6 expression. Cathepsin D (Cath-D) is overproduced and hypersecreted by breast cancer (BC) cells and is a poor prognostic marker. We recently showed that in TNBC, Cath-D is a potential target for antibody-based therapy. This study evaluated the frequency of AR/Cath-D co-expression and its prognostic value in a large series of patients with non-metastatic TNBC. Methods: AR and Cath-D expression was evaluated by immunohistochemistry in 147 non-metastatic TNBC. The threshold for AR positivity (AR+) was set at ≥1% of stained cells, and the threshold for Cath-D positivity (Cath-D+) was moderate/strong staining intensity. Lymphocyte density, macrophage infiltration, PD-L1 and programmed cell death (PD-1) expression were assessed. Results: Scarff-Bloom-Richardson grade 1–2 and lymph node invasion were more frequent, while macrophage infiltration was less frequent in AR+/Cath-D+ tumors (62.7%). In multivariate analyses, higher tumor size, no adjuvant chemotherapy and AR/Cath-D co-expression were independent prognostic factors of worse overall survival. Conclusions: AR/Cath-D co-expression independently predicted overall survival. Patients with TNBC in which AR and Cath-D are co-expressed could be eligible for combinatory therapy with androgen antagonists and anti-Cath-D human antibodies.

Circular RNA expression profiles in extracellular vesicles from the plasma of patients with pancreatic ductal adenocarcinoma

Tumor-derived extracellular vesicles (EVs) and their contents are involved in the development of human malignancies. Circular RNAs (circRNAs), enriched in EVs, can regulate diverse cellular processes by acting as microRNA (miRNA) sponges or through other mechanisms. In the present study, we explored the potential roles of circRNAs in EVs in the development of pancreatic ductal adenocarcinoma (PDAC). First, plasma was obtained from patients with PDAC (n = 8) and healthy volunteers (n = 8), and EVs were isolated by the ultracentrifugation method. Nanoparticle tracking analysis and transmission electron microscopy confirmed the size and form of the isolated EVs. The circRNA expression profiles of EVs were investigated by high-throughput whole transcriptome sequencing. We then further validated the accuracy of the circRNA sequencing data by quantitative real-time PCR analysis using plasma samples and PC cell lines, and subsequently performed bioinformatics analysis to reveal the potential functional roles of the differentially expressed circRNAs and to construct a circRNA-miRNA interaction network to predict the target miRNAs of these circRNAs. Our work provides novel targets for further studies concerning the pathogenesis of PDAC.

How latent viruses cause breast cancer: An explanation based on the microcompetition model

Most breast cancer cases show a decrease in the concentration of the breast cancer type 1 susceptibility protein (BRCA1). However, only a small portion of these cases have a mutated BRCA1 gene. Although many attempts have been made to identify the reason for the decrease in BRCA1 concentration in sporadic, non-heritable breast cancer cases, the cause is still unknown. In this review, we use the Microcompetition Model to explain how certain latent viruses, which are frequently detected in breast cancer tumors, can decrease the expression of the BRCA1 gene and cause the development of breast tumors.

Epstein-Barr virus and risk of breast cancer: a systematic review and meta-analysis

Despite the numerous publications regarding the role of Epstein-Barr virus (EBV) in breast cancer development, the topic has still remained controversial. The aim of the meta-analysis was to estimate the overall prevalence of EBV in the breast cancer population, and to investigate the association between EBV and breast cancer risk. The overall prevalence of EBV was calculated 26.37% (95% CI: 22-31%) from the 44 included studies. Meta-analysis of 30 case-control studies showed that the pooled association between EBV and risk of breast cancer is odds ratio 4.74 (95% CI: 2.92-7.69; Z = 6.30; p < 0.0001). Our analyses indicate a strong statistical relationship between EBV infection and risk of breast cancer, suggesting a potential role of EBV infection in the development of breast cancer.

Breast cancer and cytomegalovirus

PURPOSE

To determine whether cytomegalovirus is causally associated with breast cancer and whether cytomegalovirus should be categorised as an oncogenic virus.

METHODS

We undertook a review of published epidemiological and laboratory studies, using established causal criteria: Bradford Hill criteria to determine whether cytomegalovirus is associated with breast cancer; and Evans/Mueller criteria to determine whether cytomegalovirus should be categorised as an oncogenic virus.

