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 in gastric carcinomas with lymphoid stroma

AIMS: To clarify the relationship between the Epstein-Barr virus (EBV) and gastric carcinoma with lymphoid stroma (GCLS) in Koreans, and to characterize the EBV-positive GCLS. METHODS AND RESULTS: EBV infection was examined using EBER in-situ hybridization and polymerase chain reaction in 45 cases of GCLS among Koreans, and in 292 consecutive cases of gastric carcinomas without lymphoid stroma (non-GCLS) as controls. EBV infection was found in 30 tumours (67%) of GCLS and 10 tumours (3.4%) of non-GCLS (P < 0.05). EBV-positive GCLS was more prevalent in males, poorly differentiated histological type and diffuse type in Lauren's classification, and tended to be located more in the middle third of the stomach than EBV-negative GCLS (P < 0.05). p53 overexpression was observed in 22% of GCLS (17% of EBV-positive GCLS and 33% of EBV-negative GCLS), and 34% of non-GCLS (EBV-positive GCLS vs. non-GCLS: P = 0.056). The survival of the patient with GCLS was not correlated with EBV infection or p53 immunoexpression (follow-up period: 11-97 months). CONCLUSIONS: GCLS in Koreans is strongly associated with EBV infection. The prognosis in GCLS is not dependent upon either the status of EBV infection or the status of p53 immunoexpression.     

Epstein-Barr virus (EBV) infection and p53 protein expression in gastric carcinoma

In the presented studies p53 protein expression was evaluated in samples of gastric carcinoma originating from 32 selected adult patients (with documented diagnosis of adenocarcinoma of the stomach and without the presence of Helicobacter pylori infection). Among the patients 14 individuals carried EBV-positive gastric carcinoma (group 1) while the 18 remaining patients carried EBV-negative gastric carcinoma (group 2). EBV infection was detected testing the tissue material for the presence of EBER by RNA in situ hybridization (ISH) and testing sera of the patients for EBV-specific antibodies. Expression of p53 protein was analysed using immunohistochemistry. Presence of p53 protein was noted in 9 (64.3%) cases of EBV-positive gastric cancer (group 1) and in 10 (55.5%) cases of EBV-negative gastric cancer (group 2). No significant differences were detected in the frequencies of p53 protein expression in the two studied groups. The results permit to conclude that abnormalities in p53 in gastric cancer are independent of EBV infection, even if EBV may participate in development of the tumour.     

Epstein-Barr virus (EBV) and gastric carcinoma in Malaysian patients

Epstein-Barr virus (EBV) has consistently been detected in the tumour cells of nasopharyngeal carcinoma and lymphoepithelial-like carcinoma of the salivary glands, and have occasionally been found in similar tumours at other sites. Moreover, recent studies from various parts of the world including the Orient have shown about 10% of gastric carcinomas to be EBV-associated. We studied 50 gastric carcinomas from Malaysia to investigate its association with EBV in the Malaysian population. They comprised 37 intestinal and 13 diffuse type carcinomas from 32 male and 18 female patients, age range from 29 to 86 years with an ethnic distribution of Malay: Chinese: Indian with the ratio of 4: 27: 19. EBV gene and gene-expression were examined in sections of formalin-fixed, paraffin-embedded tissue using commercially available probes for detecting EBV encoded RNAs (EBERs) by in situ hybridization and monoclonal antibodies to EBV latent membrane protein-1 (LMP-1) by standard immunohistochemistry. Five of 50 gastric carcinomas showed EBER intranuclear positivity in all tumour cells but no cases expressed LMP-1. The EBV-associated cases were classified as intestinal type in 4 and diffuse type in one case and all were histologically unremarkable. EBV-positive tumours were found in 3 Chinese and 2 Indian patients with none in the small Malay group. Four EBV-positive tumours were in male patients, with age-range of 65 to 86 years. We conclude that our findings of about 10% of Malaysian gastric carcinomas being EBV-associated is in line with the results from other parts of the world and from other ethnic groups.     

