Prognostic significance of Epstein-Barr virus infection in gastric cancer: a meta-analysis

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.

Plasma EBV DNA as a prognostic factor in EBV associated gastric cancer: a multicenter, prospective study (EBV PRESAGE study)

Purpose

The Cancer Genome Atlas Research Network identified Epstein-Barr-Virus (EBV)-positive gastric cancer as a distinct molecular subtype. The prevalence is 8-9% and the histological examination shows pronounced lymphocytic infiltration, elevated levels of IFN-γ and consequently overexpression of PD-L1. The role of plasma EBV DNA load as a prognostic factor in patients with this cancer subtype is still to be defined.

Methods and analysis

The present multicenter prospective observational study "EBV PRESAGE", involving German and Italian cancer centers, aims to evaluate the prognostic role of plasma EBV DNA in EBV-related gastric cancer (GC). The objective is to study the association between plasma EBV DNA load at different consecutive time points and the patient's prognosis. Every patient with a new diagnosis of gastric cancer (including gastroesophageal junction adenocarcinoma) will be screened for Epstein-Barr encoded small Region (EBER) on tissue biopsies using in situ hybridization (ISH). If EBER ISH is positive, blood analysis for plasma EBV DNA will be conducted. The plasma EBV quantitative analysis will be centralized, and extraction, detection, and quantification of EBV DNA in plasma samples will be performed using real-time PCR.

Discussion

We hypothesized that plasma EBV DNA represents a non-invasive tool for monitoring EBV-related GC and might be valuable as a prognostic marker.

Pathogenesis and therapeutic implications of EBV-associated epithelial cancers

Epstein-Barr virus (EBV), one of the most common human viruses, has been associated with both lymphoid and epithelial cancers. Undifferentiated nasopharyngeal carcinoma (NPC), EBV associated gastric cancer (EBVaGC) and lymphoepithelioma-like carcinoma (LELC) are amongst the few common epithelial cancers that EBV has been associated with. The pathogenesis of EBV-associated NPC has been well described, however, the same cannot be said for primary pulmonary LELC (PPLELC) owing to the rarity of the cancer. In this review, we outline the pathogenesis of EBV-associated NPC and EBVaGCs and their recent advances. By drawing on similarities between NPC and PPLELC, we then also postulated the pathogenesis of PPLELC. A deeper understanding about the pathogenesis of EBV enables us to postulate the pathogenesis of other EBV associated cancers such as PPLELC.

Prognostic Implication of EBV Infection in Gastric Carcinomas: A Systematic Review and Meta-Analysis

Background and objectives: This study aims to elucidate the prognostic implications of Epstein-Barr virus (EBV) infection in gastric carcinomas (GCs) through a systematic review and meta-analysis. Materials and Methods: In total, 57 eligible studies and 22,943 patients were included in this meta-analysis. We compared the prognoses of EBV-infected and non-infected GC patients. The subgroup analysis was performed based on the study location, molecular classification, and Lauren's classification. This study was checked according to the PRISMA 2020. The meta-analysis was performed using the Comprehensive Meta-Analysis software package. Results: EBV infection was found in 10.4% (95% confidence interval (CI) 0.082-0.131) of GC patients. The EBV-infected GC patients had a better overall survival compared with the EBV-non-infected GC patients (hazard ratio (HR) 0.890, 95% CI 0.816-0.970). In the subgroup analysis based on molecular classification, no significant differences were found between EBV+ and microsatellite instability and microsatellite stable (MSS)/EBV- subgroups (HR 1.099, 95% CI 0.885-1.364 and HR 0.954, 95% CI 0.872-1.044, respectively). In the diffuse type of Lauren's classification, EBV-infected GCs have a better prognosis compared with the EBV-non-infected GCs (HR 0.400, 95% CI 0.300-0.534). The prognostic impact of EBV infection was found in the Asian and American subgroups but not in the European subgroup (HR 0.880, 95% CI 0.782-0.991, HR 0.840, 95% CI 0.750-0.941, and HR 0.915, 95% CI 0.814-1.028). Conclusions: EBV infection is a favorable survival factor for GCs. However, the prognostic implications of EBV infection in the new molecular classification are not clear.

Assessing Epstein-Barr virus in gastric cancer: clinicopathological features and prognostic implications

BACKGROUND

Epstein-Barr virus (EBV)-associated gastric cancer (EBVaGC) was a unique molecular subtype of gastric cancer (GC). However, the clinicopathological characteristics and prognostic role of EBV infection remains unclear. We aimed to evaluate the clinicopathological features of EBVaGC and its role on prognosis.

METHODS

EBV-encoded RNA (EBER) in situ hybridization method was used to evaluate the EBV status in GC. The serum tumor markers AFP, CEA, CA19-9 and CA125 of patients were detected before treatment. HER2 expression and microsatellite instability (MSI) status was evaluated according to established criteria. The relationship between EBV infection and clinicopathological factors as well as its role on prognosis were investigated.

RESULTS

420 patients were enrolled in the study and of 53 patients (12.62%) were identified as EBVaGC. EBVaGC was more common in males (p = 0.001) and related to early T stage (p = 0.045), early TNM stage (p = 0.001) and lower level of serum CEA (p = 0.039). No association could be found between EBV infection and HER2 expression, MSI status and other factors (p all > 0.05). Kaplan-Meier analysis revealed that both the overall survival and disease-free survival of EBVaGC patients were similar to that of EBV-negative GC (EBVnGC) patients (p = 0.309 and p = 0.264, respectively).

CONCLUSION

EBVaGC was more common in males and in patients with the early T stage and TNM stage as well as patients with lower serum CEA level. Difference in overall survival and disease-free survival between EBVaGC and EBVnGC patients cannot be detected.

Tumor-Infiltrating T Cells in EBV-Associated Gastric Carcinomas Exhibit High Levels of Multiple Markers of Activation, Effector Gene Expression, and Exhaustion

Epstein-Barr virus (EBV) is a gamma-herpesvirus associated with 10% of all gastric cancers (GCs) and 1.5% of all human cancers. EBV-associated GCs (EBVaGCs) are pathologically and clinically distinct entities from EBV-negative GCs (EBVnGCs), with EBVaGCs exhibiting differential molecular pathology, treatment response, and patient prognosis. However, the tumor immune landscape of EBVaGC has not been well explored. In this study, a systemic and comprehensive analysis of gene expression and immune landscape features was performed for both EBVaGC and EBVnGC. EBVaGCs exhibited many aspects of a T cell-inflamed phenotype, with greater T and NK cell infiltration, increased expression of immune checkpoint markers (BTLA, CD96, CTLA4, LAG3, PD1, TIGIT, and TIM3), and multiple T cell effector molecules in comparison with EBVnGCs. EBVaGCs also displayed a higher expression of anti-tumor immunity factors (PDL1, CD155, CEACAM1, galectin-9, and IDO1). Six EBV-encoded miRNAs (miR-BARTs 8-3p, 9-5p, 10-3p, 22, 5-5p, and 14-3p) were strongly negatively correlated with the expression of immune checkpoint receptors and multiple markers of anti-tumor immunity. These profound differences in the tumor immune landscape between EBVaGCs and EBVnGCs may help explain some of the observed differences in pathological and clinical outcomes, with an EBV-positive status possibly being a potential biomarker for the application of immunotherapy in GC.

