In situ hybridization of Epstein-Barr virus in tumor cells and tumor-infiltrating lymphocytes of the gastrointestinal tract

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.

Association between Epstein-Bar virus and colorectal cancer: A systematic review and meta-analysis

AIM

This study aimed to investigate the prevalence and any potential association between Epstein-Barr virus (EBV) infection and colorectal cancer (CRC).

METHODS

A systematic literature search was performed by finding relevant cross-sectional and case-control studies from main online databases. Heterogeneity, odds ratio (OR), and corresponding 95% confidence interval (CI) were applied to all studies through meta-analysis and forest plots. The analysis was performed using STATA Software v.14.1.

RESULTS

Twenty-three articles were included in the meta-analysis, eight of them were case/control and 15 were cross-sectional. The pooled prevalence of EBV among 1954 CRC patients was 18% (95% CI: 12%-26%; I² = 93.14%). Furthermore, in geographical regions, the highest and lowest prevalence of EBV was observed in South America 30% (95% CI: 18%-43%) and Africa 0% (95% CI: 0%-5%), respectively. An association was found between EBV infection and CRC [OR = 3.4 (95% CI (1.13-10.27); I² = 72.3%)].

CONCLUSION

EBV infection is associated with CRC and can be considered a potential risk factor for the development of CRC. Although the exact molecular mechanism of EBV infection in the development of CRC is still unknown, it seems that latent infection by EBV, intestinal damage, and inflammation can be important factors in the induction of CRC.

Defining Novel DNA Virus-Tumor Associations and Genomic Correlates Using Prospective Clinical Tumor/Normal Matched Sequencing Data

This study is the largest analysis of DNA viruses in solid tumors with associated genomics. To achieve this, a novel method for discovery of DNA viruses from matched tumor/normal next-generation sequencing samples was developed and validated. This method performed comparably to reference methods for the detection of high-risk (HR) human papilloma virus (HPV) (area under the receiver operating characteristic curve = 0.953). After virus identification in 48,148 consecutives samples from 42,846 unique patients, novel virus tumor associations were established by segregating tumor types to determine whether each DNA virus was enriched in each of the tumor types compared with the remaining cohort. All firmly established solid tumor-virus associations (eg, HR HPV in cervical cancer) were confirmed, and the novel associations discovered included: human herpes virus 6 in neuroblastoma, human herpes virus 7 in esophagogastric cancer, and HPV42 in digital papillary adenocarcinoma. These associations were confirmed in an independent validation cohort. HR HPV- and Epstein-Barr virus-associated tumors showed newly discovered genomic associations, including a lower tumor mutation burden. The study demonstrated the ability to study the role of DNA viruses in human cancer from clinical genomics data and established the largest cohort that can be utilized as a validation set for future discovery efforts.

Metagenomic analysis of primary colorectal carcinomas and their metastases identifies potential microbial risk factors

The paucity of microbiome studies at intestinal tissues has contributed to a yet limited understanding of potential viral and bacterial cofactors of colorectal cancer (CRC) carcinogenesis or progression. We analysed whole-genome sequences of CRC primary tumours, their corresponding metastases and matched normal tissue for sequences of viral, phage and bacterial species. Bacteriome analysis showed Fusobacterium nucleatum, Streptococcus sanguinis, F. Hwasookii, Anaerococcus mediterraneensis and further species enriched in primary CRCs. The primary CRC of one patient was enriched for F. alocis, S. anginosus, Parvimonas micra and Gemella sp. 948. Enrichment of Escherichia coli strains IAI1, SE11, K-12 and M8 was observed in metastases together with coliphages enterobacteria phage φ80 and Escherichia phage VT2φ_272. Virome analysis showed that phages were the most preponderant viral species (46%), the main families being Myoviridae, Siphoviridae and Podoviridae. Primary CRCs were enriched for bacteriophages, showing five phages (Enterobacteria, Bacillus, Proteus, Streptococcus phages) together with their pathogenic hosts in contrast to normal tissues. The most frequently detected, and Blast-confirmed, viruses included human endogenous retrovirus K113, human herpesviruses 7 and 6B, Megavirus chilensis, cytomegalovirus (CMV) and Epstein-Barr virus (EBV), with one patient showing EBV enrichment in primary tumour and metastases. EBV was PCR-validated in 80 pairs of CRC primary tumour and their corresponding normal tissues; in 21 of these pairs (26.3%), it was detectable in primary tumours only. The number of viral species was increased and bacterial species decreased in CRCs compared with normal tissues, and we could discriminate primary CRCs from metastases and normal tissues by applying the Hutcheson t-test on the Shannon indices based on viral and bacterial species. Taken together, our results descriptively support hypotheses on microorganisms as potential (co)risk factors of CRC and extend putative suggestions on critical microbiome species in CRC metastasis.

