Helicobacter pylori-associated oxidant monochloramine induces reactivation of Epstein-Barr virus (EBV) in gastric epithelial cells latently infected with EBV

Transcriptional and microbial profile of gastric cancer patients infected with Epstein-Barr virus

Introduction

Gastric cancer (GC), which has low survival rates and high mortality, is a major concern, particularly in Asia and South America, with over one million annual cases. Epstein-Barr virus (EBV) is recognized as a carcinogen that may trigger gastric carcinogenesis by infecting the stomach epithelium via reactivated B cells, with growing evidence linking it to GC. This study investigates the transcriptional and microbial profiles of EBV-infected versus EBV-non-infected GC patients.

Methods

Using Illumina NextSeq, cDNA libraries were sequenced, and reads were aligned to the human genome and analyzed with DESeq2. Kegg and differential analyses revealed key genes and pathways. Gene sensitivity and specificity were assessed using ROC curves (p < 0.05, AUC > 0.8). Non-aligned reads were used for microbiome analysis with Kraken2 for bacterial identification. Microbial analysis included LDA score, Alpha and Beta diversity metrics, with significance set at p ≤ 0.05. Spearman's correlation between differentially expressed genes (DEGs) and bacteria were also examined.

Results

The data revealed a gene expression pattern in EBV-positive gastric cancer, highlighting immune response, inflammation, and cell proliferation genes (e.g., GBP4, ICAM1, IL32, TNFSF10). ROC analysis identified genes with high specificity and sensitivity for discriminating EBV+ gastric cancer, including GBP5, CMKLR1, GM2A and CXCL11 that play pivotal roles in immune response, inflammation, and cancer. Functional enrichment pointed to cytokine-cytokine receptor interactions, antigen processing, and Th17 immune response, emphasizing the role of the tumor microenvironment, shaped by inflammation and immunomodulation, in EBV-associated GC. Microbial analysis revealed changes in the gastric microbiota in EBV+ samples, with a significant reduction in bacterial taxa. The genera Choristoneura and Bartonella were more abundant in EBV+ GC, while more abundant bacteria in EBV- GC included Citrobacter, Acidithiobacillus and Biochmannia. Spearman's correlation showed a strong link between DE bacterial genera and DEGs involved in processes like cell differentiation, cytokine production, digestion, and cell death.

Conclusion

These findings suggest a complex interaction between the host (EBV+ GC) and the microbiota, possibly influencing cancer progression, and offering potential therapeutic targets such as microbiota modulation or gene regulation. Comparing with EBV- samples further highlights the specific impact of EBV and the microbiota on gastric cancer pathogenesis.

Awakening the sleeping giant: Epstein-Barr virus reactivation by biological agents

Epstein-Barr virus (EBV) may cause harm in immunocompromised conditions or on stress stimuli. Various chemical agents have been utilized to induce the lytic cycle in EBV-infected cells. However, apart from chemical agents and external stress stimuli, certain infectious agents may reactivate the EBV. In addition, the acute infection of other pathogens may provide suitable conditions for EBV to thrive more and planting the roots for EBV-associated pathologies. Various bacteria such as periodontal pathogens like Aggregatibacter, Helicobacter pylori, etc. have shown to induce EBV reactivation either by triggering host cells directly or indirectly. Viruses such as Human simplex virus-1 (HSV) induce EBV reactivation by HSV US3 kinase while other viruses such as HIV, hepatitis virus, and even novel SARS-CoV-2 have also been reported to cause EBV reactivation. The eukaryotic pathogens such as Plasmodium falciparum and Aspergillus flavus can also reactivate EBV either by surface protein interaction or as an impact of aflatoxin, respectively. To highlight the underexplored niche of EBV reactivation by biological agents, we have comprehensively presented the related information in this review. This may help to shedding the light on the research gaps as well as to unveil yet unexplored mechanisms of EBV reactivation.

Helicobacter pylori and Epstein-Barr virus infection in cell polarity alterations

The asymmetrical distribution of the cellular organelles inside the cell is maintained by a group of cell polarity proteins. The maintenance of polarity is one of the vital host defense mechanisms against pathogens, and the loss of it contributes to infection facilitation and cancer progression. Studies have suggested that infection of viruses and bacteria alters cell polarity. Helicobacter pylori and Epstein-Barr virus are group I carcinogens involved in the progression of multiple clinical conditions besides gastric cancer (GC) and Burkitt's lymphoma, respectively. Moreover, the coinfection of both these pathogens contributes to a highly aggressive form of GC. H. pylori and EBV target the host cell polarity complexes for their pathogenesis. H. pylori-associated proteins like CagA, VacA OipA, and urease were shown to imbalance the cellular homeostasis by altering the cell polarity. Similarly, EBV-associated genes LMP1, LMP2A, LMP2B, EBNA3C, and EBNA1 also contribute to altered cell asymmetry. This review summarized all the possible mechanisms involved in cell polarity deformation in H. pylori and EBV-infected epithelial cells. We have also discussed deregulated molecular pathways like NF-κB, TGF-β/SMAD, and β-catenin in H. pylori, EBV, and their coinfection that further modulate PAR, SCRIB, or CRB polarity complexes in epithelial cells.

Modulation of Epstein-Barr-Virus (EBV)-Associated Cancers by Co-Infections

The oncogenic and persistent Epstein Barr virus (EBV) is carried by more than 95% of the human adult population. While asymptomatic in most of these, EBV can cause a wide variety of malignancies of lymphoid or epithelial cell origin. Some of these are also associated with co-infections that either increase EBV-induced tumorigenesis or weaken its immune control. The respective pathogens include Kaposi-sarcoma-associated herpesvirus (KSHV), Plasmodium falciparum and human immunodeficiency virus (HIV). In this review, I will discuss the respective tumor entities and possible mechanisms by which co-infections increase the EBV-associated cancer burden. A better understanding of the underlying mechanisms could allow us to identify crucial features of EBV-associated malignancies and defects in their immune control. These could then be explored to develop therapies against the respective cancers by targeting EBV and/or the respective co-infections with pathogen-specific therapies or vaccinations.

The role of gastric microecological dysbiosis in gastric carcinogenesis

Gastric cancer (GC) is the leading cause of cancer-related death worldwide, and reducing its mortality has become an urgent public health issue. Gastric microecological dysbiosis (including bacteria, fungi, viruses, acid suppressants, antibiotics, and surgery) can lead to gastric immune dysfunction or result in a decrease in dominant bacteria and an increase in the number and virulence of pathogenic microorganisms, which in turn promotes development of GC. This review analyzes the relationship between gastric microecological dysbiosis and GC, elucidates dynamic alterations of the microbiota in Correa's cascade, and identifies certain specific microorganisms as potential biomarkers of GC to aid in early screening and diagnosis. In addition, this paper presents the potential of gastric microbiota transplantation as a therapeutic target for gastric cancer, providing a new direction for future research in this field.

Current progress and challenges of immunotherapy in gastric cancer: A focus on CAR-T cells therapeutic approach

Gastric cancer (GC) is a severe malignancy, accounting for the third most common cancer death worldwide. Despite the development of chemo-radiation therapy, there has not been sufficient survival advantage in patients with GC who were treated by these methods. GC immunogenicity is hampered by a highly immunosuppressive microenvironment; therefore, further understanding of the molecular biology of GC is the potential to achieve new therapeutic strategies in GC therapy, including specific immunotherapy. Current immunotherapies are mainly based on cytokines, immune checkpoints, monoclonal antibodies (mAb), bispecific antibodies (BisAbs), antibody-drug conjugates (ADCs), and chimeric antigen receptor (CAR). Immunotherapy has made significant progress in the treatment of GC, so that studies show that nivolumab as a programmed death 1 (PD1) inhibitor has proper safety and effectiveness as a third-line treatment for GC patients. Multiple monoclonal antibodies like ramucirumab and claudiximab were effective in treating GC patients, especially in combination with other treatments. Despite the challenges of CAR therapy in solid tumors, CAR therapy targets various GC cells targets; among them, intercellular adhesion molecule (ICAM)-1 CAR-T cell and CLDN18.2 CAR-T cell have shown promising results. Although responses to all these treatments are encouraging and in some cases, durable, these successes are not seen in all treated patients. The present review represents the development of various immunotherapies especially CAR-T cell therapy, its current use, clinical data in GC, and their limitations.

