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

Is gastric lymphoepithelioma-like carcinoma a special subtype of EBV-associated gastric carcinoma? New insight based on clinicopathological features and EBV genome polymorphisms

BACKGROUND

Gastric lymphoepithelioma-like carcinoma (LELC) is a rare entity that is closely associated with Epstein-Barr virus (EBV). However, the EBV latency pattern and genome polymorphisms in gastric LELC have not been systematically explored.

METHODS

The clinicopathological features, EBV latency pattern and genome polymorphisms of EBV-positive gastric LELC in Guangzhou, southern China were investigated and compared with those of ordinary EBV-associated gastric carcinoma (EBVaGC) in the same area.

RESULTS

Ten (1.42%) of 702 gastric carcinoma cases were identified as gastric LELC, in which eight (80%) cases were EBV-positive. The clinicopathological characteristics and EBV latency pattern of EBV-positive gastric LELC were similar to those of ordinary EBVaGC. In EBV genotype analysis, type A strain, type F, I, mut-W1/I, XhoI- and del-LMP1 variants were predominant among EBV-positive gastric LELCs, accounting for eight (100%), six (75%), eight (100%), seven (87.5%), five (62.5%) and six (75%) cases, respectively, which are similar to those in ordinary EBVaGC. For EBNA1 polymorphisms, the V-leu and P-ala subtypes were predominant in EBV-positive gastric LELC, which is different from the predominant V-val subtype in ordinary EBVaGC. EBV-positive gastric LELC has a favorable prognosis when compared to ordinary EBVaGC (median survival time 43.0 vs. 18.0 months).

CONCLUSIONS

Gastric LELC is strongly associated with EBV and EBV-positive gastric LELC should be regarded as a special subtype of EBVaGC. This, to our best knowledge, is the first time in the world that the EBV latency pattern and genome polymorphisms of EBV-positive gastric LELC are systematically revealed.

Microsatellite instability and survival in gastric cancer: A systematic review and meta-analysis

Microsatellite instability (MSI) is associated with the prognosis in several cancers and is used for determination of the chemotherapy regimen in stage II colon cancer in the National Comprehensive Cancer Network guideline. However, the association between MSI and the prognosis of gastric cancer remains unclear. PubMed database was searched until January 2014 using MeSH terms and key words to identify the studies evaluating MSI and prognosis of gastric cancer and the references were manually searched. The main outcome was the overall survival rate and the subordinate outcome was the association between high-frequency MSI (MSI-H) and clinicopathological characteristics. Eight studies met the inclusion criteria and the majority of data were collected retrospectively. There were 1,976 patients, 431 of which were MSI-H patients, with a range of 11.68-33.82%. Four studies used the National Cancer Institute panel to define MSI-H, the other four had microsatellite markers ranging 2-11. Significant associations were found in three studies and the overall summary estimate was hazard ratio, 0.63 (95% confidence interval, 0.52-0.77), with no evidence of inter-study heterogeneity (I²=0.0%). MSI-H patients were identified to have a tendency to have less lymph node (LN) metastasis, superficial tumor invasion and to be intestinal type. In conclusion, MSI-H gastric cancers have an improved prognosis, accompanied with reduced risk of LN metastasis, tumor invasion and mortality.

Thyroid carcinoma showing thymus-like elements: a clinicopathologic, immunohistochemical, ultrastructural, and molecular analysis

OBJECTIVES

To investigate the clinicopathologic, immunophenotypic, ultrastructural, and molecular features of thyroid carcinoma showing thymus-like elements (CASTLE).

METHODS

We retrospectively analyzed the clinicopathologic data of 10 patients with CASTLE and described the immunophenotypic and ultrastructural features of these tumors. The expression of Epstein-Barr virus-encoded RNA and the gene status of EGFR, C-KIT, and HER-2 were also assessed by molecular techniques.

RESULTS

The tumor cells were positive for CD5, CD117, p63, HMWK, EGFR, GLUT-1, Pax8, E-cadherin, bcl-2, and p53 in all cases and for CA-IX, CEA, p16, HER-2, and neuroendocrine markers in some cases. Ultrastructural examination indicated that the tumor cells contained large quantities of tonofilament with abundant intercellular desmosomes, including intracytoplasmic neuroendocrine granules in one case. EGFR gene amplification in two patients and polyploidy of chromosome 7 in one patient were identified by fluorescence in situ hybridization. Sequencing analysis revealed that a synonymous mutation, Q787Q 2363 (G→A), occurred on exon 20 of the EGFR gene in three patients.

