Clinicopathologic characteristics of Epstein-Barr virus-incorporated gastric cancers in Korea

Prognostic Effect of Tertiary Lymphoid Structures in Epstein-Barr Virus-Associated Gastric Carcinomas Measured by Digital Image Analysis

Epstein-Barr virus-associated gastric carcinoma (EBVaGC) is characterized by prominent tumor-infiltrating lymphocytes (TILs) and has a favorable prognosis. Tertiary lymphoid structures (TLS), characterized by ectopic aggregated lymphocytes with high-endothelial venules (HEV), are associated with favorable outcomes in various solid tumors. We hypothesized that EBVaGC, characterized by intense TILs, may be closely associated with TLS or HEV. To test this hypothesis, we digitally analyzed the TLS, HEV, and TILs in 73 surgically resected advanced EBVaGCs. For HEV, dual MECA-79 and CD31 dual immunohistochemistry were performed, and the ectopic expression of MECA-79 in tumor cells was measured. In 73 patients with EBVaGC, a high-TLS ratio was found in 29 (39.7%) cases, high-tumor-associated HEV density in 44 (60.3%) cases, and high-CD8+ TIL density in 38 (52.1%) cases. Ectopic tumor expression of MECA-79 was observed in 36 patients (49.3%) cases. A low-TLS ratio and tumor-associated HEV density were significantly associated with lymph node metastasis (P = .005 and .042, respectively). Ectopic MECA-79 expression was significantly associated with lymph node metastasis (P = .003). Patients with a low-TLS ratio (P = .038), low-HEV density (P = .042), and ectopic tumor MECA-79 expression (P = .032) had significantly worse prognoses. In conclusion, TLS ratio and HEV density affect the survival of patients with EBVaGC and may be related to the immune response that interrupts lymph node metastasis.

Unusual or Uncommon Histology of Gastric Cancer

This review comprehensively examines the diverse spectrum of gastric cancers, focusing on unusual or uncommon histology that presents significant diagnostic and therapeutic challenges. While the predominant form, tubular adenocarcinoma, is well-characterized, this review focuses on lesser-known variants, including papillary adenocarcinoma, micropapillary carcinoma, adenosquamous carcinoma, squamous cell carcinoma (SCC), hepatoid adenocarcinoma, gastric choriocarcinoma, gastric carcinoma with lymphoid stroma, carcinosarcoma, gastroblastoma, parietal cell carcinoma, oncocytic adenocarcinoma, Paneth cell carcinoma, gastric adenocarcinoma of the fundic gland type, undifferentiated carcinoma, and extremely well-differentiated adenocarcinoma. Although these diseases have different nomenclatures characterized by distinct histopathological features, these phenotypes often overlap, making it difficult to draw clear boundaries. Furthermore, the number of cases was limited, and the unique histopathological nature and potential pathogenic mechanisms were not well defined. This review highlights the importance of understanding these rare variants for accurate diagnosis, effective treatment planning, and improving patient outcomes. This review emphasizes the need for ongoing research and case studies to enhance our knowledge of these uncommon forms of gastric cancer, which will ultimately contribute to more effective treatments and better prognostic assessments. This review aimed to broaden the pathological narrative by acknowledging and addressing the intricacies of all cancer types, regardless of their rarity, to advance patient care and improve prognosis.

Genetic landscape and PD-L1 expression in Epstein-Barr virus-associated gastric cancer according to the histological pattern

Epstein-Barr virus (EBV)-associated gastric cancer (EBVaGC) is a distinct molecular subtype of gastric cancer. This study aims to investigate genomic and clinicopathological characteristics of EBVaGC according to the histological pattern. We retrospectively collected 18 specimens of surgically resected EBVaGCs. Whole-exome sequencing was performed for all cases. Moreover, PD-L1 expression and tumor-infiltrating lymphocyte (TIL) percentage were investigated. Among 18 EBVaGCs, 10 cases were of intestinal histology, 3 were of poorly cohesive histology, and the remaining 5 were of gastric carcinoma with lymphoid stroma histology. Whole-exome sequencing revealed that EBVaGCs with intestinal histology harbored pathogenic mutations known to frequently occur in tubular or papillary adenocarcinoma, including TP53, KRAS, FBXW7, MUC6, ERBB2, CTNNB1, and ERBB2 amplifications. One patient with poorly cohesive carcinoma histology harbored a CDH1 mutation. Patients with EBVaGCs with intestinal or poorly cohesive carcinoma histology frequently harbored driver mutations other than PIK3CA, whereas those with EBVaGCs with gastric carcinoma with lymphoid stroma histology lacked other driver mutations. Moreover, the histological pattern of EBVaGCs was significantly associated with the levels of TILs (P = 0.005) and combined positive score (P = 0.027). In conclusion, patients with EBVaGCs with different histological patterns exhibited distinct genetic alteration, PD-L1 expression, and degree of TILs.

Plasma EBV DNA as a prognostic factor in EBV associated gastric cancer: a multicenter, prospective study (EBV PRESAGE study)

Purpose

The Cancer Genome Atlas Research Network identified Epstein-Barr-Virus (EBV)-positive gastric cancer as a distinct molecular subtype. The prevalence is 8-9% and the histological examination shows pronounced lymphocytic infiltration, elevated levels of IFN-γ and consequently overexpression of PD-L1. The role of plasma EBV DNA load as a prognostic factor in patients with this cancer subtype is still to be defined.

Methods and analysis

The present multicenter prospective observational study "EBV PRESAGE", involving German and Italian cancer centers, aims to evaluate the prognostic role of plasma EBV DNA in EBV-related gastric cancer (GC). The objective is to study the association between plasma EBV DNA load at different consecutive time points and the patient's prognosis. Every patient with a new diagnosis of gastric cancer (including gastroesophageal junction adenocarcinoma) will be screened for Epstein-Barr encoded small Region (EBER) on tissue biopsies using in situ hybridization (ISH). If EBER ISH is positive, blood analysis for plasma EBV DNA will be conducted. The plasma EBV quantitative analysis will be centralized, and extraction, detection, and quantification of EBV DNA in plasma samples will be performed using real-time PCR.

Discussion

We hypothesized that plasma EBV DNA represents a non-invasive tool for monitoring EBV-related GC and might be valuable as a prognostic marker.

Gastric cancer with distinct Epstein-Barr virus-positive and -negative tumor components and their whole exome sequencing result: a case Report

BACKGROUND

Epstein-Barr virus (EBV)-associated gastric cancer exhibits distinct clinicopathologic characteristics, showing a good response to immune checkpoint inhibitors and a favorable prognosis. However, gastric cancer comprising distinct EBV-positive and -negative components in a single mass have been rarely reported, and their detailed genetic characteristics have not yet been investigated. Therefore, we reported the case of gastric cancer exhibiting distinct EBV-positive and -negative areas and further investigated its genetic characteristics.

CASE PRESENTATIONS

A 70-year-old man underwent distal gastrectomy for gastric cancer, which was detected during a routine health check-up. EBV-encoded RNA in situ hybridization revealed distinct EBV-positive and -negative components at each other's borders, morphologically consistent with collision tumor. We separately sequenced EBV-positive and -negative tumor areas through whole exome sequencing (WES) with matched normal tissue. Remarkably, both EBV-positive and -negative areas shared pathogenic mutations of ARID1A, KCNJ2, and RRAS2. Furthermore, they shared 92 somatic single nucleotide variants and small insertion or deletion mutations, of which 32.7% and 24.5% are EBV-positive and -negative tumor components, respectively.

CONCLUSIONS

WES results suggested that gastric cancer with distinct EBV-positive and -negative tumor components, formerly categorized as a collision tumor, can be clonally related. EBV-negative tumor component might be associated with loss of EBV during tumor progression.

Estimating the Global Burden of Epstein-Barr Virus-Associated Gastric Cancer: A Systematic Review and Meta-Analysis

BACKGROUND & AIMS

Evidence suggests that a fraction of new gastric cancer cases may be etiologically associated with Epstein-Barr virus (EBV), a known carcinogenic agent. We aimed to systematically explore the proportion of EBV-positive gastric cancer.

METHODS

We did a systematic review (PROSPERO CRD42020164473) from January 1990 to August 2021. For each country and geographical region with available data, pooled prevalence and corresponding 95% confidence intervals (CIs) of EBV in gastric tumors were calculated for 3 subtypes of gastric adenocarcinoma (conventional adenocarcinoma, lymphoepithelioma-like gastric carcinoma, and remnant/stump carcinoma). For conventional adenocarcinoma, prevalence ratios (PRs) were presented for sex, Lauren's classification, gastric cancer stage, and anatomical location of the stomach.