Predictive biomarkers in gastric cancer

Predictive biomarkers are the mainstay of precision medicine. This review summarizes the advancements in tissue-based diagnostic biomarkers for gastric cancer, which is considered the leading cause of cancer-related deaths worldwide. A disease seen in the elderly, it is often diagnosed at an advanced stage, thereby limiting therapeutic options. In Western countries, neoadjuvant/perioperative (radio-)chemotherapy is administered, and adjuvant chemotherapy is administered in the East. The morpho-molecular classification of gastric cancer has opened novel avenues identifying Epstein-Barr-Virus (EBV)-positive, microsatellite instable, genomically stable and chromosomal instable gastric cancers. In chromosomal instable tumors, receptor tyrosine kinases (RKTs) (e.g., EGFR, FGFR2, HER2, and MET) are frequently overexpressed. Gastric cancers such as microsatellite instable and EBV-positive types often express immune checkpoint molecules, such as PD-L1 and VISTA. Genomically stable tumors show alterations in claudin 18.2. Next-generation sequencing is increasingly being used to search for druggable targets in advanced palliative settings. However, most tissue-based biomarkers of gastric cancer carry the risk of a sampling error due to intratumoral heterogeneity, and adequate tissue sampling is of paramount importance.

Association between human herpesvirus-6 and primary brain tumors: a systematic review and meta-analysis

Aim: The present study aimed to find out the prevalence and any possible association between human herpesvirus (HHV-6) and primary brain tumors. Materials & methods: The systematic literature search was performed by finding related articles from major databases. Analysis was performed by comprehensive meta-analysis software. Results: A total of 13 (25 datasets) articles were included in the study, seven (15 datasets) of which were case/control and the rest (ten datasets) were cross-sectional studies. The pooled prevalence of HHV-6 among primary brain cancer patients was 29% (95% CI: 24–33%; I2 = 97.89%). An association was found between HHV-6 and primary brain cancer (summary odds ratio: 3.77% [95% CI: 2.59–5.49%; I2 = 19.0%]). Conclusion: Our analysis demonstrated that HHV-6 is associated with primary brain cancer. Reactivation of the virus could be triggered by the tumor, therefore, we cannot be certain that the virus appeared before the cancer development.

Efficacy and predictive biomarkers of immunotherapy in Epstein-Barr virus-associated gastric cancer

Background

Epstein-Barr virus (EBV)-associated gastric cancer (GC) (EBVaGC) is a distinct molecular subtype of GC with a favorable prognosis. However, the exact effects and potential mechanisms of EBV infection on immune checkpoint blockade (ICB) efficacy in GC remain to be clarified. Additionally, EBV-encoded RNA (EBER) in situ hybridization (ISH), the traditional method to detect EBV, could cause false-positive/false-negative results and not allow for characterizing other molecular biomarkers recommended by standard treatment guidelines for GC. Herein, we sought to investigate the efficacy and potential biomarkers of ICB in EBVaGC identified by next-generation sequencing (NGS).

Design

An NGS-based algorithm for detecting EBV was established and validated using two independent GC cohorts (124 in the training cohort and 76 in the validation cohort). The value of EBV infection for predicting ICB efficacy was evaluated among 95 patients with advanced or metastatic GC receiving ICB. The molecular predictive biomarkers for ICB efficacy were identified to improve the prediction accuracy of ICB efficacy in 22 patients with EBVaGC.

Results

Compared with orthogonal assay (EBER-ISH) results, the NGS-based algorithm achieved high performance with a sensitivity of 95.7% (22/23) and a specificity of 100% (53/53). EBV status was identified as an independent predictive factor for overall survival and progression-free survival in patients with DNA mismatch repair proficient (pMMR) GC following ICB. Moreover, the patients with EBV+/pMMR and EBV−/MMR deficient (dMMR) had comparable and favorable survival following ICB. Twenty-two patients with EBV+/pMMR achieved an objective response rate of 54.5% (12/22) on immunotherapy. Patients with EBVaGC with a high cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) level were less responsive to anti-programmed death-1/ligand 1 (PD-1/L1) monotherapy, and the combination of anti-CTLA-4 plus anti-PD-1/L1 checkpoint blockade benefited patients with EBVaGC more than anti-PD-1/L1 monotherapy with a trend close to significance (p=0.074). There were nearly significant differences in tumor mutational burden (TMB) level and SMARCA4 mutation frequency between the ICB response and non-response group.

Conclusions

We developed an efficient NGS-based EBV detection strategy, and this strategy-identified EBV infection was as effective as dMMR in predicting ICB efficacy in GC. Additionally, we identified CTLA-4, TMB, and SMARCA4 mutation as potential predictive biomarkers of ICB efficacy in EBVaGC, which might better inform ICB treatment for EBVaGC.

Epstein–Barr Virus Epithelial Cancers—A Comprehensive Understanding to Drive Novel Therapies

Epstein–Barr virus (EBV) is a ubiquitous oncovirus associated with specific epithelial and lymphoid cancers. Among the epithelial cancers, nasopharyngeal carcinoma (NPC), lymphoepithelioma-like carcinoma (LELC), and EBV-associated gastric cancers (EBVaGC) are the most common. The role of EBV in the pathogenesis of NPC and in the modulation of its tumour immune microenvironment (TIME) has been increasingly well described. Much less is known about the pathogenesis and tumour–microenvironment interactions in other EBV-associated epithelial cancers. Despite the expression of EBV-related viral oncoproteins and a generally immune-inflamed cancer subtype, EBV-associated epithelial cancers have limited systemic therapeutic options beyond conventional chemotherapy. Immune checkpoint inhibitors are effective only in a minority of these patients and even less efficacious with molecular targeting drugs. Here, we examine the key similarities and differences of NPC, LELC, and EBVaGC and comprehensively describe the clinical, pathological, and molecular characteristics of these cancers. A deeper comparative understanding of these EBV-driven cancers can potentially uncover targets in the tumour, TIME, and stroma, which may guide future drug development and cast light on resistance to immunotherapy.

Reproduction of the Cancer Genome Atlas (TCGA) and Asian Cancer Research Group (ACRG) Gastric Cancer Molecular Classifications and Their Association with Clinicopathological Characteristics and Overall Survival in Moroccan Patients

Introduction

The Cancer Genome Atlas (TCGA) project and Asian Cancer Research Group (ACRG) recently categorized gastric cancer into molecular subtypes. Nevertheless, these classification systems require high cost and sophisticated molecular technologies, preventing their widespread use in the clinic. This study is aimed to generating molecular subtypes of gastric cancer using techniques available in routine diagnostic practice in a series of Moroccan gastric cancer patients. In addition, we assessed the associations between molecular subtypes, clinicopathological features, and prognosis.

Methods

Ninety-seven gastric cancer cases were classified according to TCGA, ACRG, and integrated classifications using a panel of four molecular markers (EBV, MSI, E-cadherin, and p53). HER2 status and PD-L1 expression were also evaluated. These markers were analyzed using immunohistochemistry (E-cadherin, p53, HER2, and PD-L1), in situ hybridization (EBV and HER2 equivocal cases), and multiplex PCR (MSI).

