Features of Gastric Carcinoma With Lymphoid Stroma Associated With Epstein-Barr Virus

Clinicopathological Characteristics and Lymph Node Metastasis Rates in Early Gastric Lymphoepithelioma-Like Carcinoma: Implications for Endoscopic Resection

Background/Aims

Lymphoepithelioma-like carcinoma (LELC) is a rare subtype of gastric cancer. We aimed to identify the clinicopathological features and rate of lymph node metastasis (LNM) to investigate the feasibility of endoscopic submucosal dissection for early gastric LELC confined to the mucosa or submucosa.

Methods

We compared the clinicopathological characteristics of 116 early gastric LELC patients and 5,753 early gastric well- or moderately differentiated (WD or MD) tubular adenocarcinoma patients treated by gastrectomy.

Results

Compared to WD or MD early gastric cancer (EGC) patients, early LELC patients were younger and had a higher prevalence of proximally located tumors. Despite more frequent deep submucosal invasion (86.2% vs 29.8%), lymphatic invasion was less frequent (6.0% vs 16.2%) in early LELC patients than in WD or MD EGC patients. Among tumors with deep submucosal invasion, the tumor size was smaller, lymphatic invasion was less frequent (6.0% vs 40.2%) and the rate of LNM was lower (10.0% vs 19.4%) in patients with LELC than in those with WD or MD EGC. The overall rate of LNM in early LELC patients was 8.6% (10/116). The risk of LNM in patients with mucosal, shallow submucosal invasive, or deep submucosal invasive LELC was 0% (0/6), 0% (0/10), and 10% (10/100), respectively.

Conclusions

Early LELC is a distinct subtype of EGC with more frequent deep submucosal invasion but less lymphatic invasion and LNM than WD or MD EGCs. Endoscopic submucosal dissection may be considered curative for patients with early LELC confined to the mucosa or shallow submucosa, given its negligible rate of LNM.

Unlocking the Potential: Epstein-Barr Virus (EBV) in Gastric Cancer and Future Treatment Prospects, a Literature Review

Gastric cancer (GC) is a complex disease with various etiologies. While Helicobacter pylori infection is still one of the leading risk factors for GC, increasing evidence suggests a link between GC and other infective agents such as Epstein Bar Virus (EBV). EBV-associated gastric cancer (EBVaGC) is now recognized as a distinct subgroup of GC, and the complex interactions between the virus and gastric mucosa may influence its development. A recent integrative analysis of the genome and proteome of GC tissues by The Cancer Genome Atlas project has identified EBVaGC as a specific subtype characterized by PIK3CA and ARID1A mutations, extensive DNA hyper-methylation, and activation of immune signaling pathways. These molecular characteristics are markers of the unique molecular profile of this subset of GC and are potential targets for therapy. This review aims to provide an overview of the current knowledge on EBVaGC. It will focus on the epidemiology, clinic-pathological features, and genetic characteristics of EBVaGC. Additionally, it will discuss recent data indicating the potential use of EBV infection as a predictive biomarker of response to chemotherapy and immune checkpoint inhibitors. The review also delves into potential therapeutic approaches for EBVaGC, including targeted therapies and adoptive immunotherapy, highlighting the promising potential of EBV as a therapeutic target.

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.

Prognosis of EBV-positive gastric cancer with lymphoid stroma: systematic review and meta-analysis

BACKGROUND

Although gastric cancer with lymphoid stroma (GCLS) presents better prognosis, uncertainty still exists regarding the association of Epstein-Barr virus (EBV) infection with prognosis of GCLS. Therefore, it is urgent to evaluate the outcome and characteristics of EBV-positive GCLS via a systematic review and meta-analysis.

METHODS

Three medical databases, with a period ranging from 2000 to so far, were searched for observational studies on EBV infection, clinical characteristics and prognosis. Odds ratio (OR) was used to evaluate the mortality and clinical characteristics of EBV-positive GCLS patients. Egger's test and subgroup analysis were conducted to identify the source of heterogeneity.

RESULTS

Nine retrospective studies were finally identified, which involved 618 EBV-positive and 153 EBV-negative GCLS patients. The forest plot indicated that EBV-positive GCLS patients had lower mortality (p = .009; 95% CI: 0.15-0.77; I2 = 48.6%). Both of funnel plot and Egger's tests suggested that there was no publication bias. Nonetheless, subgroup analysis indicated that T1-2 stage ratio more than 50% (p < .001; I2 = 6.7%) and male ratio more than 80% (p < .001; I2 = 0.0%) were valuable for eliminating the heterogeneity. Seven studies including valid information showed that TNM stage of EBV-positive and negative GCLS patients was not statistically different (p = .644; 95% CI: 0.50-1.53; I2 = 0.0%).

CONCLUSIONS

EBV-positive GCLS tends to have lower mortality, suggesting that detection of EBV infection is necessary to predict prognosis of GCLS.

Clinical outcomes of Epstein-Barr virus (EBV)-associated metastatic and locally advanced unresectable gastric cancers (GCs) in patients receiving first-line fluoropyrimidine and platinum (FP) doublet chemotherapy

BACKGROUND

Epstein-Barr virus-associated gastric cancer (EBVaGC) is a distinct molecular subgroup showing excellent outcomes after surgery for localized disease. Prominent immune cell infiltration in EBVaGC reflects the immunogenicity of Epstein-Barr virus (EBV) and, as suggested by some investigators, responsiveness to immune checkpoint inhibitors in the palliative setting. However, few data are available on the prevalence, clinical characteristics, and prognosis of EBVaGC patients receiving palliative cytotoxic chemotherapy.

METHODS

In this retrospective study, we identified 1061 patients with metastatic, recurrent, or locally advanced unresectable gastric cancer (GC) who started first-line fluoropyrimidine/platinum (FP) doublet chemotherapy with or without trastuzumab from January 2015 to August 2018. For 766 patients with available tumor tissue, the presence of EBV in cancer cells was evaluated by EBV-encoded RNA in situ hybridization and correlated with clinical characteristics and treatment outcomes.

RESULTS

Among the patients evaluated (n = 766), 40 (5.0%) were EBV-positive. EBVaGC was associated with male sex (p = 0.009) and lower neutrophil-lymphocyte ratio (NLR < 2.46, p = 0.03). Efficacy of first-line FP chemotherapy, in terms of response rate ad progression-free survival (PFS), did not differ between EBVaGC and EBV-negative GC (overall response rate: 53.8% vs. 51.8%, p = 0.99; median PFS: 6.4 vs. 6.7 months, p = 0.90). However, overall survival tended to be better with EBVaGC than EBV-negative GC (16.4 vs. 14.0 months, p = 0.07).

CONCLUSIONS

EBVaGC accounted for 5% of metastatic/unresectable GCs. While EBVaGC was not associated with better response to or PFS following first-line cytotoxic chemotherapy, it showed a trend toward better overall survival.

Clinical and pathologic characteristics of gastric adenocarcinoma associated with Epstein-Barr virus in a region with a high incidence of gastric cancer in Colombia

INTRODUCTION AND AIMS

Epstein-Barr virus (EBV) infection is an etiologic factor in EBV-associated gastric carcinoma (EBVaGC). The aim of our study was to describe the clinical and histopathologic characteristics of EBV infection in intestinal-type gastric adenocarcinoma samples.

MATERIAL AND METHODS

Of 180 paraffin-embedded gastrectomy samples, 28 were studied. Chromogenic in situ hybridization was performed to detect EBV. Sociodemographic and histopathologic data were obtained from the patients' clinical histories.

RESULTS

A total of 21.4% of the samples were positive for EBV. The predominant morphologic characteristic was the lace pattern, with dense inflammatory infiltration. Fifty percent of the EBVaGC+ patients were men, and the median age of the positive patients was 59 years (range: 50-75); 77.2% of the EBVaGC- patients were men, and the median age of the negative patients was 66 years (range: 34-89). Helicobacter pylori infection was associated with 10.7% of the EBVaGC+ patients and 53.6% of the EBVaGC- patients. In the EBVaGC+ patients, the cardia was the most frequent tumor location (17.9%), 7.1% had histologic grades 2 and 3, and 17.9% presented with Borrmann classification type III. In the EBVaGC- patients, the cardia and fundus were the most frequent tumor locations (71.4%), 35.7% had histologic grade 2, and 39.3% and 21.4% presented with Borrmann classification type III and IV, respectively.