Epstein-Barr Virus in the Development of Colorectal Cancer (Review)

The study of the influence of the Epstein–Barr virus (EBV) on the development of colorectal cancer is of current interest, particularly in light of the active discussion of the participation of this virus in the carcinogenesis of stomach cancer. In this review, aimed at a fundamental understanding of the processes associated with the impact of EBV on the human body, attention is paid to the issues of the life cycle of the virus, its phases (latent and lytic), as well as proteins that may be detected in each of the phases. The papers reporting on the role of EBV in the development of colorectal cancer have been analyzed. A summary table indicating the population under study, the number of samples, the method, and the result obtained is provided. Given that the primary cells affected by EBV are lymphocytes, it is logical to assume the involvement of this virus in the development of inflammatory bowel diseases. The review cites studies which confirm the presence of virus DNA in tissues in the inflammatory diseases of the colon, including microscopic and ulcerative colitis. To confirm the direct impact of EBV on the development of colorectal cancer, large studies with applying various methods for detecting the virus and the mandatory description of its localization are required. Besides, it is necessary to correlate these data with the clinical and morphological characteristics of EBV.

Viruses in colorectal cancer

Increasing evidence suggests that microorganisms might represent at least highly interesting cofactors in colorectal cancer (CRC) oncogenesis and progression. Still, associated mechanisms, specifically in colonocytes and their microenvironmental interactions, are still poorly understood. Although, currently, at least seven viruses are being recognized as human carcinogens, only three of these – Epstein–Barr virus (EBV), human papillomavirus (HPV) and John Cunningham virus (JCV) – have been described, with varying levels of evidence, in CRC. In addition, cytomegalovirus (CMV) has been associated with CRC in some publications, albeit not being a fully acknowledged oncovirus. Moreover, recent microbiome studies set increasing grounds for new hypotheses on bacteriophages as interesting additional modulators in CRC carcinogenesis and progression. The present Review summarizes how particular groups of viruses, including bacteriophages, affect cells and the cellular and microbial microenvironment, thereby putatively contributing to foster CRC. This could be achieved, for example, by promoting several processes – such as DNA damage, chromosomal instability, or molecular aspects of cell proliferation, CRC progression and metastasis – not necessarily by direct infection of epithelial cells only, but also by interaction with the microenvironment of infected cells. In this context, there are striking common features of EBV, CMV, HPV and JCV that are able to promote oncogenesis, in terms of establishing latent infections and affecting p53‐/pRb‐driven, epithelial–mesenchymal transition (EMT)‐/EGFR‐associated and especially Wnt/β‐catenin‐driven pathways. We speculate that, at least in part, such viral impacts on particular pathways might be reflected in lasting (e.g. mutational or further genomic) fingerprints of viruses in cells. Also, the complex interplay between several species within the intestinal microbiome, involving a direct or indirect impact on colorectal and microenvironmental cells but also between, for example, phages and bacterial and viral pathogens, and further novel species certainly might, in part, explain ongoing difficulties to establish unequivocal monocausal links between specific viral infections and CRC.