Results

Our results showed that the subtypes presented distinct clinicopathological features and prognosis. EBV-positive gastric cancers were found exclusively in male patients. The GS (TCGA classification), MSS/EMT (ACRG classification), and E-cadherin aberrant subtype (integrated classification) presented the Lauren diffuse histology enrichment and tended to be diagnosed at a younger age. The MSI subtype was associated with a better overall survival across all classifications (TCGA, ACRG, and integrated classification). The worst prognosis was observed in the EBV subtype (TCGA and integrated classification) and MSS/EMT subtype (ACRG classification). Discussion/Conclusion. We reported a reproducible and affordable gastric cancer subtyping algorithms that can reproduce the recently recognized TCGA, ACRG, and integrated gastric cancer classifications, using techniques available in routine diagnosis. These simplified classifications can be employed not only for molecular classification but also in predicting the prognosis of gastric cancer patients.

Epstein-Barr Virus Positive Gastric Cancer: A Distinct Subtype Candidate for Immunotherapy

BACKGROUND

Epstein-Barr virus (EBV) positive gastric cancer (GC) has been described as a distinct molecular subtype of the disease, especially associated with gastric carcinoma with lymphoid stroma (GCLS). The possibility that EBV associated GC (EBVaGC) had better prognosis and may be susceptible to immunotherapy has increased the interest in this subtype. However, immune checkpoint and survival of EBVaGC are still controversial, especially with regard to GCLS and conventional gastric adenocarcinoma (CGA). This study aimed to evaluate the clinicopathological characteristics, immunohistochemical profiles and prognosis of EBVaGC according to the histological type GCLS and CGA.

METHODS

we retrospectively evaluated a series of EBVaGC who underwent gastrectomy with D2-lymphadenectomy. Biomarkers and tumor-infiltrating cells were evaluated by immunohistochemistry. PD-L1 was evaluated using a combined positive score (CPS).

RESULTS

From a total of 30 EBVaGC, 14 (46.7%) were identified as GCLS and 16 (53.3%) as CGA (9 Intestinal, 6 diffuse, 1 undetermined). There were no significant differences in age, sex, and pTNM between GCLS and CGA. CPS-positivity and high-CD8⁺ was significantly higher in GCLS compared with CGA (P = 0.007 and P = 0.005, respectively). Diffuse EBVaGC had worse survival than intestinal type (P = 0.020). There was no difference in survival between GCLS and intestinal CGA (P = 0.260). In multivariate analysis, CPS and pN status were related with survival in EBVaGC.

CONCLUSIONS

CGLS was associated with a predominance of CD8⁺ cell infiltration and PD-L1 expression. CPS and lymph node metastasis were independent factors associated with prognosis in EBVaGC. These results suggest that specifically EBV-positive GCLS may be prime candidates for PD-1 directed therapy.

Low Epstein-Barr Virus Prevalence in Cardia Gastric Cancer Among a High-Incidence Chinese Population

BACKGROUND

Epstein-Barr virus (EBV) positivity is associated with better gastric cancer prognosis and is found in a relatively fixed 9% of tumors worldwide.

AIM

We aimed to examine the EBV status of gastric adenocarcinomas in a very high-incidence population and to compare prevalence between cardia and non-cardia anatomic subsites.

METHODS

We evaluated 1035 adult gastric adenocarcinoma cases presenting during 1997-2005 to the Shanxi Cancer Hospital in Taiyuan, Shanxi Province, China. EBV-encoded RNA was detected in alcohol-fixed paraffin-embedded tumor specimens by in situ hybridization. Associations were assessed in case-case comparisons using the Chi-squared test for categorical variables and the Mann-Whitney U test for continuous variables, with p values < 0.05 considered statistically significant. Adjusted odds ratios were calculated using logistic regression, and mortality hazard ratios (HRs) were estimated by Cox proportional hazards regression.

RESULTS

Sixty-four percent of the evaluated cancers were found in the cardia. Cardia tumor localization was associated with male sex, advanced primary tumor stage, better differentiated histology, and intestinal-type Lauren classification. Four percent of the non-cardia and only 0.9% of cardia cancers were EBV-positive. EBV positivity was associated with better overall survival (adjusted HR 0.30, 95% CI 0.14-0.63).

CONCLUSIONS

Our study highlights unusually low EBV prevalence in gastric adenocarcinoma among a high-incidence population, particularly for cardia cancers. These findings suggest a unique risk factor profile for the high incidence of gastric cancer in this population.

Isolated brachioradialis metastasis of gastric adenocarcinoma after R0 resection

BACKGROUND

Gastric cancer is the fifth most common cancer worldwide, with an incidence of 6.72 per 100,000 people. Thirty-two percent of gastric cancer patients will live 5 years after diagnosis. Single-site metastasis is noted in 26% of patients with gastric cancer, most commonly in the liver (48%), peritoneum (32%), lung (15%), and bone (12%). Here, a case is presented in which a single skeletal muscle metastasis appeared after appropriate resection and treatment.

CASE PRESENTATION

A 63-year-old man underwent neoadjuvant chemotherapy and a multivisceral en bloc R0 resection. Final pathology showed no evidence of lymph node metastasis with 31 negative lymph nodes. Four months postoperatively, the patient was found to have a rapidly growing biopsy-proven extremity soft tissue gastric metastasis within the brachioradialis muscle. He subsequently underwent metastasectomy and immunotherapy.

CONCLUSION

This case is a rare example of an isolated extremity metastasis of gastric adenocarcinoma in the setting of an R0 resection of the primary tumor and negative nodal disease on final pathology, suggestive of hematogenous spread. We review the biology, workup, and management of gastric cancer and highlight new advancements in the treatment of this aggressive cancer.

LGR5 expression is associated with prognosis in poorly differentiated gastric adenocarcinoma

Background

Leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5) is an important cancer stem cell marker in gastric cancer. However, no detailed studies are available on LGR5 expression in poorly differentiated gastric adenocarcinoma (PD-AC). Therefore, we investigated the relationship between LGR5 expression and clinicopathological data in PD-AC.

Methods

LGR5 mRNA expression levels were quantified in 41 PD-AC specimens using a highly sensitive RNAscope in situ hybridization technique. Epstein–Barr virus (EBV) infection was also detected by EBV in situ hybridization.

Results

LGR5 expression levels were measured in 38 of 41 PD-AC cases, and 17 cases were identified as LGR5 high. The frequency of EBV positivity tended to be higher in the LGR5-low group than in the LGR5-high group (P = 0.0764). Furthermore, the frequency of vascular invasion tended to be higher in the LGR5-high group than in the LGR5-low group (P = 0.0764). The overall survival of PD-AC patients in the LGR5-high group was significantly lower than in the LGR5-low group (log-rank test, P = 0.0108). The Cox proportional hazard regression model revealed that the LGR5-low group (HR = 0.29; 95% CI: 0.11–0.74; P = 0.01) showed independently better OS for PD-AC.

Conclusions

Quantifying the levels of LGR5 expression may facilitate defining prognosis in Japanese patients with PD-AC. Further study of LGR5 in this context is warranted.

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

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

Epstein-Barr virus-encoded miR-BART5-5p upregulates PD-L1 through PIAS3/pSTAT3 modulation, worsening clinical outcomes of PD-L1-positive gastric carcinomas

BACKGROUND

Epstein-Barr virus (EBV) is etiologically associated with ~ 10% of all gastric carcinomas. However, the molecular mechanisms and roles of EBV miRNAs in gastric carcinoma oncogenesis are yet to be elucidated.