IL-8 Secreted by Gastric Epithelial Cells Infected with Helicobacter pylori CagA Positive Strains Is a Chemoattractant for Epstein-Barr Virus Infected B Lymphocytes

Helicobacter pylori and EBV are considered the main risk factors in developing gastric cancer. Both pathogens establish life-lasting infections and both are considered carcinogenic in humans. Different lines of evidence support that both pathogens cooperate to damage the gastric mucosa. Helicobacter pylori CagA positive virulent strains induce the gastric epithelial cells to secrete IL-8, which is a potent chemoattractant for neutrophils and one of the most important chemokines for the bacterium-induced chronic gastric inflammation. EBV is a lymphotropic virus that persists in memory B cells. The mechanism by which EBV reaches, infects and persists in the gastric epithelium is not presently understood. In this study, we assessed whether Helicobacter pylori infection would facilitate the chemoattraction of EBV-infected B lymphocytes. We identified IL-8 as a powerful chemoattractant for EBV-infected B lymphocytes, and CXCR2 as the main IL-8 receptor whose expression is induced by the EBV in infected B lymphocytes. The inhibition of expression and/or function of IL-8 and CXCR2 reduced the ERK1/2 and p38 MAPK signaling and the chemoattraction of EBV-infected B lymphocytes. We propose that IL-8 at least partially explains the arrival of EBV-infected B lymphocytes to the gastric mucosa, and that this illustrates a mechanism of interaction between Helicobacter pylori and EBV.

Epstein-Barr Virus Infection Is Associated with Elevated Hepcidin Levels

EBV and Helicobacter pylori (H. pylori) cause highly prevalent persistent infections as early as in childhood. Both pathogens are associated with gastric carcinogenesis. H. pylori interferes with iron metabolism, enhancing the synthesis of acute-phase proteins hepcidin, C-reactive protein (CRP), and α-1 glycoprotein (AGP), but we do not know whether EBV does the same. In this study, we correlated the EBV antibody levels and the serum levels of hepcidin, CRP, and AGP in 145 children from boarding schools in Mexico City. We found that children IgG positive to EBV antigens (VCA, EBNA1, and EA) presented hepcidin, AGP, and CRP levels higher than uninfected children. Hepcidin and AGP remained high in children solely infected with EBV, while CRP was only significantly high in coinfected children. We observed positive correlations between hepcidin and EBV IgG antibodies (p < 0.5). Using the TCGA gastric cancer database, we also observed an association between EBV and hepcidin upregulation. The TCGA database also allowed us to analyze the two important pathways controlling hepcidin expression, BMP−SMAD and IL-1β/IL-6. We observed only the IL-1β/IL-6-dependent inflammatory pathway being significantly associated with EBV infection. We showed here for the first time an association between EBV and enhanced levels of hepcidin. Further studies should consider EBV when evaluating iron metabolism and anemia, and whether in the long run this is an important mechanism of undernourishment and EBV gastric carcinogenesis.

[Epstein-Barr virus-associated subacute sensorimotor neuropathy with multiple cerebellar microbleeding: a case report]

We report the case of an 82-year-old male with subacute sensorimotor neuropathy associated with Epstein-Barr virus (EBV) infection, who presented with diplopia followed by gait disturbance due to limb weakness. Pathological findings of a biopsied cervical lymph node showed a high frequency of EBV-positive cells. EBV-DNA was detected in blood. A nerve conduction study suggested a mixture of axonal damage and demyelination. Brain MRI showed multiple microbleeds in cerebellar cortices, but cerebrospinal fluid EBV-PCR was negative, suggesting bleeding due to EBV-related vasculitis. Corticosteroid therapy improved the neurological symptoms and the patient was able to walk independently four months later. The main pathogenesis of the neuropathy in this case is likely to be a mixture of vasculitic neuropathy and immune-mediated demyelinating neuropathy, which are considered to be due to EBV reactivation.

Co-infection relationship with Epstein-Barr virus in gastroduodenal diseases with Helicobacter Pylori. Quantitative PCR and EBNA-1 gene-based approach

Objective: Helicobacter pylori (Hp) and Epstein-Barr virus (EBV) are involved in gastric cancer (GC) etiology. EBV/Hp co- infection was thought synergistically increase gastroduodenal disease occurence. We aimed to determine the presence of EBV/Hp co-infection in gastroduodenal diseases. Methods: The study group had 68 Hp (+) cases [25 GC, 13 IM (intestinal metaplasia), 30 PU (peptic ulcer)], and the control group had 40 NUD (non-ulcer dyspepsia) cases [20 Hp+, 20 Hp-]. EBV-DNA was detected by non-polymorphic EBNA-1 gene-based qPCR. EBV/EBNA-1 IgG levels were determined by quantitative and qualitative ELISA methods, respectively. Results: EBV-DNA positivity was 32% (8/25), 6.6% (2/30) and 5% (1/20) in GC, PU and NUD Hp (+) cases, respectively. There was a significant difference (p = 0.001) between GC (32%) and NUD Hp (+) (5%) cases in terms of EBV-DNA positivity. Mean EBV-DNA copy numbers were 6568.54 ± 20351, 30.60 ± 159.88 and 13.85 ± 61.93 for GC, PU, and NUD, respectively. In terms of the mean EBV-DNA copy number, a significant difference was found between the groups (p = 0.005). In terms of EBV/EBNA-1 IgG antibody positivity, no significant difference was found between GC and NUD cases (p = 0.248). EBV DNA positivity was found to be significant (odds ration [OR] = 26.71 (p=0.009, %95CI 2.286- 312.041) in multivariate logistic regression. Conclusioin: Although we had a small number of GC cases, it can be suggested that the estimated risk created by the synergistic effect based on the addition of EBV increased 26 times in the presence of Hp in GC.

Role of Gastric Microorganisms Other than Helicobacter pylori in the Development and Treatment of Gastric Diseases

The microenvironment in the stomach is different from other digestive tracts, mainly because of the secretion of gastric acid and digestive enzymes, bile reflux, special mucus barrier, gastric peristalsis, and so on, which all contribute to the formation of antibacterial environment. Microecological disorders can lead to gastric immune disorders or lead to the decrease of dominant bacteria and the increase of the abundance and virulence of pathogenic microorganisms and then promote the occurrence of diseases. The body performs its immune function through innate and adaptive immunity and maintains microbial balance through the mechanism of immune homeostasis. Microecological imbalance can lead to the invasion of pathogenic microorganisms and damage mucosal barrier and immune system. The coexistence of gastric microorganisms (including viruses and fungi) may play a synergistic or antagonistic role in the pathogenesis of gastric diseases. Probiotics have the ability to compete with intestinal pathogens, increase the secretion of immunoglobulin A (IgA), stimulate the production of mucin, bacteriocin, and lactic acid, regulate the expression and secretion of cytokines, and regulate the growth of microbiota, which all have beneficial effects on the host microbial environment. At present, most studies focused on Helicobacter pylori, ignoring other stomach microbes and the overall stomach microecology. So, in this article, we reviewed advances in human gastric microecology, the relationship between gastric microecology and immunity or gastric diseases, and the treatment of probiotics in gastric diseases, in order to explore new area for further study of gastric microorganisms and treatment of gastric diseases.

Bacterial-Viral Interactions in Human Orodigestive and Female Genital Tract Cancers: A Summary of Epidemiologic and Laboratory Evidence

Infectious agents, including viruses, bacteria, fungi, and parasites, have been linked to pathogenesis of human cancers, whereas viruses and bacteria account for more than 99% of infection associated cancers. The human microbiome consists of not only bacteria, but also viruses and fungi. The microbiome co-residing in specific anatomic niches may modulate oncologic potentials of infectious agents in carcinogenesis. In this review, we focused on interactions between viruses and bacteria for cancers arising from the orodigestive tract and the female genital tract. We examined the interactions of these two different biological entities in the context of human carcinogenesis in the following three fashions: (1) direct interactions, (2) indirect interactions, and (3) no interaction between the two groups, but both acting on the same host carcinogenic pathways, yielding synergistic or additive effects in human cancers, e.g., head and neck cancer, liver cancer, colon cancer, gastric cancer, and cervical cancer. We discuss the progress in the current literature and summarize the mechanisms of host-viral-bacterial interactions in various human cancers. Our goal was to evaluate existing evidence and identify gaps in the knowledge for future directions in infection and cancer.

Epstein-Barr Virus-Associated Gastric Cancer: Old Entity with New Relevance

Gastric cancer (GC) represents a major public health issue worldwide, being the fifth most common cancer and one of the leading causes of death by cancer. In 2014, The Cancer Genome Atlas (TCGA) established that tumors positive for Epstein-Barr virus (EBV) are considered a specific subtype of GC (EBVaGC). Several meta-analyses have shown that EBVaGC represents almost 10% of all gastric cancer worldwide, with small differences in the geographic distribution. This tumor subtype has a high potential of being clinically relevant and studies have shown that it has specific features, a better prognosis, and increased overall survival. In this review, we summarize some of the most frequent aspects of EBVaGC, including the specific features of this GC subtype, data regarding the potential steps of EBVaGC carcinogenesis, and perspectives on treatment opportunities.