Copresence of High-Risk Human Papillomaviruses and Epstein-Barr Virus in Colorectal Cancer: A Tissue Microarray and Molecular Study from Lebanon

Colorectal cancer (CRC) is the third most common cause of cancer-related deaths worldwide. Human papillomaviruses (HPVs) and Epstein-Barr virus (EBV) have been reported to be present in different types of human cancers, including CRCs, where they can play a key role in the onset and/or progression of these cancers. Thus, we herein explored the prevalence of high-risk HPVs and EBV in a cohort of 94 CRC tissue samples and 13 colorectal normal tissues from the Lebanese population using polymerase chain reaction, immunohistochemistry, and tissue microarray methodologies. We found that high-risk HPVs are present in 64%, while EBV is present in 29% of our CRC samples. Additionally, our data showed that high-risk HPV types (16, 18, 35, 58, 51, 45, 52, 31, and 33) are the most frequent in CRC in the Lebanese cohort, respectively. Our data point out that HPVs and EBV are copresent in 28% of the samples. Thus, this study clearly suggests that high-risk HPVs and EBV are present/copresent in CRCs, where they could play an important role in colorectal carcinogenesis. Nevertheless, further investigations using a larger cohort are needed to elucidate the possible cooperation between these oncoviruses in the development of CRC.

Effects of Epstein-Barr Virus Infection on the Risk and Prognosis of Primary Laryngeal Squamous Cell Carcinoma: A Hospital-Based Case-Control Study in Taiwan

Mounting molecular evidence supports Epstein-Barr virus (EBV) involvement in the pathogenesis of laryngeal squamous cell carcinoma (LSCC); however, the epidemiological data are inconsistent. In this retrospective case-control study, we aimed to determine whether EBV infection underlies the risk and prognosis of LSCC. The prevalence of EBV infection, as analyzed using an EBV DNA polymerase chain reaction assay, was significantly higher in 42 Taiwanese patients with newly diagnosed primary LSCC, compared to 39 age- and sex-matched control patients without cancer (48% vs. 19%). Furthermore, most of the EBER signals detected using in situ hybridization were localized to the nuclei of tumor-infiltrating lymphocytes. In multivariate analysis, EBV DNA positivity, age ≥ 55 years, cigarette smoking, and high BCL-2, B2M, and CD161 expression (assessed using immunohistochemistry) were identified as independent risk factors for LSCC. Furthermore, five-year local recurrence and disease-free survival rates were 34% and 58%, respectively, with a high EBER signal and low CD3 expression independently predicting five-year local recurrence and disease-free survival. Our comprehensive profiling data accurately identified patients at risk for LSCC development, local recurrence, or disease-free survival. The information obtained in this study improves our understanding of EBV infection in LSCC, and may guide precision medicine for patients with LSCC.

Patient-individual cancer cell lines and tissue analysis delivers no evidence of sequences from DNA viruses in colorectal cancer cells

Background

Several DNA viruses are highly suspicious to have oncogenic effects in humans. This study investigates the presence of potentially oncogenic viruses such as SV40, JCV, BKV and EBV in patient-derived colorectal carcinoma (CRC) cells typifying all molecular subtypes of CRC.

Methods

Sample material (gDNA and cDNA) of a total of 49 patient-individual CRC cell lines and corresponding primary material from 11 patients, including normal, tumor-derived and metastasis-derived tissue were analyzed for sequences of SV40, JVC, BKV and EBV using endpoint PCR. In addition, the susceptibility of CRC cells to JCV and BKV was examined using a long-term cultivation approach of patient-individual cells in the presence of viruses.

Results

No virus-specific sequences could be detected in all specimens. Likewise, no morphological changes were observed and no evidence for viral infection or integration could be provided after long term CRC cell cultivation in presence of viral particles.

Conclusions

In summary, the presented data suggest that there is no direct correlation between tumorigenesis and viral load and consequently no evidence for a functional role of the DNA viruses included into this analysis in CRC development.

Human Papillomaviruses and Epstein-Barr Virus Interactions in Colorectal Cancer: A Brief Review

Human papillomaviruses (HPVs) and the Epstein-Barr virus (EBV) are the most common oncoviruses, contributing to approximately 10%-15% of all malignancies. Oncoproteins of high-risk HPVs (E5 and E6/E7), as well as EBV (LMP1, LMP2A and EBNA1), play a principal role in the onset and progression of several human carcinomas, including head and neck, cervical and colorectal. Oncoproteins of high-risk HPVs and EBV can cooperate to initiate and/or enhance epithelial-mesenchymal transition (EMT) events, which represents one of the hallmarks of cancer progression and metastasis. Although the role of these oncoviruses in several cancers is well established, their role in the pathogenesis of colorectal cancer is still nascent. This review presents an overview of the most recent advances related to the presence and role of high-risk HPVs and EBV in colorectal cancer, with an emphasis on their cooperation in colorectal carcinogenesis.