CONCLUSIONS

GLUT-1 can be used as a novel biomarker for CASTLE, and combined detection of GLUT-1 with CD5 and CD117 aids in the diagnosis of this tumor. Aberrant expression of Bcl-2, p53, p16, E-cadherin, EGFR, C-KIT, and HER-2 may play important roles in the development of CASTLE.

Lymphoepithelioma-like carcinoma: a distinct type of gastric cancer

BACKGROUND

Lymphoepithelioma-like carcinoma (LELC) is a rare type of gastric carcinoma and has histologic features of intense lymphocytic infiltration. In this study, we attempted to analyze the clinicopathologic characteristics and survival outcome of patients with LELC compared with those with non-lymphoepithelioma-like carcinoma (NLELC).

METHODS

We studied 4282 patients who underwent gastrectomies to treat gastric cancer at the Department of Surgery of the Samsung Medical Center in Seoul, between January 2008 and December 2010. The clinicopathologic features and clinical outcomes of patients with LELC (n = 46) were compared with those with NLELC (n = 4236). In situ hybridization for Epstein-Barr virus (EBV) positivity was performed on the tissue of patients with LELC (n = 46) and NLELC (n = 1247).

RESULTS

The patients with LELC are male predominant and had more upper locations, more indeterminate Lauren classifications, lower T stages, less lymphatic invasion, and more positive EBV in situ hybridization compared with those of the NLELC group (80.4% versus 6.5%). Age, histologic type, Lauren type, the location of the tumor, the depth of the invasion, lymph node metastasis, and venous invasion were independent prognostic factors; however, the LELC type itself was not predictive of outcome. The 5-y survival rate of the LELC group (97.7%) was better than that of the NLELC group (89.4%); however, this difference was not statistically significant (P = 0.127).

CONCLUSIONS

The results of our study suggest that LELC is a less advanced disease than NLELC in terms of depth of invasion and lymphatic invasion at diagnosis. However, our study does not examine LELC as an independent prognostic factor of gastric cancer. Further studies are needed to explore its associations with EBV and a distinct pathway of carcinogenesis from NLELC.

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

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

Is microsatellite instability a prognostic marker in gastric cancer? A systematic review with meta-analysis

BACKGROUND AND OBJECTIVE

The relationship between survival in gastric cancer patients and the status of microsatellite instability (MSI) has not yet been established. The purpose of this meta-analysis was to obtain integrated and more precise data for the value of MSI as a prognostic marker in gastric cancer.

METHODS

A comprehensive systematic review and meta-analysis were conducted using major electronic databases (PubMed, EMBASE, and the Cochrane Central) with keywords related to "microsatellite instability," "gastric cancer," and "prognosis."

RESULTS

Twenty-four studies with 5,438 participants (712 cases were MSI gastric cancer) were included for pooling risk estimates of MSI in gastric cancer. Seventeen studies reported overall survival. The pooled hazard ratio (HR) for overall survival of MSI vs. non-MSI was 0.72 (95%CI: 0.59-0.88, P = .001) in a random-effects model. In the sensitivity analysis, the result from the most recent study showed the most heterogeneity.

CONCLUSION

MSI gastric cancer was associated with good prognosis but there was heterogeneity in the recent studies. Changed epidemiology and effects of chemotherapy are potential causes of heterogeneity. Establishing a consensus for defining MSI in gastric cancer should be preferred for future studies.