Helicobacter pylori and Epstein-Barr Virus Coinfection Stimulates Aggressiveness in Gastric Cancer through the Regulation of Gankyrin

Persistent coinfection with Helicobacter pylori and Epstein-Barr virus (EBV) promotes aggressive gastric carcinoma (GC). The molecular mechanisms underlying the aggressiveness in H. pylori and EBV-mediated GC are not well characterized. We investigated the molecular mechanism involved in H. pylori- and EBV-driven proliferation of gastric epithelial cells. Results showed that the coinfection is significantly more advantageous to the pathogens as coinfection creates a microenvironment favorable to higher pathogen-associated gene expression. The EBV latent genes ebna1 and ebna3c are highly expressed in the coinfection compared to lone EBV infection at 12 and 24 h. The H. pylori-associated genes 16S rRNA, cagA, and babA were also highly expressed during coinfection compared to H. pylori alone. In addition, upregulation of gankyrin, which is a small oncoprotein, modulates various cell signaling pathways, leading to oncogenesis. Notably, the knockdown of gankyrin decreased the cancer properties of gastric epithelial cells. Gankyrin showed a similar expression pattern as that of ebna3c at both transcript and protein levels, suggesting a possible correlation. Further, EBV and H. pylori created a microenvironment that induced cell transformation and oncogenesis through dysregulation of the cell cycle regulatory (ccnd1, dapk3, pcna, and akt), GC marker (abl1, tff-2, and cdx2), cell migration (mmp3 and mmp7), DNA response (pRB, pten, and p53), and antiapoptotic (bcl2) genes in infected gastric epithelial cells through gankyrin. Our study provides a new insight into the interplay of two oncogenic agents (H. pylori and EBV) that leads to an enhanced carcinogenic activity in gastric epithelial cells through overexpression of gankyrin. IMPORTANCE In the present study, we evaluated the synergistic effects of EBV and H. pylori infection on gastric epithelial cells in various coinfection models. These coinfection models were among the first to depict the exposures of gastric epithelial cells to EBV followed by H. pylori; however, coinfection models exist that narrated the scenario upon exposure to H. pylori followed by that to EBV. We determined that a coinfection by EBV and H. pylori enhanced the expression of oncogenic protein gankyrin. The interplay between EBV and H. pylori promoted the oncogenic properties of AGS cells like elevated focus formation, cell migration, and cell proliferation through gankyrin. EBV and H. pylori mediated an enhanced expression of gankyrin, which further dysregulated cancer-associated genes such as cell migratory, tumor suppressor, DNA damage response, and proapoptotic genes.

Recent advances in immune therapies for gastric cancer

Gastric cancer (GC) is an aggressive malignancy that is the third leading cause of cancer mortality worldwide. Localized GC can be cured with surgery, but most patients present with more advanced non-operable disease. Until recently, treatment options for relapsed and refractory advanced GC have been limited to combination chemotherapy regimens, HER-2 directed therapy, and radiation, which lead to few durable responses. Over the past decade, there have been significant advances in our understanding of the molecular and immune pathogenesis of GC. The infectious agents Epstein-Barr virus and Helicobacter pylori perturb the gastric mucosa immune equilibrium, which creates a microenvironment that favors GC tumorigenesis and evasion of immune surveillance. Insights into immune mechanisms of GC have translated into novel therapeutics, including immune checkpoint inhibitors, which have become a treatment option for select patients with GC. Furthermore, chimeric antigen receptor T-cell therapies have emerged as a breakthrough treatment for many cancers, with recent studies showing this to be a potential therapy for GC. In this review, we summarize the current state of knowledge on immune mechanisms of GC and the status of emerging immunotherapies to treat this aggressive cancer, as well as outline current challenges and directions for future research.

The Role of Coinfections in the EBV-Host Broken Equilibrium

The Epstein–Barr virus (EBV) is a well-adapted human virus, and its infection is exclusive to our species, generally beginning in the childhood and then persisting throughout the life of most of the affected adults. Although this infection generally remains asymptomatic, EBV can trigger life-threatening conditions under unclear circumstances. The EBV lifecycle is characterized by interactions with other viruses or bacteria, which increases the probability of awakening its pathobiont capacity. For instance, EBV infects B cells with the potential to alter the germinal center reaction (GCR)—an adaptive immune structure wherein mutagenic-driven processes take place. HIV- and Plasmodium falciparum-induced B cell hyperactivation also feeds the GCR. These agents, along with the B cell tropic KSHV, converge in the ontogeny of germinal center (GC) or post-GC lymphomas. EBV oral transmission facilitates interactions with local bacteria and HPV, thereby increasing the risk of periodontal diseases and head and neck carcinomas. It is less clear as to how EBV is localized in the stomach, but together with Helicobacter pylori, they are known to be responsible for gastric cancer. Perhaps this mechanism is reminiscent of the local inflammation that attracts different herpesviruses and enhances graft damage and chances of rejection in transplanted patients. In this review, we discussed the existing evidence suggestive of EBV possessing the potential to synergize or cooperate with these agents to trigger or worsen the disease.

Overview of Epstein-Barr-Virus-Associated Gastric Cancer Correlated with Prognostic Classification and Development of Therapeutic Options

Gastric cancer (GC) is a deadly disease with poor prognosis that is characterized by heterogeneity. New classifications based on histologic features, genotypes, and molecular phenotypes, for example, the Cancer Genome Atlas subtypes and those by the Asian Cancer Research Group, help understand the carcinogenic differences in GC and have led to the identification of an Epstein-Barr virus (EBV)-related GC subtype (EBVaGC), providing new indications for tailored treatment and prognostic factors. This article provides a review of the features of EBVaGC and an update on the latest insights from EBV-related research with a particular focus on the strict interaction between EBV infection and the gastric tumor environment, including the host immune response. This information may help increase our knowledge of EBVaGC pathogenesis and the mechanisms that sustain the immune response of patients since this mechanism has been demonstrated to offer a survival advantage in a proportion of patients with GC.

Detection of Epstein-Barr Virus DNA in Gastric Biopsies of Pediatric Patients with Dyspepsia

In this study, we assessed the presence of Epstein-Barr virus (EBV) in gastric samples derived from pediatric patients with dyspeptic symptoms, aiming to understand whether EBV participates in the development of early gastric lesions influencing chronic inflammation, in conjunction with the Helicobacter pylori (Hp) bacterium. We analyzed EBV load in 236 gastric biopsies derived from 186 pediatric patients with chronic dyspepsia and compared it with EBV serology, Hp load and serology, and with immune cell infiltration. We found that 7.5% of patients were positive for EBV load, ranging from 240 to 29,685 genomic copies/μg of DNA. Hp genomic sequences were found in 24.7% of patients. EBV positive samples did not correlate with Hp status and were characterized by absent to moderate immune cell infiltration. To our knowledge, this is the first study addressing EBV load in the stomach in a large cohort of pediatric patients with dyspeptic symptoms, providing evidence of EBV localization in the gastric mucosa in early inflammatory lesions. The lack of correlation between EBV and both Hp infection and inflammation is perhaps explained by independent pathogenic mechanisms or because of the randomness of the gastritis sampling. This is also supported by a moderate association between EBV load and serology.

Application of Biopsy Samples Used for Helicobacter pylori Urease Test to Predict Epstein-Barr Virus-Associated Cancer

Persistent gastric mucosal damage caused by Helicobacter pylori infection is a major risk factor for gastric cancer (GC). The Epstein-Barr virus (EBV) is also associated with GC. Most patients with EBV-associated GC are infected with H. pylori in East Asia. However, very few reports have described where and when both H. pylori and EBV infect the gastric mucosa. To clarify this, old biopsy samples used for the rapid urease test (RUT) were applied to count EBV genomic DNA (gDNA) copies using DNA probe quantitative polymerase chain reaction. DNA extracted from the gastric biopsy samples of 58 patients with atrophic gastritis was used to analyze the correlation between the degree of atrophic gastritis and the copy number of EBV gDNA. EBV was detected in 44 cases (75.9%), with viral copy numbers ranging from 12.6 to 4754.6. A significant correlation was found between patients with more than 900 copies of EBV gDNA and those with a more severe grade of atrophic gastritis (p = 0.041). This study shows that EBV can be detected in RUT samples in a manner that reduces patient burden.