METHODS

MicroRNA microarray and TaqMan quantitative real-time RT-PCR were conducted. RT-PCR and luciferase reporter assay for PIAS3, western blotting for 20 proteins, immunofluorescence for STAT3, transfection with miRBART5-5p-plasmid, STAT3-plasmid, miRBART5-5p mimic, or PIAS3-siRNA, and in vitro assays for biological effects of PD-L1 were implemented. In situ hybridization for EBV-encoded small RNAs and immunohistochemistry were performed on gastric carcinoma tissues.

RESULTS

Transfecting miR-BART5-5p into EBV(-) gastric carcinoma cell lines caused a decrease in PIAS3 3'-UTR reporter activity, PIAS3 downregulation, and subsequent STAT3 activation followed by PIAS3/pSTAT3-dependent PD-L1 upregulation. Interestingly, due to PD-L1 knockdown, apoptosis was increased, while the rate of cell proliferation, invasion capacity, and migration were decreased in miR-BART5-5p-transfected cells. In EBV(+) gastric carcinoma cells, anti-miR-BART5-5p reduced PD-L1 levels through PIAS3/pSTAT3 control. Among 103 patients with EBV-associated gastric carcinomas, overall survival was significantly shortened for those with PD-L1(+) tumors compared to those with PD-L1(-) tumors (P = 0.049).

CONCLUSIONS

Our findings imply that miR-BART5-5p directly targets PIAS3 and augments PD-L1 through miR-BART5/PIAS3/pSTAT3/PD-L1 axis control. This contributes to antiapoptosis, tumor cell proliferation, invasion and migration, as well as immune escape, furthering gastric carcinoma progression and worsening the clinical outcome, especially in the PD-L1(+) group of patients with EBV-associated gastric carcinomas. miR-BART5-5p may, therefore, be amenable to PD-1/PD-L1 immune checkpoint inhibitor therapy.

Epstein-Barr virus infection and genome polymorphisms on gastric remnant carcinoma: a meta-analysis

Background

Previous studies reported that Epstein–Barr virus (EBV) may play a causal role in the pathogenesis of gastric remnant carcinoma (GRC). However, there was still some controversy.

Methods

Articles published until July 15, 2020, in PubMed, MEDLINE, Embase and CNKI databases were selected. According to the inclusion criteria, corresponding data of included articles were abstracted and used for statistical analysis.

Results

Thirteen papers were finally enrolled, nine of which showed the result that the risk of EBV infection rate in the GRC was higher than conventional gastric carcinoma (OR = 5.22, 95% CI 3.89–7.00). In addition, we found that EBV associated GRC (EBVaGRC) had higher rate of Billroth-II (OR = 3.80, 95% CI 1.90–7.57), carcinoma in anastomotic site (OR = 2.41, 95% CI 1.27–4.56) and diffuse type (Lauren classification) (OR = 1.97, 95% CI 1.04–3.73),while sex, initial diagnosis and lymphocytic infiltration were calculated no statistical difference. By genetic polymorphism analysis, “V-val” subtype of EBNA1 (OR = 21.84, 95% CI 11.92–31.76) and “C” subtype of BamHI-W1/I1 (OR = 7.07, 95% CI 1.47–34.03) were observed to be highly expressed in EBVaGRC.

Conclusion

EBV infection rate in the GRC was higher. Further analysis showed that Billroth-II, carcinoma in anastomotic site and diffuse type (Lauren classification) were associated to EBVaGRC. Through analysis of EBV genome polymorphisms, we thought that “V-val” subtype of EBNA1 and “C” subtype of BamHI-W1/I1 may become predictor of EBVaGRC.

Epstein-Barr virus BART microRNAs in EBV- associated Hodgkin lymphoma and gastric cancer

Background

EBV produces miRNAs with important functions in cancer growth, tumor invasion and host immune surveillance. The discovery of EBV miR-BARTs is recent, and most of their functions are still unknown. Nonetheless, some new studies underline their key roles in EBV-associated malignancies.

Main body

In EBV-associated tumors, the expression profile of miR-BARTs varies according to the cell type, autophagic process and signals received from the tumor microenvironment. By the same way of interest is the interaction between tumor cells and the tumor environment by the release of selected EBV miR-BARTs in addition to the tumor proteins trough tumor exosomes.

Conclusion

In this review, we discuss new findings regarding EBV miR-BARTs in Hodgkin lymphoma and gastric cancer. The recent discovery that miRNAs are released by exosomes, including miR-BARTs, highlights the importance of tumor and microenvironment interplay with more specific effects on the host immune response.

Gastric Cancer in History: A Perspective Interdisciplinary Study

Background: Gastric adenocarcinoma is the fourth most common type of cancer and the second leading cause of cancer death in the world. Despite abundant traces of an ancient history, the comprehension of its pathogenic mechanisms is rather recent and continuously updated. Methods: We investigated about how the ancient civilizations tried to understand the exactly physiopathology of gastric cancer, from the time when they could not examine deeply the histological and pathophysiologic aspects of the disease, but they just based their knowledge on a visual analysis of the signs and consequences of such disease. We examined the historical evolving knowledge of the disease along the centuries on the gastroenterological, pharmacological, and surgical fields, defining how gastric cancer became an increasingly curable disease. Results: Cancer was known in the ancient world. Ancient people did not know exactly the causes but the climatic, hygienic, and food conditions were the first to be considered over time, also taking into consideration supernatural negative influences. During the Renaissance, a tumultuous time of scientific discoveries started, thanks to an increasing number of autopsies made on cadavers and to the progressions in visual analysis of the stomach mucosa throughout endoscopy. From the first gastric surgery in 1879, many steps forward have been made and, today, gastric cancer is regarded as a more curable disease; one important discovery in this field has been the revelation of the role of Helicobacter pylori in the peptic ulcer disease (PUD) and in some forms of gastric lymphoma. Conclusions: Gastric cancer has the fourth highest incidence of various cancers worldwide and is ranked second as a cause of cancer-related death. It exists from the antiquity and a lot of hypotheses have been developed about its etiology during the centuries, influencing its therapy. During the 20th century, thanks to the scientific and technological progresses the causes of the cancer have been discovered and the role of the bacterium Helicobacter pylori has been demonstrated, and new perspective research are currently trying to investigate the role of other microorganisms in gastric physiopathology, as well as its possible modulation by probiotics.

Young-onset gastric cancer and Epstein-Barr Virus (EBV) - a major player in the pathogenesis?

Objective

Gastric cancer (GC) is a leading cause of cancer death, occurs predominantly in older age, with increasing incidence in young patients. The Cancer Genome Atlas indicates four subtypes for GC among which Epstein-Barr virus (EBV) subtype is estimated at 8.7%. We aim to determine the prevalence of EBV subtype in young GC patients (≤45 years) compared with an average-onset cohort (≥55 years) and characterize the clinicopathologic pattern of young-onset GC.

Methods

Gastric cancer samples of patients of both cohorts were screened for EBV by qPCR. Additional staining was done for Human epidermal growth factor receptor 2 (HER2), microsatellite instability (MSI) status and Programmed death-ligand 1 (PD-L1). Demographics and clinical data were retrieved from the medical records.