The Very Low Frequency of Epstein-Barr JC and BK Viruses DNA in Colorectal Cancer Tissues in Shiraz, Southwest Iran

Viruses including Epstein-Barr virus (EBV), JCV and BKV have been reported to be associated with some cancers. The association of these viruses with colorectal cancers remains controversial. Our objective was to investigate their infections association with adenocarcinoma and adenomatous polyps of the colon. Totally, 210 paraffin-embedded tissue specimens encompassing 70 colorectal adenocarcinoma, 70 colorectal adenomatous and 70 colorectal normal tissues were included. The total DNA was extracted, then qualified samples introduced to polymerase chain reaction (PCR). The EBV, JCV and BKV genome sequences were detected using specific primers by 3 different in-house PCR assays. Out of 210 subjects, 98 cases were female and the rest were male. The mean age of the participants was 52 ± 1.64 years. EBV and JCV DNA was detected just in one (1.42%) out of seventy adenocarcinoma colorectal tissues. All adenomatous polyp and normal colorectal tissues were negative for EBV and JCV DNA sequences. Moreover, all the patients and healthy subjects were negative for BKV DNA sequences. The results suggested that EBV and JCV genomes were not detectable in the colorectal tissue of patients with colorectal cancer in our population. Hence, BKV might not be necessitated for the development of colorectal cancer. The findings merit more investigations.

Epstein-Barr virus (EBV) status in colorectal cancer: a mini review

Epstein-Barr virus (EBV) is a well-characterized oncovirus, associated with several malignancies. The complex and heterogeneous nature of colorectal cancer (CRC) has led to many epidemiological causal associations with CRC. However, a direct causal link between microbial infections and CRC has not been established yet. Our review indicates that the current evidence for the presence and role in EBV in CRC is insufficient and contradictory. The design of the analyzed studies, sample size as well as methodology used for EBV detection varied markedly and consequently may not lead to meaningful conclusions. The presence of EBV in other colorectal tumors (lymphomas, smooth muscle tumors) is in line with their status at other anatomic locations and may have therapeutic implications with EBV-specific vaccines. On the other hand, studies exploring EBV in colorectal adenoma-carcinoma sequence and its molecular genetic characteristics are largely missing and may significantly contribute to a better understanding of the role of EBV in CRC.

The prevalence of viral agents in esophageal adenocarcinoma and Barrett's esophagus: a systematic review

BACKGROUND AND AIMS

Human papilloma virus (HPV), which may reach the esophagus through orogenital transmission, has been postulated to be associated with esophageal adenocarcinoma (EAC). A systematic review of the literature investigating the prevalence of infectious agents in EAC and Barrett's esophagus (BE) was carried out.

METHODS

Using terms for viruses and EAC, the Medline, Embase, and Web of Science databases were systematically searched for studies published, in any language, until June 2016 that assessed the prevalence of viral agents in EAC or BE. Random-effects meta-analyses of proportions were carried out to calculate the pooled prevalence and 95% confidence intervals (CIs) of infections in EAC and BE.

RESULTS

A total of 30 studies were included. The pooled prevalence of HPV in EAC tumor samples was 13% (n=19 studies, 95% CI: 2-29%) and 26% (n=6 studies, 95% CI: 3-59%) in BE samples. HPV prevalence was higher in EAC tissue than in esophageal tissue from healthy controls (n=5 studies, pooled odds ratio=3.31, 95% CI: 1.15-9.50). The prevalence of Epstein-Barr virus (EBV) in EAC was 6% (n=5, 95% CI: 0-27%). Few studies have assessed other infectious agents. For each of the analyses, considerable between-study variation was observed (I=84-96%); however, sensitivity analyses did not show any major sources of heterogeneity.

