Epstein-Barr virus and gastric carcinoma in Western patients: comparison of pathological parameters and p53 expression in EBV-positive and negative tumours

The tumor immune composition of mismatch repair deficient and Epstein-Barr virus-positive gastric cancer: A systematic review

BACKGROUND

Gastric cancer (GC), known for its unfavorable prognosis, has been classified in four distinct molecular subtypes. These subtypes not only exhibit differences in their genome and transcriptome but also in the composition of their tumor immune microenvironment. The microsatellite instable (MSI) and Epstein-Barr virus (EBV) positive GC subtypes show clear clinical benefits from immune checkpoint blockade, likely due to a neoantigen-driven and virus-driven antitumor immune response and high expression of immune checkpoint molecule PD-L1. However, even within these subtypes response to checkpoint inhibition is variable, which is potentially related to heterogeneity in the tumor immune microenvironment (TIME) and expression of co-inhibitory molecules. We conducted a systematic review to outline the current knowledge about the immunological features on the TIME of MSI and EBV + GCs.

METHODS

A systematic search was performed in PubMed, EMBASE and Cochrane Library. All articles from the year 1990 and onwards addressing immune features of gastric adenocarcinoma were reviewed and included based on predefined in- and exclusion criteria.

RESULTS

In total 5962 records were screened, of which 139 were included that reported immunological data on molecular GC subtypes. MSI and EBV + GCs were reported to have a more inflamed TIME compared to non-MSI and EBV- GC subtypes. Compared to microsatellite stable (MSS) tumors, MSI tumors were characterized by higher numbers of CD8 + and FoxP3 + T cells, and tumor infiltrating pro- and anti-inflammatory macrophages. HLA-deficiency was most common in MSI tumors compared to other molecular GC subtypes and associated with lower T and B cell infiltrates compared to HLA-proficient tumors. EBV + was associated with a high number of CD8 + T cells, Tregs, NK cells and macrophages. Expression of PD-L1, CTLA-4, Granzyme A and B, Perforin and interferon-gamma was enriched in EBV + tumors. Overall, MSI tumors harbored a more heterogeneous TIME in terms of immune cell composition and immune checkpoints compared to the EBV + tumors.

DISCUSSION AND CONCLUSION

MSI and EBV + GCs are highly Handbook for Conducting a Literature-Based Health Assessment Using OHAT Approach for Systematic Review and Evidence Integration.; 2019pro-inflammatory immune cell populations. Although studies on the direct comparison of EBV + and MSI tumors are limited, EBV + tumors show less intra-subgroup heterogeneity compared to MSI tumors. More studies are needed to identify how Intra-subgroup heterogeneity impacts response to immunotherapy efficacy.

The viral etiology of EBV-associated gastric cancers contributes to their unique pathology, clinical outcomes, treatment responses and immune landscape

Epstein-Barr virus (EBV) is a pathogen known to cause a number of malignancies, often taking years for them to develop after primary infection. EBV-associated gastric cancer (EBVaGC) is one such malignancy, and is an immunologically, molecularly and pathologically distinct entity from EBV-negative gastric cancer (EBVnGC). In comparison with EBVnGCs, EBVaGCs overexpress a number of immune regulatory genes to help form an immunosuppressive tumor microenvironment (TME), have improved prognosis, and overall have an "immune-hot" phenotype. This review provides an overview of the histopathology, clinical features and clinical outcomes of EBVaGCs. We also summarize the differences between the TMEs of EBVaGCs and EBVnGCs, which includes significant differences in cell composition and immune infiltration. A list of available EBVaGC and EBVnGC gene expression datasets and computational tools are also provided within this review. Finally, an overview is provided of the various chemo- and immuno-therapeutics available in treating gastric cancers (GCs), with a focus on EBVaGCs.

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.

Infection pattern and immunological characteristics of Epstein-Barr virus latent infection in cervical squamous cell carcinoma

Previous studies reported the association between Epstein-Barr virus (EBV) and cervical squamous cell carcinoma (CSCC), but its infection pattern and clinical significance unclear. This study aimed to comprehensively investigate the infection pattern, clinicopathology, outcomes, and immunology of this entity in central China. We evaluated a total of 104 untreated CSCC tumor tissue specimens using in situ hybridization for EBV-encoded small RNAs (EBERs), and by employing flowcytometry fluorescence hybridization for human papillomavirus (HPV) genotyping. The expression of EBV latency proteins and immune biomarkers was evaluated and quantified by immunohistochemistry. EBERs transcripts were detected in 21 (20.2%) cases overall (in malignant epithelial cells of 13 cases and in lymphocytes of 8 cases). EBV belonged to latency type I infection in CSCC. The high-risk (HR)-HPV was detected in all of EBV-positive CSCC, and the difference of detection rate of HR-HPV was significant when compared with EBV-negative CSCC (p = 0.001). The specific clinicopathology with increased frequency of advanced clinical stages, tumor-positive lymph nodes, neural invasion, and increased infiltration depth (all p value < 0.05) were observed in cases with EBV. However, EBV infection was found to have no impact on prognosis of patients with CSCC. Increased densities of forkhead box P3 (FoxP3)⁺-tumor infiltrating lymphocytes (TILs) (p = 0.005) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4)⁺-TILs (p = 0.017) and higher expression of programmed cell death-1 (PD-1) (p = 0.002) and programmed cell death-1 ligand 1 (PD-L1) (p = 0.040) were associated with EBV latent infection in CSCC, and these immunological changes were more likely to be associated with the infection in lymphocytes rather than tumor cells. Moreover, in patients with HPV-positive CSCC, similar significant differences were still found. In conclusions, EBV-positive CSCC may have specific infection pattern and clinicopathology and can exhibit an immunosuppressive microenvironment dominated by Treg cells aggregation and immune checkpoint activation.