Epstein-Barr Virus Associated Lymphoepithelioma-like Carcinoma at the Lesser Curvature of the Upper Gastric Body: A Case Report

Lymphoepithelioma-like gastric carcinoma (LELGC) is a rare neoplasm of the stomach with dense lymphocytic infiltration. More than 80% of LELGCs are positive for the Epstein-Barr virus (EBV). Here, we report a 64-year old Chinese man with swallowing discomfort while eating food. Endoscopy and computed tomography both showed a submucosal lesion at the lesser curvature of the upper gastric body. The first diagnostic impression was a gastrointestinal stromal tumour. Subsequently, the patient received a wedge resection of the stomach. On histopathological examination, the tumour was found to consist of small nests of neoplastic cells within dense lymphocytic infiltration. Additionally, most of the neoplastic cells were positive for cytokeratin and Epstein-Barr virus-encoded RNA (EBER). Subsequently, the diagnosis of LELGC was made. We believe that physicians should be aware of the diagnosis of submucosal gastric lesions, particularly in older male patients.

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

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

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

The contribution of cell phenotype to the behavior of gastric cancer

BACKGROUND

Several histochemical studies suggest a role of tumor cell phenotype and related differentiation markers in the prognostic assessment of gastric cancer. Unfortunately, most studies have dealt with single or a few markers and have paid limited attention to their interplay with tumor histological types, which are potentially informative of prognosis.

METHODS

In this study, 292 invasive (T1b to T4) gastric cancers with prolonged follow-up and carefully analyzed histotype, inclusive of histotype-based grade, were investigated histochemically with a panel of 14 phenotypic markers known to be expressed in normal gut tissues and gastric cancer.

RESULTS

Three of seven intestinal type markers investigated showed a trend for improved prognosis, one of which, CDX2, was stage independent. Three among gastric and pancreatobiliary duct markers (MUC1, MUC6, and pepsinogen II), predicted more severe prognosis stage independently, as did a combination of eight potentially informative (p < 0.1 at univariable Cox analysis) markers. Cancers with predominantly intestinal phenotype had significantly better prognosis than those with predominantly gastric, mixed, or poorly defined phenotypes; among the latter, those with high lymphocyte response, with favorable outcome, were separated from anaplastic cancers, with ominous prognosis. At multivariable analysis, CDX2 and the eight marker combination proved to be stage- and grade-independent predictors.

CONCLUSIONS

When individually considered, and with the exception of CDX2, the biomarkers investigated gave an appreciable, although moderate, contribution to the prognostic evaluation of gastric cancer. Combined analysis of all potentially informative markers gave more important information, highly additive to both stage and histotype-based grade.

Non-Epstein-Barr virus associated lymphoepithelioma-like carcinoma of the esophagogastric junction with microsatellite instability, K-ras wild type

A 60-year-old male was admitted to our hospital for gastric cancer. Considering his general condition, total gastrectomy and dissection of regional lymph nodes were performed. Macroscopically, a 45 mm × 20 mm × 10 mm-sized, ulcero-infiltrative tumor located in the esophagogastric junction was described. Microscopically, the tumor consisted of a poorly differentiated adenocarcinoma intermingled with dense lymphoid infiltration predominantly composed of T-cell lymphocytes. The tumor cells infiltrated the submucosa, muscularis and subserosal layers of the stomach, respectively the esophageal adventitia. No metastases were noticed in the 58 regional lymph nodes. Based on the histopathological features, the diagnosis was lymphoepithelioma-like carcinoma, pT3N0 stage. In situ hybridization for Epstein-Barr virus showed no nuclear signal in tumor cells. The p53 expression was observed in fewer than 10% of the tumor cells. Real-time PCR analysis showed microsatellite instability without K-ras mutation in codon 12. No recurrences or metastases were reported 6 months after surgical intervention. No adjuvant therapy was performed.

Gastric cancer: Classification, histology and application of molecular pathology

Gastric cancer remains one of the deadly diseases with poor prognosis. New classification of gastric cancers based on histologic features, genotypes and molecular phenotypes helps better understand the characteristics of each subtype, and improve early diagnosis, prevention and treatment. The objective of this article is to review the new classification of gastric cancers and the up-to-date guidance in the application of molecular testing.