RESULTS

Although there are inconsistencies in the findings of published epidemiological and laboratory studies, these may be explained by factors such as: differences in timing of blood samples, differences in selection of cases and controls, or high cytomegalovirus seroprevalence among participants in the epidemiological studies; and, in the laboratory studies, differences in sample preparations, age of sample, whether or not paired breast cancer and normal breast tissue samples were used, differences in the tests, primers and/or antibodies used, differences in histological types of breast cancer studied, and/or features of the virus.

CONCLUSIONS

Overall, the results of published studies of cytomegalovirus and breast cancer suggest cytomegalovirus is a causal factor for at least some types of breast cancer. If the evidence for a link between cytomegalovirus and breast cancer continues to strengthen, further research could lead to: targeted screening; therapy using antiviral drugs; and, perhaps, primary prevention of a significant proportion of breast cancer. Vaccination against viruses has already been shown to be effective in preventing cervix and liver cancer; cytomegalovirus vaccines are already under development.

Frequency of Epstein–Barr Virus DNA in Formalin-Fixed Paraffin-Embedded Tissue of Patients with Ductal Breast Carcinoma

Background:

Ductal carcinoma is one of the most common breast cancer (BrC) among the women in the world. Several factors may involve in establishment of breast cancer. The role of viral infections have been investigated in BrC, Among them the association of Epstein Barr virus have been reported in the patients with breast cancer type ductal carcinoma. Thus this study was conducted to evaluate the rate of Epstein Barr virus in women with breast cancer type ductal carcinoma.

Material and methods:

A total of 72 formalin-fixed paraffin-embedded tissue blocks samples were collected from 37 (51.38%) women with breast cancer type ductal carcinoma and 35 (48.61%) samples of breast with fibro adenoma as control group. The DNA was extracted for all the samples. The detection of EBNA 3C EBV DNA was done by nested PCR. The results of positive were sequenced to confirm PCR product and determine EBV genotypes.

Results:

About 10/37 (27.02%) samples of ductal breast carcinoma were showed positive for EBNA 3C EBV DNA while 4/35 (11.42%) of fibro adenoma were positive for EBNA 3C EBV DNA (p= 0.095). Randomly 7 PCR products were sequenced and the results of sequencing EBNA 3C shows, the detected EBVDNA were type 1 EBV type.

Conclusion:

This study shows high prevalence of 27.02% EBV DNA type 1 was found in formalin-fixed paraffin-embedded tissue of Patients with ductal breast carcinoma. The outcomes of this study suggesting that EBV might have a significant role in breast cancer in Ahvaz city, south west region of Iran. However the expression of EBV oncoproteins, EBNA1, LMP1, and LMP2 require to be determined with ductal carcinoma cells. About 72.97% breast samples showed negative for EBVDNA. The role other viruses including Human cytomegalovirus, papilloma viruses and Merkel viruses are required to be investigated in further studies.

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.

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.

HSP90: a promising broad-spectrum antiviral drug target

The emergence of antiviral drug-resistant mutants is the most important issue in current antiviral therapy. As obligate parasites, viruses require host factors for efficient replication. An ideal therapeutic target to prevent drug-resistance development is represented by host factors that are crucial for the viral life cycle. Recent studies have indicated that heat shock protein 90 (HSP90) is a crucial host factor that is required by many viruses for multiple phases of their life cycle including viral entry, nuclear import, transcription, and replication. In this review, we summarize the most recent advances regarding HSP90 function, mechanisms of action, and molecular pathways that are associated with viral infection, and provide a comprehensive understanding of the role of HSP90 in the immune response and exosome-mediated viral transmission. In addition, several HSP90 inhibitors have entered clinical trials for specific cancers that are associated with viral infection, which further implies a crucial role for HSP90 in the malignant transformation of virus-infected cells; as such, HSP90 inhibitors exhibit excellent therapeutic potential. Finally, we describe the challenge of developing HSP90 inhibitors as anti-viral drugs.

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.

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.