CONCLUSIONS

The present study describes the clinical and histopathologic characteristics associated with EBVaGC positivity. Those data may aid in the selection of cases that are candidates for analysis through molecular methods aimed at identifying EBV infection in intestinal-type gastric adenocarcinoma.

Clinical Significance of Epstein-Barr Virus and Helicobacter pylori Infection in Gastric Carcinoma

Background/Aims

Epstein-Barr virus (EBV) and Helicobacter pylori (HP) coinfection may synergistically induce severe inflammatory responses in the stomach tissue, increasing the risk of developing gastric cancer. We aimed to analyze the effect of EBV and HP coinfection on the clinicopathologic features and prognosis of gastric cancer, as well as to evaluate the role of EBV infection in non-gastric carcinoma with lymphoid stroma (non-GCLS).

Methods

Overall, 956 patients who underwent surgery for gastric cancer between September 2014 and August 2015 were eligible and divided into groups, according to GCLS morphology, EBV infection, and HP infection. Clinicopathologic characteristics and oncologic outcomes were analyzed retrospectively.

Results

EBV and HP coinfection was significantly associated with male sex, proximal location, GCLS morphology, and equivocal p53 expression (p<0.001). Multivariate analysis revealed that EBV infection alone (hazard ratio [HR], 0.362; 95% CI, 0.131 to 0.996; p=0.049) and lower third location (HR, 0.624; 95% CI, 0.413 to 0.943; p=0.025) were inversely correlated with overall survival. During median follow-up period of 72 months, overall survival rate was not significantly different between the EBV and HP coinfection group and others (97.6% vs 86.8%; log-rank p=0.144). In non-GCLS patients (n=920), overall survival rate was not significantly different between the EBV infection group and others (96.9% vs 86.4%; log-rank p=0.126).

Conclusions

EBV and HP coinfection is not an independent prognostic factor for gastric cancer. EBV infection status, regardless of HP infection, affects the clinicopathologic features of all types of gastric cancer. However, it does not lead to a significant difference in overall survival of non-GCLS patients.

EBV and MSI Status in Gastric Cancer: Does It Matter?

We investigated the impactof microsatellite instability (MSI) and Epstein-Barr virus (EBV) status in gastric cancer (GC), regarding response to perioperative chemotherapy (POPChT), overall survival (OS), and progression-free survival (PFS). We included 137 cases of operated GC, 51 of which were submitted to POPChT. MSI status was determined by multiplex PCR and EBV status by EBV-encoded RNA in situ hybridization. Thirty-seven (27%) cases presented as MSI-high, and seven (5.1%) were EBV+. Concerning tumor regression after POPChT, no differences were observed between the molecular subtypes, but females were more likely to respond (p = 0.062). No significant differences were found in OS or PFS between different subtypes. In multivariate analysis, age (HR 1.02, IC 95% 1.002-1.056, p = 0.033) and positive lymph nodes (HR 1.82, IC 95% 1.034-3.211, p = 0.038) were the only prognostic factors for OS. However, females with MSI-high tumors treated with POPChT demonstrated a significantly increased OS compared to females with MSS tumors (p = 0.031). In conclusion, we found a high proportion of MSI-high cases. MSI and EBV status did not influence OS or PFS either in patients submitted to POPChT or surgery alone. However, superior survival of females with MSI-high tumors suggests that sex disparities and molecular classification may influence treatment options in GC.

Prediction of Epstein-Barr Virus Status in Gastric Cancer Biopsy Specimens Using a Deep Learning Algorithm

IMPORTANCE

Epstein-Barr virus (EBV)-associated gastric cancer (EBV-GC) is 1 of 4 molecular subtypes of GC and is confirmed by an expensive molecular test, EBV-encoded small RNA in situ hybridization. EBV-GC has 2 histologic characteristics, lymphoid stroma and lace-like tumor pattern, but projecting EBV-GC at biopsy is difficult even for experienced pathologists.

OBJECTIVE

To develop and validate a deep learning algorithm to predict EBV status from pathology images of GC biopsy.

DESIGN, SETTING, AND PARTICIPANTS

This diagnostic study developed a deep learning classifier to predict EBV-GC using image patches of tissue microarray (TMA) and whole slide images (WSIs) of GC and applied it to GC biopsy specimens from GCs diagnosed at Kangbuk Samsung Hospital between 2011 and 2020. For a quantitative evaluation and EBV-GC prediction on biopsy specimens, the area of each class and the fraction in total tissue or tumor area were calculated. Data were analyzed from March 5, 2021, to February 10, 2022.

MAIN OUTCOMES AND MEASURES

Evaluation metrics of predictive model performance were assessed on accuracy, recall, precision, F1 score, area under the receiver operating characteristic curve (AUC), and κ coefficient.

RESULTS

This study included 137 184 image patches from 16 TMAs (708 tissue cores), 24 WSIs, and 286 biopsy images of GC. The classifier was able to classify EBV-GC image patches from TMAs and WSIs with 94.70% accuracy, 0.936 recall, 0.938 precision, 0.937 F1 score, and 0.909 κ coefficient. The classifier was used for predicting and measuring the area and fraction of EBV-GC on biopsy tissue specimens. A 10% cutoff value for the predicted fraction of EBV-GC to tissue (EBV-GC/tissue area) produced the best prediction results in EBV-GC biopsy specimens and showed the highest AUC value (0.8723; 95% CI, 0.7560-0.9501). That cutoff also obtained high sensitivity (0.895) and moderate specificity (0.745) compared with experienced pathologist sensitivity (0.842) and specificity (0.854) when using the presence of lymphoid stroma and a lace-like pattern as diagnostic criteria. On prediction maps, EBV-GCs with lace-like pattern and lymphoid stroma showed the same prediction results as EBV-GC, but cases lacking these histologic features revealed heterogeneous prediction results of EBV-GC and non-EBV-GC areas.

CONCLUSIONS AND RELEVANCE

This study showed the feasibility of EBV-GC prediction using a deep learning algorithm, even in biopsy samples. Use of such an image-based classifier before a confirmatory molecular test will reduce costs and tissue waste.

Molecular Pathology of Gastric Cancer

Gastric cancer (GC) is one of the most common lethal malignant neoplasms worldwide, with limited treatment options for both locally advanced and/or metastatic conditions, resulting in a dismal prognosis. Although the widely used morphological classifications may be helpful for endoscopic or surgical treatment choices, they are still insufficient to guide precise and/or personalized therapy for individual patients. Recent advances in genomic technology and high-throughput analysis may improve the understanding of molecular pathways associated with GC pathogenesis and aid in the classification of GC at the molecular level. Advances in next-generation sequencing have enabled the identification of several genetic alterations through single experiments. Thus, understanding the driver alterations involved in gastric carcinogenesis has become increasingly important because it can aid in the discovery of potential biomarkers and therapeutic targets. In this article, we review the molecular classifications of GC, focusing on The Cancer Genome Atlas (TCGA) classification. We further describe the currently available biomarker-targeted therapies and potential biomarker-guided therapies. This review will help clinicians by providing an inclusive understanding of the molecular pathology of GC and may assist in selecting the best treatment approaches for patients with GC.

PD-L1 expression in EBV associated gastric cancer: a systematic review and meta-analysis

OBJECTIVES

The aim of this systematic review and meta-analysis is to the summarize the evidence on programmed cell death protein ligand 1 (PD-L1) in Epstein-Barr virus associated gastric cancer (EBVaGC) and to estimate the expression rate of PD-L1 among this subtype of Gastric Cancer (GC).

MATERIALS AND METHODS

For this study, PubMed^®, EMBASE^® and Web of Science^® databases were searched for articles published until 1st November 2021. A total of 43 eligible publications with a total of 11,327 patients were included analysis based on inclusion and exclusion criteria. A total of 41 publications present data for proportion estimation and 33 for comparison of PD-L1 between EBV positive and negative GC. DerSimonian-Laird random-effects model was used for meta-analysis.

RESULTS

The analysis showed that in EBVaGC the pooled positivity rate for PD-L1 was 54.6% (p < 0.001), with a high heterogeneity between the included studies, which was associated with variation on positivity criteria for PD-L1 expression. Overall, the study reveals an increased association between PD-L1 and EBVaGC (OR = 6.36, 95% CI 3.91-10.3, p < 0.001). Furthermore, the study revealed that GC with lymphoid stroma (GCLS) is highly associated with EBV (OR = 17.4, 95% CI 6.83-44.1, p < 0.001), with a pooled EBV positivity rate of 52.9% (p < 0.001).