Epstein-Barr Virus and Helicobacter Pylori Co-Infection in Non-Malignant Gastroduodenal Disorders

Epstein–Barr virus (EBV) and Helicobacter pylori (H. pylori) are two pathogens associated with the development of various human cancers. The coexistence of both microorganisms in gastric cancer specimens has been increasingly reported, suggesting that crosstalk of both pathogens may be implicated in the carcinogenesis process. Considering that chronic inflammation is an initial step in the development of several cancers, including gastric cancer, we conducted a systematic review to comprehensively evaluate publications in which EBV and H. pylori co-infection has been documented in patients with non-malignant gastroduodenal disorders (NMGDs), including gastritis, peptic ulcer disease (PUD), and dyspepsia. We searched the PubMed database up to August 2019, as well as publication references and, among the nine studies that met the inclusion criteria, we identified six studies assessing EBV infection directly in gastric tissues (total 949 patients) and three studies in which EBV infection status was determined by serological methods (total 662 patients). Due to the substantial methodological and clinical heterogeneity among studies identified, we could not conduct a meta-analysis. The overall prevalence of EBV + H. pylori co-infection in NMGDs was 34% (range 1.8% to 60%). A higher co-infection rate (EBV + H. pylori) was reported in studies in which EBV was documented by serological methods in comparison with studies in which EBV infection was directly assessed in gastric specimens. The majority of these studies were conducted in Latin-America and India, with most of them comparing NMGDs with gastric cancer, but there were no studies comparing the co-infection rate in NMGDs with that in asymptomatic individuals. In comparison with gastritis caused by only one of these pathogens, EBV + H. pylori co-infection was associated with increased severity of gastric inflammation. In conclusion, only relatively small studies testing EBV and H. pylori co-infection in NMGDs have been published to date and the variable report results are likely influenced by geographic factors and detection methods.

Benign Gastric Ulcer with Epstein-Barr Virus Infection Mimicking Malignant Gastric Ulcer

Epstein-Barr virus (EBV) is the cause of infectious mononucleosis, which is characterized by fever, lymphadenopathy, and sore throat. On the other hand, gastrointestinal symptoms of EBV infection like dyspepsia, abdominal pain are non-specific and rarely encountered, which means it is difficult to diagnose gastric involvement of EBV infection without suspicion. The relation between gastric carcinoma and gastric lymphoma associated with EBV infection is well defined, but relations with other EBV-associated gastrointestinal diseases such as gastritis and peptic ulcer disease have rarely been reported. We report a case of benign gastric ulcer with EBV infection confirmed by endoscopic and histological findings.

Epstein-Barr virus is absent in gastric superficial neoplastic lesions

Epstein-Barr virus (EBV) has been associated with about 9% of all gastric carcinomas, but its role in gastric carcinogenesis remains unclear since there is lack of evidence of EBV presence in pre-neoplastic lesions of gastric mucosa. This study intends to determine the prevalence of EBV in gastric dysplasia and superficial neoplasia to clarify whether EBV infection is an early or late event in gastric cancer development. This retrospective study included a total of 242 gastric lesions from 199 consecutive patients who were referred for endoscopic resection. The histological classification of lesions includes 137 low- and high-grade dysplasia and 105 superficial carcinomas. EBV infection was investigated by EBER-ISH. Results showed that EBV was not detected in any epithelial cells of any case with dysplasia or superficial carcinomas, although we observed the presence of a small number of EBV-infected lymphocytes in 2.1% of all lesions. These results showed that EBV is not present in gastric dysplasia neither in superficial carcinomas suggesting that EBV carcinogenesis is a late event in well/moderately differentiated gastric carcinogenesis.

Prevalence of Helicobacter pylori Infection, Its Virulent Genotypes, and Epstein-Barr Virus in Peruvian Patients With Chronic Gastritis and Gastric Cancer

PURPOSE

Helicobacter pylori (HP) and Epstein Barr virus (EBV) infections induce chronic gastritis (CG) and are accepted carcinogenics of gastric cancer (GC). Our objective for this study was to determine the prevalence of these agents and clinicopathological features of GC and CG associated with the infection.

PATIENTS AND METHODS

A single-center cohort of 375 Peruvian patients with GC and 165 control subjects with CG were analyzed. Evaluation of HP and EBV genes was performed through quantitative polymerase chain reaction.

RESULTS

Prevalence of HP was 62.9% in the whole population and 60.8% in the GC subset. The cagA gene was detected in 79.9%; vacAs1 and vacAm1 alleles in 41.6% and 60.7%, respectively; and concurrent expression of vacAs1 and vacAm1 in 30.4% of infected patients in the whole series. The prevalence of EBV was 14.1% in the whole population and was higher in GC (P < .001). Coinfection of HP and EBV was found in 7.8% and was also higher in GC in univariate (P < .001) and multivariate (P = .011) analyses. Infection rates of HP and EBV were not associated with a geographic location in the whole series. Few clinicopathological features have been associated with infectious status.

CONCLUSION

Prevalence of HP infection and virulent strains are high in the Peruvian population. Infection by EBV was more frequent in patients with GC.

Multiple infections by EBV, HCMV and Helicobacter pylori are highly frequent in patients with chronic gastritis and gastric cancer from Southwest Mexico: An observational study

The chronic inflammation and damage to the gastric epithelium induced by Helicobacter pylori (H. pylori) are the main risk factors for gastric cancer development. Epstein-Barr virus (EBV) and human cytomegalovirus (HCMV) induce chronic inflammation and have been found in gastric tumors. The objectives this observational study were to determine the frequency of multiple infections by Helicobacter pylori, Epstein-Barr virus (EBV) and human cytomegalovirus (HCMV) and to relate the infection by EBV and HCMV with H. pylori vacA/cagA genotypes in patients with chronic gastritis or gastric cancer. DNA from H. pylori, EBV and HCMV was detected by PCR in biopsies from 106 Mexican patients with chronic gastritis and 32 from gastric cancer. The cagA status and the vacA genotypes of H. pylori were determined by PCR. In chronic gastritis and gastric cancer EBV was found in 69.8% and 87.5%, HCMV in 52.8% and 53.1%, and H. pylori in 48.1% and 40.6%, respectively. In chronic gastritis, 53% of H. pylori patients were EBV and 33% were both EBV/HCMV; in gastric cancer, 92.3% of H. pylori-infected individuals were EBV and 46.1% were EVB/HCMV. All the intestinal- and mixed-type tumors and the 83.3% of diffuse-type tumors were EBV. No significant differences were found between single infections or coinfections with the diagnosis or the cancer type. The H. pylori genotypes were not related to EBV or HCMV infection. The frequency of dual infections by H. pylori, EBV and HCMV is higher in patients from southwest Mexico than other populations. It is likely that these pathogens act synergistically to induce inflammation and gastric cancer.

Association between Helicobacter pylori, Epstein-Barr virus, human papillomavirus and gastric adenocarcinomas

AIM

To correlate Helicobacter pylori (H. pylori), Epstein-Barr virus (EBV) and human papillomavirus (HPV) with gastric cancer (GC) cases in Pará State, Brazil.

METHODS

Tissue samples were obtained from 302 gastric adenocarcinomas. A rapid urease test was used to detect the presence of H. pylori, and the presence of the cagA gene in the HP-positive samples was confirmed by PCR. An RNA in situ hybridization test designed to complement Eber1 RNA was used to detect the presence of EBV in the samples, and the L1 region of HPV was detected using nested PCR. Positive HPV samples were genotyped and analyzed for E6 and E7 viral gene expression. Infections were also correlated with the clinical and pathological characteristics of the patients.

RESULTS

The majority of the 302 samples analyzed were obtained from men (65%) aged 55 years or older (67%) and were classified as the intestinal subtype (55%). All three pathogens were found in the samples analyzed in the present study (H. pylori: 87%, EBV: 20%, HPV: 3%). Overall, 78% of the H. pylori-positive (H. pylori⁺) samples were cagA+ (H. pylori-cagA⁺), and there was an association between the cytotoxic product of this gene and EBV. Coinfections of H. pylori-cagA⁺ and EBV were correlated with the most advanced tumor stages. Although only 20% of the tumors were positive for EBV, infection with this virus was associated with distant metastasis. Only the HPV 16 and 18 strains were found in the samples, although no expression of the E6 and E7 oncoproteins was detected. The fundus of the stomach was the region least affected by the pathogens.

CONCLUSION

HPV was not involved in gastric tumorigenesis. Prophylactic and therapeutic measures against H. pylori and EBV may prevent the development of GC, especially the more aggressive forms.