Epstein-Barr Virus Infection of Mammary Epithelial Cells Promotes Malignant Transformation

Whether the human tumor virus, Epstein-Barr Virus (EBV), promotes breast cancer remains controversial and a potential mechanism has remained elusive. Here we show that EBV can infect primary mammary epithelial cells (MECs) that express the receptor CD21. EBV infection leads to the expansion of early MEC progenitor cells with a stem cell phenotype, activates MET signaling and enforces a differentiation block. When MECs were implanted as xenografts, EBV infection cooperated with activated Ras and accelerated the formation of breast cancer. Infection in EBV-related tumors was of a latency type II pattern, similar to nasopharyngeal carcinoma (NPC). A human gene expression signature for MECs infected with EBV, termed EBVness, was associated with high grade, estrogen-receptor-negative status, p53 mutation and poor survival. In 11/33 EBVness-positive tumors, EBV-DNA was detected by fluorescent in situ hybridization for the viral LMP1 and BXLF2 genes. In an analysis of the TCGA breast cancer data EBVness correlated with the presence of the APOBEC mutational signature. We conclude that a contribution of EBV to breast cancer etiology is plausible, through a mechanism in which EBV infection predisposes mammary epithelial cells to malignant transformation, but is no longer required once malignant transformation has occurred.

Incidence of Epstein-Barr virus in Syrian women with breast cancer: A tissue microarray study

Epstein-Barr virus (EBV) has been recently shown to be present in human breast cancer worldwide, which could play an important role in the initiation and progression of this cancer. In this regard, we aimed to explore the prevalence of EBV in 108 breast cancer tissues from Syrian women using polymerase chain reaction (PCR) and tissue microarray (TMA) analysis. We found that EBV is present in 56 (51.85%) of breast cancers samples. Additionally, we report that the expression of LMP1 gene of EBV is associated with a cancer invasive phenotype in the majority of the cancer samples. These data imply that EBV is present in breast cancer worldwide including Syria and its presence is associated with more aggressive cancer phenotype. Thus, future investigations are needed to elucidate the exact role of EBV in breast carcinogenesis and metastasis.

Ultrasensitive detection of DNA and protein markers in cancer cells

Cancer cells differ from normal cells in various parameters, and these differences are caused by genomic mutations and consequential altered gene expression. The genetic and functional heterogeneity of tumor cells is a major challenge in cancer research, detection, and effective treatment. As such, the use of diagnostic methods is important to reveal this heterogeneity at the single-cell level. Droplet microfluidic devices are effective tools that provide exceptional sensitivity for analyzing single cells and molecules. In this review, we highlight two novel methods that employ droplet microfluidics for ultra-sensitive detection of nucleic acids and protein markers in cancer cells. We also discuss the future practical applications of these methods.

Distinct microbiological signatures associated with triple negative breast cancer

Infectious agents are the third highest human cancer risk factor and may have a greater role in the origin and/or progression of cancers, and related pathogenesis. Thus, knowing the specific viruses and microbial agents associated with a cancer type may provide insights into cause, diagnosis and treatment. We utilized a pan-pathogen array technology to identify the microbial signatures associated with triple negative breast cancer (TNBC). This technology detects low copy number and fragmented genomes extracted from formalin-fixed paraffin embedded archival tissues. The results, validated by PCR and sequencing, define a microbial signature present in TNBC tissue which was underrepresented in normal tissue. Hierarchical clustering analysis displayed two broad microbial signatures, one prevalent in bacteria and parasites and one prevalent in viruses. These signatures demonstrate a new paradigm in our understanding of the link between microorganisms and cancer, as causative or commensal in the tumor microenvironment and provide new diagnostic potential.

Epstein-Barr virus infection is equally distributed across the invasive ductal and invasive lobular forms of breast cancer

The role of Epstein-Barr virus (EBV) in the pathogenesis of breast cancer is still unclear, although a growing body of evidence supports a link. The aim of this study was to investigate if EBV infection was more prevalent in invasive ductal carcinoma or invasive lobular carcinoma. An immunohistochemical marker for EBV (Epstein-Barr virus nuclear antigen 1 (EBNA1) clone E1-2.5) was applied to a tissue micro array section. The tissue micro array contained 80 cases of invasive ductal carcinoma, and 80 cases of invasive lobular carcinoma. Each case was scored as positive or negative for nuclear expression of EBNA1 in tumor cells using standard light microscopy. EBNA1 staining was evident in the tumor cells of 63 cases (39.4% of tumor cases). By tumor type (ductal/lobular) EBV infection was noted in 34 (42.5%) cases of invasive ductal carcinoma and 29 (36.2%) cases of invasive lobular carcinoma, this difference was not found to be significant (P=0.518). This study indicates that EBV infection is equally distributed across the ductal and lobular tumor types.

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.