CONCLUSION

The prevalence of HPV and EBV in EAC is low compared with other viral-associated cancers, but may have been hampered by small sample sizes and detection methods susceptible to fixation processes. Additional research with adequate sample sizes and high-quality detection methods is required.

Epstein-barr virus in gastro-esophageal adenocarcinomas - single center experiences in the context of current literature

Epstein–Barr virus (EBV)-associated gastric carcinomas (GC) represent a distinct and well-recognized subtype of gastric cancer with a prevalence of around 10% of all GC. In contrast, EBV has not been reported to play a major role in esophageal adenocarcinomas (EAC) and adenocarcinomas of the gastro-esophageal junction (GEJ). We report our experiences on EBV in collections of gastro-esophageal adenocarcinomas from two surgical centers and discuss the current state of research in this field. Tumor samples from 465 primary resected gastro-esophageal adenocarcinomas (118 EAC, 73 GEJ, and 274 GC) were investigated. Presence of EBV was determined by EBV-encoded small RNAs (EBER) in situ hybridization. Results were correlated with pathologic parameters (UICC pTNM category, Her2 status, tumor grading) and survival. EBER positivity was observed in 14 cases. None of the EAC were positive for EBER. In contrast, we observed EBER positivity in 2/73 adenocarcinomas of the GEJ (2.7%) and 12/274 GC (4.4%). These were of intestinal type (seven cases) or unclassifiable (six cases), while only one case was of diffuse type according to the Lauren classification. No association between EBV and pT, pN, or tumor grading was found, neither was there a correlation with clinical outcome. None of the EBER positive cases were Her2 positive. In conclusion, EBV does not seem to play a role in the carcinogenesis of EAC. Moreover, adenocarcinomas of the GEJ show lower rates of EBV positivity compared to GC. Our data only partially correlate with previous reports from the literature. This highlights the need for further research on this distinct entity. Recent reports, however, have identified specific epigenetic and genetic alterations in EBV-associated GC, which might lead to a distinct treatment approach for this specific subtype of GC in the future.

Barrett's esophageal carcinoma consisting of undifferentiated carcinoma and differentiated adenocarcinoma: report of case

We report on a 53-year-old male with esophageal cancer. He had no evidence of distant metastasis, and received a subtotal esophagectomy. Histopathologically, the tumors were contiguous with Barrett's epithelium. Undifferentiated carcinoma components existed independently of differentiated adenocarcinoma components. Undifferentiated carcinoma was present proximal to the esophagogastric junction. Both tumors had invaded the submucosa and were associated with a prominent lymphoid stroma. Metastasis from undifferentiated carcinoma was found in the paraesophageal lymph nodes. Immunohistochemically, both components were negative for 34bE12 and positive for CAM5.2 and showed nearly identical staining patterns for p53, indicating that the tumors were derived from Barrett's epithelium. Because the undifferentiated carcinoma did not express CK20 or carcinoembryonic antigen, the properties of adenocarcinoma had apparently been lost during the process of tumor cell progression. This is the first report of undifferentiated carcinoma associated with Barrett's esophagus with adenocarcinoma.

Epstein-Barr virus-associated gastric carcinoma in Brazil: comparison between in situ hybridization and polymerase chain reaction detection

Epstein-Barr virus (EBV) has been associated with 10% of gastric carcinomas. The aim of this study was to determine the frequency of EBV in gastric carcinomas in Brazil assessed by in situ hybridization (ISH) and PCR, which would contribute to the characterization of the clinical and pathological aspects of EBV-associated gastric carcinomas. One hundred and ninety-two gastric carcinoma cases were collected at hospitals in two Brazilian states. Seventy-three out of 151 cases were PCR(+), while 11/160 cases were ISH(+). Nine out of eleven ISH(+) cases displayed a diffuse staining pattern and 2 out of 11 a focal pattern. Both techniques showed that the EBV(+) cases were characterized by their association with males, older patients, lower gastric region, intestinal type, advanced stage and poorly to moderately differentiated tumors. The concordance between the two techniques was 55.8% (Cohen's kappa index = 0.034). Four cases were ISH(+)/PCR(-), while 49 cases were PCR(+)/ISH(-). Only two cases showed stained lymphocytes by ISH and one of them was PCR(-). The observed discrepancy between the two techniques could not be explained just by the elevated accuracy of PCR. ISH(+)/PCR(-) carcinomas may be encountered if EBV is not present in the whole tumor tissue or if there are polymorphisms in the sequences of the viral genome amplified. On the other hand, the high frequency of PCR(+) results associated with the absence of ISH staining in lymphocytes and/or tumors cells suggests that the virus may be present in tumor cells or other cell types without expressing EBER1, the target of the ISH technique.