Low rate of apoptosis and overexpression of bcl-2 in Epstein–Barr virus-associated gastric carcinoma

AIMS: Epstein-Barr virus (EBV) has been demonstrated in about 10% of gastric carcinomas. However, the pathogenetic role of EBV in gastric carcinoma is uncertain. We compared the rate of apoptotic cell death, cell proliferation and the expression of apoptosis-related proteins in gastric carcinomas with or without EBV. METHODS AND RESULTS: Epstein-Barr virus was detected in 40 gastric carcinomas by EBV-encoded small RNA-1 in-situ hybridization. Apoptotic cell death, MIB-1, p53, bcl-2 and bcl-x were examined by the terminal deoxynucleotidyl-mediated dUTP-nick end labelling method and immunohistochemistry. We also included 40 age-, sex- and disease stage-matched EBV-negative cases as a control. The number of apoptotic cells was significantly lower in EBV-positive (20 +/- 15. 1/1000 cells) and bcl-2-positive (17 +/- 12.9/1000 cells) tumours than in EBV-negative (43 +/- 37.1) and bcl-2-negative tumours (38 +/- 32.1, P < 0.001, P < 0.001, respectively). bcl-2 immunostaining was significantly higher in EBV-positive tumours (24 cases) than in EBV-negative tumours (12 cases, P < 0.05). There was no significant difference in bcl-x and p53 expression between EBV-positive and -negative tumours. The number of MIB-1-positive cells in EBV-positive tumours (237 +/- 161/1000) was significantly lower than in EBV-negative tumours (480 +/- 208/1000 cells, P < 0.001). CONCLUSIONS: A low rate of apoptosis and high bcl-2 expression were recognized in EBV-positive gastric carcinomas, suggesting that bcl-2 protein is the main inhibitor of apoptosis in EBV-positive carcinomas. In addition, the low apoptotic and proliferative activities may reflect a low biological activity in EBV-positive gastric carcinomas.     

Prognostic significance of Epstein-Barr virus involvement in gastric carcinoma in Japan

We examined the prognosis of 64 EBV-associated gastric carcinoma (EBV-GC) cases and 128 EBV-negative gastric carcinoma cases. EBV-GCs were identified by detecting EBV-encoded small RNA (EBER) using in situ hybridization assay of paraffin-embedded tissue. For each EBV-GC case, 2 EBER-negative cases (EBV-negative cases) were selected, matching the EBV-GC case with respect to age, sex, tumor location, and depth of invasion. The average follow-up period was 70.9 months (SD=61.1) in EBV-GCs and 63.8 months (SD=59.7) in EBV-negative cases. Tumor-advanced stage determined by TNM classification of UICC, tumor location, and p53 over-expression were statistically significant prognostic factors. On the other hand, EBER expression was not related to the survival of patients. However, further analysis specific for intestinal and diffuse types of Lauren classification revealed that the association of EBER expression with prognosis was different in the two histological types. EBER expression was related to poor prognosis in intestinal-type carcinoma [hazard ratio (HR) =2.5, 95% confidence intervals (CI) =1.3-4.8] after adjusting for stage, p53 over-expression, and tumor location, whereas the diffuse-type EBV-GC had better prognosis (HR=0.4, 95% CI=0.2-0.9) even when lymphoepithelioma-like carcinomas were excluded. To examine the interactive prognostic effects between EBER expression and p53 over-expression, the study subjects were divided into 4 groups on the basis of EBER expression and p53 over-expression. In intestinal-type tumors, the cases having both EBER expression and p53 over-expression showed the poorest prognosis (HR=10.0, 95% CI=3.3-30.4), and the cases with either EBER expression or p53 over-expression had an intermediate prognosis. In diffuse-type tumor, only EBER was an important prognostic factor. These results give additional evidence implicating EBV in the natural history of EBV-GCs.     