Role of serum EBV-VCA IgG detection in assessing gastric cancer risk and prognosis in Northern Chinese population

The study aimed to investigate the role of serum EBV‐VCA IgG in assessing gastric cancer (GC) risk and prognosis. A total of 1790 Northern Chinese participants with pathologically confirmed disease underwent EBV‐VCA IgG serologic testing using enzyme‐linked immunosorbent assay (ELISA), including 821 controls, 410 atrophic gastritis (AG) patients, and 559 GC patients. We found that positive EBV‐VCA IgG was significantly associated with GC and its precursor, conferring a 1.55‐ and 1.36‐fold increased risk of GC and AG, respectively (P = 0.001, 95% CI = 1.21‐1.99; P = 0.011, 95% CI = 1.07‐1.72, respectively). The risk effects were more remarkable in younger, female, and Helicobacter pylori‐negative individuals than in older, male, and H. pylori‐positive individuals. EBV‐VCA IgG‐positive subjects had a lower PGI/II ratio than EBV‐VCA IgG‐negative subjects (median 8.0 vs 8.8, P = 0.001), especially those in the H. pylori‐positive (median 6.1 vs 6.8, P = 0.027) and GC subgroups (median 6.4 vs 7.9, P = 0.020). In the intestinal GC subgroup, the survival of EBV‐VCA IgG‐positive patients was worse than that of EBV‐VCA IgG‐negative patients (P = 0.041, HR = 2.45, 95% CI = 1.04‐5.78). Our study suggests that EBV‐VCA IgG seropositivity has potential in predicting the risk of GC and its precursor as well as the prognosis of histologically classified GC.

This is an innovative report about the role of serum EBV‐VCA IgG detection in assessing the risk of gastric cancer (GC) and its precursor as well as GC prognosis. And this is the first report about the relationship between EBV‐VCA IgG serology assay and gastric function status. Our study provides theoretical and experimental basis for evaluating the potential of serum EBV‐VCA IgG as a biomarker in prediction of GC risk and prognosis.

Clinical and pathological characterization of Epstein-Barr virus-associated gastric carcinomas in Portugal

AIM

To determine the prevalence of Epstein-Barr virus (EBV)-associated gastric carcinomas in the North Region of Portugal and to study its clinicopathological characteristics.

METHODS

We have performed a retrospective study including a total of 179 consecutive patients with gastric cancer (GC) submitted to gastrectomy during 2011 at the Portuguese Oncology Institute of Porto. Clinical and pathological data was collected from individual clinical records and inserted on a database with unique codification. Tumour tissues were collected from the institutional tumour bank. EBV was detected by in situ hybridization for the detection of EBV-encoded small RNAs (EBERs) and EBV latent proteins (LMP1 and LMP2A) were detected by immunohistochemistry.

RESULTS

The analysis showed that EBV-associated gastric carcinomas (EBVaGC) represents 8.4% (15/179) of all GC cases, with a significant differential distribution among histological types (P < 0.001): 100% (3/3) of medullary carcinomas, 100% (1/1) of adenosquamous carcinoma, 8.7% (8/92) of tubular adenocarcinomas, 8.0% (2/25) of mixed carcinomas and 2% (1/51) in poorly cohesive carcinomas. The analysis revealed a higher predominance of EBVaGC in the upper third and middle (cardia, fundus and body) of the stomach (P = 0.041), a significant lower number of regional lymph nodes invasion (P = 0.025) and a tendency for better prognosis (P = 0.222). EBV latent protein expression revealed that all EBVaGC cases were LMP1-negative, nevertheless 6 cases (40%) expressed LPM2A, which reveals that these cases show a distinct EBV-Latency profile (latency II-like).

CONCLUSION

EBVaGC represents 8.4% of all GC in the North Region of Portugal. The EBV-infected patients have specific clinic-pathological features that should be further explored to develop new strategies of management and treatment.

Prevalence and characteristics of Epstein-Barr virus-associated gastric carcinomas in Portugal

Background

Gastric cancer (GC) is one of the most common malignant tumors of the digestive tract and is the third leading cause of cancer death worldwide. Epstein–Barr virus (EBV) has been associated with approximately 10% of the total cases of gastric carcinomas. No previous study has analyzed the prevalence of EBV infection in gastric cancer of the Portuguese population.

Methods

In the present study, we have analyzed 82 gastric carcinoma cases and 33 healthy individuals (control group) from Coimbra region for the presence of EBV by polymerase chain reaction (PCR) and by in situ hybridization (ISH) for EBV-encoded small RNAs (EBERs). The status of H. pylori infection was assessed by serology and by PCR.

Results

EBV was detected by PCR in 90.2% of stomach cancer cases, whereas EBERs were detected in 11%. In our series, EBV-associated gastric carcinoma (EBVaGC) were significantly associated with gender and the majority of them presented lymph node metastasis. These cases were generally graded in more advanced pTNM stages and, non-surprisingly, showed worse survival. H. pylori infection was detected in 62.2% of the gastric cancers and 64.7% of these patients were CagA+. On the other hand, the H. pylori prevalence was higher in the EBV-negative gastric carcinomas (64.4%) than in those carcinoma cases with EBV+ (44.4%).

Conclusions

The present study shows that prevalence of EBVaGC among Portuguese population is in accordance with the worldwide prevalence. EBV infection seems to be associated to poorer prognostic and no relation to H. pylori infection has been found. Conversely, the presence of H. pylori seems to have a favourable impact on patient’s survival. Our results emphasize that geographic variation can contribute with new epidemiological data on the association of EBV with gastric cancer.

Reaction of tetracycline with biologically relevant chloramines

Helicobacter pylori (H. pylori) infection triggers inflammatory processes with the consequent production of hypochlorous acid (HOCl), monochloramine (NH₂Cl), and protein-derived chloramines. As the therapy for eradicating H. pylori is partially based on the use of tetracycline, we studied the kinetic of its consumption elicited by HOCl, NH₂Cl, N-chloro-n-butylamine (NHCl-But, used as a lysine-derived chloramine model), and lysozyme-derived chloramines. In the micromolar concentration range, tetracycline reacted rapidly with HOCl, generating in the first few seconds intermediates of short half-life. In contrast, a slow tetracycline consumption was observed in the presence of high NH₂Cl and NHCl-But concentrations (millimolar range). Similar chlorinated products of tetracycline were identified by mass spectrometry, in the presence of HOCl and NH₂Cl. These results evidenced that tautomers of tetracycline are pivotal intermediates in all reactions. In spite of the low reactivity of chloramines towards tetracycline, it is evident that, in the concentration range where they are produced in a H. pylori infection (millimolar range), the reactions lead to oxidation and/or chlorination of tetracycline. This kind of reactions, which were also observed triggered by lysozyme-derived chloramines, could limit the efficiency of the tetracycline-based therapy.

Status of Epstein-Barr Virus Coinfection with Helicobacter pylori in Gastric Cancer

Epstein-Barr virus is a ubiquitous human herpesvirus whose primary infection causes mononucleosis, Burkett's lymphoma, nasopharyngeal carcinoma, autoimmune diseases, and gastric cancer (GC). The persistent infection causes malignancies in lymph and epithelial cells. Helicobacter pylori causes gastritis in human with chronic inflammation. This chronic inflammation is thought to be the cause of genomic instability. About 45%-word population have a probability of having both pathogens, namely, H. pylori and EBV. Approximately 180 per hundred thousand population is developing GC along with many gastric abnormalities. This makes GC the third leading cause of cancer-related death worldwide. Although lots of research are carried out individually for EBV and H. pylori, still there are very few reports available on coinfection of both pathogens. Recent studies suggested that EBV and H. pylori coinfection increases the occurrence of GC as well as the early age of GC detection comparing to individual infection. The aim of this review is to present status on coinfection of both pathogens and their association with GC.

