Epstein-Barr virus and mismatch repair deficiency status differ between oesophageal and gastric cancer: A large multi-centre study

Association Between Epstein-Barr Virus Infection and PD-L1 Expression in Gastric Cancer: Prevalence, Clinicopathological Features, and Prognostic Implications

BACKGROUND

Epstein-Barr virus-associated gastric cancer (EBVaGC) represents a distinct molecular subgroup with potential responsiveness to immunotherapy approved for programmed death-ligand 1 (PD-L1)-positive gastric cancer. This retrospective study aimed to assess the prevalence and association between EBVaGC and PD-L1 positivity among patients with gastric adenocarcinoma treated at a university hospital in Southern Thailand from January 2017 to October 2023.

METHODS

The EBV status of the patients and PD-L1 expression were determined using in situ hybridization and immunohistochemistry, respectively.

RESULTS

The prevalence of EBVaGC was 4.5% among 132 patients, whereas 9.1% of patients exhibited a PD-L1 combined positive score (CPS) of ≥1, with no significant association observed between them. EBVaGC was more prevalent in males, non-antral tumors, diffuse/mixed histologic subtypes, and poorly differentiated tumors. Median overall survival for patients with EBVaGC and PD-L1 CPS ≥ 1 was 9.48 and 14.19 months, respectively, compared with 10.32 and 9.79 months for those with non-EBVaGC (hazard ratio: 1.24; 95% CI: 0.50-3.04; p = 0.645) and PD-L1 CPS < 1 (hazard ratio: 0.82; 95% CI: 0.40-1.69; p = 0.590), respectively.

CONCLUSIONS

Our findings revealed a low prevalence of EBVaGC and PD-L1 positivity in Thailand, with no significant association or survival impact observed. These findings highlight the regional variation in these biomarkers and support EBV as an independent biomarker from PD-L1. However, further research, particularly studies evaluating immunotherapy outcomes, is warranted to clarify the predictive and clinical significance of EBV in gastric cancer.

Genomic Landscape of Late-Stage Gastric Cancer: Analysis From KEYNOTE-059, KEYNOTE-061, and KEYNOTE-062 Studies

PURPOSE

The Cancer Genome Atlas (TCGA) classifies gastric cancer (GC) into four molecular subtypes: Epstein-Barr virus-positive, microsatellite instability-high (MSI-H), genomically stable (GS), and chromosomal instability (CIN). This exploratory analysis compared the genomic landscape of late-stage GC from KEYNOTE-059, KEYNOTE-061, and KEYNOTE-062 studies with early-stage GC from TCGA and evaluated the genomic characteristics of late-stage GC in patients of Western and Asian origin.

MATERIALS AND METHODS

Using pretreatment tumor samples, bulk DNA was analyzed via whole-exome sequencing (WES; KEYNOTE-059/KEYNOTE-061) and FoundationOneCDx (KEYNOTE-062) to determine TCGA-defined molecular subtypes (only MSI-H is determinable from FoundationOneCDx), genomic alterations, homologous recombination deficiency (HRD), and tumor mutational burden (TMB); gene expression signatures were analyzed using RNA sequencing.

RESULTS

When comparing KEYNOTE-059/061/062 combined WES and FoundationOneCDx data with data from TCGA, the MSI-H subtype prevalence was numerically lower in patients of Western (5% v 22%) and Asian origin (5% v 19%). When comparing KEYNOTE-059/061 WES data with the TCGA data set, the GS subtype prevalence was numerically higher (36% v 21%) in patients of Western or Asian origin. Among subtypes in KEYNOTE-059/061, HRD scores and TMB trended highest in CIN and MSI-H subtypes, respectively. TP53 mutation was the most prevalent genomic characteristic per KEYNOTE-059/061/062 combined analysis in patients of Western or Asian origin. Gene expression signature distributions were generally similar between patients of Western and Asian origin.

CONCLUSION

Numerical differences in the prevalence of MSI-H and GS subtypes were observed between early-stage and late-stage GC. Genomic characteristics of late-stage GC were generally similar between patients of Western and Asian origin.

Clinicopathological features and prognostic significance of TAF1L in gastric cancer

BACKGROUND

TAF1L may play an important role in the occurrence and development of gastric cancer (GC), but the correlation between the expression of TAF1L and the clinicopathological factors and prognosis of GC is still unclear.

METHODS

A total of 1053 GC patients in Zhejiang Cancer Hospital between January 1st, 2018 to December 31th, 2019 were screened. Finally, 120 patients met the inclusion criteria. TAF1L expression was detected by immunohistochemistry, and the correlations of TAF1L in clinicopathological characteristics and prognosis were analyzed. TCGA GC dataset was used to perform further bioinformatics analysis.