CONCLUSIONS

Patients with EBVaGC tend to show higher PD-L1 expression, which enhances EBV positivity as a promising marker for patient selection for immunotherapy targeted agents. A uniform criteria for PD-L1 positivity in tumor cells is needed, as well as further prospective studies to validate our findings and their prognostic significance.

Epstein-Barr Virus-Associated Gastric Cancer: Old Entity with New Relevance

Gastric cancer (GC) represents a major public health issue worldwide, being the fifth most common cancer and one of the leading causes of death by cancer. In 2014, The Cancer Genome Atlas (TCGA) established that tumors positive for Epstein-Barr virus (EBV) are considered a specific subtype of GC (EBVaGC). Several meta-analyses have shown that EBVaGC represents almost 10% of all gastric cancer worldwide, with small differences in the geographic distribution. This tumor subtype has a high potential of being clinically relevant and studies have shown that it has specific features, a better prognosis, and increased overall survival. In this review, we summarize some of the most frequent aspects of EBVaGC, including the specific features of this GC subtype, data regarding the potential steps of EBVaGC carcinogenesis, and perspectives on treatment opportunities.

Incidence and survival rates of lymphoepithelioma-like gastric carcinoma: analysis of the Korea Central Cancer Registry Database

BACKGROUND

Lymphoepithelial carcinoma of the stomach (LEGC) is a rare type of gastric carcinoma. There is a limited understanding of the incidence and survival rates of LEGC. The aim was to investigate the nationwide incidence and survival rates of LEGC in Korea using the Korea Central Cancer Registry.

METHODS

The data on LEGC were retrieved from the Korea Central Cancer Registry of Korean Cancer Center. The age and sex of the patients and the Surveillance, Epidemiology, and End Results (SEER) summary stage of the tumor were analyzed, and the relative survival rates (RSRs) were calculated. The Korea Central Cancer Registry has data of patients with LEGC from 1993 to 2017 but is approved to use personal information only from 2006 to 2017 due to privacy restrictions of the institute. The RSRs, as calculated data, were able to be disclosed from 1993 to 2017.

RESULTS

Between 2006 and 2017, the total number of LEGC was 1,030, and the trend of incidence increased ty time (p = .002). In the SEER stage, the proportion of localized stage was 54.3% in 2006, and 73.9% in 2017, which increased from 2006 to 2017 significantly (p = .002). The RSR was higher in men than in women. The cumulative 5-year RSRs were 98.0% in the localized stage and 88.0% in the regional stage during 1993-2017. The 5-year RSRs increased 79.5% in 1996-2000 to 93.4% in 2013-2017.

CONCLUSIONS

The incidence of LEGC is low, which has been increasing in recent years in South Korea. The prognosis of LEGC is good even at advanced stages and gets better as time goes by. Our findings provide useful insights to clinicians about LEGC and inform patients about the survival rate.

Gastric medullary carcinoma: clinicopathological features and prognosis-a single-center study

BACKGROUND

Gastric medullary carcinoma (GMC) is a distinct histologic subtype of gastric adenocarcinoma, which prominently associated with Epstein-Barr virus infection. This study aimed to evaluate the clinicopathological features and prognosis of patients with medullary carcinoma in one center.

METHODS

Data regarding patients with gastric cancer were retrospectively analyzed at Marmara University between 2014 and 2019. Demographics, pathological features, and overall survival of patients with GMC were evaluated. The primary outcome of this study was to compare the pathological features of GMC to non-GMC (NGMC). The secondary outcome was comparing overall survival between the two groups.

RESULTS

A total of 412 patients were enrolled in the study. Of 412 patients, 19 (5%) were diagnosed with medullary cancer. Compared to NGMC, no significant differences were observed in patient age, gender, tumor macroscopic pattern, size, lymphovascular invasion, pathological stage, location and size of the tumors, and the number of metastatic lymph nodes in GMC. However, perineural invasion and Borrmann ulcerated type rates were significantly higher among NGMC. Whereas the microsatellite instability (MSI) rate was significantly higher in the GMC (64% and 11%, respectively, p < 0.001). Multivariate analysis showed that the MSI status was the solely significantly different feature between the two groups.

CONCLUSION

This study showed that GMC was associated with MSI, which could explain the better prognosis of medullary carcinomas.

A rare case of Epstein-Barr virus-positive early gastric carcinoma with lymphoid stroma successfully treated by endoscopic submucosal dissection alone

Gastric carcinoma with lymphoid stroma (GCLS), a rare subset of gastric cancer, has a low frequency of lymphovascular invasion and a relatively better prognosis compared with conventional gastric cancer. We herein report a rare case of early GCLS successfully treated by endoscopic submucosal dissection alone. The lesion was located in the upper gastric body and approximately 9 mm in size. We assessed that the lesion was within an absolute indication for endoscopic resection. We performed endoscopic submucosal dissection and succeeded in en bloc resection. A histopathological assessment disclosed that the carcinoma was poorly differentiated with massive infiltration of lymphocyte and invaded the submucosal layer massively at 1000 μm in depth. There were no visible lymphovascular invasions in the specimen. Since the Epstein-Barr virus (EBV)-encoded small RNA in situ hybridization revealed that cancer cells were positive for EBV, the patient was finally diagnosed with EBV-positive GCLS. We persuaded the patient to receive an additional surgery; however, the patient refused to undergo it. The patient has been followed for more than 5 years without recurrence.

Select Epstein-Barr Virus-Associated Digestive Tract Lesions for the Practicing Pathologist

CONTEXT.—

Epstein-Barr virus is a ubiquitous oncogenic virus. During the past 5 decades, the virus has been linked to several disease entities, both neoplastic and nonneoplastic. Several Epstein-Barr virus-associated conditions affect the digestive organs, ranging from mild transient inflammatory conditions to more debilitating and even fatal diseases.

OBJECTIVE.—

To discuss the clinicopathologic aspects of some newly or recently recognized Epstein-Barr virus-related conditions encountered in the digestive system and their therapeutic implications.

DATA SOURCES.—

Published peer-reviewed literature was reviewed.

CONCLUSIONS.—

This article highlights the importance of recognizing the discussed lesions because they influence the direct clinical management or serve as a potential predictive marker for therapy.

Clinicopathological characteristics of Epstein-Barr virus and microsatellite instability subtypes of early gastric neoplasms classified by the Japanese and the World Health Organization criteria

Gastric cancer is a heterogenous disease with different phenotypes, genotypes, and clinical outcomes, including sensitivity to treatments and prognoses. Recent medical advances have enabled the classification of this heterogenous disease into several groups and the consequent analysis of their clinicopathological characteristics. Gastric cancer associated with Epstein–Barr virus (EBV) and microsatellite‐unstable tumors are considered to be the two major subtypes as they are clearly defined by well‐established methodologies, such as in situ hybridization and polymerase chain reaction‐based analyses, respectively. However, discrepancies in the histological diagnosis of gastric neoplasms remain problematic, and international harmonization should be performed to improve our understanding of gastric carcinogenesis. We re‐evaluated Japanese cases of early gastric cancer according to the current World Health Organization (WHO) criteria and classified them into genomic subtypes based on microsatellite instability (MSI) and EBV positivity to determine the initial genetic events in gastric carcinogenesis. A total of 113 Japanese early gastric cancers (including low‐ and high‐grade dysplasias) treated with endoscopic resection over 5 years were archived in our hospital. A histological re‐evaluation according to the WHO criteria revealed 54 adenocarcinomas, which were divided into 6 EBV‐positive (11.1%), 7 MSI‐high (MSI‐H, 13.0%), and 41 microsatellite stable cases (75.9%). MSI‐H adenocarcinoma was confirmed by an immunohistochemistry assay of mismatch repair proteins. Programmed death‐ligand 1 immunostaining with two antibodies (E1L3N and SP263) was positive in tumor cells of one MSI‐H adenocarcinoma case (1/7, 14.3%). The proportion of stained cells was higher with clone SP263 than with E1L3N. Histologically, EBV‐positive carcinomas were poorly differentiated (83.8%), and MSI‐H cancers were frequent in well to moderately differentiated adenocarcinoma (85.7%), indicating that the EBV‐positive subtype presented with high‐grade morphology even when an early lesion. Our study indicates that the WHO criteria are useful for subdividing Japanese early gastric cancers, and this subdivision may be useful for comparative analysis of precursor lesions and early carcinoma.