Redox signaling in the gastrointestinal tract

Redox signaling regulates physiological self-renewal, proliferation, migration and differentiation in gastrointestinal epithelium by modulating Wnt/β-catenin and Notch signaling pathways mainly through NADPH oxidases (NOXs). In the intestine, intracellular and extracellular thiol redox status modulates the proliferative potential of epithelial cells. Furthermore, commensal bacteria contribute to intestine epithelial homeostasis through NOX1- and dual oxidase 2-derived reactive oxygen species (ROS). The loss of redox homeostasis is involved in the pathogenesis and development of a wide diversity of gastrointestinal disorders, such as Barrett's esophagus, esophageal adenocarcinoma, peptic ulcer, gastric cancer, ischemic intestinal injury, celiac disease, inflammatory bowel disease and colorectal cancer. The overproduction of superoxide anion together with inactivation of superoxide dismutase are involved in the pathogenesis of Barrett's esophagus and its transformation to adenocarcinoma. In Helicobacter pylori-induced peptic ulcer, oxidative stress derived from the leukocyte infiltrate and NOX1 aggravates mucosal damage, especially in HspB+ strains that downregulate Nrf2. In celiac disease, oxidative stress mediates most of the cytotoxic effects induced by gluten peptides and increases transglutaminase levels, whereas nitrosative stress contributes to the impairment of tight junctions. Progression of inflammatory bowel disease relies on the balance between pro-inflammatory redox-sensitive pathways, such as NLRP3 inflammasome and NF-κB, and the adaptive up-regulation of Mn superoxide dismutase and glutathione peroxidase 2. In colorectal cancer, redox signaling exhibits two Janus faces: On the one hand, NOX1 up-regulation and derived hydrogen peroxide enhance Wnt/β-catenin and Notch proliferating pathways; on the other hand, ROS may disrupt tumor progression through different pro-apoptotic mechanisms. In conclusion, redox signaling plays a critical role in the physiology and pathophysiology of gastrointestinal tract.

Anti-Helicobacter pylori Antibody Profiles in Epstein-Barr virus (EBV)-Positive and EBV-Negative Gastric Cancer

BACKGROUND

Helicobacter pylori is the primary cause of gastric cancer, but about 9% of cases harbor Epstein-Barr virus (EBV) in the tumor cells. There is limited evidence on the possible interaction or antagonism between these infectious agents in gastric carcinogenesis.

METHODS

We compared H. pylori serologic profiles of EBV-positive (n = 58) and EBV-negative (n = 111) noncardia gastric cancer patients from the United States National Cancer Institute's International EBV-Gastric Cancer Consortium. EBV positivity of tumors was assessed by in situ hybridization. Serum levels of 15 antibodies to immunogenic proteins of H. pylori (Cad, CagA, Cagδ, CagM, Catalase, GroEL, HcpC, HP0231, HP0305, HpaA, HyuA, NapA, Omp, UreA, VacA) were assessed using bead-based multiplex serology. Logistic regression models were used to adjust odds ratios (OR) for country, age, sex, and year of diagnosis.

RESULTS

Seropositivity to individual proteins ranged up to 90% overall. Antibodies to Catalase were borderline associated with tumor EBV positivity (adjusted OR = 3.15, p = .0024, Bonferroni corrected p = .036). Distributions of other antibodies did not vary by tumor EBV status.

CONCLUSION

Similarity of host-response indicates the essential etiological role of H. pylori in EBV-positive gastric cancer.

Epstein- Barr Virus: Clinical and Epidemiological Revisits and Genetic Basis of Oncogenesis

Epstein-Barr virus (EBV) is classified as a member in the order herpesvirales, family herpesviridae, subfamily gammaherpesvirinae and the genus lymphocytovirus. The virus is an exclusively human pathogen and thus also termed as human herpesvirus 4 (HHV4). It was the first oncogenic virus recognized and has been incriminated in the causation of tumors of both lymphatic and epithelial nature. It was reported in some previous studies that 95% of the population worldwide are serologically positive to the virus. Clinically, EBV primary infection is almost silent, persisting as a life-long asymptomatic latent infection in B cells although it may be responsible for a transient clinical syndrome called infectious mononucleosis. Following reactivation of the virus from latency due to immunocompromised status, EBV was found to be associated with several tumors. EBV linked to oncogenesis as detected in lymphoid tumors such as Burkitt's lymphoma (BL), Hodgkin's disease (HD), post-transplant lymphoproliferative disorders (PTLD) and T-cell lymphomas (e.g. Peripheral T-cell lymphomas; PTCL and Anaplastic large cell lymphomas; ALCL). It is also linked to epithelial tumors such as nasopharyngeal carcinoma (NPC), gastric carcinomas and oral hairy leukoplakia (OHL). In vitro, EBV many studies have demonstrated its ability to transform B cells into lymphoblastoid cell lines (LCLs). Despite these malignancies showing different clinical and epidemiological patterns when studied, genetic studies have suggested that these EBV- associated transformations were characterized generally by low level of virus gene expression with only the latent virus proteins (LVPs) upregulated in both tumors and LCLs. In this review, we summarize some clinical and epidemiological features of EBV- associated tumors. We also discuss how EBV latent genes may lead to oncogenesis in the different clinical malignancies

Occurrence of Helicobacter pylori and Epstein-Barr virus infection in endoscopic and gastric cancer patients from Northern Brazil

BACKGROUND

Helicobacter pylori (HP) and Epstein-Barr virus (EBV) have been associated with cancer development. We evaluated the prevalence of HP, HP CagA+ and EBV infection in gastric cancer (GC) samples from adults and in gastric tissues from patients who underwent upper endoscopy (UE).

METHODS

Samples from UE and GC were collected to investigate the presence of HP infection and the HP virulence factor CagA by a urease test and PCR. The presence of EBV was detected by Eber-1 in situ hybridization.

RESULTS

In UE, 85.5% of juvenile patients showed some degree of gastritis (45.3% of patients with mild gastritis and 54.7% with moderate/severe gastritis) and patients with mild gastritis were younger than patients with moderate/severe gastritis. Among adults, 48.7% presented mild gastritis and 51.3% moderate/severe gastritis. HP infection was detected in 0% of normal mucosa, 58.5% of juvenile gastritis patients, 69.2% of adult gastritis patients and 88% of GC patients. In these same groups, HP CagA+ was detected in 0%, 37.7%, 61.5% and 67.2% of tissue samples, respectively. In juvenile patients, HP infection was more common in those with gastritis than in normal samples (p = 0.004). The patients with either HP or HP CagA+ were older than patients without these pathogens (p < 0.05). In juvenile patients, HP infection was more frequent in cases of moderate/severe gastritis than in cases of mild gastritis (p = 0.026). Moreover, in patients with GC, HP infection was more frequent in males than in females (p = 0.023). GC patients with HP CagA+ were older than patients with HP CagA- (p = 0.027). HP CagA+ was more common in intestinal-type than diffuse-type GC (p = 0.012). HP CagA+ was also associated with lymph-node (p = 0.024) and distal (p = 0.005) metastasis. No association between EBV infection and HP infection or any clinicopathological variable was detected.

CONCLUSIONS

Our results suggest that HP is involved in the pathophysiology of severe gastric lesions and in the development of GC, particularly when CagA+ is present. EBV was not the primary pathogenic factor in our samples.

Co-infections, inflammation and oncogenesis: future directions for EBV research

Epstein-Barr virus (EBV) is aetiologically linked to a wide range of human tumours. Some arise as accidents of the virus' lifestyle in its natural niche, the B lymphoid system; these include B-lymphoproliferative disease of the immunocompromised, Hodgkin Lymphoma, Burkitt Lymphoma and particular forms of diffuse large B cell lymphoma. Interestingly, HIV infection increases the incidence of each of these B cell malignancies, though by different degrees and for different reasons. Other EBV-associated tumours arise through rare viral entry into unnatural target tissues; these include all cases of nasal T/NK cell lymphoma and of undifferentiated nasopharyngeal carcinoma plus a small but significant subset of gastric carcinomas, a tumour type more generally associated with chronic Helicobacter pylori infection. Understanding EBV's involvement in the pathogenesis of these different malignancies is an important long-term goal. This article focuses on two overlapping, but relatively neglected, areas of research that could contribute to that goal. The first addresses the mechanisms whereby coincident infections with other pathogens increase the risk of EBV-positive malignancies, and takes as its paradigm the actions of holoendemic malaria and HIV infections as co-factors in Burkitt lymphomagenesis. The second widens the argument to include both infectious and non-infectious sources of chronic inflammation in the pathogenesis of EBV-positive tumours such as T/NK cell lymphoma, nasopharyngeal carcinoma and gastric carcinoma.

Oxidative stress: an essential factor in the pathogenesis of gastrointestinal mucosal diseases

Reactive oxygen species (ROS) are generated as by-products of normal cellular metabolic activities. Superoxide dismutase, glutathione peroxidase, and catalase are the enzymes involved in protecting cells from the damaging effects of ROS. ROS are produced in response to ultraviolet radiation, cigarette smoking, alcohol, nonsteroidal anti-inflammatory drugs, ischemia-reperfusion injury, chronic infections, and inflammatory disorders. Disruption of normal cellular homeostasis by redox signaling may result in cardiovascular, neurodegenerative diseases and cancer. ROS are produced within the gastrointestinal (GI) tract, but their roles in pathophysiology and disease pathogenesis have not been well studied. Despite the protective barrier provided by the mucosa, ingested materials and microbial pathogens can induce oxidative injury and GI inflammatory responses involving the epithelium and immune/inflammatory cells. The pathogenesis of various GI diseases including peptic ulcers, gastrointestinal cancers, and inflammatory bowel disease is in part due to oxidative stress. Unraveling the signaling events initiated at the cellular level by oxidative free radicals as well as the physiological responses to such stress is important to better understand disease pathogenesis and to develop new therapies to manage a variety of conditions for which current therapies are not always sufficient.