RESULTS

In 220 eligible studies including over 68,000 cases of conventional gastric adenocarcinoma, EBV prevalence in tumor cells was 7.5% (95% CI, 6.9%-8.1%) and was higher in men compared with women (PR, 2.1; 95% CI, 1.9-2.4), in diffuse type compared with intestinal type (PR, 1.3; 95% CI, 1.1-1.5), and in the proximal region compared with the distal region (PR, 2.5; 95% CI, 2.0-3.1). There was no difference in EBV prevalence by gastric cancer stage. EBV prevalence was 75.9% (95% CI, 62.8%-85.5%) among lymphoepithelioma-like gastric carcinoma and 26.3% (95% CI, 22.2%-32.0%) among remnant or stump carcinoma.

CONCLUSIONS

Assuming a causal association between EBV and gastric cancer, our findings, when applied to the GLOBOCAN 2020 gastric cancer incidence, suggest that primary prevention such as the development of an effective EBV vaccine might prevent 81,000 EBV-associated gastric cancer cases worldwide annually.

Genomic landscape of virus-associated cancers

It has been estimated that 15%-20% of human cancers are attributable to infections, mostly by carcinogenic viruses. The incidence varies worldwide, with a majority affecting developing countries. Here, we present a comparative analysis of virus-positive and virus-negative tumors in nine cancers linked to five viruses. We find that virus-positive tumors occur more frequently in males and show geographical disparities in incidence. Genomic analysis of 1,658 tumors reveals virus-positive tumors exhibit distinct mutation signatures and driver gene mutations and possess a lower somatic mutation burden compared to virus-negative tumors of the same cancer type. For example, compared to the respective virus-negative counterparts, virus-positive cases across different cancer histologies had less often mutations of TP53 and deletions of 9p21.3/ CDKN2 A- CDKN1A ; Epstein-Barr virus-positive (EBV+) gastric cancer had more frequent mutations of EIF4A1 and ARID1A and less marked mismatch repair deficiency signatures; and EBV-positive cHL had fewer somatic genetic lesions of JAK-STAT, NF-κB, PI3K-AKT and HLA-I genes and a less pronounced activity of the aberrant somatic hypermutation signature. In cHL, we also identify germline homozygosity in HLA class I as a potential risk factor for the development of EBV-positive Hodgkin lymphoma. Finally, an analysis of clinical trials of PD-(L)1 inhibitors in four virus-associated cancers suggested an association of viral infection with higher response rate in patients receiving such treatments, which was particularly evident in gastric cancer and head and neck squamous cell carcinoma. These results illustrate the epidemiological, genetic, prognostic, and therapeutic trends across virus-associated malignancies.

Epstein-Barr Virus-Positive Lymphoepithelioma-Like Carcinoma in Celiac Disease

Lymphoepithelioma-like carcinoma (LELC) is a rare lymphoproliferative malignancy that has been described in many organs over the years. LELC in the duodenum has rarely been described in literature. This article aims to present a rare cause of melena in a young man and the diagnostic challenge that ensued to throw more light on this rare disease. In this article, we describe a 43-year-old man who presented with melena and weight loss and was subsequently diagnosed with LELC after multiple endoscopic biopsies. The patient was also found to have celiac disease in association with his LELC.

Short-term outcomes of three rare cases of intramucosal Epstein-Barr virus-associated gastric cancer treated with endoscopic submucosal dissection

Epstein-Barr virus-associated gastric cancer (EBVaGC) is a subtype of gastric cancer morphologically characterized by massive lymphocyte infiltration. We herein report the short-term outcomes of three rare cases of intramucosal EBVaGC treated with endoscopic submucosal dissection (ESD). Histologically, the lesions exhibited poorly to moderately differentiated tubular adenocarcinoma without lymphovascular invasion, and in situ hybridization revealed EBV-encoded small RNA. Helicobacter pylori infection was not found in any of the lesions. During the 3 to 12 months of follow-up following ESD, none of the ESD-treated patients showed evidence of local recurrence or distant metastases. Essential characteristics of intramucosal EBVaGC may include lymphocyte infiltration into the mucosal stroma or cancer nests as well as the presence of a lace pattern. We believe that ESD might be a safe and suitable treatment method for intramucosal EBVaGC that avoids needless surgery, particularly in patients with severe comorbidities or a high operational risk.

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.

Viral status, immune microenvironment and immunological response to checkpoint inhibitors in hepatocellular carcinoma

Background and aims

Immune checkpoint inhibitors (ICIs) targeting the programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) pathway have clinical activity in hepatocellular carcinoma (HCC), but only a subset of patients respond to these therapies, highlighting a need for novel biomarkers to improve clinical benefit. HCC usually occurs in the setting of liver cirrhosis from chronic hepatitis B or C viral infection, but the effects of viral status on the tumor immune microenvironment and clinical responses to ICIs in HCC remains unclear.

Methods

We conducted a meta-analysis to estimate the objective response rates for PD-1/PD-L1 inhibitors in virally-infected and uninfected patients, and examined the effects of viral etiology on the tumor microenvironment using data from The Cancer Genome Atlas, as well as peripheral blood responses using an independent cohort of patients studied by mass cytometry (cytometry by time-of-flight (CyTOF)).

Results

Meta-analysis comparing objective response rates (ORR) between virally-infected and uninfected patients showed no clinically meaningful difference (absolute difference of ORR in virally-infected vs uninfected=−1.4%, 95% CI: −13.5% to 10.6%). There was no relationship between viral etiology on features of the tumor immune microenvironment that are known to modulate responses to PD-1/PD-L1 inhibitors, and the tumor mutational burden was similar between virally-infected and uninfected HCC. RNA sequencing of tissue-resident T cell and B cell repertoires similarly showed no effect of viral status on their diversity. CyTOF analysis of peripheral blood specimens further demonstrated similar expression of immune-related markers in response to PD-1 inhibitor therapy in virally-infected and uninfected HCC.

Conclusion

There is no significant effect of viral etiology on the tumor immune microenvironment in HCC, and viral status should not be used as a criterion to select patients for PD-1/PD-L1 therapy.

Clinicopathological Features and Prognostic Implication of Gastric Carcinoma with Lymphoid Stroma

Methods

This study included 34 eligible studies and 1757 GCLSs. The clinicopathologic characteristics of GCLS were investigated from eligible studies, and the meta-analysis was performed. In addition, we compared the survival rates between GCLS and non-GCLS.

Results

The estimated rate of GCLS was 0.062 (95% confidence interval (CI) 0.040-0.097). GCLS was significantly correlated with the diffuse type of Lauren's classification, proximal tumor location, less-frequent lymphatic invasion, and lower pTNM stage. However, there was no significant difference in age, sex, tumor differentiation, vascular invasion, perineural invasion, pT stage, lymph node metastasis, and distant metastasis between GCLS and non-GCLS patients. EBV positive rates in GCLS and non-GCLS patients were 0.723 (95% CI 0.643-0.791) and 0.064 (95% CI 0.039-0.103), respectively. HER2 expression in GCLS was significantly lower than that in non-GCLS. GCLS patients had a more favorable prognosis than that of non-GCLS patients (hazard ratio 0.500, 95% CI 0.305-0.821).

Conclusion

GCLS comprised 6.2% of overall GC and more frequent in the proximal portion of the stomach. Since GCLS was associated with better prognosis, the histologic finding can be useful for predicting the patient's prognosis.

Potential prognostic impact of EBV RNA-seq reads in gastric cancer: a reanalysis of The Cancer Genome Atlas cohort

Epstein-Barr virus (EBV)-associated gastric cancer (EBVaGC), whose prognosis remains controversial, is diagnosed by in situ hybridization of EBV-derived EBER1/2 small RNAs. In The Cancer Genome Atlas (TCGA) Stomach Adenocarcinoma (STAD) project, the EBV molecular subtype was determined through a combination of multiple next-generation sequencing methods, but not by the gold standard in situ hybridization method. This leaves unanswered questions regarding the discordance of EBV positivity detected by different approaches and the threshold of sequencing reads. Therefore, we reanalyzed the TCGA-STAD RNA sequencing (RNA-seq) dataset including 375 tumor and 32 normal samples, using our analysis pipeline. We defined a reliable threshold for EBV-derived next-generation sequencing reads by mapping them to the EBV genome with three different random arbitrary alignments. We analyzed the prognostic impact of EBV status on the histopathological subtypes of gastric cancer. EBV-positive cases identified by reanalysis comprised nearly half of the cases (49.6%) independent from infiltrating lymphocyte signatures, and showed significantly longer overall survival for adenocarcinomas of the 'not-otherwise-specified' type [P = 0.016 (log-rank test); hazard ratios (HR): 0.476; 95% CI: 0.260-0.870, P = 0.016 (Cox univariate analysis)], but shorter overall survival for the tubular adenocarcinoma type [P = 0.005 (log-rank test); HR: 3.329; 95% CI: 1.406-7.885, P = 0.006 (Cox univariate analysis)]. These results demonstrate that the EBV positivity rates were higher when determined by RNA-seq than when determined by EBER1/2 in situ hybridization. The RNA-seq-based EBV positivity demonstrated distinct results for gastric cancer prognosis depending on the histopathological subtype, suggesting its potential to be used in clinical prognoses.