Detection of viral DNA sequences in sporadic colorectal cancers in relation to CpG island methylation and methylator phenotype

There is evidence that insertion of viral DNA into a mammalian genome can lead to alterations of methylation patterns. The aim of the present study was to examine the presence of DNA sequences of five human DNA viruses (assessed by PCR): JC polyoma virus (JCV), human adenovirus (AdV), Epstein-Barr virus (EBV), Kaposi sarcoma-associated herpesvirus (KSHV/HHV8) and human papillomavirus (HPV) in a cohort of 186 sporadic colorectal cancers (CRCs) and related these data with the methylation status of six CpG island methylator phenotype (CIMP)-specific genes (MLH1, CACNA1G, NEUROG1, IGF2, SOCS1, RUNX3) and seven cancer-related genes markers (p16, MINT1, MINT2, MINT31, EN1, SCTR and INHBB) assessed by methylation-specific PCR in 186 and 134 CRC cases, respectively. The AdV, KSHV and HPV were detected in four (2%), two (1%) and zero CRC cases, respectively, and thus were excluded from further analyses. Although 19% and 9% of the CRCs were positive for EBV and JCV, respectively, no associations between virus presence and CpG island methylation were found after correction for multiple testing. Our results demonstrate that the presence of DNA sequences of JCV and EBV in CRC is unrelated to the methylation of the 13 cancer-related CpG islands and CIMP.

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.

Detection of Epstein-Barr virus in lower gastrointestinal tract lymphomas: a study in Malaysian patients

BACKGROUND

Many studies in the literature have shown that Epstein-Barr virus (EBV) is associated with several human lymphoid and epithelial malignancies. However, the prevalence of EBV in non-Hodgkin lymphoma (NHL) of the lower gastrointestinal (GI) tract has not been fully elucidated.

AIM

The aim of this study was to determine the presence and distribution of EBV in formalin-fixed paraffin-embedded tissue samples obtained from 18 Malaysian patients diagnosed with NHL of the lower GI tract.

METHODS

The GI tract lymphoma tissue samples analyzed for the presence of EBV were divided into the following groups: NHL of the small intestine (seven cases); NHL of the ileocecum (ten cases); and NHL of the rectum (one case). The presence of EBV-encoded RNA (EBER) in all of the above tissue samples was tested for using conventional in situ hybridization technology.

RESULTS

Two of 18 cases (11.1%) of NHL of the lower GI tract demonstrated positive signals for EBV/EBER. In the first positive case, EBV/EBER signals were located in lymphoma cells in the serosa layer of the small intestine. In the second EBV/EBER-positive case, EBV/EBER signals were detected in diffuse B-cell lymphoma of the ileocecum.

CONCLUSION

These findings demonstrate a rare association between EBV and lower GI tract lymphomas in this group of Malaysian patients.

No association of primary adenocarcinomas of the small bowel with Epstein-Barr virus infection

Epstein-Barr Virus (EBV) infection is considered to play an etiologic role in human malignancies, including a subset of gastric and cardiac cancers. Adenocarcinomas of the small bowel comprise a very rare entity, with little knowledge about molecular properties and etiological aspects. We have investigated the prevalence of EBER expression (EBV-encoded small RNAs) in a series of small bowel adenocarcinomas (n=56) utilizing RNA in situ hybridization (EBER-RISH). The patients had undergone primary surgical resection at either the Technical University of Munich or at the University of Graz. A surgical series of 82 primary resected gastric (n=36) or cardiac (n=46) adenocarcinomas (TU Munich) was used as control group. None of the 56 small bowel carcinomas exhibited EBER expression whereas in the control group the rate of EBER expression accounted for 4.4% in the group of cardia carcinomas and 8.6% in the group of gastric cancers. These results indicate that EBV infection plays no etiologic role in primary small bowel adenocarcinomas.