Different pattern of allelic loss in Epstein-Barr virus-positive gastric cancer with emphasis on the p53 tumor suppressor pathway

Both Helicobacter pylori (HP) and Epstein-Barr virus (EBV) have been implicated in carcinogenesis of the stomach. Fifty-seven gastric carcinomas were tested for microsatellite instability and allelic loss at several tumor suppressor loci using 21 polymorphic microsatellite markers. Furthermore, immunohistochemistry for p53 and DPC4/SMAD4 was performed. Results were analyzed according to HP and EBV status of the tumors, as assessed by immunohistochemistry and RNA in situ hybridization, respectively. Fractional allelic loss was lower in EBV-positive carcinomas (n = 15) when compared to EBV-negative carcinomas (P < 0.001). EBV positivity was inversely associated with allelic loss at specific markers on chromosomal arms 5q (APC), 17p (TP53), and 18q (DPC4/SMAD4). Allelic loss at the TP53 locus was not encountered in EBV-positive carcinomas, but occurred in 51% of EBV-negative carcinomas (P < 0.005). Moreover, none of the EBV-positive carcinomas showed unequivocal p53 immunopositivity in contrast to 39% of the EBV-negative carcinomas (P < 0.01). EBV-status was not related to microsatellite instability. There was no correlation between HP-status and any of the molecular alterations tested. In conclusion, EBV-positive gastric carcinomas follow a distinct pathogenesis at the molecular level, in which p53 is not, or differently inactivated.     

Overexpression of p53 in Hodgkin's disease: Lack of correlation with Epstein–Barr virus infection

Recent work has shown that p53 gene mutations are frequently found in Epstein-Barr virus (EBV)-positive and EBV-negative cases of Burkitt's lymphoma but not in EBV-associated undifferentiated nasopharyngeal carcinomas (NPCs). Similar viral gene expression patterns are observed in undifferentiated NPCs and in EBV-positive cases of Hodgkin's disease (HD), suggesting that the contribution of the virus to the pathogenesis of these malignancies may also be similar. We have analysed 116 cases of HD for EBV association and for immunohistologically detectable overexpression of p53. p53 overexpression was detected in the tumour cell population of 37 (32 per cent) of the cases. Fifteen cases showed p53-specific labelling of more than 40 per cent of tumour cells; in six of these, virtually all tumour cells were stained. In eight cases, between 5 and 40 per cent of tumour cells were labelled, and in another 14 cases, less than 5 per cent of tumour cells expressed detectable amounts of p53. EBV-positive HD cases were found in all groups with different levels of p53 overexpression as well as amongst p53-negative cases. While a more detailed analysis of the p53 gene in HD is required, these data show that overexpression of p53 in HD is heterogeneous and that there is no simple correlation between EBV infection and p53 overexpression.     

Chromosome 11 copy number gains and Epstein-Barr virus-associated malignancies.

Epstein-Barr virus (EBV) genome can be found in many malignant tumors in China. Previous data of interphase cytogenetics, by comparative genomic hybridization and/or fluorescence in situ hybridization, on nasopharyngeal carcinomas and natural killer cell-type non-Hodgkin lymphomas in Hong Kong have noted gains in chromosome 11. This study compares the frequency of chromosome 11 copy number gains in three different types of EBV-associated tumors in Hong Kong. Using alpha-satellite probes, the authors studied by fluorescence in situ hybridization 31 EBV-positive tumors comprising 10 EBV-positive gastric carcinomas, 8 lung lymphoepithelioma-like carcinomas, and 13 non-Hodgkin lymphomas. Trisomy or polysomy 11 was detected in 10 of 10 (100%) EBV-positive gastric carcinomas, 6 of 8 (75%) lung lymphoepithelioma-like carcinomas, and 4 of 13 (30.8%) non-Hodgkin lymphomas. Compared with the EBV-positive gastric carcinomas, the 10 EBV-negative gastric carcinomas that were also studied showed chromosome 11 copy number gains in 3 of 10 (30%), a significantly lower frequency. The authors conclude that gains in chromosome 11 are common in EBV-associated malignancies in Hong Kong, with the strongest association found in gastric carcinoma. There seems to be differences between EBV-associated tumors of different locations, and between gastric carcinomas with and without EBV.     