Identifying the key genes of Epstein-Barr virus-regulated tumour immune microenvironment of gastric carcinomas

The Epstein-Barr virus (EBV) is involved in the carcinogenesis of gastric cancer (GC) upon infection of normal cell and induces a highly variable composition of the tumour microenvironment (TME). However, systematic bioinformatics analysis of key genes associated with EBV regulation of immune infiltration is still lacking. In the present study, the TCGA and GEO databases were recruited to analyse the association between EBV infection and the profile of immune infiltration in GC. The weighted gene co-expression analysis (WGCNA) was applied to shed light on the key gene modules associated with EBV-associated immune infiltration in GC. 204 GC tissues were used to analysed the expression of key hub genes by using the immunohistochemical method. Real-time PCR was used to evaluate the association between the expression of EBV latent/lytic genes and key immune infiltration genes. Our results suggested that EBV infection changed the TME of GC mainly regulates the TIICs. The top three hub genes of blue (GBP1, IRF1, and LAP3) and brown (BIN2, ITGAL, and LILRB1) modules as representative genes were associated with EBV infection and GC immune infiltration. Furthermore, EBV-encoded LMP1 expression is account for the overexpression of GBP1 and IRF1. EBV infection significantly changes the TME of GC, and the activation of key immune genes was more dependent on the invasiveness of the whole EBV virion instead of single EBV latent/lytic gene expression.

Tumor Molecular and Microenvironment Characteristics in EBV-Associated Malignancies as Potential Therapeutic Targets: Focus on Gastric Cancer

Although most people are infected with Epstein-Barr Virus (EBV) during their lifetime, only a minority of them develop an EBV-associated malignancy. EBV acts in both direct and indirect ways to transform infected cells into tumor cells. There are multiple ways in which the EBV, host, and tumor environment interact to promote malignant transformation. This paper focuses on some of the mechanisms that EBV uses to transform the tumor microenvironment (TME) of EBV-associated gastric cancer (EBVaGC) for its benefit, including overexpression of Indoleamine 2,3-Dioxygenase 1 (IDO1), synergism between H. pylori and EBV co-infection, and M1 to M2 switch. In this review, we expand on different modalities and combinatorial approaches to therapeutically target this mechanism.

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.

Isoforms of the p53 Family and Gastric Cancer: A Ménage à Trois for an Unfinished Affair

Simple Summary

The p53 family is a complex family of transcription factors with different cellular functions that are involved in several physiological processes. A massive amount of data has been accumulated on their critical role in the tumorigenesis and the aggressiveness of cancers of different origins. If common features are observed, there are numerous specificities that may reflect particularities of the tissues from which the cancers originated. In this regard, gastric cancer tumorigenesis is rather remarkable, as it is induced by bacterial and viral infections, various chemical carcinogens, and familial genetic alterations, which provide an example of the variety of molecular mechanisms responsible for cell transformation and how they impact the p53 family. This review summarizes the knowledge gathered from over 40 years of research on the role of the p53 family in gastric cancer, which still displays one of the most elevated mortality rates amongst all types of cancers.

Abstract

Gastric cancer is one of the most aggressive cancers, with a median survival of 12 months. This illustrates its complexity and the lack of therapeutic options, such as personalized therapy, because predictive markers do not exist. Thus, gastric cancer remains mostly treated with cytotoxic chemotherapies. In addition, less than 20% of patients respond to immunotherapy. TP53 mutations are particularly frequent in gastric cancer (±50% and up to 70% in metastatic) and are considered an early event in the tumorigenic process. Alterations in the expression of other members of the p53 family, i.e., p63 and p73, have also been described. In this context, the role of the members of the p53 family and their isoforms have been investigated over the years, resulting in conflicting data. For instance, whether mutations of TP53 or the dysregulation of its homologs may represent biomarkers for aggressivity or response to therapy still remains a matter of debate. This uncertainty illustrates the lack of information on the molecular pathways involving the p53 family in gastric cancer. In this review, we summarize and discuss the most relevant molecular and clinical data on the role of the p53 family in gastric cancer and enumerate potential therapeutic innovative strategies.

Clinicopathological and Immunomicroenvironment Characteristics of Epstein-Barr Virus-Associated Gastric Cancer in a Chinese Population

BACKGROUND

Epstein-Barr virus-associated gastric cancer(EBVaGC)has a unique tumor immune microenvironment. We performed a comprehensive analysis of the tumor-infiltrating immune cells in a cohort of EBVaGC in a Chinese population.

METHODS

Epstein-Barr encoding region (EBER) in situ hybridization was performed in 1,328 consecutive cases of surgically resected GC. Densities of immune cells, including T cells, B cells, natural killer cells, and macrophages from the patients were calculated after immunohistochemical staining with CD3, CD20, CD57, and CD68 antibodies in tissue microarrays, respectively.

RESULTS

EBVaGC patients accounted for 4.1% (55 of 1,328) cases in the overall population. The average age of patients with EBVaGC was lower than that of non-EBVaGC patients. Histologically, EBVaGC patients exhibited poorly differentiated adenocarcinoma (P = 0.004) and lower frequency of vascular invasion (P = 0.034). The density of CD3+ T lymphocytes (CD3, 23.84 ± 14.49 vs. 12.76 ± 8.93, P < 0.001) and CD68+ macrophages (CD68, 9.73 ± 5.25 vs. 5.44 ± 4.18, P < 0.001) was significantly higher in EBVaGC patients. CD3+ T cell density predicted better 5-year overall survival of EBVaGC patients (P = 0.022).

CONCLUSIONS

EBVaGC patients were younger with low-differentiated adenocarcinoma and less vascular invasion. Increased infiltration of multiple immune cells affected the prognosis of patients, especially EBVaGC patients with more CD3+ T lymphocytes, who survived longer.