ARID1A expression loss in gastric cancer: pathway-dependent roles with and without Epstein-Barr virus infection and microsatellite instability

The AT-rich interactive domain 1A gene (ARID1A), which encodes one of the subunits in the Switch/Sucrose Nonfermentable chromatin remodeling complex, carries mutations and is responsible for loss of protein expression in gastric carcinoma, particularly with Epstein-Barr virus (EBV) infection and a microsatellite instability-high phenotype. We used immunohistochemistry to investigate the significance of ARID1A loss in 857 gastric carcinoma cases, including 67 EBV(+) and 136 MLH1-lost gastric carcinomas (corresponding to a microsatellite instability-high phenotype). Loss of ARID1A expression was significantly more frequent in EBV(+) (23/67; 34 %) and MLH1-lost (40/136; 29 %) gastric carcinomas than in EBV(-)MLH1-preserved (32/657; 5 %) gastric carcinomas (P < 0.01). Loss of ARID1A correlated with larger tumor size, advanced invasion depth, lymph node metastasis, and poor prognosis in EBV(-)MLH1-preserved gastric carcinoma. A correlation was found only with tumor size and diffuse-type histology in MLH1-lost gastric carcinoma, but no correlation was observed in EBV(+) gastric carcinoma. Loss of ARID1A expression in EBV(+) gastric carcinoma was highly frequent in the early stage of gastric carcinoma, although EBV infection did not cause downregulation of ARID1A: EBV-positive nasopharyngeal carcinomas (n = 8) and lymphomas (n = 15) failed to show loss of ARID1A, and EBV infection did not cause loss of ARID1A in gastric carcinoma cell lines. Taken together, loss of ARID1A may be an early change in carcinogenesis and may precede EBV infection in gastric epithelial cells, while loss of ARID1A promotes cancer progression in gastric cancer cells without EBV infection or loss of MLH1 expression. Loss of ARID1A has different and pathway-dependent roles in gastric carcinoma.

Histotype-based prognostic classification of gastric cancer

AIM: To test the efficiency of a recently proposed histotype-based grading system in a consecutive series of gastric cancers.

METHODS: Two hundred advanced gastric cancers operated upon in 1980-1987 and followed for a median 159 mo were investigated on hematoxylin-eosin-stained sections to identify low-grade [muconodular, well differentiated tubular, diffuse desmoplastic and high lymphoid response (HLR)], high-grade (anaplastic and mucinous invasive) and intermediate-grade (ordinary cohesive, diffuse and mucinous) cancers, in parallel with a previously investigated series of 292 cases. In addition, immunohistochemical analyses for CD8, CD11 and HLA-DR antigens, pancytokeratin and podoplanin, as well as immunohistochemical and molecular tests for microsatellite DNA instability and in situ hybridization for the Epstein-Barr virus (EBV) EBER1 gene were performed. Patient survival was assessed with death rates per 100 person-years and with Kaplan-Meier or Cox model estimates.

RESULTS: Collectively, the four low-grade histotypes accounted for 22% and the two high-grade histotypes for 7% of the consecutive cancers investigated, while the remaining 71% of cases were intermediate-grade cancers, with highly significant, stage-independent, survival differences among the three tumor grades (P = 0.004 for grade 1 vs 2 and P = 0.0019 for grade 2 vs grade 3), thus confirming the results in the original series. A combined analysis of 492 cases showed an improved prognostic value of histotype-based grading compared with the Lauren classification. In addition, it allowed better characterization of rare histotypes, particularly the three subsets of prognostically different mucinous neoplasms, of which 10 ordinary mucinous cancers showed stage-inclusive survival worse than that of 20 muconodular (P = 0.037) and better than that of 21 high-grade (P < 0.001) cases. Tumors with high-level microsatellite DNA instability (MSI-H) or EBV infection, together with a third subset negative for both conditions, formed the T8 cell-rich HLR group, the largest group among low-grade histotypes. Coexisting HLR proved to be a factor in improved prognosis in tumors with microsatellite instability (P = 0.0015 vs HLR-/MSI-H tumors) or DR type human leukocyte antigen expression (P = 0.033 vs HLR^-/HLA-DR⁺ tumors).

CONCLUSION: Identification of low- and high-grade histotypes can improve the prognostic assessment of a substantial proportion of gastric cancers in routine diagnostic practice.