Prevalence of papillomaviruses, polyomaviruses, and herpesviruses in triple-negative and inflammatory breast tumors from algeria compared with other types of breast cancer tumors

BACKGROUND

The possible role of viruses in breast cancer etiology remains an unresolved question. We hypothesized that if some viruses are involved, it may be in a subgroup of breast cancers only. Epidemiological arguments drove our interest in breast cancer subgroups that are more frequent in Africa, namely inflammatory breast cancer (IBC) and triple-negative breast cancer. We tested whether viral prevalence was significantly higher in these subgroups.

MATERIALS AND METHODS

One hundred fifty-five paraffin-embedded malignant breast tumors were randomly selected at the pathology laboratory of the University Hospital of Annaba (Algeria) to include one third of IBC and two thirds of non-IBC. They were tested for the presence of DNA from 61 viral agents (46 human papillomaviruses, 10 polyomaviruses, and 5 herpesviruses) using type-specific multiplex genotyping assays, which combine multiplex PCR and bead-based Luminex technology.

RESULTS

Viral DNA was found in 22 (17.9%) of 123 tumors. The most prevalent viruses were EBV1 and HPV16. IBC tumors carried significantly more viruses (any type) than non-IBC tumors (30% vs. 13%, p<0.04). Similarly, triple-negative tumors displayed higher virus-positivity than non-triple-negative tumors (44% vs. 14%, p<0.009).

CONCLUSIONS

Our results suggest an association between the presence of viral DNA and aggressive breast cancer phenotypes (IBC, triple-negative). While preliminary, they underline the importance of focusing on subgroups when studying viral etiology in breast cancer. Further studies on viruses in breast cancer should be conducted in much larger samples to confirm these initial findings.

Outcome of Epstein-Barr virus-associated primary breast cancer

The presence of the Epstein-Barr-virus (EBV) has been reported to be a pathogenic factor in breast cancer (BC). We previously demonstrated the aggressiveness of EBV-positive BC. The purpose of the present study was to evaluate the effect of EBV on the prognosis of BC according to the BC phenotype. A total of 117 patients with primary BC previously tested for the presence of EBV were evaluated. The presence of the virus was evaluated in breast specimens using quantitative PCR (qPCR). Disease-free survival (DFS) and overall survival (OS) were evaluated for 4 molecular subtypes, namely luminal A and B (lumA and lumB, respectively), human epidermal growth factor receptor 2 (HER2) and triple-negative (TN) subtypes and according to the EBV status. EBV positivity was observed in 32.5% of the cases. TN, HER2 and lumB tumours were more frequent among EBV-BC cases (P=0.02). The DFS rates were different between BC subtypes (P=0.002), but the differences were not statistically significant when the cases were stratified according to the EBV status (P=0.08 for EBV-negative and 0.06 for EBV-positive cases). The OS rates were similar for BC subtypes (P= 0.50) and when the cases were stratified according to the EBV status (P=0.16 and P=0.67 for EBV-positive and -negative cases, respectively). EBV was not associated with DFS or OS, in contrast to BC phenotypes, tumour size or nodal status. Therefore, EBV positivity was found to exert no effect on survival, despite its association with aggressive BC phenotypes.

The influence of the environment on the development of thyroid tumors: a new appraisal

Most epidemiological studies concerning differentiated thyroid cancers (DTC) indicate an increasing incidence over the last two decades. This increase might be partially explained by the better access to health services worldwide, but clinicopathological analyses do not fully support this hypothesis, indicating that there are carcinogenetic factors behind this noticeable increasing incidence. Although we have undoubtedly understood the biology and molecular pathways underlying thyroid carcinogenesis in a better way, we have made very little progresses in identifying a risk profile for DTC, and our knowledge of risk factors is very similar to what we knew 30-40 years ago. In addition to ionizing radiation exposure, the most documented and established risk factor for DTC, we also investigated the role of other factors, including eating habits, tobacco smoking, living in a volcanic area, xenobiotics, and viruses, which could be involved in thyroid carcinogenesis, thus, contributing to the increase in DTC incidence rates observed.

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.