Results

Thirty-nine young-onset and 35 average-onset GC patients were reviewed. There was no apparent difference in tumor location, family history, histology and HER2 status between the cohorts. More young-onset patients were diagnosed with metastatic disease (27% vs 9%, p = 0.0498). EBV was significantly more prevalent in the young-onset cohort (33% vs 11%, p = 0.025). 15/17 EBV positive patients were under the median age of diagnosis for GC in the US (68 years). MSI-H was found only in the average-onset cohort [0% vs 27%, p = 0.001). PD-L1 positivity was higher in the young-onset cohort (31% vs 3%, p = 0.002).

Conclusion

Our study indicates that EBV subtype is more prevalent in young-onset GC and may play a key role in the pathogenesis. Higher rate of PD-L1 positivity in young-onset GC could change treatment strategies. We are currently evaluating these findings in a prospective trial.

Molecular Classification of Gastric Cancer among Alaska Native People

Gastric cancer is an aggressive and heterogeneous malignancy that often varies in presentation and disease among racial and ethnic groups. The Alaska Native (AN) people have the highest incidence and mortality rates of gastric cancer in North America. This study examines molecular markers in solid tumor samples from eighty-five AN gastric adenocarcinoma patients using next-generation sequencing, immunohistochemistry, and in situ hybridization analysis. AN patients have a low mutation burden with fewer somatic gene mutations in their tumors compared to other populations, with the most common mutation being TP53. Epstein-Barr virus (EBV) was associated with 20% of AN gastric cancers, which is higher than the world average of 10%. The inflammation marker, cyclooxygenase-2 (COX-2), is highly expressed in patients with the lowest survival rates. Mismatch repair deficiency was present in 10% of AN patients and was associated with patients who were female, 50 years or older, gene mutations, and tumors in the distal stomach. Program death-ligand 1 (PD-L1) was expressed in 14% of AN patients who were more likely to have MMR deficiency, EBV-associated gastric cancers, and mutations in the PIK3CA gene, all of which have been linked to clinical response to PD-1 inhibitors. These studies suggest a portion of AN gastric cancer patients could be candidates for immunotherapy. Overall, this study highlights future avenues of investigation for clinical and translational studies, so that we can improve early detection and develop more effective treatments for AN patients.

Classification of gastric cancer by EBV status combined with molecular profiling predicts patient prognosis

PURPOSE

To identify how Epstein-Barr virus (EBV) status combined with molecular profiling predicts the prognosis of gastric cancer patients and their associated clinical actionable biomarkers.

EXPERIMENTAL DESIGN

A next-generation sequencing assay targeting 295 cancer-related genes was performed in 73 EBV-associated gastric cancer (EBVaGC) and 75 EBV-negative gastric cancer (EBVnGC) specimens and these results were compared with overall survival (OS).

RESULTS

PIK3CA, ARID1A, SMAD4, and PIK3R1 mutated significantly more frequently in EBVaGC compared with their corresponding mutation rate in EBVnGC. As the most frequently mutated gene in EBVnGC (62.7%), TP53 also displayed a mutation rate of 15.1% in EBVaGC. PIK3R1 was revealed as a novel mutated gene (11.0%) associated almost exclusively with EBVaGC. PIK3CA, SMAD4, PIK3R1, and BCOR were revealed to be unique driver genes in EBVaGC. ARID1A displayed a significantly large proportion of inactivated variants in EBVaGC. A notable finding was that integrating the EBV status with tumor mutation burden (TMB) and large genomic instability (LGI) categorized the tumors into four distinct molecular subtypes and optimally predicted patient prognosis. The corresponding median OSs for the EBV+/TMB-high, EBV+/TMB-low, EBV-/LGI-, and EBV-/LGI+ subtypes were 96.2, 75.3, 44.4, and 20.2 months, respectively. The different subtypes were significantly segregated according to distinct mutational profiles and pathways.

CONCLUSIONS

Novel mutations in PIK3R1 and TP53 genes, driver genes such as PIK3CA, SMAD4, PIK3R1, BCOR, and ARID1A, and distinguished genomic profiles from EBVnGC were identified in EBVaGC tumors. The classification of gastric cancer by EBV, TMB, and LGI could be a good prognostic indicator, and provides distinguishing, targetable markers for treatment.

Clinicopathological characteristics of Epstein-Barr virus-positive gastric cancer in Latvia

OBJECTIVE

Epstein-Barr virus (EBV)-associated gastric cancer has been proposed to be a distinct gastric cancer molecular subtype. The prognostic significance of EBV infection in gastric cancer remains unclear and needs further investigation. Our study aimed to analyze EBV-positive and EBV-negative gastric cancer patients regarding their personal and tumor-related characteristics, and compare their overall survival.

METHODS

Gastric cancer patients consecutively treated at the Riga East University Hospital during 2009-2016 were identified retrospectively. Tumor EBV status was determined by in-situ hybridization for EBV-encoded RNA (EBER). Information about clinicopathological characteristics was obtained from patient questionnaires, hospital records. Overall survival was ascertained through 30 July 2017. Cox proportional hazard regression models adjusted for personal and tumor-related covariates compared survival between EBV-positive and EBV-negative patients.

RESULTS

There were a total of 302 gastric cancer patients (61% males) with mean and SD age 63.6 ± 11.5 years. EBER positivity was present in 8.6% of tumors. EBV-positive gastric cancer patients had better survival at 80 months [adjusted hazard ratio = 0.37, 95% confidence interval (CI) = 0.19-0.72] compared to EBV-negative patients. Worse survival was observed for patients with stage III (hazard ratio = 2.76, 95% CI = 1.67-4.56) and stage IV (hazard ratio = 10.02, 95% CI = 5.72-17.57) compared to stage I gastric cancer, and overlapping and unspecified subsite (hazard ratio = 1.85; 95% CI = 1.14; 3.00) compared to distal tumors.

CONCLUSION

Tumor EBV positivity is a favorable prognostic factor in gastric cancer.

Expression of Phosphoinositide 3-Kinase p110α and p110β Subunits and PIK3CA Mutation in Patients With Advanced Gastric Carcinoma

Activation of phosphoinositide 3-kinase (PI3K) is pivotal for the activity of the oncogenic PI3K/AKT signaling pathway. This study assessed the expression of 2 PI3K isoform proteins, p110α and p110β, and PIK3CA mutational status in advanced gastric carcinoma (AGC) and their correlation with clinicopathologic factors. Tissue microarray blocks were generated from 99 AGCs and immunohistochemically stained for p110α and p110β. Analysis of mutations in the PIK3CA gene, which encodes p110α, was performed using the PNAClamp PIK3CA Mutation Detection kit. Of the 99 tumors, positivity was seen in 62 (62.6%) for p110α and 97 (98.0%) for p110β with variable intensity and extent of staining. The median H-scores were 40 (range: 0 to 300) for p110α and 180 (range: 0 to 300) for p110β. Isoform p110α was more highly expressed in tumors with a lower pathologic T stage (P=0.035) and TNM stage (P=0.165), while p110β was not significantly associated with clinicopathologic factors. Samples with high p110α expression had a trend toward longer overall survival (OS) although it was not statistically significant (P=0.271), whereas high p110β expression correlated with shorter OS (P=0.016). In addition, p110β was an independent factor for poor prognosis in multivariate analysis for OS. Eight (8.1%) samples had PIK3CA mutations in exon 9. Mutational status at this locus was not significantly correlated with clinicopathologic factors. These results imply that p110β could have a more important role in the progression and aggressiveness of AGC than p110α and has potential as a prognostic biomarker in patients with AGC.