High MHC-II expression in Epstein-Barr virus-associated gastric cancers suggests that tumor cells serve an important role in antigen presentation

EBV-associated gastric adenocarcinomas (EBVaGCs) often exhibit better clinical outcomes than EBV negative gastric cancers (GCs), which could be related to their consistent expression of foreign viral antigens. Antigen-presenting cells (APCs) present peptide antigens in the context of the class-II major histocompatibility complex (MHC-II). During inflammatory conditions, epithelial cells express MHC-II and function as accessory APCs. Utilizing RNA-seq data from nearly 400 GC patients, we determined the impact of EBV-status on expression of MHC-II components, genes involved in their regulation, and T-cell co-stimulation. Virtually all MHC-II genes were significantly upregulated in EBVaGCs compared to normal tissues, or other GC subtypes. Genes involved in antigen presentation were also significantly upregulated in EBVaGCs, as were the key MHC-II transcriptional regulators CIITA and RFX5. This was unexpected as the EBV encoded BZLF1 protein can repress CIITA transcription and is expressed in many EBVaGCs. Furthermore, MHC-II upregulation was strongly correlated with elevated intratumoral levels of interferon-gamma. In addition, expression of co-stimulatory molecules involved in T-cell activation and survival was also significantly increased in EBVaGCs. Thus, gastric adenocarcinoma cells may functionally contribute to the highly immunogenic tumor microenvironment observed in EBVaGCs via a previously unappreciated role in interferon-induced antigen presentation.

Clinicopathological Significance of EBV-Infected Gastric Carcinomas: A Meta-Analysis

Background and objectives: The present study aims to elucidate the clinicopathologic significance of Epstein-Barr virus (EBV) infection in gastric carcinomas (GCs) through a meta-analysis. Materials and Methods: Sixty-one eligible studies were included in the present meta-analysis. The included patients, with and without EBV infection, were 2063 and 17,684, respectively. We investigated the clinicopathologic characteristics and various biomarkers, including programmed death-ligand 1 (PD-L1) expression and tumor-infiltrating lymphocytes (TILs). Results: The estimated EBV-infected rate of GCs was 0.113 (95% confidence interval (CI): 0.088-0.143). The EBV infection rates in GC cells were 0.138 (95% CI: 0.096-0.194), 0.103 (95% CI: 0.077-0.137), 0.080 (95% CI: 0.061-0.106), and 0.042 (95% CI: 0.016-0.106) in the population of Asia, America, Europe, and Africa, respectively. There was a significant difference between EBV-infected and noninfected GCs in the male: female ratio, but not other clinicopathological characteristics. EBV infection rates were higher in GC with lymphoid stroma (0.573, 95% CI: 0.428-0.706) than other histologic types of GCs. There were significant differences in high AT-rich interactive domain-containing protein 1A (ARID1A) and PD-L1 expressions, and high CD8+ TILs between EBV-infected and noninfected GCs. Conclusions: Our results showed that EBV infection of GCs was frequently found in male patients and GCs with lymphoid stroma. EBV infection was significantly correlated with ARID1A and PD-L1 expressions and CD8+ TILs in GCs.

Association between Epstein-Barr virus infection and gastric cancer: a systematic review and meta-analysis

BACKGROUND

Numerous studies conducted over the past 30 years have pointed to the presence of Epstein-Barr virus (EBV) in gastric cancer samples. This study was aimed to provide a meta-analytic review of the prevalence of EBV in gastric cancer patients, and to clarify the relationship between EBV infection and gastric cancer.

METHODS

A literature search was performed electronically using online databases for English language publications until July 1, 2019. The pooled EBV prevalence and 95% confidence intervals (CIs) were estimated using a random-effects model. To determine the association between EBV and gastric cancer, pooled odds ratio (OR) and its 95% CI were computed for case-control studies. Two separate analyses were performed on data from case-control studies with matched and non-match pairs designs to calculate the pooled estimates of ORs.

RESULTS

The pooled prevalence of EBV in 20,361 gastric cancer patients was 8.77% (95% CI: 7.73-9.92%; I² = 83.2%). There were 20 studies with matched pairs design, including tumor and tumor-adjacent normal tissue pairs from 4116 gastric cancer patients. The pooled ORs were 18.56 (95% CI: 15.68-21.97; I² = 55.4%) for studies with matched pairs design and 3.31 (95% CI: 0.95-11.54; I² = 55.0%) for studies with non-matched pairs design. The proportion of EBV-associated gastric cancer among male cases was significantly higher than among female cases (10.83%, vs. 5.72%) (P < 0.0001). However, the pooled OR estimate for EBV-associated gastric cancer was significantly higher among females (21.47; 95% CI: 15.55-29.63; I² = 0%) than in males (14.07; 95% CI: 10.46-18.93; I² = 49.0%) (P = 0.06). EBV was more prevalent in the cardia (12.47%) and the body (11.68%) compared to the antrum (6.29%) (P = 0.0002).

CONCLUSIONS

EBV infection is associated with more than 18 times increase the risk of gastric cancer. Although the prevalence of EBV was higher in male patients than in female patients with gastric cancer, women are more likely than men to develop EBV-associated gastric cancer. Our findings showed that using tumor-adjacent normal tissues as the control group provides more robust and accurate results regarding the relationship between EBV infection and gastric cancer.

A Rare Case of Moderately Differentiated Adenocarcinoma With PD-L1 Overexpression and a Heterogeneous LELC Component in the Ascending Colon

Background

Lymphoepithelioma-like carcinomas (LELCs), especially colorectal cancers (CRCs), are uncommon pathological phenotypes generally associated with poor aggressiveness and a preferable prognosis. However, PD-L1 overexpression in CRCs is associated with poor outcomes. We report a case of moderately differentiated adenocarcinoma with PD-L1 overexpression, an LELC component, and Crohn’s-like lymphoid reaction (CLR) presenting with extreme locoregional aggression and complete remission with chemotherapy after noncurative excision.