The oncogenic potential of human cytomegalovirus and breast cancer

Breast cancer is the leading causes of cancer-related death among women. The vast majority of breast cancers are carcinomas that originate from cells lining the milk-forming ducts of the mammary gland. Numerous articles indicate that breast tumors exhibit diverse phenotypes depending on their distinct physiopathological signatures, clinical courses, and therapeutic possibilities. The human cytomegalovirus (HCMV) is a multifaceted highly host specific betaherpesvirus that is regarded as asymptomatic or mildly pathogenic virus in immunocompetent host. HCMV may cause serious in utero infections as well as acute and chronic complications in immunocompromised individual. The involvement of HCMV in late inflammatory complications underscores its possible role in inflammatory diseases and cancer. HCMV targets a variety of cell types in vivo, including macrophages, epithelial cells, endothelial cells, fibroblasts, stromal cells, neuronal cells, smooth muscle cells, and hepatocytes. HCMV can be detected in the milk after delivery and thereby HCMV could spread to adjacent mammary epithelial cells. HCMV also infects macrophages and induces an atypical M1/M2 phenotype, close to the tumor-associated macrophage phenotype, which is associated with the release of cytokines involved in cancer initiation or promotion and breast cancer of poor prognosis. HCMV antigens and DNA have been detected in tissue biopsies of breast cancers and elevation in serum HCMV IgG antibody levels has been reported to precede the development of breast cancer in some women. In this review, we will discuss the potential role of HCMV in the initiation and progression of breast cancer.

Multiplex PCR/mass spectrometry screening of biological carcinogenic agents in human mammary tumors

BACKGROUND

While many studies have suggested a possible link between breast cancer pathogenesis and infection by viruses, the role of viruses in breast carcinogenesis remains controversial.

OBJECTIVES

We analyzed the prevalence of 30 oncogenic human papillomaviruses (HPVs), Epstein-Barr virus (EBV), Kaposi's sarcoma herpes virus (KSHV) and six polyomaviruses in breast tumor specimens.

STUDY DESIGN

We analyzed breast specimens from 100 breast cancer patients (group 1) and 50 benign breast disease patients (group 2) from Shaanxi Province in China. We also screened for the viruses in blood samples from the patients and 96 female blood donor volunteers (group 3).

RESULTS

EBV, Merkel cell polyomavirus (MCPyV) and HPV-18 were detected in 60, 14 and 2 breast cancer patients, respectively, and EBV and MCPyV were detected in 16 and 1 benign breast disease patients, respectively. EBV and MCPyV were more prevalent in group 1 than in group 2 (EBV: 60.0% vs. 32.0%, p = 0.0012; MCPyV: 14.0% vs. 2.0%; p = 0.02). In contrast, there was no difference in the prevalence of EBV and MCPyV in blood samples between group 1 and group 2, group 1 and group 3. EBV was detected in malignant breast tissue and its presence was confined to the malignant cells using in situ hybridization.

CONCLUSIONS

We found that EBV and MCPyV were more prevalent in the tumors of women with breast cancer than in samples from women with benign breast disease. Our results support an etiologic role for EBV in breast cancer pathogenesis in Chinese patients.

Association of Epstein-Barr virus with invasive breast carcinoma and its impact on well-known clinicopathologic parameters in Iranian women

Background:

The association between Epstein-Barr virus (EBV) and breast carcinoma in Iranian women is uncertain. We examined EBV latent membrane protein-1 (LMP-1) antigen expression in breast carcinoma and its relationship with clinicopathologic parameters among a population of Iranian patients.

Materials and Methods:

This study was performed on formalin fixed and paraffin embedded tissue specimens with a diagnosis of invasive breast carcinoma archived at one university hospital in Isfahan city, Iran. We used immunohistochemistry to detect LMP-1 of EBV in carcinoma and its adjacent normal tissue. The frequency of LMP-1 expression in breast carcinoma and its relationship with age, tumor size, tumor type, tumor grade and lymph node status were then determined.

Results:

A total of 80 cases were evaluated including 77 (96.3%) ductal, 1 (1.3%) lobular, 1 (1.3%) medullary and 1 (1.3%) mucinous carcinoma. LMP-1 expression was seen in 6 cases (7.5%) of breast carcinoma whereas normal breast tissue adjacent to carcinoma was negative for LMP-1 in all of the cases. A statistically significant association was seen between EBV and invasive breast carcinoma (P = 0.03). No significant relationship was observed between LMP-1 expression on one hand and age, tumor size, tumor type, tumor grade and lymph node status on the other.

Conclusion:

EBV may play an etiological role in some of the cases of breast carcinoma in Iranian women. EBV expression does not seem to have a significant impact on the major clinicopathologic prognostic determinants of breast carcinoma.