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.

High Proportion of Potential Candidates for Immunotherapy in a Chilean Cohort of Gastric Cancer Patients: Results of the FORCE1 Study

Gastric cancer (GC) is a heterogeneous disease. This heterogeneity applies not only to morphological and phenotypic features but also to geographical variations in incidence and mortality rates. As Chile has one of the highest mortality rates within South America, we sought to define a molecular profile of Chilean GCs (ClinicalTrials.gov identifier: NCT03158571/(FORCE1)). Solid tumor samples and clinical data were obtained from 224 patients, with subsets analyzed by tissue microarray (TMA; n = 90) and next generation sequencing (NGS; n = 101). Most demographic and clinical data were in line with previous reports. TMA data indicated that 60% of patients displayed potentially actionable alterations. Furthermore, 20.5% were categorized as having a high tumor mutational burden, and 13% possessed micro-satellite instability (MSI). Results also confirmed previous studies reporting high Epstein-Barr virus (EBV) positivity (13%) in Chilean-derived GC samples suggesting a high proportion of patients could benefit from immunotherapy. As expected, TP53 and PIK3CA were the most frequently altered genes. However, NGS demonstrated the presence of TP53, NRAS, and BRAF variants previously unreported in current GC databases. Finally, using the Kendall method, we report a significant correlation between EBV+ status and programmed death ligand-1 (PDL1)+ and an inverse correlation between p53 mutational status and MSI. Our results suggest that in this Chilean cohort, a high proportion of patients are potential candidates for immunotherapy treatment. To the best of our knowledge, this study is the first in South America to assess the prevalence of actionable targets and to examine a molecular profile of GC patients.

Prospective observation: Clinical utility of plasma Epstein-Barr virus DNA load in EBV-associated gastric carcinoma patients

Epstein-Barr virus (EBV)-associated gastric carcinomas (EBVaGCs) may account for 8-9% of all gastric cancer (GC) patients. All previous reports on EBVaGC were retrospective. Prospective study is warranted to evaluate the exact role of EBV status in predicting the prognosis of GC. It is of special interest to figure out whether dynamic detection of plasma EBV-DNA load could be a feasible biomarker for the monitor of EBVaGC. From October 2014 to September 2017, we consecutively collected GC patients (n = 2,760) from Sun Yat-sen University Cancer Center for EBER examination. We detected EBV-DNA load in plasma and tissue samples of EBVaGC patients at baseline. Subsequently, plasma EBV-DNA load was dynamically monitored in EBVaGC patients. The overall prevalence of EBVaGC is 5.1% (140/2,760). The incidence rate of EBVaGC decreased with advanced AJCC 7th TNM stage (p < 0.001), with the corresponding percentages of 9.3, 9.9, 6.7 and 1.4% for Stage I, II, III and IV patients. EBVaGC patients were predominately young males with better histologic differentiation and earlier TNM stage than EBV-negative GC (EBVnGC) patients. EBVaGC patients were confirmed to had a favorable 3-year survival rate (EBVaGC vs. EBVnGC: 76.8% vs. 58.2%, p = 0.0001). Though only 52.1% (73/140) EBVaGC patients gained detectable EBV-DNA and 43.6% (61/140) reached a positive cutoff of 100 copies/ml, we found the plasma EBV-DNA load in EBVaGC decreased when patients got response, while it increased when disease progressed. Our results suggested that plasma EBV-DNA is a good marker in predicting recurrence and chemotherapy response for EBVaGC patients.

Associations of PIK3CA mutations with clinical features and prognosis in gastric cancer

Aim: The clinical implications of PIK3CA mutations in gastric cancer (GC) are not conclusive. Materials & methods: A systematic searching of the previous publications and related studies in The Cancer Genome Atlas (TCGA) database were performed to investigate the clinical implications of PIK3CA mutations in GC.  Results: Twenty-six independent cohort studies including six studies with original data were identified. Meta-analysis suggested PIK3CA mutations were associated with high T stage, poor differentiation and microsatellite instability, but not with prognosis in overall. However, PIK3CA mutation was found to be associated with favorable overall survival in subgroup of patients with low PIK3CA mutation prevalence. Conclusion: PIK3CA mutations might be involved in GC development and might be used as favorable prognostic factor in GC population with low PIK3CA mutations prevalence.

Screening responsive or resistant biomarkers of immune checkpoint inhibitors based on online databases

Immune checkpoint inhibitors are a promising strategy in the treatment of cancer, especially advanced types. However, not all patients are responsive to immune checkpoint inhibitors. The response rate depends on the immune microenvironment, tumor mutational burden (TMB), expression level of immune checkpoint proteins, and molecular subtypes of cancers. Along with the Cancer Genome Project, various open access databases, including The Cancer Genome Atlas and Gene Expression Omnibus, provide large volumes of data, which allow researchers to explore responsive or resistant biomarkers of immune checkpoint inhibitors. In this review, we introduced some methodologies on database selection, biomarker screening, current progress of immune checkpoint blockade in solid tumor treatment, possible mechanisms of drug resistance, strategies of overcoming resistance, and indications for immune checkpoint inhibitor therapy.

Role of serum EBV-VCA IgG detection in assessing gastric cancer risk and prognosis in Northern Chinese population

The study aimed to investigate the role of serum EBV‐VCA IgG in assessing gastric cancer (GC) risk and prognosis. A total of 1790 Northern Chinese participants with pathologically confirmed disease underwent EBV‐VCA IgG serologic testing using enzyme‐linked immunosorbent assay (ELISA), including 821 controls, 410 atrophic gastritis (AG) patients, and 559 GC patients. We found that positive EBV‐VCA IgG was significantly associated with GC and its precursor, conferring a 1.55‐ and 1.36‐fold increased risk of GC and AG, respectively (P = 0.001, 95% CI = 1.21‐1.99; P = 0.011, 95% CI = 1.07‐1.72, respectively). The risk effects were more remarkable in younger, female, and Helicobacter pylori‐negative individuals than in older, male, and H. pylori‐positive individuals. EBV‐VCA IgG‐positive subjects had a lower PGI/II ratio than EBV‐VCA IgG‐negative subjects (median 8.0 vs 8.8, P = 0.001), especially those in the H. pylori‐positive (median 6.1 vs 6.8, P = 0.027) and GC subgroups (median 6.4 vs 7.9, P = 0.020). In the intestinal GC subgroup, the survival of EBV‐VCA IgG‐positive patients was worse than that of EBV‐VCA IgG‐negative patients (P = 0.041, HR = 2.45, 95% CI = 1.04‐5.78). Our study suggests that EBV‐VCA IgG seropositivity has potential in predicting the risk of GC and its precursor as well as the prognosis of histologically classified GC.

This is an innovative report about the role of serum EBV‐VCA IgG detection in assessing the risk of gastric cancer (GC) and its precursor as well as GC prognosis. And this is the first report about the relationship between EBV‐VCA IgG serology assay and gastric function status. Our study provides theoretical and experimental basis for evaluating the potential of serum EBV‐VCA IgG as a biomarker in prediction of GC risk and prognosis.