RESULTS

In this study, TAF1L expression was evaluated in 120 clinical samples of GC. TAF1L expression was higher in tumor tissues and was associated with tumor differentiation (p = 0.046), signet-ring cells (p = 0.043), dMMR status (p = 0.011), lympho-vascular invasion (p = 0.038), and neural invasion (p = 0.005) in our cohort. Cases with high expression of TAF1L presented worse mean OS than those with low expression (40.3 months vs. 51.8 months, p = 0.019), and the difference was also significant in HER2-positive cases (20.9 months vs. 51.2 months, p = 0.007) as well as pMMR cases (38.8 months vs. 51.6 months, p = 0.006). Multivariate Cox regression analysis showed that TAF1L (HR = 2.044, 95%CI = 1.007-4.147, p = 0.048) and HER2 status (HR = 2.383, 95%CI = 1.087-5.222, p = 0.030) were independent prognosis factors of these patients. In subgroup analysis, TAF1L was the independent prognostic risk factor in HER2-positive patients (HR = 6.736, 95%CI = 1.373-33.032, p = 0.019). and pMMR patients (HR = 2.291, 95%CI = 1.126-4.660, p = 0.022). Besides, HER2 status was the independent prognostic risk factor in TAF1L-H patients (HR = 4.832, 95%CI = 1.908-12.239, p = 0.001). TCGA dataset also indicated the higher expression of TAF1L in tumors than normal tissues (p < 0.001). High TAF1L expression is linked to worse survival in MSS (11.0 months vs. 35.0 months, p = 0.0046) groups, and is negatively associated with overall survival in HER2-positive cases (24.0 months vs. 57.0 months, p = 0.0039).

CONCLUSION

TAF1L is closely related to the occurrence and development of GC. Our results suggested that TAF1L is a significant biomarker for predicting prognosis of GC and may play an important role in immunotherapy and targeted therapy.

SMARCA4-Deficient Undifferentiated Tumor of the Esophagus: Diagnostic Pitfalls in Immunohistochemical Profiles

SMARCA4-deficient undifferentiated tumors (SMARCA4-UT) are a newly described entity and are typically seen in the thoracic cavity. However, these tumors have been described in other body sites, including the esophagus. These tumors are rare, aggressive neoplasms, characterized by the loss of protein product of SMARCA4 (Brahma-related gene-1) and the preservation of INI1 (SMARCB1) expression. Here, we present two tumors of SMARCA4-UT of the esophagus with its microscopic appearance and immunohistochemical profile. We also include a literature review of SMARCA4-deficient tumors of the tubular gastrointestinal tract with their immunohistochemical and mismatch repair profiles for each specimen. Due to its non-specific histologic appearance and variable staining in expanded immunohistochemical panels, this tumor frequently overlaps with other tumor types, making the diagnosis of SMARCA4-UT challenging. These tumors are often associated with intestinal metaplasia of the esophagus and are thought to represent a high-grade undifferentiated transformation of a conventional esophageal adenocarcinoma. These tumors are typically associated with poor clinical outcomes and have poor response to conventional therapies. Currently, there are no standard guidelines for treatment of these tumors; however, palliative radiotherapy and systemic chemotherapy may provide benefit. More recently, immunotherapy and novel therapeutic targets have shown some promise for these patients.

Gastric cancer molecular classification based on immunohistochemistry and in-situ hybridisation and mortality

BACKGROUND AND AIMS

Gastric cancers (GC) are divided into subtypes based on molecular profile: Epstein-Barr virus (EBV)-positive, microsatellite instability (MSI), chromosomal instability (CIN) and genomically stable (GS) tumours. The prognostic impact of this classification is unclear. The aim was to evaluate whether the molecular subtypes determined using in-situ hybridisation (ISH) and immunohistochemistry (IHC) are associated with clinicopathological parameters and prognosis.

METHODS AND RESULTS

The study included 503 GC patients. Based on ISH (EBV) and IHC (MSI and TP53), tumours were divided into EBV-positive, MSI, CIN (EBVneg/MSS/TP53aberrant) and GS (EBVneg/MSS/TP53wild-type) subgroups. Survival analyses with intestinal- and diffuse-type tumours were examined separately. EBV-positive tumours associated with male sex. Both EBV-positive and MSI tumours associated with intestinal type. CIN tumours associated with intestinal-type and positive lymph node status. GS tumours associated with diffuse-type and negative lymph node status. In the total cohort, no significant differences in the 5-year survival were observed. In intestinal tumours, the 5-year survival was better in EBV-positive tumours compared with GS tumours [hazard ratio (HR) = 0.57, 95% confidence interval (CI) = 0.33-0.99]. In diffuse tumours, the 5-year survival was worse in CIN tumours compared with GS tumours (HR = 1.57, 95% CI = 1.14-2.18). In radically resected diffuse tumours, the 5-year survival was worse in MSI tumours compared with GS tumours (HR = 3.26, 95% CI = 1.20-8.82).