Gastric carcinoma with lymphoid stroma diagnosed by endoscopic ultrasound-guided fine-needle aspiration

A 78-year-old man with a subepithelial lesion (SEL) in the gastric body and two carcinomas in the gastric antrum was referred to our hospital. Following a diagnosis of SEL, the patient was followed-up by esophagogastroduodenoscopy annually for 4 years. Although the SEL had increased in size over the years, histological evaluation of the forceps biopsies did not reveal any significant findings. We detected a hypoechoic mass in the submucosa by endoscopic ultrasonography, and suspected the lesion to be an aberrant pancreas or mesenchymal tumor. The patient first underwent endoscopic submucosal dissection for the 2 gastric cancers. Histological examination of the resected specimens revealed intramucosal well-differentiated tubular adenocarcinomas. Next, endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) was performed for the gastric SEL. Aspirated specimens revealed an adenocarcinoma with lymphocyte infiltration. The lesion was diagnosed as a gastric carcinoma with lymphoid stroma (GCLS). Subsequently, he underwent distal gastrectomy, and the surgical specimen was confirmed as GCLS corresponding to preoperative diagnosis. In addition, the adenocarcinoma cells were positive for Epstein-Barr (EB) virus-encoded small RNA-1 by in situ hybridization. Finally, the lesion was diagnosed as GCLS associated with EB virus. Thus, EUS-FNA is advantageous for diagnosing GCLS associated with EB virus.

Clinicopathological Features and Prognostic Implication of Gastric Carcinoma with Lymphoid Stroma

Methods

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

Results

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

Conclusion

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

An Integrative Morphomolecular Classification System of Gastric Carcinoma With Distinct Clinical Outcomes

A robust morphomolecular classification system for gastric carcinoma is required. A 4-tier morphologic classification is proposed, including diffuse, intestinal, tubular, and lymphoid types. A tissue microarray for mismatch repair immunohistochemistry and Epstein-Barr virus (EBV) in situ hybridization were performed in 329 gastric carcinomas. DNA flow cytometry was used to detect aneuploidy in formalin-fixed paraffin-embedded samples. Lymphoid histology was the third most common histologic pattern at our institute and strongly associated with EBV infection and PMS2/MLH1-deficiency (both P<0.001). HER2 overexpression and SATB2 expression more frequently occurred in intestinal histology (both P<0.001). Loss of ARID1A expression was strikingly associated with lymphoid histology (P<0.001) and negative E-cadherin expression was correlated with diffuse histology (P=0.001). Programmed death-ligand 1 expression was most frequently present in lymphoid-type gastric carcinoma than other histologic subtypes and correlated with the molecular features of PMS2/MLH1-deficiency and EBV infection (all P<0.001). Aneuploidy was detected in 53% of gastric carcinomas and was highly correlated with intestinal type and the least with the lymphoid type (P<0.001). Notably, lymphoid-type gastric carcinoma showed the best outcome, whereas tubular type showed the worst survival rate (P<0.001). We integrated aneuploidy with morphologic patterns to propose a morphomolecular classification scheme, which served as a successful and independent prognostic factor in multivariate 5-year disease-free survival analysis (P<0.001). Overall, we describe an integrated morphomolecular classification system for gastric carcinomas to effectively predict patient outcomes. This system is cost-effective and reliable and can help select target therapeutics and facilitate clinical management.

Postoperative outcomes of gastric carcinoma with lymphoid stroma

BACKGROUND

Gastric carcinoma with lymphoid stroma (GCLS) is a rare subtype of gastric cancer. There have been several reports demonstrating the favorable prognosis of early GCLS without lymph node metastasis (LNM) compared with gastric adenocarcinomas. However, it remains unknown whether advanced GCLS (AGCLS) with LNM has a similar prognosis and clinicopathological features. This study aimed to assess the clinicopathological features of GCLS of all stages.

METHODS

We retrospectively assessed 375 patients who were pathologically diagnosed with gastric cancer and underwent curative surgical resection at Tokyo Medical University, Japan, between September 2013 and October 2019. Of these patients, 357 (95.2%) patients were pathologically diagnosed with gastric adenocarcinomas, and 18 (4.8%) patients were diagnosed with GCLS. The GCLS patients (n = 18) were compared with the gastric adenocarcinoma patients (non-GCLS patients, control) (n = 357) in terms of their clinicopathological features and clinical outcome.

RESULTS

The GCLS patients showed significantly predominant upper gastric locations (P = 0.003), lower number of LNM (P = 0.01), and better overall survival rate than the non-GCLS patients (P = 0.029). The predominant upper gastric locations (P = 0.0002), lower number of LNM (P = 0.003), and better overall survival rate (P = 0.04) were significantly correlated in the AGCLS with LNM patients compared with the advanced non-GCLS with LNM patients. For survival analyses, surgical procedure, tumor location, and numbers of positive LNM were adjusted by 1:1 propensity score matching. After adjustment, the overall survival rate was significantly higher in the AGCLS group than in the advanced non-GCLS group (P = 0.03).

CONCLUSION

AGCLS has distinct clinicopathological features and clinical behavior that are similar to those of early GCLS. AGCLS with LNM patients showed a significantly lower number of LNM and a better survival rate than advanced non-GCLS with LNM patients. To our knowledge, this study is the first report to describe the clinicopathological features of AGCLS.

Clinical impact of Epstein-Barr virus status on the incidence of lymph node metastasis in early gastric cancer

Epstein-Barr virus-positive gastric cancer (EBVGC) comprises approximately 9% of all gastric cancers and is associated with a low prevalence of lymph node metastasis (LNM). Given that limited data concerning LNM in EBV-related early GC are available, EBV status is not considered an indicator for endoscopic submucosal dissection (ESD). In this review, we focused on pT1 EBVGC and on gastric carcinoma with lymphoid stroma (GCLS), and discuss expanded ESD indications and curative resection criteria. In pT1b EBVGC, the incidence of LNM was low (6/180 patients, 3.3%; 95% confidence interval [CI] 1.2-7.1), especially in lymphovascular invasion-negative EBVGC (1/109 patients, 0.9%). No patients with pT1a EBVGC had LNM (0/38 patients, 0%; 95% CI 0-7.6), even those who did not meet the current curative ESD criteria. Although the frequency of LNM in GCLS was low (5.0-10.6%), the incidence of LNM in non-EBV GCLS was relatively high (10.0-20.0%); therefore, EBV status can be considered a more important factor than GCLS. In summary, the clinicopathological characteristics of EBVGC differ from those of conventional GC, and EBV negativity is a risk factor for LNM in early GC. Therefore, patients in this group are likely to be promising candidates for ESD, and we recommend that EBV status evaluation be included in early GC treatment guidelines.

Thirty years of Epstein-Barr virus-associated gastric carcinoma

Thirty years have passed since a possible association of Epstein-Barr virus (EBV) with gastric carcinoma was reported. We now know EBV-associated gastric carcinoma to be a specific subtype of gastric carcinoma. Global epigenetic methylation and counteraction of the antitumour microenvironment are two major characteristics of this subtype of gastric carcinoma. Recent development of therapeutic modalities for gastric carcinoma, such as endoscopic mucosal dissection and immune checkpoint inhibitor therapy, has made the presence of EBV infection a biomarker for the treatment of gastric carcinoma. This review presents a portrait of EBV-associated gastric carcinoma from initiation to maturity that we define as the 'gastritis-infection-cancer sequence', followed by its molecular abnormalities and interactions with immune checkpoint molecules and the microenvironment. EBV non-coding RNAs (microRNA and circular RNA) and exosomes derived from EBV-infected cells that were previously behind the scenes are now recognized for their roles in EBV-associated gastric carcinoma. The virus utilizes cellular machinery skilfully to control infected cells and their microenvironment. We should thus strive to understand virus-host interactions more fully in the following years to overcome this virus-driven subtype of gastric carcinoma.

Gastric submucosa-invasive carcinoma associated with Epstein-Barr virus and endoscopic submucosal dissection: A case report

BACKGROUND

Epstein-Barr virus (EBV)-associated carcinoma is a gastric cancer subtype with a morphology characterized by gastric carcinoma with lymphoid stroma (GCLS). Clinicopathological studies have indicated a better prognosis for GCLS than for common gastric carcinomas. Some previous cases of early gastric cancer associated with EBV had been diagnosed by endoscopic resection.