Epstein-Barr virus-associated gastric carcinoma

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

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

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

Correlation between genomic alterations assessed by array comparative genomic hybridization, prognostically informative histologic subtype, stage, and patient survival in gastric cancer

It is difficult to evaluate the prognostic value of histologic criteria in gastric cancer because of the high variability of morphologic patterns. Recently, histologic subtypes of low, intermediate, or high malignant potential have been identified, providing the basis for a prognostically informative grading system. Because array comparative genomic hybridization systems allow systematic analysis of chromosome alterations, which may be prognostically and pathogenetically informative, we applied high-resolution genome-wide array comparative genomic hybridization to archival material from 81 gastric cancer cases followed for a median of 150 months after surgery. The DNA extracted from paraffin sections gave useful results in 49 tumors, 18 of which were of low-grade, 24 of intermediate, and 7 of high-grade histotypes. Based on the number of chromosome aberrations and the presence/absence of amplifications, 3 tumor clusters of increasing genomic lesion severity were constructed, which proved to correlate significantly with histologic grade and stage as well as with patient survival. Further investigation documented the lower number and severity of genomic alterations in tumors with microsatellite DNA instability and high CD8-rich lymphoid response; the close association of 8p23.1 amplification with cardial cancer; the frequent amplification of genes involved in cell renewal (CDC6, HER2, GRB7, IGFBP4) at 17q12-q21.1, with close histochemical correlation with HER2 membranous expression; and more sporadic amplification of chromosome regions harboring important oncogenes like MYC, KRAS, NRAS, CRKL, CCNE1, or ZNF217. We conclude that genome-wide array comparative genomic hybridization of gastric cancer contributes prognostically relevant information providing a genetic background for histologic grading.

High microsatellite instability predicts good prognosis in intestinal-type gastric cancers

BACKGROUND AND AIM

A subset of gastric cancers showed high microsatellite instability (MSI-H). The reported clinicopathological features of MSI-H gastric cancers are heterogeneous, and specific factors associated with prognosis have not been identified.

METHODS

We analyzed the clinicopathological characteristics and prognostic factors in a large series (161 cases) of MSI-H gastric cancers, and compared the results to 315 cases of microsatellite-stable or low microsatellite-instable gastric cancers.

RESULTS

The frequency of MSI-H gastric cancers was 9% (161/1786). MSI-H gastric cancers have distinct clinicopathological features, including female sex, older age, antral location, well-to-moderate differentiation, intestinal-type Lauren classification, expanding-type Ming classification, a non-signet-ring cell component, the presence of a mucinous component, a moderate-to-severe lymphoid stromal reaction, and a lower tumor stage. The MSI-H phenotype was associated with better prognosis (P = 0.044), and male sex (P = 0.035, hazard ratios [HR]: 0.23), intestinal-/mixed-type Lauren classification (P < 0.001, HR: 0.09) and lower tumor stages (1 and 2, P = 0.001, HR: 0.08) were independently-favorable prognostic factors.

CONCLUSIONS

With unique clinicopathological features, intestinal-type MSI-H gastric cancers are associated with good prognosis and can be classified as a different subset of gastric cancers.

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

BACKGROUND & AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND & AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

A combined histologic and molecular approach identifies three groups of gastric cancer with different prognosis

The limited prognostic value of currently used histologic classifications of gastric cancer and their failure to account for the complexity of the disease as revealed by more recent investigations prompted a combined reinvestigation of histologic, molecular, and clinicopathologic patterns in 294 extensively sampled, invasive gastric cancers representing all main histotypes and stages of the disease and followed for a median of 150 months. Among histologic parameters tested, only cellular atypia, angio-lympho- or neuroinvasion, Ki67 proliferation index, expansile/infiltrative type growth, and T8 cell-rich high lymphoid intra-/peritumor response (HLR) proved to be stage-independent predictors of patient survival. Among molecular tests, p53 gene exon 7 (loop 3) and 8 (loop-sheet-helix motif and S-10 band), but not p53 protein overexpression, TP53 LOH or 18qLOH, were found to worsen prognosis. Microsatellite DNA instability was a favorable prognostic factor when coupled with HLR. Patient survival analysis of the main histotypes and their subtypes confirmed the favorable prognosis of HLR, well-differentiated tubular, muconodular, and low grade diffuse desmoplastic cancers, and highlighted the worse prognosis of anaplastic and infiltrative-lymphoinvasive mucinous cancers compared to ordinary cohesive and diffuse cancers. Distinct roles of individual morphologic and molecular factors in tumor progression of the different histotypes have been recognized. The combination of survival-predictive histotypes and individual histologic or molecular parameters allowed us to develop a classification of all gastric cancers into three grades of increasing malignancy which proved to be of high prognostic value.