Detection of Epstein–Barr virus infection and gene expression in human tumors by microarray analysis

Epstein-Barr virus (EBV) genome-chips are employed to determine the EBV infection rate and to reveal the gene expression patterns of EBV in tumor biopsies. These chips are produced with 71 consecutive PCR-amplified EBV DNA fragments of 1-3 kbp covering the entire EBV genome. The specificity of the EBV-chips is determined by hybridizing the DNA on the chips with biotin-labeled cDNA probes reverse transcribed from the mRNA of P3HR1 cells, which were B-cell infected latently by EBV. Hybridization results revealed only the expression of EBNA1, EBNA2, EBER1 and EBER2 in these cells. On the other hand, EBV lytic genes are expressed after the cells are treated with 12-O-tetradecanoylphorbol-13-acetate and sodium butyrate to induce the EBV lytic cycle. Fourty-four tumor biopsies from different organs are assayed with these chips, which showed many defined and interesting EBV gene expression patterns. This study demonstrates that the EBV-chip is useful for screening infection with EBV in tumors, which may lead to insights into tumorigenesis associated with this virus.

Absence of Epstein-Barr virus in esophageal squamous cell carcinoma

It is strongly suspected that the Epstein-Barr virus (EBV) plays a role in the genesis of nasopharyngeal and gastric carcinoma. The aim of this study was to search for such a connection between esophageal squamous cell carcinoma (ESCC) and EBV. We investigated 104 surgically resected esophageal cancers using in situ hybridization (ISH) for EBV-encoded RNA (EBER). We found no EBER-positive cancer cells in any tests, although there were five samples in which EBER-positive tumor-infiltrating lymphocytes (TILs) were found. We conclude from this study that EBV is not associated with ESCC.

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.

Presence of Epstein-Barr virus in esophageal cancer is restricted to tumor infiltrating lymphocytes

As representatives of low and high incidence countries respectively, 72 esophageal squamous cell carcinomas and 40 adenocarcinomas from Germany, and 43 esophageal squamous cell carcinomas from Russia were tested for the presence of Epstein-Barr virus (EBV) DNA by PCR and in situ hybridization. Thirty-four percent of the squamous cell carcinomas (SCC) and 26% of the adenocarcinomas (AC) contained EBV DNA as detected by nested PCR. Quantitative analysis using real time PCR revealed one copy of the EBV genome per every 27-200,000 cells. EBER RNA in situ hybridization showed no EBV-specific transcripts in the nuclei of the tumor cells. However, EBER transcripts were expressed in the nuclei of tumor infiltrating lymphocytes in 7 SCC and 1 AC of 24 EBV DNA positive cases. The present data provide no evidence for the persistence of EBV in the tumor cells of esophageal cancer. In contrast to a previous report from Taiwan, EBV is unlikely to play a role in esophageal carcinogenesis.

Detection of HSV and EBV in esophageal carcinomas from a high-incidence area in Shantou China

An association between viral infection, particularly the human papillomavirus, and the development of esophageal carcinoma (EC) has been reported. However, reports concerning the relationship between herpes simplex virus (HSV) and Epstein-Barr virus (EBV) with EC are few. There are geographic variations in infection rates. This study was aimed to determine the co-incidence of infection of the two viruses' with esophageal carcinoma and the differentiation of cancer tissues and lymphocytes infiltration in the tumor stroma of the high-incidence area of Shantou China. To determine the association between viral infection (HSV and EBV) and EC, we applied in situ hybridization (ISH) and immunohistochemistry (IHC) in 164 esophageal carcinoma surgical specimens from the high-incidence area of Shantou China. HSV DNA and HSVI, II protein expression were found in 52 (31.7%) of the 164 tumors; EBV EBER and LMP-1 proteins were identified in only 10 (6.1%) carcinoma specimens by in situ hybridization and immunohistochemistry. In histopathology analysis, the positive cases of HSV appeared to be more predominant in well and moderately differentiated squamous cell carcinomas, and the positive cases of EBV were found in poorly differentiated squamous cell carcinomas or undifferentiated carcinomas with intense lymphoid infiltration. Our results confirm the involvement of HSV and EBV in esophageal carcinomas and the relationship between HSV and EBV infection and esophageal carcinoma cell differentiation with lymphocyte infiltration in the tumor stroma. However, the two herpes viruses, HSV and EBV, particularly the human HSV may be one of the etiological factors in development of this malignancy among the high-incidence population of Shantou China.