Epstein-Barr virus-specific antibodies in Epstein-Barr virus-positive and -negative gastric carcinoma cases in Japan

We examined Epstein-Barr virus (EBV)-specific antibodies in serum samples from 64 and 59 patients with EBV-positive and -negative gastric carcinomas, respectively, and 73 healthy controls using immunofluorescence assays. EBV capsid antigen (VCA) IgG and EBV-determined nuclear antigen (EBNA) IgG were detected in all 196 subjects. The geometric mean titer (GMT) of VCA-IgG, but not EBNA-IgG, was higher in EBV-positive carcinoma cases than in EBV-negative carcinoma cases (P < 0.001). The seroprevalence rates of VCA-IgA and EBV early antigen (EA) IgG were higher in EBV-positive carcinoma cases than in EBV-negative carcinoma cases. Odds ratios (ORs) comparing seroprevalence rates between EBV-positive and -negative carcinoma cases were 3.4 (95% confidence interval [CI] = 1.3-8.8) and 6.6 (95% CI = 2.7-16.3) for VCA-IgA and EA-IgG, respectively. These results suggest that EBV reactivation occurs in vivo, since more than 90% of Japanese are infected with EBV in early childhood. The GMT of VCA-IgG in EBV-negative carcinoma cases was higher than that of healthy controls (P = 0.028). The seroprevalence rates of EA-IgG were greater in EBV-negative carcinoma cases than in healthy controls (OR = 4.9, 95% CI = 1.2-19. 7). VCA-IgA was the only antibody that showed a significantly high seroprevalence and GMT in EBV-positive carcinoma cases, but not in EBV-negative carcinoma cases. Thus, VCA-IgA can be a marker of immune response to EBV in EBV-positive carcinoma cases. Our findings support the hypothesis that if EBV is involved in the development of EBV-positive gastric carcinoma, the EBV reactivation occurs in vivo.     

A case of gastric cancer with heterogeneous components of EB virus (+)/TP53 (+) and EB virus (-)/TP53 (-)

Epstein-Barr virus (EBV)-associated gastric adenocarcinoma is a histological subtype of gastric adenocarcinoma, in which all of the carcinoma cells are basically positive for EBV-encoded small RNA (EBER) by in situ hybridization. Although its typical histology has some overlap with gastric carcinoma with lymphoid stroma, absence of massive lymphoid infiltrate is sometimes observed either in whole or in part. EBV-associated adenocarcinoma is one of the four representative molecular pathological subtypes recently identified by comprehensive genomic analysis of gastric adenocarcinomas. According to the analysis, typical EBV-associated gastric adenocarcinoma constitutes an independent molecular pathological subgroup, which is mutually exclusive to TP53-mutated adenocarcinoma with chromosomal instability, another molecular pathological subtype in gastric adenocarcinomas. Here, we report a rare case of gastric cancer heterogeneously composed of EBER (+)/TP53 (+) and EBER (-)/TP53 (-) portions. The EBER (+)/TP53 (+) component with massive lymphoid infiltrate surrounded the EBER (-)/TP53 (-) component showing well to moderately differentiated tubular adenocarcinoma. Although collision of two independent gastric cancers could be the simplest and most possible explanation for this situation, we discussed another possibility. In the case of gastric collision tumors, concurrent development of EBER (+) gastric adenocarcinomas and EBER (-) gastric adenocarcinomas in a single stomach is a rare incident. Since presence of the EBER (+)/TP53 (+) tumor component is atypical in itself, we also discussed the mechanism of development of the clone.     