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.

Epidermal growth factor receptor (EGFR) expression is associated with a worse prognosis in gastric cancer patients undergoing curative surgery

BACKGROUND

In gastric cancer, the recurrence rate is high even after curative surgery. A relevant issue is the identification of independent prognostic factors to select high-risk patients; such features can be used as predictive factors for tailored therapies. In this study we have investigated the role of epidermal growth factor receptor (EGFR) expression as a prognostic marker for predicting cancer behavior and clinical outcome in gastric cancer patients undergoing potentially curative surgery.

METHODS

Epidermal growth factor receptor determination using a commercially available immunohistochemistry (IHC) kit was performed in tissues from 82 gastric cancer patients receiving primary surgical treatment and in 25 normal gastric mucosa specimens from noncancer patients. The EGFR positivity was correlated with disease recurrence and survival in univariate and multivariate analyses.

RESULTS

Forty-four percent (36 cases) of gastric cancers were EGFR positive. In 66 curatively treated patients, EGFR expression correlated with disease recurrence and poorer survival in both univariate and multivariate analyses. In a multivariate model for predicting recurrence and survival, advanced tumor extension (T(3) or T(4)), nodal metastases, and EGFR expression were the only independent covariates. In particular, EGFR expression was shown to be a significant predictor of poor prognosis among gastric cancer patients having the same stage according to the current TNM staging system.

CONCLUSIONS

These findings suggest that EGFR expression may be useful in identifying high-risk gastric cancer patients undergoing potentially curative surgery. Multimodal treatments should be considered in the adjuvant treatment of these patients.

Expression of vascular endothelial growth factor (VEGF) and epidermal growth factor receptor (EGFR) is an independent prognostic indicator of worse outcome in gastric cancer patients

BACKGROUND

Unlike other human tumors, gastric cancer remains a great therapeutic challenge since no standardized postoperative treatment exists. Knowledge of molecular pathways determining the behavior of individual gastric tumors seems to be crucial for therapeutic decisions, and evaluation of vascular endothelial growth factor (VEGF) and epidermal growth factor receptor (EGFR) expression might be critical for prognosis, assessment, and identification of patients that could be treated with tailored therapies.

METHODS

VEGF and EGFR determination was performed in 88 gastric cancer samples as well as 25 normal gastric mucosa specimens from non-cancer patients using a commercially available immunohistochemistry kit. In all samples, the correlation of VEGF and EGFR expression was investigated with each other, and with other prognostic indicators in all samples, and, finally, with survival rates in 69 patients undergoing potentially curative surgery.

RESULTS

Forty-eight per cent (42 cases) of gastric cancers expressed VEGF, and 44% (39 cases) stained for EGFR. In curatively treated patients, VEGF and EGFR expression was demonstrated to correlate with worse survival in both univariate and multivariate analyses. Molecular profiling was shown to more accurately estimate the risk of cancer-related death than TNM stage, and, of most interest, to allow sorting out high-risk patients within the same stage.

CONCLUSIONS

These findings provide evidence that contemporary evaluation of VEGF and EGFR expression may be crucial to select gastric cancer patients with poor prognosis who may benefit of tailored treatments.

Elevated tumour interleukin-1beta is associated with systemic inflammation: A marker of reduced survival in gastro-oesophageal cancer