Comprehensive expression profiles of gastric cancer molecular subtypes by immunohistochemistry: implications for individualized therapy

Gastric cancer (GC) is a leading cause of death. We aim to establish a clinically relevant assay that encompasses recent molecular classifications and provides useful clinical information in a large cohort of GC patients. A consecutive series of 438 GC patients that underwent palliative chemotherapy between 2014 and 2015 were assessed using 10 GC panels: EBER in-situ hybridization, immunohistochemistry for mismatch repair (MMR) proteins (MLH1, PMS2, MSH2, and MSH6), receptor tyrosine kinases (RTKs; HER2, EGFR, and MET), PTEN, and p53 protein. With a median of one aberration, 3.3 % of samples analyzed were Epstein-Barr virus (EBV)-positive; 4.8%, MMR-deficient. RTKs were overexpressed in 218 patients; EGFR was most commonly overexpressed (39.9%), followed by HER2 (13.5%) and MET (12.1%). Furthermore, 2.5 % and 10.7 % of cases had simultaneous overexpression of three and two RTKs, respectively. p53 overexpression/null tumors were identified in 259 patients (59.1%), and PTEN loss was identified in 89 patients (20.3%). EBV-positivity was mutually exclusive with MMR-deficiency, predominantly identified in male patients, and these tumors were undifferentiated with proximal location. p53 mutant type was significantly found predominantly in the EBV-negative (60.6% vs 14.3%, P=0.001) and HER2-positive (78.0% vs 56.2%, P=0.002) groups. We described a molecular spectrum of distinct GC subtypes using clinically applicable assay. This assay will provide a convenient screening tool and facilitate the development of targeted agents in clinical trials.

Immunoclassification characterized by CD8 and PD-L1 expression is associated with the clinical outcome of gastric cancer patients

Background

Gastric cancer (GC) is a major cause of cancer deaths, especially in Eastern Asia. Current classification systems, including the WHO, Lauren, and TCGA, have clarified the pathological and molecular profiles of GC. However, these classifications lack an association with clinical outcome and guidance for medication selection.

Objective

We aimed to identify a new immunoclassification for GC to better predict patient prognosis and aid in patient selection for immunotherapy.

Results

For all samples, 35 were EBV positive (+) and 112 were EBV negative (-). EBV infection was associated with the number of CD3+ T cells (OR = 2.91 95% CI 1.27-6.68, p = 0.012) and PD-L1 expression in TME (OR = 2.57, 95% CI 1.13–5.82, p = 0.024). EBV+ patients showed a poor overall survival (OS) compared with EBV- patients (HR = 2.37; 95% CI, 1.03–5.41; p = 0.011). Importantly, WIR patients lived significantly shorter than SIR patients with high CD8+ T cells and low PD-L1 expression (HR = 3.37; 95% CI, 1.63–6.97; p = 0.015).

Materials and Methods

147 formalin-fixed and paraffin-embedded (FFPE) samples of GC were obtained. Epstein-Barr virus (EBV) infection was measured. Immune markers including CD3, CD8 and PD-L1 were detected by immunohistochemistry (IHC) at tumor infiltration area (TI) and invasive margin area (IM) in tumor microenvironment (TME). PD-L1 expression was assessed by immunoreactive score (IRS) system. For immunoclassification, patients were classified into two subgroups: strong immunoreaction (SIR) and weak immunoreaction (WIR) defined by the number of CD8+ T cells and PD-L1 expression in TI.

Conclusions

In this study, we suggest a new immunoclassification for gastric cancer which is associated with patient outcome and may provide a way to guide immunotherapy in the future.

Identification of Epstein-Barr Virus in the Human Placenta and Its Pathologic Characteristics

Epstein-Barr virus (EBV), a common pathogen in humans, is suspected as the cause of multiple pregnancy-related pathologies including depression, preeclampsia, and stillbirth. Moreover, transmission of EBV through the placenta has been reported. However, the focus of EBV infection within the placenta has remained unknown to date. In this study, we proved the expression of latent EBV genes in the endometrial glandular epithelial cells of the placenta and investigated the cytological characteristics of these cells. Sixty-eight placentas were obtained from pregnant women. Tissue microarray was constructed. EBV latent genes including EBV-encoding RNA-1 (EBER1), Epstein-Barr virus nuclear antigen 1 (EBNA1), late membrane antigen (LMP1), and RPMS1 were detected with silver in situ hybridization and/or mRNA in situ hybridization. Nuclear features of EBV-positive cells in EBV-infected placenta were compared with those of EBV-negative cells via image analysis. Sixteen placentas (23.5%) showed positive expression of all 4 EBV latent genes; only the glandular epithelial cells of the decidua showed EBV gene expression. EBV infection status was not significantly correlated with maternal, fetal, or placental factors. The nuclei of EBV-positive cells were significantly larger, longer, and round-shaped than those of EBV-negative cells regardless of EBV-infection status of the placenta. For the first time, evidence of EBV gene expression has been shown in placental tissues. Furthermore, we have characterized its cytological features, allowing screening of EBV infection through microscopic examination.

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.

EBV infection and MSI status significantly influence the clinical outcomes of gastric cancer patients

BACKGROUND

Epstein-Barr virus (EBV) and microsatellite instability (MSI) are associated with the carcinogenesis of many kinds of tumors, including gastric cancer (GC). However, the impact of EBV and MSI status on the prognosis of stage II and III GC is still unclear. The aim of this study was to find out the prognostic value of EBV and MSI status in a population of GC patients from Southern China.

METHODS

Patients were genotyped for EBV infection based on the detection of EBV DNA from the formalin-fixed paraffin-embedded (FFPE) specimens. Sequentially, MSI status was measured by direct sequencing. Clinical characteristics and overall survival (OS) were analyzed in 202 GC patients. Additionally, the association of EBV and MSI status with chemotherapy-based toxicity was analyzed in 324 GC patients.

RESULTS

The survival analysis revealed EBV+ patients had a poorer OS than EBV- patients (HR=1.75, 95% CI: 1.08-2.82, FDR p=0.04). This survival advantage for EBV- patients was also found in patients <60y (FDR p=0.04) and patient with stage III disease (FDR p=0.04).

CONCLUSIONS

EBV infection and MSI status are associated with overall survival of gastric cancer patients. However, traditional chemotherapy showed no difference on outcome of patients in EBV and MSI subgroups.

EBV相关性胃癌研究进展

胃癌细胞中存在Epstein-Barr病毒(Epstein-Barr virus, EBV)者被称为EBV相关性胃癌(Epstein-Barr virus-associated gastric carcinoma, EBVaGC). 近年来EBVaGC作为一种独特的分子亚型疾病逐渐被人们所认知, 全球胃癌患者中平均有10%者为EBVaGC. 本文对EBVaGC近年来在流行病学、临床病理特征、发病机制、治疗及预后等方面的研究进展作一综述. 但目前对EBVaGC的研究尚不明确, 且尚无临床诊疗规范与共识, 也带来了新的挑战和机遇.

Epstein-Barr virus BARF1-induced NFκB/miR-146a/SMAD4 alterations in stomach cancer cells

Epstein-Barr virus (EBV)-encoded BamHI-A rightward frame 1 (BARF1) is a putative viral oncogene in EBV-infected stomach cancer. The aim of the present study was to investigate BARF1-induced cellular protein and microRNA alterations. In this study, BARF1-expressing stomach cancer cells showed a high rate of proliferation, high levels of NFκB, and miR-146a upregulation, which was reversed by NFκB knockdown. During BARF1-induced NFκB upregulation, hCSF1 receptor level was unchanged. Knockdown of BARF1 in the naturally EBV-infected YCCEL1 stomach cancer cells suppressed cell proliferation, and downregulated NFκB and miR-146a. SMAD4 was identified as a miR-146a target and was downregulated in BARF1-expressing cells, whereas SMAD4 expression was restored by anti-miR-146a. Knockdown of BARF1 in YCCEL1 cells upregulated SMAD4, and this effect was reversed by miR-146a overexpression. Transfection of BARF1-expressing cells with pCEP4-SMAD4 abolished the cell proliferating effect of BARF1. In stomach cancer tissues, miR-146a was expressed at higher levels, and more frequent NFκB nuclear positivity immunohistochemically, but not of SMAD4 nuclear loss was found in the EBV-positive group compared with the EBV-negative group. In conclusion, EBV-encoded BARF1 promotes cell proliferation in stomach cancer by upregulating NFκB and miR-146a and downregulating SMAD4, thereby contributing to EBV-induced stomach cancer progression.