Different roles of p53 between Epstein-Barr virus-positive and -negative gastric carcinomas of matched histology

To clarify the role of p53 in the development of Epstein-Barr virus (EBV)-associated gastric carcinoma, we examined DNA-ploidy pattern, the immunoreactivity of p53, p21(WAF1) and Ki-67 and the incidence of mitosis and apoptosis in EBV-positive and -negative gastric carcinomas of similar histology: a lace pattern and/or gastric carcinoma with lymphoid stroma. There was no significant difference in DNA-ploidy pattern, Ki-67 index or frequencies of mitosis and apoptosis between the two groups. In deeply invasive tumours (involving the muscularis propria or deeper), p53-positive ones were rare in the EBV-encoded small RNA (EBER)-positive group and very common in the EBER-negative group, while in superficial tumours, around one-half of them were p53-positive in both groups. In p53-positive superficial tumours, p21(WAF1)-positive ones accounted for 80% in the EBER-positive group and were scarce in the EBER-negative group. It is thus possible that p53 immunoreactivity reflects the overexpression of wild-type p53 and the stabilization of mutant p53 in the EBER-positive and -negative groups, respectively. The role of p53 in tumour development seems to be smaller in EBER-positive than in -negative gastric carcinomas.     

Epstein Barr virus-associated tumours: an update for the attention of the working pathologist

Epstein-Barr virus (EBV) is a herpesvirus associated with approximately 1% of tumours worldwide. EBV is the epitome of B lymphotropic viruses, but the spectrum of tumours it is associated with extends to T lymphocyte and NK cell malignancies, various types of carcinomas and smooth muscle tumours. Ubiquitous EBV infection in humans implies that most individuals carry EBV-infected cells. Therefore, mere detection of the virus in individuals with a tumour is not sufficient for establishing a causal relationship between both events, but instead requires unequivocal detection of viral nucleic acids or viral proteins in the tumour cells. Recent controversies about EBV infection in several carcinomas mainly resulted from such technical issues. The gold standard remains in situ EBER detection, but detection of EBNA1 would be an interesting alternative. EBV detection can be helpful for diagnostic, prognostic and therapeutic purposes. The rate of EBV association with entities such as NK/T cell tumours of the nasal type is so high that absence of detection of the virus in such a lesion should cast doubt of the accuracy of the diagnosis. Similarly, diagnosis of EBV-associated follicular pseudo-tumour obviously requires detection of the virus. EBV-positive common gastric adenocarcinomas seem to have a better prognosis than their EBV-negative counterparts and identification of the virus in B cell lymphoproliferations in immunocompromised individuals will guide therapeutic options. In conclusion, EBV-associated tumours are common enough to be relevant for the pathologist in everyday practice, but there is a need to facilitate detection of the virus (eg EBNA1 antibody).     

Association of Epstein-Barr virus with gastric carcinoma with lymphoid stroma.

Epstein-Barr virus (EBV) has been detected in lymphoepithelioma of nasopharynx and lymphoepitheliomalike carcinomas in various organs. To clarify the association of EBV with gastric carcinoma with lymphoid stroma, which often resembles lymphoepithelioma, the authors examined 22 such cases by polymerase chain reaction and in situ hybridization techniques. In 18 informative cases, EBV DNA was detected by polymerase chain reaction in 14 (77.8%) cases, including lymph node metastases. EBV RNA was detected within the nuclei of carcinoma cells by in situ hybridization in all cases that were positive by polymerase chain reaction. Infiltrating lymphocytes and normal epithelia adjacent to carcinoma were EBV-negative. Southern blot analysis indicated clonal proliferation of tumor cells and episomal form of EBV. These findings suggest that EBV infection occurs before transformation and may be related to oncogenesis of EBV-associated gastric carcinoma.     