Systemic inflammation is associated with adverse prognosis cancer but its aetiology remains unclear. We investigated the expression of proinflammatory cytokines within normal mucosa from healthy controls and tumour tissue in cancer patients and related these levels with markers of systemic inflammation and with the presence of a tumour inflammatory infiltrate. Tissue was collected from 56 patients with gastro-oesophageal cancer and from 12 healthy controls. Tissue cytokine mRNA concentrations were measured by real-time PCR and tissue protein concentrations by cytometric bead array. The degree of chronic inflammatory cell infiltrate was recorded. Serum cytokine and acute phase protein concentrations (including C-reactive protein (CRP)) were measured by enzyme-linked immunosorbent assay. Proinflammatory cytokines were significantly overexpressed (interleukin (IL)-1β, IL-6, IL-8 and tumour necrosis factor-α) both at mRNA and protein levels in the cancer specimens compared with mucosa from controls. Interleukin-1β was expressed in greatest (10–100-fold) concentration and protein levels correlated significantly with systemic inflammation (CRP) (P=0.05, r=0.31). A chronic inflammatory infiltrate was observed in 75% of the cancer specimens and was associated with systemic inflammation (CRP: P=0.01). However, the presence of chronic inflammation per se was not associated with altered cytokine expression within the tumour. Both a chronic inflammatory infiltrate and systemic inflammation (CRP) were associated with reduced survival (P=0.05 and P=0.03, respectively). Tumour chronic inflammatory infiltrate and tumour tissue IL-1β overexpression are potential independent factors influencing systemic inflammation in oesophagogastric cancer patients.

p27 downregulation and metallothionein overexpression in gastric cancer patients are associated with a poor survival rate

BACKGROUND AND OBJECTIVES

As a significant number of curatively treated gastric cancer patients will ultimately relapse, there is an urgent need to investigate new prognostic markers for identification of high-risk patients. In this study, we investigated the possible role of molecular markers involved in cell cycle regulation (B1 and D3 cyclins, and p27) and cell protection (metallothionein, MT) in predicting tumor behavior and clinical outcome in gastric cancer patients.

METHODS

Analysis of the above indicators was performed by immunohistochemistry on 73 gastric cancer patient samples and 25 normal gastric mucosa specimens.

RESULTS

Normal gastric mucosa cells displayed low expressions of B1 and D3 cyclins and MT, and intense p27 staining. Conversely, gastric tumor cells showed higher cyclin D3 and MT, and lower p27 expressions. B1 cyclin expressions were not different between normal and tumor tissue. p27 and MT expressions were altered in almost all cancer samples, and were strongly correlated with tumor progression. Advanced extent of the primary tumor, nodal metastasis, low p27, and high MT expressions were the best combination of variables for prediction of poor clinical outcome. Each marker predicted outcome better than staging based on tumor-node (TNM) system. Survival and recurrence rates decreased as molecular alterations increased. Finally, molecular profile determination correctly predicted the prognosis in patients with same TNM stage.

CONCLUSIONS

p27 and MT expressions strongly correlated with clinical outcome allowing to identify an unfavorable group of patients that may benefit from tailored treatments. The role of B1 and D3 cyclins in gastric cancer remains to be elucidated.

Differences in genomic instability between intestinal- and diffuse-type gastric cancer

BACKGROUND

Microsatellite instability (MSI) and loss of heterozygosity (LOH) are lesions in the genome found with different frequencies in gastric carcinomas (GCAs). Despite a great body of studies, no systematic approach to the detailed classification of MSI and LOH in the two major types of GCA has been published.

METHODS

Thirty-seven advanced GCAs, 25 intestinal-type (IGCAs) and 12 diffuse-type (DGCAs), were assayed with 15 autosomal tetranucleotide markers on 14 chromosomal arms. The observed frequencies and types of microsatellite alterations allowed stratification into subgroups, i.e., high- and low-grade MSI (MSI-H, MSI-L) or microsatellite-stable (MSS), and high- or low-grade, or non-detectable LOH (LOH-H, LOH-L, LOH-N).

RESULTS

Collectively, the markers detected MSI-H tumors with sensitivity equal to that of BAT-26 (a single marker highly specific for MSI-H). Likewise, the markers detected LOH at chromosomal arms 5q, 18q, and 21q with a sensitivity equal to markers used previously. Seven (19%) MSI-H and six (16%) LOH-H tumors were found, with a significant association (P = 0.027) with IGCA: 92% of MSI-H and LOH-H occurred in IGCA patients only. Conversely, in DGCA, a significantly higher prevalence of a stable (LOH-N/MSS) phenotype was found as compared with IGCA (75.1% vs 28.0%; P = 0.035). The MSI-L phenotype was found in 57.9% of non-MSI-H IGCA tumors and was associated significantly (P = 0.015) with LOH-H.