Case presentation

A 69-year-old man was referred to our hospital for abdominal fullness and pain. Computed tomography (CT) showed a circumferential tumor in the ascending colon, accompanied by bulky swollen lymph nodes. Under the preoperative diagnosis of T4N2M1 (lymph nodes) ascending colon cancer, we performed a right hemicolectomy; however, paracaval and parailiac vein lymph nodes were abandoned. Pathological findings showed moderate to poorly differentiated adenocarcinoma invading the subserosa accompanied by an LELC component invading the superficial muscularis propria. Lymph node metastases were found in a neighboring tumor and in retroperitoneal lymph nodes with glandular differentiation. No relation to microsatellite instability (MSI) or Epstein-Barr virus (EBV) was observed. In the component with glandular differentiation, PD-L1 overexpression was revealed. CLR findings were also observed. The tumor was diagnosed as T3N2M1 cancer that was moderately to poorly differentiated and had an LELC component. The patient was treated with chemotherapy, and the metastasized lymph nodes ultimately disappeared. He was alive without tumor recurrence 5-years post-operation.

Conclusion

This is a very rare case of moderately differentiated adenocarcinoma with PD-L1 overexpression and a heterogeneous LELC component that developed in the ascending colon. Unlike the previously reported weak aggressive properties of LELCs, the present case showed an extremely aggressive locoregional extent, but complete remission was finally achieved with chemotherapy. This type of LELC with CLR could be associated with a good response to chemotherapy and a good prognosis in CRC patients.

A case of poorly differentiated adenocarcinoma with lymphoid stroma originated in the ascending colon diagnosed as lymphoepithelioma-like carcinoma

An 86-year-old woman’s stool sample was positive for blood. Computed tomography (CT) showed wall thickening of the ascending colon at the hepatic flexure. Colonoscopy showed near-complete obturation by colon cancer. Since she was asymptomatic, elective surgery was planned. Laparoscopic right hemicolectomy was performed. Histopathological examination showed poorly differentiated carcinoma cells proliferating in a solid pattern with marked lymphocyte infiltration. The diagnosis was lymphoepithelioma-like carcinoma (LELC) associated with Epstein-Barr virus (EBV) infection; however, EBV-encoded small RNA–in situ hybridization was negative. Microsatellite instability was not assessed. The postoperative course was uneventful and she was discharged on the 15th postoperative day. She remains recurrence-free at 2 years after surgery. Past reports note that colorectal carcinomas with dense lymphoid stroma may be related to LELC or medullary carcinoma (MC). Gastrointestinal LELC is rare, with some reports on LELC of the esophagus and stomach. Reports on LELC of the large intestine are very rare. MC of the large intestine is relatively new concept, firstly described in the WHO Classification of Tumours of the Digestive System 3rd Edition in 2000. We herein present a case of lymphoepithelioma-like carcinoma of the ascending colon and relevant case reports about LELC and MC of the large intestine.

Role of Cancer-Associated Fibroblast in Gastric Cancer Progression and Resistance to Treatments

Although the survival of gastric cancer (GC) patients has gradually improved, the outcomes of advanced GC patients remain unsatisfactory despite standard treatment with conventional chemotherapy or targeted agents. Several studies have shown that cancer-associated fibroblasts (CAFs), a major component of tumor stroma in GC, may have significant roles in GC progression and resistance to treatments. CAFs are a major source of various secreted molecules in the tumor microenvironment, which stimulate cancer cells and other noncancerous components of GC. Surprisingly, these factors could be involved in gastric carcinogenesis. Cytokines, including interleukin-6 and interleukin-11, or growth factors, such as fibroblast growth factor produced from CAFs, can directly activate GC cells and consequently lead to the development of an aggressive phenotype. Galectin-1 or hepatocyte growth factor can be involved in CAF-derived neovascularization in GC. In addition, recent studies showed that CAFs can affect tumor immunity through M2 polarization of tumor-associated macrophages. Finally, the current study aimed to introduce several inhibitory agents and evaluate their suppressive effects on CAFs in patients with GC progression. However, further studies are required to evaluate their safety and select appropriate patients for application in clinical settings.

The Microenvironment in Epstein-Barr Virus-Associated Malignancies

The Epstein–Barr virus (EBV) can cause a wide variety of cancers upon infection of different cell types and induces a highly variable composition of the tumor microenvironment (TME). This TME consists of both innate and adaptive immune cells and is not merely an aspecific reaction to the tumor cells. In fact, latent EBV-infected tumor cells utilize several specific mechanisms to form and shape the TME to their own benefit. These mechanisms have been studied largely in the context of EBV+ Hodgkin lymphoma, undifferentiated nasopharyngeal carcinoma, and EBV+ gastric cancer. This review describes the composition, immune escape mechanisms, and tumor cell promoting properties of the TME in these three malignancies. Mechanisms of susceptibility which regularly involve genes related to immune system function are also discussed, as only a small proportion of EBV-infected individuals develops an EBV-associated malignancy.

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.

Epstein-Barr Virus and Gastric Cancer Risk: A Meta-analysis With Meta-regression of Case-control Studies

Objectives:

Research on how the risk of gastric cancer increases with Epstein-Barr virus (EBV) infection is lacking. In a systematic review that investigated studies published until September 2014, the authors did not calculate the summary odds ratio (SOR) due to heterogeneity across studies. Therefore, we include here additional studies published until October 2015 and conduct a meta-analysis with meta-regression that controls for the heterogeneity among studies.