CASE SUMMARY

We present two GCLS cases subjected to endoscopic submucosal dissection (ESD) for a definitive diagnosis. A protruded gastric lesion was identified by routine endoscopic examination, but forceps biopsy showed no atypical cells before ESD. The resected specimen showed a poorly differentiated adenocarcinoma with lymphoid cells involving the mucosa and submucosa. The final diagnosis was submucosa-invasive poorly differentiated gastric adenocarcinoma. Accordingly, additional gastrectomy was recommended to obtain a complete cure. One patient underwent additional distal gastrectomy with lymph node dissection, but the other was refused because of cardiovascular complications. Both patients remained in remission for more than half a year. EBV positivity was determined by EBV-encoded RNA in situ hybridization. We also conducted a literature review of cases of early gastric cancer associated with EBV that had been diagnosed by ESD.

CONCLUSION

Submucosa-invasive GCLS could be dissected using ESD, and EBV positivity should be subsequently assessed to determine whether or not any additional curative surgery is required. Further prospective investigations on the prevalence of lymph node metastasis in EBV-associated carcinoma should be performed to expand the indications for endoscopic resection.

A case of gastric carcinoma with lymphoid stroma diagnosed by an endoscopic ultrasound-guided fine-needle biopsy

Endoscopic ultrasound-guided sampling is indicated to achieve an accurate diagnosis of subepithelial lesions of the stomach when a standard biopsy fails. Gastric carcinoma with lymphoid stroma (GCLS) is located under the epithelial layer with dense lymphocytic infiltration, making a pathological diagnosis by a biopsy difficult. We herein report a case of the pathological diagnosis of GCLS using an endoscopic ultrasound-guided fine-needle biopsy. The patient underwent distal gastrectomy and was diagnosed with Epstein-Barr virus-negative cancer.

Epstein-Barr virus status is a promising biomarker for endoscopic resection in early gastric cancer: proposal of a novel therapeutic strategy

BACKGROUND

Epstein-Barr virus-positive gastric cancer (EBVGC) is associated with a low prevalence of lymph node metastasis (LNM); however, EBV status is not considered in the indication of endoscopic resection (ER). We aimed to clarify the implication of EBV status for ER of pT1b GC.

METHODS

Consecutive cases of pT1b GCs treated with surgery between 2005 and 2014 were retrospectively analyzed. Clinicopathological factors and LNM status were compared between EBVGC and non-EBVGC groups.

RESULTS

EBVGC accounted for 7.9% (71 of 898) cases. Compared to non-EBVGC, EBVGC was more frequent in males (p = 0.0055), the upper third region (p < 0.0001), showed elevated growth features (p = 0.0059), and was associated with a lower frequency of accompanying ulceration (p = 0.002), greater depth of submucosal invasion (p = 0.017), and lower frequency of lymphatic invasion (p < 0.0001). Frequency of LNM was significantly lower in EBVGC than in non-EBVGC (4.2% vs. 21.9%, p < 0.0001). In EBVGC, tumors without lymphovascular invasion showed significantly lower frequency of LNM than those with lymphovascular invasion (0 of 50, 0%; vs 3 of 21, 14.3%; p = 0.023). Histologically, 84.5% (60 of 71) of EBVGC included carcinomas with lymphoid stroma and/or lace pattern components.

CONCLUSIONS

pT1b EBVGC is a convincing candidate for ER, regardless of risk factors other than lymphovascular invasion.

Simultaneous gastric adenosquamous carcinoma and gastric carcinoma with lymphoid stroma: A case report

Primary gastric adenosquamous carcinoma (ASC) is a rare tumor, and gastric carcinoma with lymphoid stroma (GCLS) is a distinct and relatively rare tumor, which is characterized histopathologically by prominent lymphoid infiltration and is commonly associated with Epstein-Barr virus (EBV) infection. The association between ASC and GCLS has been poorly understood, and only two cases of concomitant occurrence of ASC and GCLS have been reported previously. In this report, we describe the first documented case of simultaneous gastric ASC and GCLS. A 58-year-old Japanese male complained of loss of appetite. Gastric endoscopic examination revealed a type 3 tumor in the antrum. Distal gastrectomy with lymph node dissection was performed after neoadjuvant chemotherapy. Macroscopic examination of the resected specimen revealed two discontinuous lesions in the antrum. The first lesion, an ASC, was detected preoperatively by endoscopic examination. This type 3 tumor was composed of a mixture of squamous cell carcinoma (~75% of the tumor) and poorly-to-moderately differentiated adenocarcinoma (~25%). No EBV-encoded RNA (EBER)-positive neoplastic cells were noted. The tumor had invaded into the serosa. The second lesion was a GCLS, which was not preoperatively detected by endoscopic examination. The neoplastic cells of the GCLS were EBER-positive. The tumor had invaded into the muscularis propria. Accordingly, a diagnosis of simultaneous gastric ASC (pT4a) and GCLS (pT2) was made. The pathogenesis of gastric ASC has been under debate. Only limited cases of ASC associated with EBV have been reported. Notably, EBV has not been associated with the development of an ASC component in the previously reported concomitant cases of ASC and GCLS, as well as in the present case study. Therefore, additional studies are required to clarify the pathogenesis of gastric ASC, including its association with EBV.

Gastric Carcinomas With Lymphoid Stroma: An Evaluation of the Histopathologic and Molecular Features

Gastric carcinoma with lymphoid stroma is an uncommon variant enriched for mutually exclusive Epstein-Barr virus (EBV) positivity and mismatch repair (MMR) deficiency. We performed this study to evaluate molecular alterations in this morphologically homogeneous subtype and compare them with 295 conventional gastric cancers analyzed in The Cancer Genome Atlas study. We identified 31 study cases and subjected them to in situ hybridization for EBV-encoded RNAs and assessment for MMR status. Immunostains for PD-L1, β-catenin, and HER2 were performed; extracted DNA was sequenced with a Comprehensive Cancer Panel. Most study patients were older adult men with stage I or II disease (76%). Tumors were classified as EBV/MMR-proficient (MMR-P) (n=7), EBV/MMR deficient (n=12), and EBV/MMR-P (n=12). EBV/MMR-P tumors were usually located in the proximal stomach (83%) and showed heterogenous growth patterns with glandular differentiation (83%). Tumors in all groups showed numerous tumor infiltrating lymphocytes and PD-L1 expression, infrequent nuclear β-catenin accumulation (10%), and lacked both membranous HER2 staining and HER2 amplification. EBV/MMR-deficient tumors showed significantly higher tumor mutation burden (P=0.001) and KRAS alterations (56%) compared with EBV/MMR-P tumors (9%, P=0.05). TP53 variants were more common among EBV/MMR-P tumors (82%) compared with EBV/MMR proficient (0%, P=0.01) and EBV/MMR-deficient (11%, P<0.01) tumors. Alterations in KRAS, ARID1A, PIK3CA, and TP53 followed similar patterns of distribution compared with The Cancer Genome Atlas dataset. We conclude that gastric carcinomas with lymphoid stroma show a spectrum of molecular changes and frequent PD-L1 expression, raising the possibility that this subgroup of tumors may be susceptible to checkpoint inhibitors and/or agents that target receptor tyrosine kinase-mediated signaling.

Pitfalls in the Interpretation of Publications about Endoscopic Submucosal Dissection of Early Gastric Cancer with Undifferentiated-Type Histology

Endoscopic submucosal dissection (ESD) is a standard treatment for patients with gastrointestinal neoplasms with a negligible risk of lymph node metastasis. ESD enables en bloc resection of gastrointestinal neoplasms and organ preservation, thereby, avoiding surgical treatment. Although small (<2 cm) intramucosal early gastric cancer with undifferentiated-type histology (EGC-UH) without ulceration is included in the expanded criteria for ESD, controversies remain due to different biology and characteristics compared to EGC with differentiated-type histology. The authors previously presented studies about the technical feasibility of ESD for these lesions using a meta-analysis and retrospective multicenter analysis. However, many pitfalls were identified in the interpretation of studies analyzing histologic discrepancy, mixed-type histology, criteria-based analysis of therapeutic outcomes, interpretation of curative resection, and long-term clinical outcomes. In this review, the authors discuss pitfalls in the interpretation of publications on ESD for EGC-UH.