CONCLUSION

A clear difference in genomic instability between IGCA and DGCA was found. In IGCA, the MSI and LOH pathways were more commonly involved, whereas in DGCA, a stable phenotype was predominant. As a novel finding, MSI-L as a true phenomenon and its association with LOH was observed in IGCA.

Intratumour T cells, their activation status and survival in gastric carcinomas characterised for microsatellite instability and Epstein-Barr virus infection

Gastric carcinomas (GCs) with high microsatellite instability (MSI) or an Epstein-Barr virus (EBV) infection are prevalently poorly differentiated adenocarcinomas with abundant lymphoid infiltration. The aims of the study were to clarify (1) if tumour-infiltrating lymphocytes (TILs) and cytotoxic-activated TILs are associated with a better clinical outcome in patients with GCs characterised for the presence of MSI and EBV; (2) if the nature and the activation status of TILs are involved in tumour cell apoptosis, evaluated using the M30 antibody, directed against a fragment of cytokeratin-18 caspase-cleaved during early steps of epithelial cell apoptosis. The immunophenotype of TILs and the tumour cell apoptosis were analysed with immunohistochemistry in 96 GCs, including 35 MSI GCs, and 61 GCs without MSI [microsatellite stable (MSS)], 17 of which were EBV+. MSI and MSS/EBV+ GCs displayed a significantly higher mean number of cytotoxic-activated TILs and apoptotic tumour cells than MSS/EBV- GCs (CD8+ TILs/HPF, 21.7 and 69.6 vs 6.4; T-cell intracellular antigen (TIA)-1+ TILs/HPF, 16.7 and 32.05 vs 5.2; granzyme B+ TILs/HPF, 7.5 and 8.6 vs 0.8; perforin+ TILs/HPF, 5.9 and 9.2 vs 0.9; and M30 IR tumour cells, 5.9 and 2.9 vs 2.3%). In addition to the most reliable clinico-pathological parameters (lymph node status, depth of tumour invasion and tumour stage), a univariate analysis showed that the presence of CD3+ TILs higher than 14.9 (p=0.01), CD8+ TILs higher than 9.5 (p<0.05) and MSI (p=0.02) were associated with better overall patient survival. Using a Cox regression model, only a high number of CD3+ TILs (p=0.02) and a low tumour stage (p=0.00001) were identified as independent prognostic factors. In conclusion, our study demonstrates that a high number of CD3+ and CD8+ TILs is a characteristic of MSI- and EBV-associated GCs and represents a favourable prognostic factor, independently of the pathogenesis of GCs.

The role of defective mismatch repair in small bowel adenocarcinoma in celiac disease

Celiac disease is associated with an increased risk of small bowel adenocarcinoma. The aims of this study were to investigate the molecular basis, assess outcomes, and identify clinicopathologic characteristics of small bowel adenocarcinoma in celiac disease. Retrospective case control cohort study of all celiac disease patients treated at our institution for small bowel adenocarcinoma and matched control patients with sporadic small bowel adenocarcinoma from July 1960 to November 2002. Mismatch repair (MMR) status was accessed by testing tissue for microsatellite instability (MSI) and for hMLH1 and hMSH2 protein expression. Over a 40-year time period, 18 patients with small bowel adenocarcinoma and celiac disease were treated at the Mayo Clinic. One celiac disease patient was excluded. High-frequency MSI (MSI-H) was identified in 8 of 11 (73%) and 2 of 22 (9%) available small bowel adenocarcinoma specimens in the celiac disease and control groups, respectively. In the celiac disease group, MSI-H was associated with loss of hMLH1 and hMSH2 in 6 and 1 specimens, respectively. Loss of hMLH1 occurred in both control tumors. Stage was associated with celiac disease status (P = 0.018), and 78% of controls were stage III or IV compared with 47% of celiac disease patients. Overall, survival was better (P = 0.025) in the celiac disease group compared with stage-matched controls. Celiac disease patients with small bowel adenocarcinoma had a high incidence defective MMR (73%) compared with controls and had better survival compared with stage-matched controls. In addition, celiac disease patients presented more frequently with early-stage small bowel adenocarcinoma. The better survival and earlier presentation of small bowel adenocarcinoma in celiac disease appears to be biologically associated with defective MMR.

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