Methods:

Using the studies selected in the previously published systematic review, we formulated lists of references, cited articles, and related articles provided by PubMed. From the lists, only case-control studies that detected EBV in tissue samples were selected. In order to control for the heterogeneity among studies, subgroup analysis and meta-regression were performed.

Results:

In the 33 case-control results with adjacent non-cancer tissue, the total number of test samples in the case and control groups was 5280 and 4962, respectively. In the 14 case-control results with normal tissue, the total number of test samples in case and control groups was 1393 and 945, respectively. Upon meta-regression, the type of control tissue was found to be a statistically significant variable with regard to heterogeneity. When the control tissue was normal tissue of healthy individuals, the SOR was 3.41 (95% CI, 1.78 to 6.51; I-squared, 65.5%).

Conclusions:

The results of the present study support the argument that EBV infection increases the risk of gastric cancer. In the future, age-matched and sex-matched case-control studies should be conducted.

Epstein-Barr virus infection and gastric cancer: a systematic review

Epstein-Barr virus (EBV) infection is found in a subset of gastric cancers. Previous reviews have exclusively focused on EBV-encoded small RNA (EBER) positivity in gastric cancer tissues, but a comprehensive evaluation of other type of studies is lacking.We searched the PubMed database up to September, 2014, and performed a systematic review.We considered studies comparing EBV nucleic acids positivity in gastric cancer tissue with positivity in either adjacent non-tumor tissue of cancer patients or non-tumor mucosa from healthy individuals, patients with benign gastric diseases, or deceased individuals. We also considered studies comparing EBV antibodies in serum from cancer patients and healthy controls.Selection of potentially eligible studies and data extraction were performed by 2 independent reviewers. Due to the heterogeneity of studies, we did not perform formal meta-analysis.Forty-seven studies (8069 cases and 1840 controls) were identified. EBER positivity determined by in situ hybridization (ISH) was significantly higher in cancer tissues (range 5.0%-17.9%) than in adjacent mucosa from the same patients or biopsies from all control groups (almost 0%). High EBV nuclear antigen-1 (EBNA-1) positivity by PCR was found in gastric cancer tissues, but most were not validated by ISH or adjusted for inflammatory severity and lymphocyte infiltration. Only 4 studies tested for EBV antibodies, with large variation in the seropositivities of different antibodies in both cases and controls, and did not find an association between EBV seropositivity and gastric cancer.In summary, tissue-based ISH methods strongly suggest an association between EBV infection and gastric cancer, but PCR method alone is invalid to confirm such association. Very limited evidence from serological studies and the lack of novel antibodies warrant further investigations to identify potential risk factors of EBV for gastric cancer.

Update on Epstein-Barr virus and gastric cancer (review)

Epstein-Barr virus-associated gastric carcinoma (EBVaGC) is a distinct subtype that accounts for nearly 10% of gastric carcinomas. EBVaGC is defined by monoclonal proliferation of carcinoma cells with latent EBV infection, as demonstrated by EBV-encoded small RNA (EBER) in situ hybridization. EBVaGC has characteristic clinicopathological features, including predominance among males, a proximal location in the stomach, lymphoepithelioma-like histology and a favorable prognosis. EBVaGC belongs to latency type I or II, in which EBERs, EBNA-1, BARTs, LMP-2A and BART miRNAs are expressed. Previous studies have shown that some EBV latent genes have oncogenic properties. Recent advances in genome-wide and comprehensive molecular analyses have demonstrated that both genetic and epigenetic changes contribute to EBVaGC carcinogenesis. Genetic changes that are characteristic of EBVaGC include frequent mutations in PIK3CA and ARID1A and amplification of JAK2 and PD-L1/L2. Global CpG island hypermethylation, which induces epigenetic silencing of tumor suppressor genes, is also a unique feature of EBVaGC and is considered to be crucial for its carcinogenesis. Furthermore, post-transcriptional gene expression regulation by cellular and/or EBV-derived microRNAs has attracted considerable attention. These abnormalities result in significant alterations in gene expression related to cell proliferation, apoptosis, migration and immune signaling pathways. In the present review we highlight the latest findings on EBVaGC from clinicopathological and molecular perspectives to provide a better understanding of EBV involvement in gastric carcinogenesis.

Advanced gastric cancer patients with lymphoid stroma have better survival than those without

BACKGROUND

Lymphoid stroma is a specific pathologic appearance in gastric cancer. This study aims to compare the clinicopathological characteristics of gastric cancer patients with and without lymphoid stroma.

METHODS

From January 1988 to February 2009, 222 out of 1,959 patients with lymphoid stroma of gastric cancer received gastrectomy at the Department of Surgery, Taipei Veterans General Hospital. Clinicopathological characteristics and survival rates were analyzed and compared among the gastric cancer patients with and without lymphoid stroma. For patients with lymphoid stroma, CD20 expression of B lymphocytes and CD3 expression of T lymphocytes were examined using immunohistochemical stains.

RESULTS

Advanced gastric cancer patients with lymphoid stroma had better 5-year survival status than those without lymphoid stroma (44.5% vs. 20.5%, P < 0.001). Univariate and multivariate analyses showed that male gender (P = 0.034), tumor invasion depth (P = 0.001), pathological staging (P = 0.006), and Ming's histological classification (P = 0.041) were significantly correlated with patients with lymphoid stroma. B lymphocytes appeared more in Borrmann type III and IV, diffuse Lauren's histological type, and lymph nodes metastases.

CONCLUSION

Advanced gastric cancer patients with lymphoid stroma had better prognosis than those without lymphoid stroma. B lymphocytes appeared more in aggressive gastric cancer tissues with lymphoid stroma.

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.

