Epstein-Barr Virus and Breast Cancer: State of the Evidence for Viral Carcinogenesis

Female patients with hepatitis B may exhibit a reduced risk of breast cancer: A review of NHANES data

Hepatic viral infections and breast cancer (BC) constitute major global health challenges, yet the interconnection between these hepatic infections and BC continues to be ambiguous. Conducting a comprehensive evaluation of the link between hepatitis virus infection and the incidence of BC and leveraging data from the National Health and Nutrition Examination Survey covering the period from 1999 to March 2022, we utilized logistic regression and subgroup analysis, among other methodologies, to execute a cross-sectional investigation. The univariate logistic regression analysis elucidates that individuals classified as non-Hispanic White exhibit a markedly higher incidence of BC at 2.620 (95% confidence interval [CI], 1.117-7.676; P = .045); moreover, advanced age at 1.063 (95% CI, 1.036-1.093; P < .001), elevated educational attainment at 1.962 (95% CI, 1.17-3.366; P = .012), and higher income levels at 2.835 (95% CI, 1.303-7.439; P = .017) emerge as significant predisposing factors for BC. In contrast, a greater number of live births significantly diminishes the risk of BC, reducing the incidence to 81.1% with each additional birth. Pertaining to hepatitis and vaccination status, our analysis distinctly demonstrates that only hepatitis B at 0.110 (95% CI, 0.018-0.353; P = .002) bears a significant inverse relationship with BC risk, suggesting a protective effect. The multivariate logistic regression analysis further reveals a negative association between hepatitis B infection and BC incidence, whereas hepatitis B vaccination shows a positive correlation with the disease incidence. After adjusting for all covariates, model 3 delineates odds ratios (95% CI) as follows: 0.14 (0.02-0.50; P = .009) and 1.92 (0.99-3.62; P = .046). Our investigation uncovers that within the general populace, there exists an inverse correlation between hepatitis B infection and BC incidence; in addition, the administration of the hepatitis B virus vaccine is potentially positively associated with the prevalence of 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.

Tumor grade-associated genomic mutations in Chinese patients with non-small cell lung cancer

Background

Lung cancer is the most prevalent cancer worldwide and accounts for approximately 20% of cancer-related death in China every year. High-grade lung cancer poses a significant threat to patients, and developing a novel treatment for these patients requires an understanding of its underlying mechanism.

Methods

Chinese patients with lung cancer were enrolled. The tumor samples were collected by surgery or puncture and applied for next-generation sequencing. A panel of pan-cancer genes was targeted, and the sequencing depth was set to over 1,000 to improve the sensitivity of detecting mutations. Short-length mutations (substitution, insertion, and deletion), copy number variation, and gene fusion were called. Gene mutations were compared between low-grade, middle-grade, and high-grade tumors using Fisher's exact test. The enriched pathways in each grade of tumors were also inferred.

Results

The study included 173 Chinese patients with non-small cell lung cancer, of whom 98 (56.6%) patients were female and 75 (43.4%) were male, with a mean age of 56.8 years. All patients were microsatellite stable; 66.4% were at the early stages (Stages 0, I, and II) with a tumor mutational burden of approximately 2.5 (confidence interval = [0, 48.3]). Compared to low-grade tumors, high-grade tumors had a significantly higher percentage of mutations in TP53 (75.9% vs 34.4%, p = 1.86e-3) and PIK3CA (24.1% vs. 0%, p = 3.58e-3). Pathway analysis found that high-grade tumors were enriched with mutations in bacterial invasion of epithelial cells (31% vs. 0%, p = 5.8e-4), Epstein-Barr virus infection (79.3% vs. 37.5%, p = 1.72e-3), and the Wnt signaling pathway (75.9% vs. 34.4%, p = 1.91e-3). High-grade tumors had a significantly higher tumor mutational burden than low-grade tumors (p-value = 0.0017). However, actionable mutations with high-level evidence were lower in high-grade tumors.

Conclusion

Patients with high-grade tumors from lung cancer may be more affected by bacteria and Epstein-Barr virus than low-grade tumors. High-grade tumors were specially mutated in TP53 and PIK3CA and may benefit more from immunotherapy. Further research on the underlying mechanism of high-grade lung cancer is necessary to develop new therapeutic options. Lung cancer, tumor grade, genomic mutations, Epstein-Barr virus, pathway analysis.

HPV-Associated Breast Cancer: Myth or Fact?

Some estimates place the proportion of human malignancies attributable to viruses at between 15 and 20 percent. Viruses including the human papillomavirus are considered an interesting but controversial etiological risk factor for breast cancer. HPV infection is anticipated to be an early trigger in breast cancer carcinogenesis, followed by cumulative alterations over time ("hit and run" mechanism) through synergy with other environmental factors. The association between HPV and breast cancer has not yet been verified. There are very conflicting data on the presence of HPV DNA in breast cancer samples, and we lack a clarified, exact mode of HPV transmission to the breast. In our review article we analyzed the up-to-date knowledge about the association of HPV and breast cancer. Furthermore, we summarized the available original research published since 2010. In conclusion, the complexity and inconsistency of the available results together with the relatively low prevalence of HPV infection requires extensive research with much larger studies and exact and unified diagnostic methods are required to better understand the role of the HPV in breast carcinogenesis.

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.

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.

Variation in risk and outcomes of Epstein-Barr virus-associated breast cancer by epidemiologic characteristics and virus detection strategies: an exploratory study

PURPOSE

A relationship of Epstein-Barr virus (EBV) and breast cancer etiology and outcome may have clinical utility and potential to enhance understanding of tumor biology. Research to date has yielded variable results, likely reflecting differing virus detection assays and unaddressed epidemiologic heterogeneity across studies.

METHODS

Applying our novel, five-target assay detection strategy in an exploratory study, we examined demographic, clinical, and tumor characteristics, and overall survival, associated with EBV positivity in breast adenocarcinomas from 59 non-Hispanic white and 68 Hispanic women sampled by age (<50, 50+) and stage (localized, regional/remote) and examined associations based on single assay targets.

RESULTS

EBV was localized only to lymphocytes. Nevertheless, viral prevalence, although low, varied across patient subgroups. Adjusted odds ratios (OR) for EBV positivity were lower for younger Hispanic than white women (p _interaction = 0.05), and marginally higher for larger [OR (95% confidence intervals) 1.03 (1.00-1.05) per mm increase] and right-sided [2.8 (0.97-7.8)] tumors. In whites, ORs were marginally higher for larger tumors [1.04 (1.00-1.07)] and marginally lower for age 50+ [0.24 (0.06-1.03)]; in Hispanics, ORs were higher for ER negative [5.6 (1.1-30.5)], and marginally higher for right-sided, tumors [5.8 (0.94-36.2)]. Survival was suggestively poorer for EBV-positive than EBV-negative tumors in older women with localized disease. EBV associations differed across single assay targets, indicating variation in prior findings likely due to assay performance.

CONCLUSIONS

The differing EBV associations by age and race/ethnicity suggest a non-random role of EBV in breast cancer and support further study using multi-target assays, relevant epidemiologic design, and a larger study sample.

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.