New insights into the inflamed tumor immune microenvironment of gastric cancer with lymphoid stroma: from morphology and digital analysis to gene expression

BACKGROUND

Gastric cancer with lymphoid stroma (GCLS) is characterized by prominent stromal infiltration of T-lymphocytes. The aim of this study was to investigate GCLS biology through analysis of clinicopathological features, EBV infection, microsatellite instability (MSI), immune gene-expression profiling and PD-L1 status in neoplastic cells and tumor immune microenvironment.

METHODS

Twenty-four GCLSs were analyzed by RNA in situ hybridization for EBV (EBER), PCR/fragment analysis for MSI, immunohistochemistry (PD-L1, cytokeratin, CD3, CD8), co-immunofluorescence (CK/PD-L1, CD68/PD-L1), NanoString gene-expression assay for immune-related genes and PD-L1 copy number alterations. CD3+ and CD8+ T-cell densities were calculated by digital analysis. Fifty-four non-GCLSs were used as control group.

RESULTS

GCLSs displayed distinctive clinicopathological features, such as lower pTNM stage (p = 0.02) and better overall survival (p = 0.01). EBV+ or MSI-high phenotype was found in 66.7 and 16.7% cases, respectively. GCLSs harbored a cytotoxic T-cell-inflamed profile, particularly at the invasive front of tumors (p < 0.01) and in EBV+ cases (p = 0.01). EBV+ GCLSs, when compared to EBV- GCLSs, showed higher mRNA expression of genes related to Th1/cytotoxic and immunosuppressive biomarkers. PD-L1 protein expression, observed in neoplastic and immune stromal cells (33.3 and 91.7%, respectively), and PD-L1 amplification (18.8%) were restricted to EBV+/MSI-high tumors and correlated with high values of PD-L1 mRNA expression.

CONCLUSIONS

This study shows that GCLS has a distinctive clinico-pathological and molecular profile. Furthermore, through an in-depth study of tumor immune microenvironment-by digital analysis and mRNA expression profiling-it highlights the role of EBV infection in promoting an inflamed tumor microenvironment, with putative therapeutic implications.

A Single-Center Experience of Endoscopic Resection for Early Gastric Cancer with Lymphoid Stroma

Purpose

This study aimed to evaluate immediate outcomes and clinical courses of patients with early gastric carcinoma with lymphoid stroma (GCLS) who underwent endoscopic resection.

Materials and Methods

We retrospectively reviewed the medical records of 40 patients (mean age, 56.9 years; 90.0% male) who underwent endoscopic resection and were pathologically diagnosed with GCLS confined to the mucosa or to the submucosa between March 1998 and December 2017.

Results

Forty GCLS lesions in 40 patients were treated using endoscopic resection. Only 4 (10%) patients received diagnosis of GCLS before endoscopic resection. Fourteen (35.0%) lesions were intramucosal cancers and 26 (65.0%) exhibited submucosal invasion. En bloc resection (97.5%) was achieved for all lesions except one, with no significant complications. The complete resection rate was 85.0% (34 of 40 lesions). After endoscopic resection, 17 patients were referred for surgery and underwent gastrectomy with lymph node (LN) dissection because of deep submucosal invasion (n=16) and misclassification as undifferentiated cancer (n=1). No LN metastasis was determined in the specimens obtained during surgery. During a mean follow-up period of 49.7 months for 23 patients without surgical treatment, no regional LN enlargements, distant metastases, or gastric cancer-related deaths were found, although 1 metachronous lesion (undifferentiated adenocarcinoma, follow-up duration: 7 months) was observed.

Conclusions

In patients with early GCLS, endoscopic resection is technically feasible and has favorable clinical outcomes. Therefore, endoscopic resection might represent an alternative treatment modality in patients with early GCLS with a low likelihood of LN metastasis.

Epstein-Barr virus-associated early gastric carcinoma with lymphoid stroma, accompanied with lymph node metastasis

The present case report presents a rare case of Epstein-Barr virus (EBV)-associated early gastric carcinoma with lymphoid stroma, accompanied by lymph node metastasis. A 61-year-old woman was referred to our hospital following observation of a gastric mass lesion that was initially diagnosed at a medical check-up. Esophagogastroduodenoscopy revealed a slightly elevated lesion with a central irregular depression in the middle third of the stomach. Endoscopic ultrasonography revealed a well-circumscribed hypoechoic mass located predominantly within the submucosa and the mucosa. Biopsy specimens of the lesion indicated the possibility of carcinoma with lymphoid stroma with a lymphoepithelial lesion. Abdominal contrast-enhanced computed tomography (CT) revealed a well-defined mass with homogeneous enhancement approximately 1.2 cm in diameter in the middle part of the stomach, demonstrating lymphadenopathy in the perigastric area at a maximum size of 1.4 cm in diameter. The patient underwent laparoscopic distal gastrectomy with regional lymphadenectomy due to suspicion of a gastric carcinoma with lymphoid stroma. Histopathological and immunohistochemical findings verified the diagnosis of carcinoma with lymphoid stroma, which were positive for EBV-encoded RNA (EBER-ISH) by in situ hybridization. There was one lymph node metastasis, which was in line with the CT imaging. Marked infiltration of lymphoid cells was observed in the tumor stroma, which were negative for EBER-ISH. The present case is informative of the pathological characteristics of this condition, and clinicians should recognize the features of this disease to make an accurate diagnosis and select the appropriate treatment.

Emerging biomarkers for immunomodulatory cancer treatment of upper gastrointestinal, pancreatic and hepatic cancers

Carcinomas of the oesophagus, stomach, pancreas and liver are common and account for a disproportionately high number of cancer deaths. There is a need for new treatment options for patients with advanced disease. Immunomodulatory treatments including immune checkpoint blockade offer a promising new approach, with efficacy shown in other solid tumour types. However, only a small proportion of patients with carcinomas of the oesophagus, stomach, pancreas and liver have responded to single agent checkpoint inhibitors, and there is a need for markers that are predictive of response to guide treatment of individual patients. Predictive markers may include epidemiological factors such as ethnicity, the genomic status of the tumour, circulating markers, expression of immune checkpoint molecules, and other features of the stromal/immune response at the site of the tumour. This review will focus on predictive biomarkers for immune checkpoint blockade in oesophageal, gastric, pancreatic and hepatocellular carcinomas, including the genomic context and immune landscape in which they occur. Pancreatic carcinomas are largely resistant to immune checkpoint inhibition in trials to date, therefore emerging immunomodulatory treatments in this tumour type are also reviewed.

Gastric Carcinomas With Lymphoid Stroma: Categorization and Comparison With Solid-Type Colonic Carcinomas

OBJECTIVES

To determine whether histologic features could help identify gastric carcinomas with lymphoid stroma associated with microsatellite instability (MSI) (ie, "medullary carcinomas"), Epstein-Barr virus (EBV) infection (termed lymphoepithelioma-like carcinomas in other organ systems), or neither.

METHODS

We identified 17 solid-type gastric carcinomas with lymphoid stroma, assessed EBV and MSI status, and compared features across groups. We also compared them with 51 solid-type colorectal adenocarcinomas.

RESULTS

In the stomach, EBV-associated carcinomas (n = 8) contained intratumoral germinal centers (P = .024) and eosinophils (P = .030) and lacked necrosis (P = .019) compared with MSI-associated carcinomas (n = 5) and non-EBV, non-MSI carcinomas (n = 4). In the colon, MSI-driven carcinomas (n = 40) more frequently contained intratumoral lymphocytes (P = .017) and neutrophils (P = .0050) and less often metastasized to distant sites (P = .0040) than poorly differentiated carcinomas lacking MSI (n = 11).

CONCLUSIONS

Morphology may help classify gastric carcinomas with lymphoid stroma, although ancillary testing appears more reliable. Lymphoepithelioma-like carcinoma and medullary carcinoma should not be used interchangeably.