Genome-wide analysis of Epstein-Barr virus (EBV) isolated from EBV-associated gastric carcinoma (EBVaGC)

Epstein-Barr virus (EBV) is linked to the development of a variety of malignancies, including EBV-associated gastric carcinoma (EBVaGC). In this study, EBVaGC was detected in 15 (7.3%) of 206 GC cases. To identify the EBV genomic variation, EBV genomic sequences isolated from 9 EBVaGC biopsy specimens were successfully retrieved, designated EBVaGC1 to EBVaGC9. By comparative analysis of these strains with another 6 completely sequenced EBV strains, EBV-wild type, B95–8, AG876, GD1, GD2, and HKNPC1, it was demonstrated that EBVaGC1 to 9 were most closely related to the GD1 strain. Phylogenetic analysis of the GC biopsy specimen-derived EBV (GC-EBV) genomes was subsequently performed to assess their genomic diversity and it exhibited the greatest divergence from the type 2 strain, AG876. Compared with the reference EBV strain GD1, they harbored 961 variations in total, including 919 substitutions, 23 insertions, and 19 deletions. Single nucleotide polymorphism (SNP) density varied substantially across all known open reading frames and was highest in latency-associated genes. Moreover, we identified 2 interstrain recombinants at the EBNA1 locus, which provided a further mechanism for the generation of diversity. Some T-cell epitope sequences in EBNA1 and LMP2A genes showed extensive variation across strains, which implied their importance in the development of vaccines and T-cell therapy. In conclusion, we reported the first genome-wide view of sequence variation of EBV isolated from primary EBVaGC biopsy specimens, which might serve as an effective method for further understanding the genomic variations contribute to EBVaGC carcinogenesis and treatment.

A protein and mRNA expression-based classification of gastric cancer

The overall survival of gastric carcinoma patients remains poor despite improved control over known risk factors and surveillance. This highlights the need for new classifications, driven towards identification of potential therapeutic targets. Using sophisticated molecular technologies and analysis, three groups recently provided genetic and epigenetic molecular classifications of gastric cancer (The Cancer Genome Atlas, 'Singapore-Duke' study, and Asian Cancer Research Group). Suggested by these classifications, here, we examined the expression of 14 biomarkers in a cohort of 146 gastric adenocarcinomas and performed unsupervised hierarchical clustering analysis using less expensive and widely available immunohistochemistry and in situ hybridization. Ultimately, we identified five groups of gastric cancers based on Epstein-Barr virus (EBV) positivity, microsatellite instability, aberrant E-cadherin, and p53 expression; the remaining cases constituted a group characterized by normal p53 expression. In addition, the five categories correspond to the reported molecular subgroups by virtue of clinicopathologic features. Furthermore, evaluation between these clusters and survival using the Cox proportional hazards model showed a trend for superior survival in the EBV and microsatellite-instable related adenocarcinomas. In conclusion, we offer as a proposal a simplified algorithm that is able to reproduce the recently proposed molecular subgroups of gastric adenocarcinoma, using immunohistochemical and in situ hybridization techniques.

Epstein-Barr virus infection serves as an independent predictor of survival in patients with lymphoepithelioma-like gastric carcinoma

BACKGROUND

The pathogenesis and clinicopathologic characteristics of Epstein-Barr virus (EBV)-negative lymphoepithelioma-like gastric carcinoma (LELC) are still unclear. In addition, it remains controversial whether EBV infection itself affects the prognosis of LELC.

METHODS

Between 1995 and 2011, 145 LELC patients (124 patients with EBV infection and 21 patients without EBV infection) underwent radical gastrectomy with D2 lymph node dissection. The clinicopathologic features and prognosis of EBV-negative LELC cases were compared with those of EBV-positive LELC cases. The median duration of follow-up after surgery was 55 months. Microsatellite instability (MSI) analysis was performed on 20 EBV-negative LELC cases.

RESULTS

EBV-negative LELC accounted for 14.5 % of the total LELC cases. EBV-negative LELC was significantly associated with older age, female sex, advanced T stage, and advanced American Joint Committee on Cancer (AJCC) tumor stage compared with EBV-positive LELC. In univariate analysis, patients with EBV-negative LELC had significantly shorter overall, disease-specific, and recurrence-free survival than those with EBV-positive LELC. The 5-year overall survival rates were 81.0 % for patients with EBV-negative LELC and 96.2 % for patients with EBV-positive LELC. In a Cox proportional hazards model, EBV infection, age, and AJCC tumor stage were identified as independent predictors of overall survival. MSI-high, MSI-low, and microsatellite-stable tumors accounted for 25, 10, and 65 % of EBV-negative LELC cases, respectively. MSI status did not affect the prognosis of EBV-negative LELC cases.

CONCLUSIONS

EBV infection serves as an independent predictor of survival in patients with LELC. EBV-negative LELC exhibited clinicopathologic features and prognosis distinct from those of EBV-positive LELC.

Epstein-Barr Virus-Associated Gastric Carcinoma and Specific Features of the Accompanying Immune Response

Epstein-Barr virus-associated gastric carcinoma (EBVaGC) is one of the four subtypes of gastric carcinoma (GC), as defined by the novel classification recently proposed by The Cancer Genome Atlas. EBVaGC has several clinicopathological features such as longer survival and higher frequency of lymphoepithelioma-like carcinoma (LELC) and carcinoma with Crohn's disease-like lymphoid reaction that distinguish it from EBV-negative GC. The intensity and pattern of host cellular immune response in GC have been found to significantly correlate with the prognosis of patients with GC, suggesting that immune reaction and tumor microenvironment have critical roles in the progression of GC, and in particular, EBVaGC. Here, we reviewed the cellular and molecular mechanisms underlying prominent immune reactions in patients with EBVaGC. In EBVaGC, deregulation of the expression of immune response-related genes promotes marked intra- or peritumoral immune cell infiltration. The expression of programmed death receptor-ligand 1 is known to be increased in EBVaGC, and therefore, it has been proposed as a favorable prognostic factor for patients with EBVaGC, albeit some data supporting this claim are controversial. Overall, the underlying mechanisms and clinical significance of the host cellular immune response in patients with EBVaGC have not been thoroughly elucidated. Therefore, further research is necessary to better understand the role of tumor microenvironment in EBVaGC.

Frequency of Epstein--Barr virus infection as detected by messenger RNA for EBNA 1 in histologically proven gastric adenocarcinoma in patients presenting to a tertiary care center in South India

BACKGROUND

Epstein-Barr virus (EBV)-associated gastric carcinoma is a relatively uncommon entity detected in approximately 10% of gastric adenocarcinoma.

OBJECTIVE

The purpose of this study is to estimate the frequency of EBV-associated gastric carcinoma and also to assess the nature of presentation, any significant difference between this subgroup and EBV-negative gastric adenocarcinomas with respect to age and sex predilection, lymph nodal status, site of presentation.

MATERIALS AND METHODS

We prospectively analyzed 100 cases of gastric adenocarcinoma who underwent either a partial or total gastrectomy during the period from March 2010 to August 2011. The tumour and the corresponding normal gastric tissue from the same patient were analyzed for the presence of Epstein-Barr nuclear antigen 1 (EBNA1) messenger ribonucleic acid (mRNA) by real-time polymerase chain reaction (PCR).

RESULT

EBV was detected in 6% cases of gastric adenocarcinoma. All the positive patients were males. The majority of cases involved the proximal stomach and there was variable lymph nodal involvement.

CONCLUSION

Our study endorses that there is an association between EBV infection and gastric adenocarcinoma in the Indian population. There was no significant difference between this subgroup and EBV-negative gastric adenocarcinomas with respect to age and sex predilection, lymph nodal status and site of presentation. Short-term follow-up of this subgroup of patients seems to indicate a good overall prognosis after appropriate treatment. However, a larger study with long-term follow-up is needed to further establish the role of EBV in gastric adenocarcinoma in this study population.

Implication of Leptin-Signaling Proteins and Epstein-Barr Virus in Gastric Carcinomas

We investigated the clinicopathological implications of leptin-signaling proteins and Epstein-Barr virus (EBV)-infection status in gastric carcinomas. Immunohistochemistry for leptin signalling-related proteins (leptin, leptin-receptor, pSTAT3, ERK, pAkt, mTOR and HIF-1 alpha), and in situ hybridization for EBV-encoded small RNAs was performed in 343 cases of gastric carcinomas. The siRNA against leptin-receptor was transfected into three stomach cancer cell lines, and western blot for caspase 3 was performed. The TNM stage was a prognostic factor in all 343 patients, and was negatively correlated with expression of leptin, pSTAT3, ERK, pAkt, mTOR and HIF-1 alpha (P < 0.05). Leptin-receptor expression was correlated with poor survival in 207 patients of the advanced gastric cancer (AGC) subgroup, 139 of the Lauren diffuse group, and in 160 patients with lymph node metastasis (P < 0.05, respectively). Additionally, in stomach cancer cells, cleaved caspase 3 level increased by leptin-receptor inhibition, that is, apoptosis increased. Interestingly, EBV-positive AGC (n = 29) tended to show better survival of patients than EBV-negative AGC (n = 178) (P = 0.06). pAkt expression was related with a good survival of 32 patients (9%) in the EBV-positive subgroup, but was not an independent prognostic factor. Among, leptin signaling-related proteins, expressions of leptin-receptor and mTOR were different between EBV-positive subgroup and EBV-negative subgroup (P < 0.05, respectively). In conclusion, leptin-signaling proteins and EBV status show different significance on patient survival, according to subsets of gastric carcinomas. The leptin-receptor may predict poor patient prognosis in the AGC, Lauren diffuse and lymph node metastasis subgroups, while EBV-positive status can show a good prognosis in the AGC. Each leptin signaling-related protein may be differently involved in carcinogenesis of EBV-negative and EBV-positive subsets.