Correlation Between Infection Status of Epstein-Barr Virus and 18F-Fluorodeoxyglucose Uptake in Patients with Advanced Gastric Cancer

BACKGROUND

Epstein-Barr virus-associated gastric cancer (EBVaGC) is one of the four molecular subtypes of gastric cancer, as defined by the classification recently proposed by The Cancer Genome Atlas. We evaluated the correlation between EBV positivity and ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) uptake by positron emission tomography/computed tomography (PET/CT) in patients with gastric cancer.

MATERIALS AND METHODS

We retrospectively enrolled patients with gastric cancer who underwent pretreatment ¹⁸F-FDG PET/CT and subsequent surgical resection, and then were diagnosed with advanced gastric cancer (pathologic stage ≥T2 with any N stage). Maximum standardized uptake values (SUV_max) of gastric cancer were measured by pretreatment ¹⁸F-FDG PET/CT. EBV sequences were detected by in situ hybridization (ISH) techniques. We analyzed the correlation between EBV positivity, clinicopathologic features and metabolic activity of the primary tumor.

RESULTS

A total of 205 patients were included and 15 (7.3%) patients were identified as having EBV-positive gastric cancer. Age, gender, tumor location, and histological type showed no significant differences between EBV-positive and negative groups. EBV-positive cancer is significantly more frequent in the higher-metabolic-tumor group than in the lower one (p=0.032). The mean SUV_max of gastric cancers showed significant differences between EBV-positive and negative groups (9.9±4.2 vs. 7.0±4.8, p=0.026).

CONCLUSION

The infection status of EBV was significantly related to the ¹⁸F-FDG uptake of primary tumors in patients with advanced gastric cancer.

Clinical utility of circulating cell-free Epstein-Barr virus DNA in patients with gastric cancer

Recent comprehensive molecular subtyping of gastric cancer (GC) identified Epstein-Barr virus (EBV)-positive tumors as a subtype with distinct salient molecular and clinical features. In this study, we aimed to determine the potential utility of circulating cell-free EBV DNA as a biomarker for the detection and/or monitoring of therapeutic response in patients with EBV-associated gastric carcinoma (EBVaGC). The EBV genes-to-ribonuclease P RNA component H1 ratios (EBV ratios) in the GC tumors and plasma samples were determined by quantitative real-time polymerase chain reaction in 153 patients with GC, including 14 patients with EBVaGC diagnosed by the conventional method. Circulating cell-free EBV DNA was detected in 14 patients with GC: the sensitivity and specificity of detection were 71.4% (10/14) and 97.1% (135/139), respectively. Plasma EBV ratios were significantly correlated with the size of EBVaGC tumors, and the plasma EBV DNA detected before surgery in EBVaGC cases disappeared after surgery. Patients with EBVaGC may have a better prognosis, but circulating cell-free EBV DNA had no or little impact on prognosis. In addition, repeated assessment of the plasma EBV ratio in EBVaGC showed a decrease and increase in plasma EBV DNA after treatment and during tumor progression/recurrence, respectively. These results suggest the potential utility of circulating cell-free DNA to reveal EBV DNA for the identification of the EBVaGC subtype and/or for real-time monitoring of tumor progression as well as treatment response in patients with EBVaGC.

A viral map of gastrointestinal cancers

Cancers of the gastrointestinal tract (GIT) are expected to account for approximately 20% of all cancers in 2017. Apart from their high incidence, GIT cancers show high mortality rates, placing these malignancies among the most prominent public health issues of our time. Cancers of the GIT are the result of a complex interplay between host genetic factors and environmental factors and frequently arise in the context of a continued active inflammatory response. Several tumor viruses are able to elicit such chronic inflammatory responses. In fact, several viruses have an impact on GIT tumor initiation and progression, as well as on patients' response to therapy and prognosis, through direct and indirect mechanisms. In this review, we have gathered information on different viruses' rates of infection, viral-driven specific carcinogenesis mechanisms and viral-related impact on the prognosis of cancers of the GIT (specifically in organs that have an interface with the environment - esophagus, stomach, intestines and anus). Overall, while some viral infections show a strong causal relation with specific gastrointestinal cancers, these represent a relatively small fraction of GIT malignancies. Other types of cancer, like Esophageal Squamous Cell Carcinoma, require further studies to confirm the carcinogenic role of some viral agents.

Characterization and validation of potential therapeutic targets based on the molecular signature of patient-derived xenografts in gastric cancer

Background

Patient-derived xenograft (PDX) models with definite molecular signature are attractive preclinical models for development of novel targeted drugs. Here, we profiled and explored potential therapeutic targets based on characterized PDX models for advanced gastric cancer (AGC).

Methods

The genomic variation and molecular profile of 50 PDX models from AGC patients were analyzed by targeted next-generation sequencing, in situ hybridization, and immunohistochemistry. The antitumor activities of several targeted drugs were investigated in the PDX models. Furthermore, response biomarkers were explored.

Results

Each PDX model had individual histopathological and molecular features, and recurrent alterations in the MAPK, ErbB, VEGF, mTOR, and cell cycle signaling pathways were major events in these PDX models. Several potential drug targets, such as EGFR, MET, and CCNE1, were selected and validated in this study. Volitinib demonstrated strong antitumor activity in PDX models with MET and phosphorylated MET (pMET) overexpression. The EGFR monoclonal antibodies BK011 and cetuximab inhibited tumor growth in a PDX model with EGFR amplification. Afatinib inhibited tumor growth in the PDX models with EGFR amplification, EGFR overexpression, or HER2 amplification. Apatinib was more sensitive in the PDX models with high microvessel density. The CDK1/2/9 inhibitor AZD5438 had superior anti-tumor activity in two models with higher copy number of CCNE1.

Conclusions

PDX models with defined molecular signature are useful for preclinical studies with targeted drugs, and the results should be validated in larger studies with PDX models or in clinical trials.

Electronic supplementary material

The online version of this article (10.1186/s13045-018-0563-y) contains supplementary material, which is available to authorized users.

Development and external validation of a prognostic nomogram for gastric cancer using the national cancer registry

A nomogram based on both western and eastern populations to estimate the Disease Specific Survival (DSS) of resectable gastric cancer (RGC) has not been established. In current study, we retrospectively analyzed 4,379 RGC patients who underwent curative resection from the Surveillance, Epidemiology, and End Results (SEER) database. Patients diagnosed between 1998 and 2009 were assigned as training set (n= 2,770), and the rest were selected as SEER validation set (n= 1,609). An external validation was performed by a set of independent 1,358 RGC patients after D2 resection from Sun Yat–sen University Cancer Center (SYSUCC) in China. The nomogram was constructed based on the training set. The multivariate analysis identified that patient's age at diagnosis, race, tumor location, grade, depth of invasion, metastatic lymph node stage (mLNS) and total number of examined lymph node (TLN) were associated with patient's DSS. The discrimination of this nomogram was superior to that of the 7th edition of AJCC staging system in SEER validation set and SYSUCC validation set (0.73 versus 0.70, p=0.005; 0.76 versus 0.72, p=0.005; respectively). Calibration plots of the nomogram showed that the probability of DSS corresponded to actual observation closely. In conclusion, our nomogram resulted in more–reliable prognostic prediction for RGC patients in general population.