The conundrum of the Epstein-Barr virus-associated gastric carcinoma in the Americas

Epstein-Barr virus-associated gastric carcinoma shows a higher prevalence in the Americas than Asia. We summarize all studies of Epstein Barr virus-associated gastric carcinoma in the Americas, focusing on host characteristics, environmental associations and phylogeographic diversity of Epstein-Barr virus strains. In the Americas, the prevalence of Epstein Barr virus-associated gastric carcinoma is 11.4%, more frequent in males and portray predominantly diffuse-type histology. EBERs, EBNAs, BARTs and LMP are the highest expressed genes; their variations in healthy individuals may explain the phylogeographic diversity of Epstein-Barr virus across the region. Gastric cancer cases harbor exclusively the western genotype (subtype D and kept Xho I site), suggesting a disrupted co-evolution between the pathogen and its host. Epstein-Barr virus-associated gastric carcinoma molecular subtype cases from The Cancer Genome Atlas display PIK3CA gene mutations, amplification of JAK2, PD-L1 and PD-L2 and CpG island methylator phenotype, leading to more extensive methylation of host and viral genomes than any other subtypes from the study. Environmental conditions include negative- and positive- associations with being firstborn child and smoking, respectively. A marginal association with H. pylori has also been reported. Lymphoepithelioma-like carcinoma is associated with Epstein Barr virus in 80%-86% of cases, most of which have been included as part of Epstein Barr virus-associated gastric carcinoma series (prevalence 1.1%-7.6%). Whether these cases represent a variant of Epstein-Barr virus-associated gastric carcinoma is discussed. We propose novel research strategies to solve the conundrum of the high prevalence of Epstein-Barr virus-associated gastric carcinoma in the Americas.

Clinical application of early gastric carcinoma with lymphoid stroma based on lymph node metastasis status

BACKGROUND

Gastric carcinoma with lymphoid stroma (GCLS) is characterized by undifferentiated carcinoma mixed with prominent lymphoid infiltration. GCLS has unique clinicopathological features and a better prognosis compared to other types of gastric cancer. We analyzed the clinicopathological features of early GCLS in relation to lymph node metastasis (LNM).

METHODS

We performed a retrospective analysis of 241 patients diagnosed with GCLS confined to the mucosa or the submucosa between March 1998 and December 2015. Their data were compared with those from 1219 patients who underwent resection for differentiated early gastric cancer (EGC).

RESULTS

Of the 241 patients analyzed, 33 (13.7%) had intramucosal cancers and 208 (86.3%) had cancers that penetrated the submucosa. Compared to differentiated EGC, early GCLS was more prevalent in younger individuals and in men, tended to be proximally located, was highly associated with Epstein-Barr virus (EBV) infection (89.2%), and had a lower risk of LNM. The 5-year disease-specific survival rate of patients with early GCLS was 98.3% but depended significantly on LNM status (p < 0.001) and EBV infection status (p = 0.039). The risk of LNM from mucosal GCLS and submucosal GCLS was 0% [95% confidence interval (CI) 0-9.1] and 10% (95% CI 6.8-15.2), respectively. On multivariate analysis, LNM was found to be associated with tumor size (p = 0.022) and lymphovascular invasion (p = 0.002) in addition to tumor depth.

CONCLUSIONS

Early GCLS has distinct clinicopathological features depending on age, sex, tumor location, EBV infection status, and LNM status. Tailored therapies, including endoscopic treatment, are needed based on the distinct clinicopathological features of early GCLS.

Sporadic Early-Onset Diffuse Gastric Cancers Have High Frequency of Somatic CDH1 Alterations, but Low Frequency of Somatic RHOA Mutations Compared With Late-Onset Cancers

BACKGROUND & AIMS

Early-onset gastric cancer, which develops in patients younger than most gastric cancers, is usually detected at advanced stages, has diffuse histologic features, and occurs more frequently in women. We investigated somatic genomic alterations associated with the unique characteristics of sporadic diffuse gastric cancers (DGCs) from younger patients.

METHODS

We conducted whole exome and RNA sequence analyses of 80 resected DGC samples from patients 45 years old or younger in Korea. Patients with pathogenic germline mutations in CDH1, TP53, and ATM were excluded from the onset of this analysis, given our focus on somatic alterations. We used MutSig2CV to evaluate the significance of mutated genes. We recruited 29 additional early-onset Korean DGC samples and performed SNP6.0 array and targeted sequencing analyses of these 109 early-onset DGC samples (54.1% female, median age, 38 years). We compared the SNP6.0 array and targeted sequencing data of the 109 early-onset DGC samples with those from diffuse-type stomach tumor samples collected from 115 patients in Korea who were 46 years or older (late onset) at the time of diagnosis (controls; 29.6% female, median age, 67 years). We compared patient survival times among tumors from different subgroups and with different somatic mutations. We performed gene silencing of RHOA or CDH1 in DGC cells with small interfering RNAs for cell-based assays.

RESULTS

We identified somatic mutations in the following genes in a significant number of early-onset DGCs: the cadherin 1 gene (CDH1), TP53, ARID1A, KRAS, PIK3CA, ERBB3, TGFBR1, FBXW7, RHOA, and MAP2K1. None of 109 early-onset DGC cases had pathogenic germline CDH1 mutations. A higher proportion of early-onset DGCs had mutations in CDH1 (42.2%) or TGFBR1 (7.3%) compared with control DGCs (17.4% and 0.9%, respectively) (P < .001 and P = .014 for CDH1 and TGFBR1, respectively). In contrast, a smaller proportion of early-onset DGCs contained mutations in RHOA (9.2%) than control DGCs (19.1%) (P = .033). Late-onset DGCs in The Cancer Genome Atlas also contained less frequent mutations in CDH1 and TGFBR1 and more frequent RHOA mutations, compared with early-onset DGCs. Early-onset DGCs from women contained significantly more mutations in CDH1 or TGFBR1 than early-onset DGCs from men. CDH1 alterations, but not RHOA mutations, were associated with shorter survival times in patients with early-onset DGCs (hazard ratio, 3.4; 95% confidence interval, 1.5-7.7). RHOA activity was reduced by an R5W substitution-the RHOA mutation most frequently detected in early-onset DGCs. Silencing of CDH1, but not RHOA, increased migratory activity of DGC cells.

CONCLUSIONS

In an integrative genomic analysis, we found higher proportions of early-onset DGCs to contain somatic mutations in CDH1 or TGFBR1 compared with late-onset DGCs. However, a smaller proportion of early-onset DGCs contained somatic mutations in RHOA than late-onset DGCs. CDH1 alterations, but not RHOA mutations, were associated with shorter survival times of patients, which might account for the aggressive clinical course of early-onset gastric cancer. Female predominance in early-onset gastric cancer may be related to relatively high rates of somatic CDH1 and TGFBR1 mutations in this population.

Clinicopathologic features of early gastric carcinoma with lymphoid stroma and feasibility of endoscopic submucosal dissection

BACKGROUND

Gastric carcinoma with lymphoid stroma (GCLS) is a rare disease known to have unique features and a favorable prognosis. This study aimed to determine the clinicopathologic features of early GCLS (EGCLS) and define the feasibility of endoscopic submucosal dissection (ESD) for EGCLS.

METHODS

We performed a retrospective analysis of 70 EGCLS patients treated via ESD or surgery and 1626 patients who underwent surgical resection for early non-GCLS (ENGCLS) between January 2007 and December 2014 at Pusan National University Hospital, Busan, Republic of Korea.

RESULTS

The mean age of EGCLS patients was 58 years (range 36-77 years); a male predominance (3.7:1) was observed, and 81.4% showed Epstein-Barr virus positivity. Compared with ENGCLS, EGCLS was macroscopically more elevated (34.3 vs. 18.0%, P = 0.003) and located more proximally (upper third: 37.1 vs. 9.7%, P < 0.001). Tumor size was smaller (2.1 ± 1.1 vs. 3.1 ± 2.0 cm, P < 0.001), but submucosal invasion was more frequent (77.1 vs. 44.4%, P < 0.001) and deeper in the EGCLS group. Among the 59 EGCLS patients who were treated surgically, only two (3.4%) showed lymph node metastasis (LNM). Despite submucosal invasion, EGCLS showed a lower LNM rate (4.0 vs. 19.4%, P = 0.007) than ENGCLS, even in patients with SM3 EGCLS (5.3 vs. 24.5%, P = 0.007). There were no recurrences in the available ten patients who underwent ESD alone during a mean follow-up of 37.2 months.

CONCLUSIONS

In this study, we observed unique clinicopathologic features with a very low LNM rate in EGCLS. We consider ESD a potentially curative treatment strategy for EGCLS despite deep submucosal invasion, especially in patients with poor performance status and significant comorbidities.