Viral genomes in the pericardial fluid and in peri- and epicardial biopsies from a German cohort of patients with large to moderate pericardial effusions

The aetiology of pericardial effusion has been generally assessed by clinical work-up only, which leaves a large cohort of patients with "idiopathic" effusions virtually undiagnosed. In accordance with the ESC guidelines, this contribution intends to change this attitude. After therapeutic or diagnostic pericardiocentesis of 259 patients with large to moderate pericardial effusions, pericardial fluid, epicardial and pericardial biopsies, and blood samples were analysed by PCR for cardiotropic microbial agents. Cytology, histology, immunohistology of tissue and fluids and laboratory tests were performed. Of the 259 patients, 35 % suffered from an autoreactive aetiology, 28 % suffered from a malignant and 14 % from an infectious cause. Investigating all samples by PCR, we identified viral genomes in 51 (19.7 %) patients, parvovirus B19 (B19 V) being identified in 25 and Epstein-Barr virus (EBV) in 19 cases. In patients with a sole infectious aetiology (n = 36), B19 V was detected in 21 and EBV in 10 cases. When differentiating with regard to the material investigated for the presence of cardiotropic viruses, parvovirus B19 was most often detected in the epicardium and EBV was most frequently detected in the pericardial fluid independent from the final diagnostic categorisation. Bacterial cultures including tests for tuberculosis were all negative. Molecular techniques improve sensitivity, specificity and diagnostic accuracy for the underlying aetiology in pericarditis patients with effusion. The identification of specific viral signatures will help to understand pathogenetic mechanisms in pericarditis and allow to tailor an adequate therapy beyond antiphlogistic treatment.

No association between Epstein-Barr Virus and Mouse Mammary Tumor Virus with breast cancer in Mexican women

Breast cancer is the most frequent malignancy affecting women worldwide. It has been suggested that infection by Epstein Barr Virus (EBV), Mouse Mammary Tumor Virus or a similar virus, MMTV-like virus (MMTV-LV), play a role in the etiology of the disease. However, studies looking at the presence of these viruses in breast cancer have produced conflicting results, and this possible association remains controversial. Here, we used polymerase chain reaction assay to screen specific sequences of EBV and MMTV-LV in 86 tumor and 65 adjacent tissues from Mexican women with breast cancer. Neither tumor samples nor adjacent tissue were positive for either virus in a first round PCR and only 4 tumor samples were EBV positive by a more sensitive nested PCR. Considering the study's statistical power, these results do not support the involvement of EBV and MMTV-LV in the etiology of breast cancer.

Role of viruses in the development of breast cancer

The most common cancer worldwide among women is breast cancer. The initiation, promotion, and progression of this cancer result from both internal and external factors. The International Agency for Research on Cancer stated that 18-20% of cancers are linked to infection, and the list of definite, probable, and possible carcinogenic agents is growing each year. Among them, biological carcinogens play a significant role. In this review, data covering infection-associated breast and lung cancers are discussed and presented as possible involvements as pathogens in cancer. Because carcinogenesis is a multistep process with several contributing factors, we evaluated to what extent infection is significant, and concluded that members of the herpesvirus, polyomavirus, papillomavirus, and retrovirus families definitely associate with breast cancer. Detailed studies of viral mechanisms support this conclusion, but have presented problems with experimental settings. It is apparent that more effort needs to be devoted to assessing the role of these viruses in carcinogenesis, by characterizing additional confounding and synergistic effects of carcinogenic factors. We propose that preventing and treating infections may possibly stop or even eliminate certain types of cancers.

Target DNA detection and quantitation on a single cell with single base resolution

In this report, we present a new method for sensitive detection of short DNA sites in single cells with single base resolution. The method combines peptide nucleic acid (PNA) openers as the tagging probes, together with isothermal rolling circle amplification (RCA) and fluorescence-based detection, all performed in a cells-in-flow format. Bis-PNAs provide single base resolution, while RCA ensures linear signal amplification. We applied this method to detect the oncoviral DNA inserts in cancer cell lines using a flow-cytometry system. We also demonstrated quantitative detection of the selected signature sites within single cells in microfluidic nano-liter droplets. Our results show single-nucleotide polymorphism (SNP) discrimination and detection of copy-number variations (CNV) under isothermal non-denaturing conditions. This new method is ideal for many applications in which ultra-sensitive DNA characterization with single base resolution is desired on the level of single cells.

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.