The expression of circRNAs as a promising biomarker in the diagnosis and prognosis of human cancers: a systematic review and meta-analysis

Background

CircRNAs, a type of non-coding RNAs with special loop structure, of which the aberrant expression is closely related to tumor growth, proliferation, metastasis and recurrence. It remains unclear whether they have the potential to be biomarkers for diagnosis and prognosis of cancers. The study aims to clarify the relationship of circRNAs expression with cancers diagnosis and prognosis.

Materials and Methods

Sensitivity, specificity, area under curve (AUC) and receiver operating characteristic curve (ROC) were calculated to evaluate the diagnostic efficacy; Hazard ratio (HR) of overall survival (OS), disease free survival (DFS) and recurrence free survival (RFS) were calculated to evaluate the association between circRNAs expression and survival of cancer patients.

Results

A total of 27 studies were involved in the meta-analysis, including 16 diagnostic and 11 prognostic articles. Among the diagnostic studies, 18 kinds of circRNAs had been investigated, in which 3 were up regulated and 15 were down regulated. Their pooled sensitivity, specificity and AUC were 0.71(0.65–0.77), 0.77(0.72–0.81) and 0.81(0.77–0.84), respectively. In stratified analysis, a higher specificity was shown in circRNAs for diagnosing gastric cancer and hepatocellular cancer. 12 circRNAs were involved in the prognostic studies, including 6 up-regulated and 6 down-regulated circRNAs. Their overall HR of OS and DFS/RFS were 1.37(0.98–1.75) and 2.28 (0.77–3.79), respectively.

Conclusions

CircRNAs have the potential to be biomarkers for diagnosis and prognosis of cancers. Further investigations are still needed to explore the clinical value of circRNAs as tumor markers.

Clinical and pathological characterization of Epstein-Barr virus-associated gastric carcinomas in Portugal

AIM

To determine the prevalence of Epstein-Barr virus (EBV)-associated gastric carcinomas in the North Region of Portugal and to study its clinicopathological characteristics.

METHODS

We have performed a retrospective study including a total of 179 consecutive patients with gastric cancer (GC) submitted to gastrectomy during 2011 at the Portuguese Oncology Institute of Porto. Clinical and pathological data was collected from individual clinical records and inserted on a database with unique codification. Tumour tissues were collected from the institutional tumour bank. EBV was detected by in situ hybridization for the detection of EBV-encoded small RNAs (EBERs) and EBV latent proteins (LMP1 and LMP2A) were detected by immunohistochemistry.

RESULTS

The analysis showed that EBV-associated gastric carcinomas (EBVaGC) represents 8.4% (15/179) of all GC cases, with a significant differential distribution among histological types (P < 0.001): 100% (3/3) of medullary carcinomas, 100% (1/1) of adenosquamous carcinoma, 8.7% (8/92) of tubular adenocarcinomas, 8.0% (2/25) of mixed carcinomas and 2% (1/51) in poorly cohesive carcinomas. The analysis revealed a higher predominance of EBVaGC in the upper third and middle (cardia, fundus and body) of the stomach (P = 0.041), a significant lower number of regional lymph nodes invasion (P = 0.025) and a tendency for better prognosis (P = 0.222). EBV latent protein expression revealed that all EBVaGC cases were LMP1-negative, nevertheless 6 cases (40%) expressed LPM2A, which reveals that these cases show a distinct EBV-Latency profile (latency II-like).

CONCLUSION

EBVaGC represents 8.4% of all GC in the North Region of Portugal. The EBV-infected patients have specific clinic-pathological features that should be further explored to develop new strategies of management and treatment.

Prevalence and characteristics of Epstein-Barr virus-associated gastric carcinomas in Portugal

Background

Gastric cancer (GC) is one of the most common malignant tumors of the digestive tract and is the third leading cause of cancer death worldwide. Epstein–Barr virus (EBV) has been associated with approximately 10% of the total cases of gastric carcinomas. No previous study has analyzed the prevalence of EBV infection in gastric cancer of the Portuguese population.

Methods

In the present study, we have analyzed 82 gastric carcinoma cases and 33 healthy individuals (control group) from Coimbra region for the presence of EBV by polymerase chain reaction (PCR) and by in situ hybridization (ISH) for EBV-encoded small RNAs (EBERs). The status of H. pylori infection was assessed by serology and by PCR.

Results

EBV was detected by PCR in 90.2% of stomach cancer cases, whereas EBERs were detected in 11%. In our series, EBV-associated gastric carcinoma (EBVaGC) were significantly associated with gender and the majority of them presented lymph node metastasis. These cases were generally graded in more advanced pTNM stages and, non-surprisingly, showed worse survival. H. pylori infection was detected in 62.2% of the gastric cancers and 64.7% of these patients were CagA+. On the other hand, the H. pylori prevalence was higher in the EBV-negative gastric carcinomas (64.4%) than in those carcinoma cases with EBV+ (44.4%).

Conclusions

The present study shows that prevalence of EBVaGC among Portuguese population is in accordance with the worldwide prevalence. EBV infection seems to be associated to poorer prognostic and no relation to H. pylori infection has been found. Conversely, the presence of H. pylori seems to have a favourable impact on patient’s survival. Our results emphasize that geographic variation can contribute with new epidemiological data on the association of EBV with gastric cancer.

A Four-Factor Immunoscore System That Predicts Clinical Outcome for Stage II/III Gastric Cancer

The American Joint Committee on Cancer (AJCC) staging system is insufficiently prognostic for operable gastric cancer patients; therefore, complementary factors are under intense investigation. Although the focus is on immune markers, the prognostic impact of a single immune factor is minimal, due to complex antitumor immune responses. A more comprehensive evaluation may engender more accurate predictions. We analyzed immune factors by immunohistochemical staining in two independent cohorts. The association with patients' survival was analyzed by the Kaplan-Meier method. Our immunoscore system was constructed using Cox proportional hazard analysis. PD-L1⁺ immune cells (IC), PD-L1⁺ tumor cells (TC), PD-1^hi, and CD8^More were found among 33.33%, 31.37%, 33.33%, and 49%, respectively, of patients from the discovery cohort, and 41.74%, 17.4%, 38.26%, and 30.43% from the validation cohort. PD-L1⁺ ICs and PD-1^hi ICs correlated with poorer overall survival (OS), but PD-L1⁺ TCs correlated with better OS and clinical outcomes and infiltration of more CD8⁺ T cells. These four factors were independently prognostic after tumor/lymph nodes/metastasis (TNM) stage adjustment. An immunoscore system based on hazard ratios of the four factors further separated gastric cancer patients with similar TNM staging into low-, medium-, or high-risk groups, with significantly different survival. Our prognostic model yielded an area under the receiver operating characteristic curve (AUC) of 0.856 for prediction of mortality at 5 years, superior to that of TNM staging (AUC of 0.676). Thus, this more comprehensive immunoscore system can provide more accurate prognoses and is an essential complement to the AJCC staging system for operable gastric cancer patients. Cancer Immunol Res; 5(7); 524-34. ©2017 AACR.

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

Objectives:

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

Methods:

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

Results:

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

Conclusions:

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