EBV-infection in cardiac and non-cardiac gastric adenocarcinomas is associated with promoter methylation of p16, p14 and APC, but not hMLH1

BACKGROUND

Epstein-Barr virus (EBV)-associated gastric carcinomas (GC) constitute a distinct clinicopathological entity of gastric cancer. In order to determine underlying distinct aberrant promoter methylation we tested cardiac and non-cardiac GC with regard to the presence of EBV.

METHODS

One hundred GC were tested by RNA-in situ hybridization for the presence of EBV by EBV-encoded small RNA (EBER). Aberrant promoter methylation was investigated by methylation-specific real-time PCR for p16, p14, APC and hMLH1. P16 protein expression was assessed by immunohistochemistry.

RESULTS

In our selected study cohort, EBER-transcripts were detected in 19.6% (18/92) of GC. EBV-positive GC revealed significantly more often gene hypermethylation of p16, p14 and APC (p<0.0001, p<0.0001 and p=0.02, respectively) than EBV-negative GC. The majority of GC with p16 hypermethylation showed a p16 protein loss (22/28). In contrast, no correlation between the presence of EBV and hMLH1 hypermethylation was found (p=0.7). EBV-positive GC showed a trend towards non-cardiac location (p=0.06) and lower stages (I/II) according to the WHO (p=0.05).

CONCLUSIONS

Hypermethylation of tumor suppressor genes is significantly more frequent in EBV-associated GC compared to EBV-negative GC. Our data add new insights to the role of EBV in gastric carcinogenesis and underline that EBV-associated GC comprise a distinct molecular-pathologic as well as a distinct clinicopathological entity of GC.

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 lymphoepithelioma-like gastric carcinoma

This article provides an overview of the pathology of Epstein-Barr virus (EBV)-associated lymphoepithelioma-like gastric carcinoma, highlighting its unique morphology and clinical features. Lymphoepithelioma-like gastric carcinoma is a rare neoplasm of the stomach with a better prognosis than conventional adenocarcinoma. Most lymphoepithelioma-like gastric carcinomas are associated with EBV infection, while a subset is associated with microsatellite instability. Even though there is a very strong association with EBV, its exact role in carcinogenesis still remains to be elucidated in those cancers that harbor EBV. Distinctive histology and demonstration of EBV using in situ hybridization, polymerase chain reaction, or Southern blotting and immunohistochemistry for the DNA mismatch repair genes or polymerase chain reaction analysis of microsatellite loci to assess microsatellite instability helps to make the diagnosis.

Epstein-Barr virus in patients with chronic lymphocytic leukemia: a pilot study

The objective of this study was to assess the incidence and the clinical significance of Epstein-Barr virus (EBV) in patients with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL). Patients with CLL/SLL who presented at The University of Texas M. D. Anderson Cancer Center over a 2-year period and had available marrow paraffin blocks were studied for evidence of EBV infection using a highly specific in-situ hybridization assay for detection of EBV encoded RNA (EBERs). Results were analysed in relation to other presenting characteristics and outcome. Thirty-two patients were examined. EBERs were detected in the bone marrow of 12 of 32 (38%) CLL/SLL marrows vs 0 of 20 normal marrows (p = 0.002). EBERs were observed in sporadic granulocytes alone or in addition to its presence in lymphocytes in nine of the 12 EBV-positive patients. EBERs were detected less frequently in patients with Rai stage 0 - 1 disease (20%) compared with Rai stage 2 - 4 (66%; p = 0.008). EBER-positive patients tended to have higher lactate dehydrogenase levels (p = 0.053). The 10-year survival rate was 22% vs 58% for patients with and without discernible EBERs (log-rank, p = 0.08). Evidence of EBV infection was found in 38% of patients with CLL/SLL. Despite the small number of patients tested, discernable EBERs were significantly more common in individuals with more advanced Rai stage and there was a trend toward shorter survival in patients in whom EBV EBERs were discerned. Larger studies are needed to determine the prognostic value and role of EBV infection in patients with CLL/SLL.

Relationship between Epstein-Barr virus-encoded proteins with cell proliferation, apoptosis, and apoptosis-related proteins in gastric carcinoma

AIM: To investigate the interrelationship between Epstein-Barr virus (EBV)-encoded proteins and cell proliferation, apoptosis and apoptosis-related proteins in gastric carcinoma, and to explore their role in gastric carcinogenesis.

METHODS: Tissues from 13 cases of EBV-associated gastric carcinoma (EBVaGC) and 45 cases of matched EBV-negative gastric carcinoma (EBVnGC) were collected, and then subjected to analysis for apoptotic index (AI) using the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end-labeling (TUNEL) assay. Nuclear cell proliferation-associated antigen ki-67 index (KI), bcl-2, and p53 expression were examined by immunohistochemistry. p53 mutation in exons 5-8 of 13 EBVaGC cases was determined by single-strand conformation polymorphism (SSCP) and DNA sequencing. RT-PCR and Southern hybridization were used to detect the expression of nuclear antigens (EBNAs) 1 and 2, latent membrane protein (LMP) 1, immediately early gene BZLF1 and early genes BARF1 and BHRF1 in 13 EBVaGC cases.

RESULTS: The percentage of AI, KI and p53 overexpression was significantly lower in the EBVaGC group than in the EBVnGC group. However, bcl-2 expression did not show significant difference between the two groups. p53 gene mutations were not found in 13 EBVaGCs. Transcripts of EBNA1 were detected in all 13 EBVaGCs, while both EBNA2 and LMP1 mRNA were not detected. Six of the thirteen cases exhibited BZLF1 transcripts and two exhibited BHRF1 transcripts. BARF1 mRNA was detected in six cases.

CONCLUSION: Lower AI and KI may reflect a low biological activity in EBVaGC. EBV infection is associated with p53 abnormal expression but not bcl-2 protein in EBVaGC. BZLF1, BARF1, and BHRF1 may play important roles in inhibiting cell apoptosis and tumorigenesis of EBVaGC through different pathways.