Prognostic factors in Epstein-Barr virus-associated stage I-III gastric carcinoma: implications for a unique type of carcinogenesis

Epstein-Barr virus-associated gastric carcinoma (EBVaGC) has distinct clinicopathological features. However, the prognostic factors remain unclear, particularly in UICC/AJCC stage I-III cancer. We retrospectively enrolled 1,020 patients with stage I-III gastric cancer that received radical gastrectomy with lymphadenectomy. Formalin-fixed, paraffin‑embedded surgical specimens were retrieved to construct tissue microarrays. EBV positivity was identified by in situ hybridization with EBV-encoded small RNA, and the histological classification was reviewed. Fifty-two cases of EBVaGC were identified, exhibiting a male predominance (p=0.003), a higher prevalence in stump cancer (p<0.001), and poorly differentiated carcinoma (p=0.010) compared with the controls. The survival analysis revealed no difference in survival between the EBVaGC cases and the EBV-negative cases (p=0.977). The multivariate analysis showed that EBVaGC cases with a tumor size >5 cm, non-lymphoepithelioma-like carcinoma (LELC), or a lymph node ratio >0.15 had a worse overall survival (hazard ratio 2.884, 12.178 and 19.352; p=0.027, 0.005 and <0.0001, respectively). The depth of tumor invasion and the number of lymph node metastases did not reach statistical significance (p=0.834 and 0.833, respectively). These prognostic factors, tumor size, LELC classification and lymph node ratio, may reflect a unique type of carcinogenesis of EBVaGC and may be considered when selecting high-risk patients for adjuvant treatment.

Improved survival of gastric cancer with tumour Epstein-Barr virus positivity: an international pooled analysis

BACKGROUND AND OBJECTIVE

About 9% of gastric carcinomas have Epstein-Barr virus (EBV) in the tumour cells, but it is unclear whether viral presence influences clinical progression. We therefore examined a large multicentre case series for the association of tumour EBV status with survival after gastric cancer diagnosis, accounting for surgical stage and other prognostic factors.

METHODS

We combined individual-level data on 4599 gastric cancer patients diagnosed between 1976 and 2010 from 13 studies in Asia (n=8), Europe (n=3), and Latin America (n=2). EBV positivity of tumours was assessed by in situ hybridisation. Mortality HRs for EBV positivity were estimated by Cox regression models stratified by study, adjusted for distributions of sex (71% male), age (mean 58 years), stage (52% tumour-node-metastasis stages III or IV), tumour histology (49% poorly differentiated, 57% Lauren intestinal-type), anatomic subsite (70% non-cardia) and year of diagnosis. Variations by study and continent were assessed using study-specific HRs for EBV positivity.

RESULTS

During median 3.0 years follow-up, 49% of patients died. Stage was strongly predictive of mortality, with unadjusted HRs (vs stage I) of 3.1 for stage II, 8.1 for stage III and 13.2 for stage IV. Tumour EBV positivity was 8.2% overall and inversely associated with stage (adjusted OR: 0.79 per unit change). Adjusted for stage and other confounders, EBV positivity was associated with lower mortality (HR, 0.72; 95% CI 0.61 to 0.86), with low heterogeneity among the study populations (p=0.2). The association did not significantly vary across patient or tumour characteristics. There was no significant variation among the three continent-specific HRs (p=0.4).

CONCLUSIONS

Our findings suggest that tumour EBV positivity is an additional prognostic indicator in gastric cancer. Further studies are warranted to identify the mechanisms underlying this protective association.

Lymphoepithelioma-like carcinoma of the stomach: a case report and review of the literature

A lymphoepithelioma-like carcinoma (LLC), characterized by a carcinoma with stromal heavy lymphocyte infiltration, is one of the histological patterns observed in patients with Epstein-Barr virus (EBV)-associated gastric carcinoma. Although this entity is hard to be recognized in the biopsy specimens, pathologists and clinicians should acknowledge this subset of gastric cancer because it generally has a better prognosis than other forms of EBV-associated gastric carcinomas and conventional gastric carcinomas. This might be due to the fact that the patient's inflammatory response may prevent the spread of tumor through the gastric wall and to the lymph nodes or remote organs.

We report a case of EBV-positive, microsatellite stable LLC as a rare morphologic variant of gastric carcinoma.

Epstein-Barr virus-encoded BARF1 promotes proliferation of gastric carcinoma cells through regulation of NF-κB

In Epstein-Barr virus (EBV)-infected gastric carcinoma, EBV-encoded BARF1 has been hypothesized to function as an oncogene. To evaluate cellular changes induced by BARF1, we isolated the full-length BARF1 gene from gastric carcinoma cells that were naturally infected with EBV and transfected BARF1 into EBV-negative gastric carcinoma cells. BARF1 protein was primarily secreted into culture supernatant and only marginally detectable within cells. Compared with gastric carcinoma cells containing empty vector, BARF1-expressing gastric carcinoma cells exhibited increased cell proliferation (P < 0.05). There were no significant differences in apoptosis, invasion, or migration between BARF1-expressing gastric carcinoma cells and empty vector-transfected cells. BARF1-expressing gastric carcinoma cells demonstrated increased nuclear expression of nuclear factor kappa B (NF-κB) RelA protein and increased NF-κB-dependent cyclin D1. The expression of p21(WAF1) was diminished by BARF1 transfection and increased by NF-κB inhibition. Proliferation of naturally EBV-infected gastric carcinoma cells was suppressed by BARF1 small interfering RNA (siRNA) (P < 0.05). Immunohistochemical analysis of 120 human gastric carcinoma tissues demonstrated increased expression of cyclin D1 and reduced expression of p21(WAF1) in EBV-positive samples versus EBV-negative gastric carcinomas (P < 0.05). In conclusion, the secreted BARF1 may stimulate proliferation of EBV-infected gastric carcinoma cells via upregulation of NF-κB/cyclin D1 and reduction of the cell cycle inhibitor p21(WAF1), thereby facilitating EBV-induced cancer progression.

Methylation and Expression of Retinoblastoma and Transforming Growth Factor-β1 Genes in Epstein-Barr Virus-Associated and -Negative Gastric Carcinomas

Background. Retinoblastoma (RB) and transforming growth factor-β1 (TGF-β1) are important tumor-related factors. Methods. A series of 30 EBV-associated gastric carcinoma (EBVaGC) and 38 matched EBV-negative gastric carcinoma (EBVnGC) tissues were examined for the promoter methylation of RB by methylation-specific PCR (MSP) method. The expression of RB and TGF-β1 in gastric carcinoma tissues was detected by immunohistochemistry. Results. The methylation rate of RB gene in EBVaGC and EBVnGC was 80.0% (24/30) and 50.0% (19/38), respectively. The difference of RB methylation rate between EBVaGC and EBVnGC was significant (χ² = 6.490, P = 0.011). There was no significant difference for RB expression between EBVaGC (43.3%, 13/30) and EBVnGC (63.2%, 24/38), and also for TGF-β1 between EBVaGC (56.7%, 17/30) and EBVnGC (63.2%, 24/38). RB methylation was not reversely correlated with RB expression in gastric carcinoma tissues (χ² = 2.943, P = 0.086, r = 0.208). RB methylation, loss expression of RB, and TGF-β1 expression were significantly associated with tumor invasion and lymph node metastasis (P < 0.05), but was not associated with sex, age, histological subtype (differentiation status) and tumor location. Conclusions. Methylation of RB is a common event in gastric carcinomas and EBV induces methylation of RB in EBVaGC, which may contribute to the development of gastric carcinomas. EBV has no significant effect on induction of TGF-β1 expression. Detection of RB methylation, RB expression, and TGF-β1 expression may be helpful to judge the status of tumor invasion and lymph node metastasis in gastric carcinomas.