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.

Expression of cytokeratins 7 and 20 in primary carcinomas of the stomach and colorectum and their value in the differential diagnosis of metastatic carcinomas to the ovary

The expressions of cytokeratin (CK) 7 and 20 have been studied in various primary and metastatic carcinomas, and their determination may help distinguish the site of origin of metastatic carcinomas. However, little is known about the factors that determine variations in their expression patterns in primary gastric and colorectal carcinomas. We investigated the expressions of CK7 and CK20 in 289 cases of gastric carcinoma and 225 cases of colorectal carcinoma using a tissue microarray. To evaluate CK7 and CK20 expression patterns of ovarian metastases from gastric or colorectal carcinomas, 54 cases of metastatic carcinomas to the ovary were examined. It was found that 71% (207 of 289) of the gastric carcinomas stained positively for CK7, whereas only 9% (21 of 225) of the colorectal carcinomas proved to be CK7 positive, and that 41% (117 of 289) of the gastric carcinomas and 73% (165 of 225) of the colorectal carcinomas were CK20 positive. The proportion of CK7+/CK20- was highest in the gastric carcinomas at 46% (132 of 289), and was independent of the histologic classification of Lauren (46% of the intestinal type, 45% of the diffuse type). The CK7 and CK20 expression patterns were different in colorectal carcinomas according to histologic grade and location of the tumor. CK7-/CK20+ had the greatest proportion (68%) in colorectal carcinomas, and this was dependent on the tumor's histologic grade (75% of low-grade versus 52% of high-grade) and location (46% of right-sided versus 76% of left-sided). Moreover, 42% (18 of 43) of gastric carcinomas metastatic to the ovary were CK7+/CK20-, whereas 19% (8 of 43) were CK7-/CK20+. All colorectal cancers metastatic to the ovary were CK7-/CK20+, except 1 case that was CK7-/CK20-. In conclusion, the CK7 and CK20 expression patterns in primary gastric carcinomas vary considerably, and those in colorectal carcinomas are associated with histologic grade and tumor location. The CK7-/CK20+ expression pattern is specific for metastatic colorectal carcinomas to the ovary, but has low predictability for colorectal origin in metastatic ovarian carcinoma.

Epstein-Barr virus, p53 protein, and microsatellite instability in the adenoma-carcinoma sequence of the stomach

To elucidate the adenoma-carcinoma sequence in the stomach, we investigated Epstein-Barr virus (EBV) incorporation, p53 overexpression, and microsatellite instability (MSI) in gastric adenomas and carcinomas. The study involved 66 cases of gastric carcinomas within or adjacent to adenomas (adenoma-carcinoma cases), 81 cases of simple adenomas (without carcinoma), and 306 de novo carcinomas (without adenoma focus). EBV incorporation was revealed in 1 (1.5%) of the adenoma-carcinomas, in none of the adenomas, and in 17 (5.6%) of the de novo carcinomas. p53 overexpression was observed in 24.2% (16 of 66) of the adenomas in the adenoma-carcinoma cases and in 36.5% (23 of 63) of corresponding carcinomas (kappa = 0.63, P = 0.00). MSI was positive in 12.3% (8 of 65) of the adenomas in the adenoma-carcinoma cases and in 18.8% (12 of 64) of the corresponding carcinomas (kappa = 0.77, P = 0.00). In conclusion, EBV incorporation is not possibly associated with the gastric adenoma-carcinoma sequence, whereas the gastric adenoma-carcinoma sequence seems to be supported in terms of p53 overexpression or MSI. The transcriptional activation of EBV may occur relatively late (after the adenoma stage) in the gastric adenoma-carcinoma sequence.