Clinicopathologic and protein expression differences between cardia carcinoma and noncardia carcinoma of the stomach

BACKGROUND

Although the incidence of adenocarcinoma of the stomach has decreased over the past several decades, gastric cardia carcinoma has increased over the same period.

METHODS

The clinicopathologic characteristics and immunohistochemical staining results of 21 proteins were investigated in 165 patients with cardia carcinoma, including 74 patients with true cardia carcinoma and 91 patients with subcardia carcinoma, and the results were compared with the results from 564 patients with noncardia carcinoma.

RESULTS

In the clinicopathologic analysis, patients who had cardia carcinoma tended to have tumors with poorly differentiated histology according to the World Health Organization classification system (P = 0.012), diffuse type according to the Lauren classification system (P = 0.049), and advanced pathologic TNM stage (P < 0.001). On immunohistochemical staining, loss of the p16 (P = 0.038) and smad4 (P < 0.001) tumor suppressor genes was more frequent in cardia carcinoma than in noncardia carcinoma. Carcinoembryonic antigen and CD44 overexpression were more frequent in patients with cardia carcinoma (P < 0.05). Conversely, patients who had cardia carcinoma exhibited less frequent expression of MUC1 (P = 0.008) and MUC5AC (P = 0.006) compared with patients who had noncardia carcinoma. Epstein-Barr virus infection was more common in patients with cardia carcinoma (P < 0.001). In the survival analysis, the patients with cardia carcinoma had a poorer prognosis. In the multivariate analysis, tumor location in the cardia was confirmed as an independent, poor prognostic factor in patients with gastric carcinoma.

CONCLUSION

Cardia carcinoma and noncardia carcinoma differed in their clinicopathologic characteristics and in their alterations of gene expression, as evaluated by immunohistochemistry. The current results support the hypothesis that cardia carcinoma forms a specific category of gastric carcinoma that is distinct from noncardia carcinoma.

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.

Lymphocyte-rich gastric cancer: associations with Epstein-Barr virus, microsatellite instability, histology, and survival

Lymphocyte-rich gastric carcinomas may have a better prognosis than cancers without a pronounced host inflammatory response. Two subsets of gastric cancer-Epstein-Barr virus-positive and microsatellite instability high-have been associated with a lymphocyte-rich phenotype. We assessed relationships between tumor-infiltrating lymphocytes, Epstein-Barr virus status, microsatellite instability status, and cancer-specific survival in 110 resected gastric cancers. Seven patients had Epstein-Barr virus-positive cancer, including 4 (3.7%) of 107 consecutive patients. Tumors from 17 patients (16%) were designated microsatellite instability high on the basis of negative immunohistochemical staining for MLH1; all tumors had intact expression of MSH2 and MSH6. Epstein-Barr virus-positive cancers had increased tumor-infiltrating lymphocytes compared with Epstein-Barr virus-negative cancers (median 450/10 HPF versus 21/10 HPF, P <.001). Microsatellite instability-high cancers also had increased tumor-infiltrating lymphocytes compared with non-microsatellite instability-high cancers (median 150/10 HPF versus 20/HPF, P <.001). Microsatellite instability-high cancers affected older patients and were more likely to be intestinal in the Lauren classification and expanding in the Ming classification. By univariate analysis, decreased risk of death from gastric cancer was significantly associated with low tumor stage, expanding growth pattern, increasing tumor-infiltrating lymphocyte count, and microsatellite instability-high status. High tumor-infiltrating lymphocyte count and microsatellite instability-high status retained statistical significance as favorable prognostic factors after adjustment for tumor stage in multivariate analysis. Tumor-infiltrating lymphocyte count retained statistical significance as a favorable prognostic factor after adjustment for microsatellite instability-high status; but microsatellite instability-high status did not remain a significant independent prognosticator after adjustment for tumor-infiltrating lymphocyte count. The association between microsatellite instability-high cancers and high tumor-infiltrating lymphocyte counts may account for the association of microsatellite instability-high gastric cancers with improved survival.

Epstein-Barr virus-associated gastric carcinoma in southern India: A comparison with a large-scale Japanese series

Epidemiological and clinicopathological features of Epstein-Barr virus (EBV) associated gastric carcinoma was compared in India and Japan, two countries differing markedly in gastric cancer incidence. Using in situ hybridization assay, the presence of EBV-encoded small RNA (EBER) was examined in 215, and 2,011 gastric cancer cases in Kerala, India, and Japan, respectively. Ten cases (5%), all males, in the Indian series were EBER-positive. This frequency was similar to that in the Japanese series (6.2%). As was the case with Japanese series, the EBV-associated gastric carcinoma in the Indian series was observed most frequently in the middle part of the stomach (1 in antrum, 4 in middle part, 2 in cardia, and 3 unknown), and, histologically, the diffuse type Lauren's classification (8 cases) was more common than the intestinal type (2 cases). Virus subtyping by PCR-RFLP revealed that all of the 10 EBV strains isolated from the EBER-positive Indian cases were subtype A, and wild-type F for Bam HI F region. In Bam HI I region, 8 cases were type C and the remaining 2 cases were type D. In either series, there was no significant difference in the frequency of tumors with p53 overexpression between EBER-positive and -negative cases. However, the proportion of cells with p53 overexpression in EBER-negative tumors was significantly higher than that in EBER-positive tumors regardless of histological type in both series. In conclusion, the frequency and major clinicopathological features of EBV-associated gastric carcinoma in south India were similar to those observed in Japanese series although gastric cancer incidence in these two countries differs markedly.