Epstein-Barr virus-associated gastric carcinoma: a newly defined entity

Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC) is a recently recognized entity, which is defined by the presence of EBV in the gastric carcinoma cells. EBVaGC represents about 10% of gastric carcinoma worldwide, and >80,000 patients are estimated to develop EBVaGC annually. EBVaGC shows some distinct clinicopathologic characteristics, such as male predominance, predisposition to the proximal stomach, and a high proportion in diffuse-type gastric carcinomas. Besides, EBVaGC also shows characteristic molecular abnormality, that is, global and nonrandom CpG-island methylation of the promoter region of many cancer-related genes, which causes downregulation of their expression. Moreover, EBVaGC has a relative favorable prognosis. The uniform presence of EBV-encoded small RNA in tumor cells but not in the surrounding normal epithelial cells, and the detection of monoclonal EBV episomes in EBVaGC, strongly suggests that EBV play an etiological role in gastric carcinogenesis. Therefore, EBVaGC should be regarded as a distinct entity of gastric carcinoma, although it only accounts for a relatively small fraction of total gastric carcinomas. In this review, the epidemiological and clinicopathologic features of EBVaGC and the genetic abnormalities of EBVaGC cell including chromosomal and epigenetic abnormalities are described. The roles of EBV in gastric carcinogenesis are discussed. We make an emphasis on the EBV latency pattern and genome polymorphisms as well as local immunity in EBVaGC. In addition, the treatment of EBVaGC is also briefly discussed. Taken together, this review aims to give the reader a full understanding of a newly defined entity of gastric carcinoma, EBVaGC.

Characteristics of epstein barr virus variants associated with gastric carcinoma in Southern Tunisia

Backgroud

EBV-associated Gastric Carcinoma (EBVaGC) has a distinct clinical features and its prevalence is variable worldwide.

Results

To determine the prevalence of EBVaGC in Tunisia, EBV-encoded small RNA (EBER) expression was assessed in 81 gastric carcinoma (GC) specimens. The nuclear EBER expression was detected in 12 out of 81 GC cases (14.81%) and concordance between the score range of EBER staining and the number of EBV DNA copies as estimate by QPCR is observed. On the other hand, we found that EBVaGC strongly correlated with age at diagnosis, and weakly with tumor differentiation and venous invasion.

Furthermore, the EBVaGC specimens were subjected to determine the EBV DNA polymorphisms. Our results show a unique genetic profile of the EBV strains regarding the A and D types, the F prototype, the retention of XhoI restriction site and the 30 bp del-LMP1 variant. According to our previous studies on nasopharyngeal carcinoma (NPC), we suggested that EBV strains associated to GC and NPC shared some similarities in Tunisian patients.

Conclusion

The prevalence of EBVaGC is of 14.81% in the southern Tunisia and that common EBV strain are associated with both NPC and GC which are likely to differ from Asian strains. Our findings support therefore a certain geographical distribution of EBV strains which is not restricted to EBV-associated malignancies.

Epstein-Barr virus-associated gastric carcinoma

Epstein-Barr virus (EBV) has been accepted as an infective agent causing gastric carcinoma (GC). EBV-associated GC, comprising nearly 10% of all cases of GC, is the monoclonal growth of EBV-infected epithelial cells, which express only several EBV-latent genes (Latency I program). Histopathologically, there are two subtypes, lymphoepithelioma-like carcinoma and the ordinary type of GC. Other features include the lace pattern of carcinoma cells in the intramucosal stage and the dense infiltration of lymphocytes and macrophages at the invasive site of the submucosa. The primary molecular abnormality in EBV-associated GC is global and non-random CpG island methylation in the promoter region of many cancer-related genes. Experimental studies have demonstrated that viral latent membrane protein 2A (LMP2A) is responsible for the promotion of DNA methylation. LMP2A up-regulates cellular DNMT1 through the phosphorylation of STAT3, resulting in the repression of tumor suppressor genes, such as PTEN, through promoter methylation. DNA methylation in EBV-infected stomach cells may be due to overdrive of the cellular defense against foreign DNA. Further studies on the mechanisms of epigenetic abnormalities will clarify the strategies for prevention and treatment of this particular type of GC with EBV infection.

Pathology of epstein-barr virus-associated gastric carcinoma and its relationship to prognosis

Among Epstein-Barr virus (EBV)-associated neoplasms, EBV-associated gastric carcinoma (EBVaGC) is the most common tumor worldwide. In contrast to the predominant site of occurrence of EBV-negative gastric carcinoma in the antrum, EBVaGC occurs most frequently in the proximal stomach, including the cardia, fundus and body. Microscopically, EBVaGC can be subclassified into three histological subtypes according to the host cellular immune responses: lymphoepithelioma-like carcinoma, carcinoma with Crohn's disease-like lymphoid reaction, and conventional-type adenocarcinoma. Recent studies have shown that patients with the lymphoepithelioma-like carcinoma subtype of EBVaGC have the best overall and disease-free survival, followed by Crohn's disease-like reactions, which in turn have better survival than patients with conventional-type adenocarcinoma. Histologic subclassifications of EBVaGCs are based on the differing degree and pattern of infl ammatory response and the extent of desmoplasia. Because these subclassifications appear to be a powerful prognostic parameter, further research into the underlying mechanisms of the cellular immune reaction in these pathologic subtypes of EBVaGCs may play a key role in understanding the innate immune response of patients with this highly aggressive carcinoma.

Host inflammatory response predicts survival of patients with Epstein-Barr virus-associated gastric carcinoma

BACKGROUND & AIMS

Lymphoepithelioma-like carcinoma (LELC) is a rare subtype of gastric carcinoma (GC) with a better survival rate than other GCs; most cases of LELC are associated with Epstein-Barr virus (EBV) infection. We investigated whether the survival advantage of LELC is related to the EBV infection itself or to associated inflammatory immune responses.

METHODS

From 1994 to 2008, 123 EBV-associated GCs were identified and compared with 405 EBV-negative GCs. EBV-associated GCs were subclassified, based on the pattern of host inflammatory immune responses, into 3 histologic subtypes: typical LELC (n = 53, 43.1%), Crohn's disease-like lymphocytic reaction (CLR) (n = 52, 42.3%), and conventional adenocarcinoma (n = 18, 14.6%). Patients with curatively resected EBV-negative GC were controls. Univariate and multivariate analyses were used, with Bonferroni correction.

RESULTS

Patients with EBV-associated GC had tumors of proximal location, lower N stage (P < .0001), and lower T stage (P = .02) and were older than controls (P = .0003). Upon univariate analysis, patients with EBV-associated GC had longer survival times than controls (P < .004); this difference was not significant in a multivariate analysis with Cox proportional hazards. Stratification of EBV-associated GCs by host cellular immune responses showed that patients with LELC and LELC+CLR have significantly longer overall survival time (hazard ratio, 0.09 and 0.42, respectively) and disease-free survival (hazard ratio, 0.05 and 0.46, respectively; P < .02).

CONCLUSIONS

Prognosis of EBV-associated GCs depends on the patient's inflammatory response. The definition of LELC should be expanded to include EBV-associated GCs with CLR because these have a prognosis similar to LELC.

Association of distinctive Epstein-Barr virus variants with gastric carcinoma in Guangzhou, southern China

To investigate the clinicopathologic features, Epstein-Barr virus (EBV) latency pattern and genome polymorphism of EBV-associated gastric carcinoma (EBVaGC) in Guangzhou, an endemic area of nasopharyngeal carcinoma (NPC), an in situ hybridization assay of EBV-encoded small RNA-1 (EBER-1) was used to identify the presence of EBV in 676 consecutive gastric carcinoma cases. EBV-encoded proteins EBNA1, EBNA2, LMP1, and ZEBRA were detected by immunohistochemistry. EBV genome polymorphism was also analyzed by PCR and DNA sequencing. Of the 676 cases, 45 EBV-positive cases (6.7%) were identified, including 37 (8.5%) male and 8 (3.3%) female cases. EBNA1 was detected in 42 cases (93.3%), while EBNA2, LMP1, and ZEBRA were all negative. In the EBV genome polymorphism analysis, type A strain, prototype F, type I, XhoI-, and del-LMP1 variants were predominant among EBVaGC patients, accounting for 44 (97.8%), 37 (82.2%), 45 (100%), 34 (75.6%), and 42 (93.3%) cases, respectively. Moreover, a new hotspot mutation in the BamHI-W1/I1 boundary region (148,972 T --> C) was found in 39 (86.7%) of the 45 cases. The predominant EBV variants in EBVaGC in Guangzhou are prototype F, type I, and XhoI-, which are different from those in NPC in this area (predominant variant-type "f") and in EBVaGC in Latin American countries (predominant type "i" and XhoI+), suggesting that the EBV variants are not only geographically distributed but also disease restricted, and the pathogenic role of EBV in different EBV associated epithelial malignancies in different areas may be distinct.