Detection of Epstein-Barr virus and genotyping based on EBNA2 protein in Mexican patients with hodgkin lymphoma: a comparative study in children and adults

BACKGROUND

Epstein-Barr virus (EBV) is a member of the Herpesviridae family and is associated with Hodgkin lymphoma (HL). Isolates of EBV are classified according to sequence variation in the latency genes such as Epstein-Barr virus nuclear antigen (EBNA). EBNA2 contains the most divergent locus and is classified into type 1 and type 2 or EBNA2A and EBNA2B, respectively. We compared the frequency of EBV and the distribution of EBNA genotypes in Mexican children and adults with HL.

PATIENTS AND METHODS

Lymph node biopsy specimens from children and adults with HL were embedded in paraffin. EBV was identified by LMP1 amplification and Epstein-Barr-encoded RNA EBER by in situ hybridization (ISH) and genotyped as EBNA2A or EBNA2B using nested polymerase chain reaction (PCR) and specific primers for the detection of subtype.

RESULTS

Sixty-six samples were obtained from 3 hospitals-42 (63%) from children and 24 (37%) from adults with HL. Thirty-two of the 42 samples (76.1%) were positive for EBV in children and 16 of 24 (66.6%) samples were positive in adults (P = .41). In both children and adults, EBV was found more frequently in male patients. Thirty-four of 48 cases could be typed (70.8%). EBNA2A was found in 7/21 (33.3%) children and in 4/13 (30.8%) adults (P = 1.0), and EBNA2B was found in 10/21 (47.6%) children and in 9/13 (69.2%) adults (P = .22). A mix of subtypes was found in 4/21 (19%) children.

CONCLUSION

EBV was found frequently in both children and adults with HL. EBNA2B was the most frequent subtype, and a high frequency of mixed subtypes was found in children.

Expression profile of latent and lytic transcripts of epstein-barr virus in patients with gastroduodenal diseases: a study from northern India

Epstein-Barr virus (EBV) has been shown to be associated with gastric cancer. However, inconsistent findings have been reported regarding the EBV reactivation in gastric cancer and non-carcinomatous gastric epithelium. Therefore, the aim of the study was to investigate the effect of clinicopathological findings on the expression of different transcripts of EBV in patients with gastric cancer, peptic ulcer, and dyspepsia. A total of 200 adult patients (dyspepsia [120], peptic ulcer [30], gastric cancer [50]) undergoing upper gastrointestinal endoscopy were enrolled. EBV infection was diagnosed with non-polymorphic Epstein-Barr nuclear antigen1 (EBNA1) gene based PCR and confirmed by real-time PCR. The transcripts of EBV were detected by real-time RT-PCR. In patients with gastric cancer and peptic ulcer, EBV DNA was detected more often than in those with dyspepsia (P < 0.05). EBNA1 transcript was detected in all EBV positive cases and its expression was neither associated with disease nor with histopathological findings. The expression of BZLF1 was significantly associated with gastric cancer and peptic ulcer compared to dyspepsia (P < 0.01). BZLF1 expression was also found to be higher in Helicobacter pylori infected patients (P = 0.058). Expression of BARF1 and BcLF1 were significantly higher in gastric epithelium of patients having severe grade chronic inflammation (P = 0.05) and gastric atrophy (P = 0.02), respectively. In conclusion, increased expression of lytic transcripts in patients with gastric cancer, peptic ulcer, gastric atrophy, chronic inflammation and H. pylori infection suggests the association of these factors with EBV reactivation.

Epstein-Barr virus DNA load and its association with Helicobacter pylori infection in gastroduodenal diseases

Helicobacter pylori and Epstein-Barr virus (EBV) infections are common worldwide. Although H. pylori infection is a major factor in gastroduodenal diseases, its role in association with EBV infection is unknown.

OBJECTIVE

To study the association of H. pylori infection and EBV DNA load in patients with gastroduodenal diseases.

METHODS

Biopsy samples were collected from 200 adult patients [non-ulcer dyspepsia (NUD) 100, peptic ulcer disease (PUD) 50, gastric carcinoma (GC) 50] undergoing upper gastrointestinal endoscopy. H. pylori infection was diagnosed by rapid urease test, culture, histopathology, PCR and Q-PCR. EBV DNA was detected by non-polymorphic Epstein-Barr nuclear antigen-1 (EBNA-1) gene based Q-PCR.

RESULTS

In patients with GC and PUD, EBV DNA was detected more often than NUD (GC versus NUD = 90% versus 37%, p < 0.001; PUD versus NUD = 70% versus 37%, p < 0.001). The dual prevalence of H. pylori infection and EBV DNA was significantly higher in patients with GC and PUD than in those with NUD. Median copy number of EBV DNA was considerably higher in GC and PUD than NUD (p < 0.01). The copy number of EBV DNA was significantly higher in H. pylori infected patients (p = 0.015). The number of ureA gene copies was also found to be significantly higher in PUD and NUD with presence of EBV DNA. However, in GC no significant difference was seen between EBV positive and negative status.

CONCLUSION

There was a trend for higher EBV DNA load in H. pylori positive individuals suggesting a probable role of H. pylori in modulating the conversion of EBV to its lytic phase.

Epstein-Barr virus infection is common in inflamed gastrointestinal mucosa

BACKGROUND AND AIMS

Epstein-Barr virus (EBV) is present in the malignant epithelial cells of 10% of all gastric adenocarcinomas; however, localization of the virus in normal gastrointestinal mucosa is largely unexplored. In the present study, we measured EBV DNA and localized viral gene products in gastritis specimens (n = 89), normal gastric and colonic mucosa (n = 14), Crohn's disease (n = 9), and ulcerative colitis (n = 11) tissues.

METHODS

A battery of sensitive and specific quantitative polymerase chain reactions targeted six disparate regions of the EBV genome: BamH1 W, EBNA1, LMP1, LMP2, BZLF1, and EBER1. EBV infection was localized by EBV-encoded RNA (EBER) in situ hybridization and by immunohistochemical stains for viral latent proteins LMP1 and LMP2 and for viral lytic proteins BMRF1 and BZLF1. B lymphocytes were identified using CD20 immunostains.

RESULTS

EBV DNA was essentially undetectable in normal gastric mucosa but was present in 46% of gastritis lesions, 44% of normal colonic mucosa, 55% of Crohn's disease, and 64% of ulcerative colitis samples. Levels of EBV DNA exceeded what would be expected based on the numbers of B lymphocytes in inflamed tissues, suggesting that EBV is preferentially localized to inflammatory gastrointestinal lesions. Histochemical staining revealed EBER expression in lymphoid cells of some PCR-positive lesions. The viral lytic viral proteins, BMRF1 and BZLF1, were expressed in lymphoid cells of two ulcerative colitis tissues, both of which had relatively high viral loads by quantitative PCR.

CONCLUSION

EBV-infected lymphocytes are frequently present in inflamed gastric and colonic mucosa. Active viral replication in some lesions raises the possibility of virus-related perpetuation of gastrointestinal inflammation.

Determinants of Epstein-Barr virus-positive gastric cancer: an international pooled analysis

BACKGROUND

Meta-analyses of the published literature indicate that about 9% of gastric cancers contain Epstein-Barr virus (EBV), with consistent and significant differences by sex and anatomic subsite. This study aimed to identify additional determinants of EBV positivity and their joint effects.

METHODS

From 15 international populations with consistent laboratory testing for EBV, we pooled individual-level data for 5081 gastric cancer cases including information on age, sex, subsite, histologic type, diagnostic stage, geographic region, and period of diagnosis. First, we combined population-specific EBV prevalence estimates using random effects meta-analysis. We then aggregated individual-level data to estimate odds ratios of EBV positivity in relation to all variables, accounting for within-population clustering.

RESULTS

In unadjusted analyses, EBV positivity was significantly higher in males, young subjects, non-antral subsites, diffuse-type histology, and in studies from the Americas. Multivariable analyses confirmed significant associations with histology and region. Sex interacted with age (P=0.003) and subsite (P=0.002) such that male predominance decreased with age for both subsites. The positivity of EBV was not significantly associated with either stage or time period.