广州地区EB病毒相关胃癌的临床病理特征及相关分子表达

目的 观察鼻咽癌高发区广州地区EB病毒相关胃癌的构成比、临床病理特征、EB病毒的潜伏类型,并初步探讨DNMT1、p16和cyclin D1在发病过程中的作用.方法 对676例胃癌采用组织芯片和EBER1原位杂交的方法筛选EB病毒相关胃癌,并用免疫组织化学EnVision法检测EB病毒潜伏期膜蛋白(LMP)和DNMT1、p16和cyclin D1的表达.结果 在676例胃癌中,45例EB病毒阳性(6.7%),EB病毒相关胃癌以男性为主,主要发生在胃的中上2/3,以弥漫型多见(P＜0.05).EBNA1和LMP2A的阳性例数分别为42例(93.3%)和24例(53.3%),EBNA2、LMP1和ZEBRA均未见表达.DNMT1、p16和cyclin D1在45例EB病毒相关胃癌的阳性例数分别为35例(77.8%)、10例(22.2%)和29例(64.4%),在40例EB病毒阴性胃癌的阳性例数分别为20例(50.0%)、25例(62.5%)和12例(30.0%),3个分子在两组胃癌的表达率差异均具有统计学意义(P＜0.05).p16与肿瘤的浸润深度有关(P＜0.05).LMP2A与DNMT1、DNMT1与p16、p16与cyclin D1存在相关关系(P＜0.05).结论 广州地区EB病毒相关胃癌占胃癌构成比的6.7%(45/676),EB病毒的潜伏类型部分为Ⅰ型,部分介于Ⅰ型和Ⅱ型之间.LMP2A、DNMT1、p16和cyclin D1的相互作用在EB病毒相关胃癌发生过程中起着重要的作用.     

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

Unlike gastric carcinoma, associations of the Epstein-Barr virus (EBV) with carcinomas of other sites in the gastrointestinal tract have not yet been clarified. To elucidate these associations, we investigated the presence of EBV in 142 cases of esophageal carcinoma, 107 cases of ampulla of Vater carcinoma, and 274 cases of colorectal carcinoma in Korean patients using EBV-encoded small RNAs (EBER)-in situ hybridization (ISH). In all cases, none of the tumor cells showed a positive signal, indicating that EBV is not generally related to the carcinogenesis of these cancers. Some EBV-positive tumor-infiltrating lymphocytes (TILs) were found in 8 of 142 cases (5.6%) of esophageal carcinoma, 8 of 107 cases (7.5%) of ampulla of Vater cancer, and 35 of 274 cases (12.8%) of colorectal carcinoma. For comparison, EBER-ISH was performed in consecutive gastric carcinomas; the EBER signal on tumor cells was observed in 17 of 306 cases (5.6%), and EBV-positive TILs were seen in 31 of the 289 cases (10.7%). There was no statistically significant difference in the frequencies of cases with EBV-positive TILs among the gastrointestinal tract cancers. We suggest that the reservoir lymphocytes carrying EBV, like other inflammatory cells, are able to reach anywhere, and that the chance for an epithelial cell to be exposed to EBV is similar at different sites of the gastrointestinal tract, regardless of its carcinogenic effect on the epithelial cell. HUM PATHOL 32:297-301.     

Epstein-Barr virus infection and its gene expression in gastric lymphoma of mucosa-associated lymphoid tissue

The role of Epstein-Barr virus (EBV) in the pathogenesis of gastric lymphoma of mucosa-associated lymphoid tissue (MALT) has not been well understood. The aim of the study was to investigate EBV infection and its gene expression in this tumor in order to understand its role in the pathogenesis. EBV infection was screened by in situ hybridization for EBV-encoded nonpolyadenylated RNA (EBER ISH) in 79 cases of gastric MALT lymphoma of nonimmunocompromised patients. The expression of EBV proteins [LMP1 (latent membrane protein 1), EBNA2 (EBV nuclear antigen 2), ZEBRA (switch protein encoded by BZLF1 gene)] was studied by immunohistochemistry in EBER-positive cases. EBV was detected with EBER ISH in 15 (19%) of the 79 cases. EBV was found in virtually all tumor cells in 2 cases of high-grade MALT lymphoma (2.5%) (EBV-associated), and was found only in occasional large or small lymphoid cells in 13 cases (16.5%). False positive EBER signal was detected in the mucinous glandular epithelial cells of gastric antrum with FITC-labeled oligonucleotide probe but not with digoxigenin or ³⁵S-labeled riboprobes. Type II latency (EBER+LMP1+ EBNA2-) was detected in both EBV-associated cases. Type III latency (EBER+LMP1+EBNA2+) was also identified in one EBV-associated case besides latency II. Double labeling showed coexpression of LMP1 and EBNA2 in a small number of tumor cells, indicating the presence of type III latency in single cell level. In cases with only occasional EBER-positive large or small lymphoid cells, LMP1 and EBNA2 were not detected. ZEBRA was negative in all the cases. These findings suggest that EBV may contribute to the pathogenesis of a small proportion of high-grade MALT lymphoma, where virtually all tumor cells harbored EBV and the oncogenic viral protein LMP1 was expressed. Moreover, latency III of EBV infection may exist in nonimmunocompromised patient. J. Med. Virol. 56:342–350, 1998 . © 1998 Wiley-Liss, Inc.     