Nuclear factor-kappa B inhibition reduces markedly cell proliferation in Epstein-Barr virus-infected stomach cancer, but affects variably in Epstein-Barr virus-negative stomach cancer

Nuclear factor-kappa B (NF-kappaB) inhibition by NF-kappaB p65-specific siRNA induced a near-cessation of cell proliferation in EBV-positive stomach cancer cell, and notably diminished cell proliferation in EBV- positive Raji lymphoma cell. In EBV-negative stomach cancer cells, NF-kappaB inhibition affected variably cell proliferation. Regardless of cell type, NF-kappaB inhibition suppressed antiapoptotic function of NF-kappaB, and tended to promote the nuclear accumulation of beta-catenin. This inverse relationship between NF-kappaB and beta-catenin was evident in 120 resected gastric carcinomas. Conclusively, NF-kappaB inhibition may be beneficial in the therapy of EBV-positive stomach cancer, but influence variously EBV-negative stomach cancer.

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

OBJECTIVE

Epstein-Barr virus (EBV) has been linked to gastric carcinoma (GC) with worldwide geographical variations of prevalence ranging from 1 to 18% of cases. Investigations carried out in north Africa have shown that some EBV-associated types of cancers are common in this area. This study was taken to determine the prevalence of EBV-associated GC in Tunisia.

METHODS

Ninety-six nonselected GC cases (male/female ratio 1.7/1, mean age 60.9 years, range: 20-88 years) were evaluated for the presence of EBV by polymerase chain reaction as well as by in-situ hybridization for EBV-encoded small RNAs (EBERs) and immunohistochemistry for LMP-1 and EBNA-2 expression.

RESULTS

EBV was detected by polymerase chain reaction in 36% of cases, whereas EBERs were detected in the tumor cells in only four cases (4.1%). Immunohistochemistry for LMP-1 and EBNA-2 was negative in all cases. The mean age for patients harboring EBERs-positive GC was 55.7 years (range: 52-59 years). All EBERs-positive GC cases were males of advanced clinical stage (pT3-pT4). According to Lauren's classification, two cases were of diffuse histological type and two cases were of intestinal type. In three cases, the tumors have a proximal location and in the remaining case the tumor arises in the antrum. All EBV strains detected from EBV-associated GC were exclusively of type A and D, prototype F, and XhoI-maintained variant.

CONCLUSION

We conclude that the prevalence of EBV-associated GC in Tunisia is low (4.1%), suggesting that this virus is not an important etiological factor in GC arising in north African populations. The clinicopathological profile of EBV-associated GC in Tunisia did not differ markedly from that found elsewhere.

Clinicopathological and molecular characteristics of Epstein-Barr virus-associated gastric carcinoma: a meta-analysis

There is conflicting data regarding the clinicopathological significance of the risk factors associated with Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC). To address this controversy, we performed a meta-analysis for the clinicopathological and molecular characteristics of EBVaGC. The relevant published studies were reviewed according to the defined selection criteria. The effect sizes of the outcome parameters were estimated by an odds ratio or a weighted mean difference. This meta-analysis included 48 studies that encompassed a total of 9738 patients. The frequency of EBVaGC was 8.8%, and EBVaGC was significantly associated with ethnicity. It was more predominant in men and in younger individuals. Interestingly, EBVaGC was more prevalent in Caucasian and Hispanic patients than in Asian ones. EBVaGC developed most often in the cardia and body, and it generally showed the diffuse histological type. EBV was highly prevalent in the patients with lymphoepithelial carcinoma. EBVaGC was closely associated with remnant cancer and a CpG island methylator-high status, but not with Helicobacter pylori infection, a TP53 expression, and p53 mutation. In addition, EBVaGC was not significantly associated with the depth of invasion, lymph node metastasis, or the clinical stage. The clinicopathological and molecular characteristics of EBVaGC are quite different from those of conventional gastric adenocarcinoma. However, further study is needed to determine the effect of EBV on the survival of EBVaGC patients.

Epstein-Barr virus-associated epithelial and mesenchymal neoplasms

Epstein-Barr virus (EBV) is a ubiquitous human pathogen that usually maintains a harmonious relationship with its host. Rarely, this host-virus balance is perturbed, causing a diverse group of malignancies in both immunocompetent and immunosuppressed patients. In addition to its role in hematologic malignancies (Burkitt lymphoma, subsets of Hodgkin and T-cell lymphomas, posttransplant lymphomas), EBV has been implicated in both epithelial (undifferentiated nasopharyngeal carcinoma, a subset of gastric adenocarcinomas) and mesenchymal (EBV-associated smooth muscle tumor, inflammatory pseudotumor-like follicular dendritic cell tumor) neoplasms. This review will focus on EBV-associated epithelial and mesenchymal neoplasms.

Epstein-Barr virus serology and gastric cancer incidence and survival

Among 185 cases of gastric cancer and 200 controls in Linxian, China, Epstein–Barr virus (EBV) seropositivity was not associated with increased risk of gastric cancer. High EBV nuclear antigen titres were associated with longer survival in cardia cancer cases, possibly due to chance.

Epstein-Barr virus associated gastric carcinoma: a report from Iran in the last four decades

BACKGROUND

Epstein-Barr virus has been proved to be associated with many of the human malignancy including gastric carcinoma, one of the most important human malignancies in the world. There has been no study about the presence of EBV in gastric adenocarcinoma in Iran.

METHODS

We examined the presence of EBV in 273 formalin fixed paraffin-embedded cases of gastric carcinoma from Cancer institute of Tehran University, from 1969 to 2004. In situ hybridization of EBV-encoded small RNA-1 (EBER-1) was conducted. The strain of positive cases was examined by means of polymerase chain reaction and/or restriction fragment length polymorphism analysis.

RESULTS

We found 9 (3%; 95% CI = 1-5%) EBV positive cases. The gender difference was not statisticaly significant. The proportion of EBV-GC cases in diffuse type was higher than intestinal type (OR = 0.08; 95% CI = 0.002-0.64). EBV-GC cases had no relation with age, location and invasion. Six out of 9 EBV-GC cases were born during the period between 1928 and 1930. All 9 cases were Type A. Prototype F was seen in 6 out of 8 cases. Type "i" was found in 8 cases and type I in 1 case. XhoI+ and XhoI- polymorphism accounted 6 and 3 of the cases, respectively.

CONCLUSION

Our study is the first to describe the frequency of EBV-GC in Iran and the Middle East, highlighting a very low prevalence with specific clinicopathologic features. The predominance of EBV-GC birth year in a fixed period, suggests that EBV infection or other events at early childhood may be related to the development of EBV-GC later in the life. The predominance of the type "i" and XhoI+ cases are contradictory to other studies in Asia and is similar to what is reported from Latin American countries.

Differential expression of apoptosis related proteins and nitric oxide synthases in Epstein Barr associated gastric carcinomas

AIM: To determine the incidence of Epstein Barr virus associated gastric carcinoma (GC) in Brazil and compare the expressions of apoptosis related proteins and nitric oxide synthases between EBV positive and negative gastric carcinoma.

METHODS: In situ hybridization of EBV-encoded small RNA-1 (EBER-1) and PCR was performed to identify the presence of EBV in GCs. Immunohistochemistry was used to identify expressions of bcl-2, bcl-xl, bak, bax, p53, NOS-1, NOS-2, and NOS-3 proteins in 25 EBV positive GCs and in 103 EBV negative GCS.

RESULTS: 12% of the cases of GC (25/208) showed EBER-1 and EBNA-1 expression. The cases were preferentially of diffuse type with intense lymphoid infiltrate in the stroma. EBV associated GCs showed higher expression of bcl-2 protein and lower expression of bak protein than in EBV negative GCs. Indeed, expressions of NOS-1 and NOS-3 were frequently observed in EBV associated GCs.

CONCLUSION: Our data suggest that EBV infection may protect tumor cells from apoptosis, giving them the capacity for permanent cell cycling and proliferation. In addition, EBV positive GCs show high expression of constitutive NOS that could influence tumor progression and aggressiveness.

Morphological Evidence of an Activated Cytotoxic T-Cell Infiltrate in EBV-Positive Gastric Carcinoma Preventing Lymph Node Metastases

Recently, we showed that Epstein-Barr virus (EBV)-positive gastric carcinoma (GC) forms a distinct clinicopathologic entity with a better prognosis due to lower incidence of lymph node metastases (LN+). Here we investigated whether in EBV-positive GC more pronounced activation of cellular immune responses is associated with absence of (micro)metastases. Twenty EBV-positive primary tumors (PT) (9 LN+) were matched with 28 EBV-negative GC (11 LN+) for T- and N-stage, gender, and age. The PT (n = 28) and its LNs were analyzed by EBER RNA in situ hybridization and by immunohistochemistry for MHC class I and II expression, for CD3, CD8, CD4, CD20, CD56, CD83, and Granzyme B (GzB) expression. In LN metastases of EBV-positive GC, the EBV genome is maintained, excluding tumor escape by virus deletion. All GC express MHC class I independently of EBV status. In comparison with EBV-negative GC, EBV-positive GC have higher expression of MHC class II on the tumor cells (P = 0.029) and a more extensive infiltrate (P < 0.0001) of activated GzB+ CD8+ T cells (P = 0.028), which is most abundant in those EBV-positive tumors that do not metastasize (P < 0.0001). In addition, in EBV-positive GC without metastases, the infiltrate contains higher numbers of mature dendritic cells (DC) (P = 0.018). At present, the antigenic target has to be determined. These data support the notion that local triggering of cellular immune responses in EBV-positive GC prevents lymph node metastasis formation.

