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

Presencia del marcador lmp-1 del virus epstein barr en linfomas de caninos

Epstein Barr virus (EBV) is a humans’ high prevalent virus associated with lymphoid B cells tumors development. In canines, few reports have been published regarding the presence of the virus in dogs but its role in this species remain unclear.  The aim of this study was to determine the presence of LMP-1 protein of EBV in 20 canine lymphomas tissues which were previously diagnosed in a period of time between 2004 -2014.  Lymphomas were reclassified in accordance with the new histopathological classifications for lymphomas and were stained by IHQ with anti-CD79a, anti-CD3 and anti-LMP1; specific antibodies for B lymphocytes, T lymphocytes and EBV biomarker respectively.  As a result, it was found that the most common lymphoma was T-zone lymphoma in 75% of the cases of the study. The distribution of the cases regarding the immunostaining were: 18 positive cases with anti- CD3, 2 positive cases with anti-CD79a and 6 positive cases with anti-LMP-1.  Positive cases of LMP1 as a biomarker of the presence of EBV corresponded to the 30% of the cases of the study. Chi-square test showed statistical significance between the presence of the virus and the presence of lymphomas, which suggests not only that the virus is circulating in the canine population but also that could have implications in the development of the disease. Regarding demographic parameters, only the Golden Retriever breed showed a relationship with the presence of lymphoma, but not with the presence of the virus.

RPS27a enhances EBV-encoded LMP1-mediated proliferation and invasion by stabilizing of LMP1

Epstein-Barr virus (EBV)-encoded latent membrane protein 1 (LMP1) is an oncoviral protein that plays a pivotal role in EBV-induced oncogenic transformation. The function of LMP1 in EBV-induced oncogenesis has been well studied. However, the molecular mechanisms underlying LMP1 protein stability remain poorly understood. In this study, we found that ribosomal protein s27a (RPS27a) regulates LMP1 stability by a tandem affinity purification analysis. RPS27a interacts directly with LMP1 in vitro and in vivo. Furthermore, overexpression of RPS27a increases the half-life of LMP1 in 293T cells, whereas downregulation of RPS27a using lentiviral shRNA technology accelerates the decrease in LMP1 protein level in EBV-transformed B cells. We show that LMP1 ubiquitination via the proteasome is completely inhibited by overexpression of RPS27a. RPS27a also enhances LMP1-mediated proliferation and invasion, suggesting that RPS27a interacts with LMP1 and stabilizes it by suppressing proteasome-mediated ubiquitination. These results suggest that RSP27a could be a potential target in EBV-infected LMP1-positive cancer cells.

PD-L1 predicts poor prognosis for nasopharyngeal carcinoma irrespective of PD-1 and EBV-DNA load

Programmed death-1 (PD-1) is an immunosuppressive receptor functionally bound with programmed death-ligand 1 (PD-L1), which has been reported in various malignancies. However, only a few studies are available for the clinical significance of PD-1/PD-L1 in nasopharyngeal carcinoma (NPC). In this study, we aim to investigate alterations in PD-1/PD-L1 by using immunohistochemistry analysis in a cohort of consecutively enrolled NPC patients (n = 99). To further analyse the correlation between PD-1/PD-L1 and factors involved in clinico-pathology, haematologic biomarkers, EBV-DNA load and outcomes, we collected clinical data for statistical analysis. We observed that lower haemoglobin (HB) and Body Mass Index (BMI) levels were associated with high levels of PD-L1 staining in NPC patients. Importantly, our results suggested that PD-L1 might be a negative indicator for NPC patients. In contrast, a correlation between the PD-1/PD-L1 level and EBV load was not identified. Moreover, PD-1 positivity was suggested to not be significantly correlated with clinical outcomes. Taken together, our results revealed that PD-L1 might be a potential prognostic biomarker for NPC patients. However, further studies are needed to clarify the underlying mechanism of EBV status in the immunosuppression process induced by the PD-1/PD-L1 axis.

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.