The antibody 2B4 directed against the Epstein-Barr virus (EBV)-encoded nuclear antigen 1 (EBNA1) detects MAGE-4: implications for studies on the EBV association of human cancers

We have previously developed two monoclonal antibodies against the Epstein-Barr Virus (EBV) nuclear antigen 1 (EBNA1), designated 1H4 and 2B4. Both detect EBNA1 by in situ staining in established EBV-positive tumours, e.g. Hodgkin's lymphoma and nasopharyngeal carcinoma. An association of EBV with other tumours, notably breast carcinomas, has been reported but remains controversial. Using the antibody 2B4, a nuclear protein has been detected in breast carcinomas that were EBV-negative by other methods, suggesting cross-reactivity with a cellular protein. Furthermore, an association of EBV with various other carcinomas has been reported on the basis of 2B4 immunohistochemistry. Here we show that 2B4 also binds to MAGE-4, a cancer testis antigen expressed in a variety of tumour cells, including breast carcinoma, seminoma and EBV-negative cases of Hodgkin's lymphoma. We conclude that the 2B4 antibody is not suitable for the detection of EBV infection but that additional techniques, particularly in situ hybridization for the detection of the EBV-encoded RNAs (EBERs), should be employed to confirm the presence of EBV. Our results add to the evidence indicating that breast cancer is not an EBV-associated disease.     

Epstein-Barr virus LMP1 modulates the malignant potential of gastric carcinoma cells involving apoptosis.

About 10% of gastric carcinomas including lymphoepithelioma-like carcinoma and adenocarcinoma are associated with Epstein-Barr virus (EBV) infection. In EBV-associated gastric carcinomas, the tumor cells express Epstein-Barr nuclear antigen 1 (EBNA-1) but not EBNA-2, -3A, -3B, or -3C, leader protein, or latent membrane proteins (LMPs) because of gene methylation. Only a few exceptional cases have LMP1 expression in tumor cells as demonstrated by immunohistochemical studies. To elucidate the biological effects of LMP1 and the significance of its restricted expression in EBV-associated gastric carcinomas, the LMP1 gene was transferred into EBV-negative gastric carcinoma cell lines (SCM1 and TMC1) and into EBV-negative nasopharyngeal carcinoma (NPC) cells (HONE-1) as a control. The biological effects of LMP1 in gastric carcinoma cells were monitored in vitro and in vivo. These results showed that the consequence of LMP1 expression is a growth enhancement in NPC cells, but it is a growth suppression in gastric carcinoma cells. The LMP1-expressing gastric carcinoma cells had a reduced growth rate, colony-forming efficiency, mean colony size, and tumorigenicity and a lower malignant cytological grade. The reduced growth rate, colony-forming efficiency, and mean colony size were partially reversible in vitro with treatment with LMP1 antisense oligonucleotide. In addition, enhanced apoptosis was found in the LMP1-expressing gastric carcinoma cells. This suggests that LMP1 may negatively modulate the malignant potential of gastric carcinoma cells via an enhancement of apoptosis. We concluded that the restriction of LMP1 expression in EBV-associated gastric carcinomas may lead to a growth advantage for tumor cells by avoiding LMP1 apoptotic effects and immunologically mediated elimination.