Aberrant expression of AID and AID activators of NF-κB and PAX5 is irrelevant to EBV-associated gastric cancers, but is associated with carcinogenesis in certain EBV-non-associated gastric cancers

Epstein-Barr virus-associated gastric carcinoma (EBVaGC) is a distinct subtype of gastric cancer characterized by clinicopathological features including lymphoepithelioma-like histology. Aberrant expression of activation-induced cytidine deaminase (AID) as a genomic modulator was demonstrated through pathogen-related nuclear factor κB (NF-κB) signaling in Helicobacter pylori-associated gastric cancer. To elucidate whether or not AID expression is relevant to carcinogenesis in EBVaGC, immunohistochemical expression of AID and AID-regulatory factors between EBVaGC and EBV-non-associated gastric carcinoma (GC) were evaluated, each using 15 cases of GC with lymphoid stroma (GCLS) and other types of GC. Aberrant expression of AID, NF-κB and paired box 5 (PAX5) were significantly decreased in EBVaGC (0/11, 1/11 and 1/11) compared with in EBV-non-associated GC (7/19, 12/19 and 11/19) (P=0.025, 0.005 and 0.01, respectively); however, no significant difference in c-Myb proto-oncogene expression was identified. AID expression was also decreased in EBV-associated GCLS (0/10) compared with in EBV-non-associated GCLS (3/5). Unexpectedly, decreased expression of NF-κB and PAX5 was observed in GCLS (1/15 and 2/15) compared with in GC without LS (12/15 and 10/15) (P<0.001 and P=0.003, respectively). Decreased AID expression observed in EBVaGC is consistent with the reported molecular characterization of hypermethylation and rare somatic gene mutation in EBVaGC. Only PAX5 was identified to be significantly associated with venous invasion (P=0.022). The results of the present study suggest that pathogen-induced AID expression may be irrelevant to carcinogenesis of EBVaGC, whereas it contributes to carcinogenesis in certain types of EBV-non-associated GC.

Oncogenic Role of Tumor Viruses in Humans

Viruses are the intracellular pathogens that reproduce only in the living cell and manipulate the cellular machinery to produce more viruses. Viral replications can affect cellular genes of the host in multiple cancerous ways. Approximately, 20% of all human oncogenesis is caused by cancer-causing viruses known as oncoviruses. Viral infection causes chronic inflammation leading to cell death, uncontrollable proliferation, and modulated expression of some of the regulatory proteins. Oncogenesis is a multistep phenomenon in which normal host cells are transformed into cancerous cells on the basis of host genetic variability. Oncogenic viruses encode genes that cause viral replication and transformation of the host cells to produce viral proteins and protein complexes. The phenomenon from basic viral infection to tumorigenesis is lengthy due to the involvement of factors like immunity complications, cellular mutations, and exposure to other cancerous agents. The viruses that are involved in human cancer development are Hepatitis B virus (HBV), Hepatitis C virus (HCV), Epstein-Barr virus (EBV), Human papilloma virus (HPV), Kaposi's sarcoma herpes virus (KSHV), and Human T lymphotrophic virus 1 (HTLV-1). This review article summarizes advanced knowledge related to human oncogenic viruses and the molecular mechanisms that lead to tumorigenesis in humans.

Gastric cancer - clinical and epidemiological aspects

Gastric cancer (GC) ranks fifth for cancer incidence and second for cancer deaths. Epidemiological data showed that survivors of Hodgkin's lymphoma and patients with pernicious anemia etiologically linked to autoimmune gastritis are at increased risk of GC. Screening of patients with autoimmune thyroid disease by means of pepsinogen (PG) I and PG I/II detected autoimmune gastritis with oxyntic gastric atrophy in one of four patients and may be recommended for GC prevention purposes. The International Agency for Research on Cancer reported a positive association between consumption of processed meet and increased GC risk. A new GC risk prediction model based on biological markers, age, gender, smoking status, family history of GC, and consumption of highly salted food showed good predictive performance, and might prompt individuals to modify their lifestyle habits, attend regular check-up visits or participate in screening programs. A novel GC classification based on gene expression of primary resected cancers correlated with clinicopathological features. Noncoding RNA for GC screening remains the focus of multiple studies. Patients with early GC undergoing endoscopic resection are more likely to develop metachronous lesions than patients undergoing surgery and endoscopic surveillance is warranted in this special cohort. The addition of gastrectomy to chemotherapy did not improve survival of patients with advanced GC and a single noncurable factor. Apatinib, a novel oral vascular endothelial growth factor receptor 2 tyrosine kinase inhibitor, improved the median overall survival of patients with advanced GC and progressive disease after two or more lines of prior chemotherapy of nearly 3 months.

Clinicopathologic features of gastric carcinoma with lymphoid stroma in early gastric cancer

BACKGROUND AND OBJECTIVES

Gastric carcinoma with lymphoid stroma (GCLS) is a rare variant of gastric cancer. The aims of this study were to investigate the clinicopathologic features of GCLS in early gastric cancer (EGC).

METHODS

Analysis included 3,385 patients who were diagnosed with EGC after surgery between 2005 and 2012. This study compared GCLS with non-GCLS patients in terms of clinicopathological features including lymph node metastasis (LNM).

RESULTS

Forty-one (1.2%) patients were diagnosed as GCLS among those with EGC. When GCLS and non-GCLS patients were compared, the GCLS group showed a greater predominance among males, greater tendency towards proximal location, a more elevated gross appearance, and deeper submucosal invasion. In particular, more than 90% of GCLS cases showed deep submucosal invasion. The LNM rate was significantly lower in GCLS than non-GCLS cases after adjustment for depth of invasion. Among the GCLS group, there was no LNM in the cases with lesions confined to the mucosa or submucosal invasive lesions with tumor size ≤10 mm.

CONCLUSIONS

In EGC, GCLS showed deeper submucosal invasion and a lower LNM rate compared with non-GCLS. Thus, clinical considerations of GCLS may be helpful to decide on a specific cancer treatment. J. Surg. Oncol. 2016;114:769-772. © 2016 Wiley Periodicals, Inc.

Recent advances in proximal gastric carcinoma

The American Joint Committee on Cancer (AJCC) staging scheme requires staging proximal gastric carcinoma (PGC) as esophageal adenocarcinoma (EAC), which has been shown to be controversial by recent research results. To update the current research findings on PGC, we systematically reviewed and analyzed the scientific evidence on key arguments related to PGC. The data of high-quality research articles showed that PGC arised in the cardiac mucosa in the proximal stomach within 3 cm below the gastroesophageal junction. Its incidence is rising in East Asian countries, but decreasing in the West, and plateaued at a low level in the United States. PGC is a slowly progressive cancer with unknown independent risk factors and the mechanisms of pathogenesis. This carcinoma exhibits a wide histopathological spectrum and heterogeneous post-resection patient survival characteristics, and cannot be adequately staged for prognotic stratification by the current AJCC staging classification. The results on PGC genomics reveal unique genetic profiles, especially in East Asian populations. In conclusion, mounting evidence defies a simple placement of PGC in a single category of EAC for disease classification; further investigations on the mechanisms of PGC pathogenesis are urgently needed.

PD-L1 expression is associated with massive lymphocyte infiltration and histology in gastric cancer

The mechanism of carcinogenesis of gastric cancer (GC) is still unclear now. This study aimed to explore the correlations among PD-L1, Epstein-Barr virus (EBV) infection, lymphocyte infiltration, HER2 expression, HER2 gene status, histology, and other clinicopathological factors in GC. A total of 44 GC patients with massive lymphocyte infiltration (GC-MLI) and 93 GC patients without massive lymphocyte infiltration were involved in this study. Immunohistochemical analysis was used to test the expression levels of PD-L1 and HER2. Fluorescence in situ hybridization was used on HER2-positive cases with a score of 2+ to test the HER2 gene status. EBV-encoded RNA was used to test for EBV infection. In univariate analysis, PD-L1 expression was significantly associated with GC-MLI (P<.001), lower age (P=.019), EBV infection (P<.001), lower HER2 expression (P=.011), and diffuse/mixed type of histology (P=.022). EBV-encoded RNA-positive cases were significantly associated with GC-MLI (P<.001), lower age (P=.016), diffuse/mixed type of histology (P=.011), and lower HER2 expression (P=.032). In the multivariate logistic regression model, GC-MLI and the diffuse/mixed type histology were identified as 2 independent factors that affected PD-L1 expression (P<.001). Furthermore, PD-L1-positive cases have worse overall survival than do PD-L1-negative cases (P=.011). These results suggest that massive lymphocyte infiltration and the diffuse/mixed type histology of GC should be taken into consideration to select the appropriate patients for PD-L1 inhibitory treatment in the future.