Low prevalence of Epstein-Barr virus in incident gastric adenocarcinomas from the United Kingdom

Epstein-Barr virus has been associated with a proportion of typical gastric adenocarcinomas. Here we report that the prevalence of Epstein-Barr virus in gastric adenocarcinomas from the United Kingdom is one of the lowest in the World. Gastric adenocarcinoma is another tumour whose association with Epstein-Barr virus varies with the population studied.

Epstein-barr virus-positive gastric carcinoma demonstrates frequent aberrant methylation of multiple genes and constitutes CpG island methylator phenotype-positive gastric carcinoma

CpG island methylation is an important mechanism for inactivating the genes involved in tumorigenesis. Gastric carcinoma (GC) is one of the tumors that exhibits a high frequency of aberrant CpG island methylation. There have been many reports suggesting a close link between Epstein-Barr virus (EBV) and the development of GC. However, little is known about the oncogenic mechanism of EBV in gastric carcinogenesis. Twenty-one cases of EBV-positive GC and 56 cases of EBV-negative GC were examined for aberrant DNA methylation of the CpG islands of 19 genes or loci and the differences in the methylation frequency between EBV-positive and -negative GCs were investigated to determine a role of aberrant methylation in EBV-related gastric carcinogenesis. The average number of methylated genes or loci was higher in EBV-positive GCs than in EBV-negative GCs (13.4 versus 7.8, respectively, P < 0.001). EBV-positive GCs showed methylation in at least 10 CpG islands (52.6% of the tested genes), whereas 62.5% of EBV-negative GCs showed methylation in <10 CpG islands. THBS1, APC, p16, 14-3-3 sigma, MINT1, and MINT25 were methylated at a frequency >90% in EBV-positive GCs. The methylation frequency difference in the respective CpG islands between EBV-positive and -negative GCs was statistically significant (P < 0.05). Among these genes or loci, the methylation frequency of p16 in the EBV-positive GCs was more than three times higher than in the EBV-negative GCs. The PTEN, RASSF1A, GSTP1, MGMT, and MINT2 were methylated in EBV-positive GCs at a frequency of more than three times that of the EBV-negative GCs. These results demonstrate a relationship between EBV and aberrant methylation in GC and suggest that aberrant methylation may be an important mechanism of EBV-related gastric carcinogenesis.

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

We evaluated the rate of Epstein-Barr virus (EBV) infection in gastric carcinomas of Korean patients and investigated the associations between EBV infection and clinicopathological characteristics, the survival rates of patients, and p53 overexpression. EBV-encoded small RNA (EBER)-in situ hybridization and immunohistochemistry for p53 protein were done in 306 consecutive gastric carcinoma cases, of which 17 (5.6%) showed EBV infection. Of these 17 EBV-positive cases, one case strongly expressed p53 protein, while 98 (34%) of 285 EBV-negative cases overexpressed p53 (p < 0.05). The EBV-positive gastric carcinomas tended to have lymphoid stroma. They were mostly of the poorly differentiated type, negative for p53 immunoexpression, more prevalent in male patients, and diffuse according to Lauren's classification (p < 0.05). There was no significant difference in the survival rate for the EBV status. In conclusion, the EBV infection rate among gastric carcinomas in Korea is similar to that ascertained in other countries. An inverse correlation between EBV and p53 overexpression was disclosed. Further study is needed to find out whether or not two genetic changes could be functionally overlapping during gastric carcinogenesis.

Epstein-Barr virus infection, drug resistance and prognosis in Korean T- and NK-cell lymphomas

T-cell lymphomas are a biologically heterogeneous group of diseases with varying clinical presentations and outcomes. We tried to understand the effect of Epstein-Barr virus (EBV) on lymphogenesis, prognostic factors and drug resistance of T-cell lymphomas, and to establish their relationship with international prognostic factors. Formalin-fixed paraffin-embedded tissue sections from 35 patients (12 women and 23 men) with T-cell lymphomas were examined to detect the presence of EBV using RNA in situ hybridization for EBV-encoded small nuclear RNA (EBER) 1/2 and immunohistochemical stain for latent membrane protein (LMP)-1. We also tried to establish the expression of p53 and P-glycoprotein (P-gp) using immunohistochemistry. The distribution according to the subgroup was: two T-lymphoblastic lymphomas, 13 NK/T-cell lymphomas, one angioimmunoblastic T-cell lymphoma, 17 peripheral T-cell lymphomas, unspecified, and two anaplastic large cell lymphomas. The EBER was detected in 15 of 35 T-cell lymphomas (42.9%) and among these it was detected in five of 17 nodal lymphomas (29.4%) and 10 of 18 extranodal lymphomas (55.6%). There was close correlation between EBER positivity and NK/T-cell lymphoma (P = 0.032). Expression of LMP was found in a proportion of tumor cells in seven of the 15 EBER-positive cases (46.7%). There was no correlation between EBER expression and complete response (CR rate), but coexpression of EBER and p53 was associated with treatment failure (P = 0.047). The 18 patients (51.4%) with p53 expression had significantly poorer outcomes compared with the 17 patients without p53 expression (CR rate, P < 0.0005; overall survival, P = 0.0102). Twenty of 35 patients (57.1%) were positive for P-gp expression. P-gp expression was significantly associated with treatment failure (P = 0.001) and overall survival (P = 0.0089). Seventeen of 35 patients (48.6%) treated with systemic chemotherapy or radiation therapy achieved a CR after initial treatment. When the prognostic factors were grouped using the international prognostic index, the CR rate was 58.8% for the low risk group, 50.0% for the low-intermediate risk group, 14.3% for the high-intermediate risk group, and 0% for the high risk group. In conclusion, high incidence of EBV was detected among Korean patients with T-cell lymphomas. Our study supports the prediction that patients who express p53 and P-gp have a poorer prognosis than those who do not and this should be considered when treatment strategies for individual patients are selected.