CONCLUSION

Aggregating individual-level data provides additional information over meta-analyses. Distinguishing histologic and geographic features as well as interactions among age, sex, and subsite further support classification of EBV-associated gastric cancer as a distinct aetiologic entity.

Meta-analysis shows that prevalence of Epstein-Barr virus-positive gastric cancer differs based on sex and anatomic location

BACKGROUND & AIMS

Epstein-Barr virus (EBV) has been causally associated with cancer; some gastric carcinomas have a monoclonal EBV genome in every cancer cell, indicating that they arose from a single infected progenitor cell. However, the proportion of EBV-positive gastric carcinomas is uncertain, and the etiologic significance is unknown.

METHODS

We conducted a meta-analysis of 70 studies including 15,952 cases of gastric cancer assessed by in situ hybridization for EBV-encoded small RNA.

RESULTS

The pooled prevalence estimate of EBV positivity was 8.7% (95% confidence interval [CI]: 7.5%-10.0%) overall, with a 2-fold difference by sex: 11.1% (95% CI: 8.7%-14.1%) of gastric cancer cases in males vs 5.2% (95% CI: 3.6%-7.4%) of cases in females. Tumors arising in the gastric cardia (13.6%) or corpus (13.1%) were more than twice as likely to be EBV-positive as those in the antrum (5.2%; P < .01 for both comparisons). EBV prevalence was 4 times higher (35.1%) for tumors in postsurgical gastric stump/remnants. Over 90% of lymphoepithelioma-like carcinomas were EBV positive, but only 15 studies reported any cases of this type; prevalence did not significantly differ between the more common diffuse (9.5%) [corrected] and intestinal (7.6%) [corrected] histologies. EBV prevalence was similar in cases from Asia (8.3%), Europe (9.2%), and the Americas (9.9%).

CONCLUSIONS

EBV-positive gastric cancers greatly differ from other gastric carcinomas based on sex, anatomic subsite, and surgically disrupted anatomy, indicating that it is a distinct etiologic entity. Epidemiologic studies comparing EBV-positive and -negative gastric cancers are warranted to investigate EBV's role in gastric carcinogenesis.

Cyclooxygenase-2 is an independent prognostic factor in gastric carcinoma patients receiving adjuvant chemotherapy and is not associated with EBV infection

PURPOSE

Cyclooxygenase-2 (COX-2) is believed to be involved in carcinogenesis in patients with chronic gastritis with Helicobacter pylori infection. EBV is detected in approximately 10% of gastric carcinomas and H. pylori induces EBV reactivation in the gastric epithelium. We aimed to evaluate significance of COX-2 in gastric carcinoma occurred in EBV and H. pylori prevalent area.

EXPERIMENTAL DESIGN

Tissue microarray samples from 457 gastric carcinoma patients who underwent gastrectomy and adjuvant chemotherapy were studied with EBER1 in situ hybridization for EBV and immunohistochemistry for COX-2 and other gastric carcinoma-related proteins (hMLH1, E-cadherin, c-erbB, and cyclin D1).

RESULTS

EBV infection was observed in 10.9% of gastric carcinomas and was associated with proximal tumor location, increased numbers of lymph node, and E-cadherin expression (P < 0.01). COX-2 overexpression was closely associated with intestinal histologic type and lower tumor stage (P = 0.01). Univariate analysis showed that pT, pN, lymph node ratio, American Joint Committee on Cancer stage, numbers of negative lymph nodes, and resection margin <1 cm were significant prognostic factors. The Cox proportional hazards regression analysis indicated that lack of COX-2 expression and resection margin <1 cm were independent prognostic factors for disease-free survival (P = 0.008 and 0.03, respectively) and overall survival (P = 0.01 and 0.007, respectively).

CONCLUSIONS

EBV infection is not associated with COX-2 expression or survival in gastric carcinoma. Lack of COX-2 expression is an independent prognostic factor in both overall and disease-free survival in gastric carcinoma. Our results indicate that COX-2 may play a role in the progression of gastric carcinoma regardless of EBV infection and is closely associated with histologic differentiation and prognosis.

Association of Helicobacter pylori and Epstein-Barr virus with gastric cancer and peptic ulcer disease

OBJECTIVE

Helicobacter pylori and Epstein-Barr virus (EBV) infections are common world-wide. Though H. pylori infection is a major factor in gastroduodenal diseases, its role in association with EBV infection is unknown. We prospectively studied the association of H. pylori and EBV in patients with gastric cancer (GC) and peptic ulcer disease (PUD).

MATERIAL AND METHODS

A total of 348 adult patients (non-ulcer dyspepsia (NUD) 241, PUD 45, GC 62) undergoing upper gastrointestinal endoscopy between September 2003 and May 2007 were enrolled in the study. H. pylori infection was diagnosed by rapid urease test, culture, histopathology and polymerase chain reaction (PCR). EBV DNA was detected by non-polymorphic Epstein-Barr nuclear antigen-1 (EBNA-1) gene-based PCR and sequence analysis.

RESULTS

The rate of H. pylori infection was higher in patients with PUD than in those with GC (80% versus 56.5%, p=0.01) and NUD (80% versus 55.2%, p=0.002). In patients with GC and PUD, EBV DNA was detected more often than in those with NUD (GC versus NUD - 82.3% versus 37.3%, p<0.001; PUD versus NUD - 75.5% versus 37.3%, p<0.001). H. pylori infection and EBV DNA detected in different groups of patients was as follows: 62.2% in PUD, 46.8% in GC and 29.5% in NUD. PUD and GC were significantly associated (p<0.001 and <0.05, respectively) with the presence of H. pylori infection and EBV DNA as compared with NUD.

CONCLUSIONS

EBV DNA either alone or in combination with H. pylori infection was significantly associated with GC and PUD, suggesting that EBV might play an important role in gastroduodenal pathology.

A molecular link between malaria and Epstein-Barr virus reactivation

Although malaria and Epstein–Barr (EBV) infection are recognized cofactors in the genesis of endemic Burkitt lymphoma (BL), their relative contribution is not understood. BL, the most common paediatric cancer in equatorial Africa, is a high-grade B cell lymphoma characterized by c-myc translocation. EBV is a ubiquitous B lymphotropic virus that persists in a latent state after primary infection, and in Africa, most children have sero-converted by 3 y of age. Malaria infection profoundly affects the B cell compartment, inducing polyclonal activation and hyper-gammaglobulinemia. We recently identified the cystein-rich inter-domain region 1α (CIDR1α) of the Plasmodium falciparum membrane protein 1 as a polyclonal B cell activator that preferentially activates the memory compartment, where EBV is known to persist. Here, we have addressed the mechanisms of interaction between CIDR1α and EBV in the context of B cells. We show that CIDR1α binds to the EBV-positive B cell line Akata and increases the number of cells switching to the viral lytic cycle as measured by green fluorescent protein (GFP) expression driven by a lytic promoter. The virus production in CIDR1α-exposed cultures was directly proportional to the number of GFP-positive Akata cells (lytic EBV) and to the increased expression of the EBV lytic promoter BZLF1. Furthermore, CIDR1α stimulated the production of EBV in peripheral blood mononuclear cells derived from healthy donors and children with BL. Our results suggest that P. falciparum antigens such as CIDR1α can directly induce EBV reactivation during malaria infection that may increase the risk of BL development for children living in malaria-endemic areas. To our knowledge, this is the first report to show that a microbial protein can drive a latently infected B cell into EBV replication.

Malaria and Epstein–Barr virus (EBV) infections are recognized cofactors in the genesis of endemic Burkitt lymphoma, the most common paediatric cancer in equatorial Africa. EBV is a ubiquitous virus residing in B lymphocytes that establishes a lifelong persistence in the host after primary infection. EBV has two lifestyles: latent infection (non-productive), and lytic replication (productive). Children living in malaria-endemic areas exhibit an elevated viral load, and acute malaria infection increases the levels of circulating EBV. The mechanisms leading to viral reactivation during Plasmodium falciparum malaria infection are not well understood. Cystein-rich inter-domain region 1α (CIDR1α) is a domain of a large protein expressed at the surface of P. falciparum–infected red blood cells. Based on previous findings showing that CIDR1α activates and expands the B cells compartment where EBV persists, we assessed the impact of CIDR1α on viral reactivation. Here, we identify CIDR1α as the first microbial protein able to drive a latently EBV-infected B cell (no virus production) into lytic replication (virus production). Our results suggest that P. falciparum–derived proteins can lead to a direct reactivation of EBV during acute malaria infection, increasing the risk of Burkitt lymphoma development for children living in malaria-endemic areas.