Epstein-Barr virus in human malignancy: a special reference to Epstein-Barr virus associated gastric carcinoma

Epstein-Bar virus (EBV), a human herpesvirus, establishes a life-long persistent infection in 90 approximately 95% of human adult population worldwide. EBV is the etiologic agent of infectious mononucleosis, and EBV is associated with a variety of human malignancy including lymphoma and gastric carcinoma. Recently, EBV has been classified as group 1 carcinogen by the WHO International Agency for Research on Cancer. Evidence is presented which suggests that failures of the EBV-specific immunity may play a role in the pathogenesis of EBV-associated malignancy. At present, the precise mechanisms by which EBV transforms B lymphocytes have been disclosed. Encouragingly, they have had enough success so far to keep them enthusiastic about novel therapeutic trial in the field of EBV-associated lymphoma. However, information on EBV-associated gastric carcinoma is still at dawn. This article reviews EBV biology, immunological response of EBV infection, unique oncogenic property of EBV, peculiarity of EBV-associated gastric carcinoma, and lastly, EBV-targeted therapy and vaccination.

Epstein-barr virus-positive gastric carcinoma has a distinct protein expression profile in comparison with epstein-barr virus-negative carcinoma

PURPOSE

EBV has been detected in 2-16% of gastric carcinomas. However, there is little information available about the gene expression profile of EBV-positive gastric carcinomas.

EXPERIMENTAL DESIGN

EBV infection was examined using EBV-encoded small RNAs (EBERs) in situ hybridization, and 63 (5.6%) of 1127 consecutive gastric carcinomas were found to be EBV-positive. The expressions of 27 tumor-associated proteins were evaluated immunohistochemically in 63 EBV-positive gastric carcinomas and 287 EBV-negative carcinomas using the tissue array method. In addition, the genotype of EBV was investigated by PCR amplification of LMP1 (latent membrane protein 1), Epstein-Barr nuclear antigen 2 (EBNA2), and EBNA3B genes.

RESULTS

EBV-positive gastric carcinomas are characterized by the presence of lymphoid stroma, proximal location, and predominance in males. In comparison with EBV-negative carcinomas, EBV-positive carcinomas showed frequent loss of expression of p16, smad4, FHIT, and KAI-1 (kangai 1; P < 0.05), but retained the expression of APC (adenomatous polyposis coli), DCC (deleted in colorectal cancer), and some DNA repair proteins (P < 0.05). There was negative association between EBV infection and the expression of MUC1, MUC2, MUC5AC, p53, CEA, C-erbB2, and smad7. Using hierarchical cluster analysis, we divided EBV-positive gastric carcinomas into two clusters. Those patients with cluster 1 (42 cases) carcinomas had a better prognosis than those with cluster 2 (12 cases; P = 0.0002) or those with EBV-negative carcinomas (280 cases; P = 0.0251). Fifty-one (92.7%) of 55 EBV-positive carcinomas demonstrated the 30-bp deletion in LMP1 gene, and 53 (96.4%) of 55 cases were type 1 for EBNA2 and EBNA3B genes.

CONCLUSION

EBV-positive gastric carcinomas have a distinct protein expression profile as well as distinct clinicopathological features, as compared with EBV-negative carcinomas. The subclassification of EBV-positive carcinomas, by hierarchical cluster analysis, is significantly associated with patient survival.

Adénocarcinomes de l’estomac et de l’œsophage distal

AIMS

Our study aimed to evaluate the incidence of EBV-associated adenocarcinomas of the stomach and distal esophagus in Lyons area and to assess their phenotypic characteristics.

METHODS

85 cases of gastric adenocarcinomas and 40 cases of esophageal adenocarcinomas were screened for EBV by in situ hybridization (EBER-1 and -2) and immunohistochemistry (LMP1 and EBNA-1); all cases positive for EBER by in situ hybridization were studied by PCR for demonstration of EBV DNA. The clinical, histological and immunophenotypic features of EBV-associated adenocarcinomas were assessed.

RESULTS

5 cases of EBV-associated adenocarcinomas, all gastric, were identified in our series (5.8%); one was diagnosed in a migrant from Algeria, a region of high endemia of EBV infection. 3 cases were located in the proximal stomach, 1 in the distal; 1 was diffuse. 4 cases were of the intestinal histological type. Proliferation index and microvessel density were high in all 5 cases. The expression of tumor markers was markedly heterogeneous from one case to another.

CONCLUSIONS

Our study shows that EBV infection is restricted to gastric adenocarcinomas. Its incidence is evaluated to 5.8% in our series: this shows that Lyons area must be considered as a low risk area. In the absence of specific histological or phenotypic features, the screening of EBV+gastric adenocarcinomas is possible only with special techniques.

EBV-Positive Gastric Adenocarcinomas: A Distinct Clinicopathologic Entity With a Low Frequency of Lymph Node Involvement

Purpose

Epstein-Barr virus (EBV) is detected in a substantial subgroup of gastric adenocarcinomas worldwide. We have previously reported that these EBV-positive gastric carcinomas carry distinct genomic aberrations. In the present study, we analyzed a large cohort of EBV-positive and EBV-negative gastric adenocarcinomas for their clinicopathologic features to determine whether they constitute a different clinical entity.

Patients and Methods

Using a validated polymerase chain reaction/enzyme immunoassay–based prescreening method in combination with EBER1/2-RNA in situ hybridization, EBV was detected in the tumor cells of 7.2% (n = 41) of the gastric carcinomas from the Dutch D1D2 trial (N = 566; mean follow-up, 9 years). EBV status was correlated with clinicopathologic features collected for the Dutch D1D2 trial.

Results

EBV-positive gastric carcinomas occurred significantly more frequently in males (P < .0001) and in younger patients (P = .012). Most were of the intestinal type according to the Laurén classification (P = .047) or tubular according to the WHO classification (P = .006) and located in the proximal part of the stomach (P < .0001). A significantly lower tumor-node-metastasis system-stage (P = .026) was observed in the patients with EBV-carrying carcinomas, which was solely explained by less lymph node (LN) involvement (P = .034) in these cases. In addition, a better prognosis, as reflected by a longer disease-free period (P = .04) and a significant better cancer-related survival (P = .02), was observed for these patients, which could be explained by less LN involvement, less residual disease, and younger patient age.

Conclusion

EBV-carrying gastric adenocarcinomas are a distinct entity of carcinomas, characterized not only by unique genomic aberrations, but also by distinct clinicopathologic features associated with significantly better prognosis.

Investigation of Epstein-barr virus in Chinese colorectal tumors

AIM: To elucidate the association of Epstein-Barr virus (EBV) with colorectal tumors and to demonstrate whether infection of EBV existed in different stages of colorectal tumors involves in the carcinogenesis.

METHODS: One hundred and thirty paraffin-embedded tissues of colorectal tumors were classified into 5 groups: 26 adenomas, 23 adenomas complicated with dysplasia, 22 adenomas complicated with carcinomatous, 36 colon carcinoma and 23 HNPCC, were examined by PCR, IHC and ISH, respectively.

RESULTS: EBV DNA was detected by PCR in 26 cases out of the 130 specimens, including 5 cases of adenomas, 5 adenomas complicated with dysplasia, 5 adenomas complicated with carcinomatous, 7 colorectal carcinoma and 4 HNPCC. IHC detection showed the expression of LMP1 in 7 cases, including 1 adenoma, 1 adenoma with dysplasia, 1 HNPPC, 2 adenomas complicated with carcinomatous, and 2 colorectal carcinomas. The expression of EBER1 detected by ISH was positive in 6 cases, including 1 adenoma with dysplasia, 2 adenomas complicated with carcinomatous and 3 colorectal carcinomas. There were no significant differences among the results of PCR, IHC and ISH in the 5 groups. In all cases of HNPCC, none of the tumor cells showed positive signals of EBER1, but some EBV-positive tumor infiltrating lymphocytes were found in 2 of 23 cases.

CONCLUSION: Our results showed that infection of EBV exists in human colorectal tumors, which indicates that EBV may be involved in the carcinogenesis of colorectal tumors but does not play an important role. The mechanisms need to be clarified further.