CONCLUSIONS

The molecular classification is associated with histological type but not prognosis in GC. As the prognostic effects of molecular subtypes in intestinal- and diffuse-type cancers may differ, combining histological and molecular information is recommended for future studies.

Upper gastrointestinal tract microbiota with oral origin in relation to oesophageal squamous cell carcinoma

Introduction: Poor oral hygiene is linked to high risks of many systemic diseases, including cancers. Oral dysbiosis is closely associated with poor oral hygiene, causing tooth loss, gingivitis, and periodontitis. We provide a summary of studies and discuss the risk factors for oesophageal squamous cell carcinoma (ESCC) from a microbial perspective in this review.Methods: A literature search of studies published before December 31, 2022 from PubMed, Web of Science, and The Cochrane Library was performed. The search strategies included the following keywords: (1) oral care, oral health, oral hygiene, dental health, dental hygiene, tooth loss, teeth loss, tooth absence, missing teeth, edentulism, tooth brushing, mouthwash, and tooth cleaning; (2) esophageal, esophagus, oesophagus, and oesophageal; (3) cancer, carcinoma, tumor, and neoplasm.Discussion: Poor oral health, indicated by infrequent tooth brushing, chronic periodontitis, and tooth loss, has been associated with an increased risk of squamous dysplasia and ESCC. Oral microbial diversity and composition are profoundly dysregulated during oesophageal tumorigenesis. Similar to the oral microbiota, the oesophageal microbiota varies distinctly in multiple bacterial taxa in ESCC and gastric cardia adenocarcinoma, both of which have high co-occurrence rates in the "Oesophageal Cancer Belt". In addition, the potential roles of oncogenic viruses in ESCC have also been discussed. We also briefly explore the potential mechanisms underlying the tumor-promoting role of dysregulated microbiota for the development of therapeutic targeting strategies.Conclusion: Poor oral health is an established risk indicator of ESCC. The dysbiosis of microbiota in upper gastrointestinal tract that highly resembles the oral microbial ecosystem but with distinct features at individual sites contributes to the development and progression of ESCC.

Heterogeneity and Adjuvant Therapeutic Approaches in MSI-H/dMMR Resectable Gastric Cancer: Emerging Trends in Immunotherapy

Gastric cancer (GC) remains one of the world's most common and fatal malignant tumors. With a refined understanding of molecular typing in recent years, microsatellite instability (MSI) has become a major molecular typing approach for gastric cancer. MSI is well recognized for its important role during the immunotherapy of advanced GC. However, its value remains unclear in resectable gastric cancer. The reported incidence of microsatellite instability-high (MSI-H)/deficient mismatch repair (dMMR) in resectable gastric cancer varies widely, with no consensus reached on the value of postoperative adjuvant therapy in patients with MSI-H/dMMR resectable GC. It has been established that MSI-H/dMMR tumor cells can elicit an endogenous immune antitumor response and ubiquitously express immune checkpoint ligands such as PD-1 or PD-L1. On the basis of these considerations, MSI-H/dMMR resectable GCs are responsive to adjuvant immunotherapy, although limited research has hitherto been conducted. In this review, we comprehensively describe the differences in geographic distribution and pathological stages in patients with MSI-H/dMMR with resectable gastric cancer and explore the value of adjuvant chemotherapy and immunotherapy on MSI-H/dMMR to provide a foothold for the individualized treatment of this patient population.

Targeted Therapies and Developing Precision Medicine in Gastric Cancer

Gastric cancer is an aggressive disease with survival remaining poor in the advanced setting. More than a decade after the first targeted treatment was approved, still only HER2, MSI and PDL-1 status have reached everyday practice in terms of guiding treatment options for these patients. However, various new targets and novel treatments have recently been investigated and have shown promise in improving survival outcomes. In this review, we will summarise previous and currently ongoing studies on predictive biomarkers, possible new targeted treatments, potential reasons for conflicting trial results and hope for the future of precision medicine in gastric cancer.

Survival of Locally Advanced MSI-high Gastric Cancer Patients Treated With Perioperative Chemotherapy: A Retrospective Cohort Study

OBJECTIVE

To evaluate the efficacy of chemotherapy in patients with microsatellite instability (MSI)-high gastric cancer.

BACKGROUND

Although MSI-high gastric cancer is associated with a superior prognosis, recent studies question the benefit of perioperative chemotherapy in this population.

METHODS

Locally advanced gastric adenocarcinoma patients who either underwent surgery alone or also received neoadjuvant, perioperative, or adjuvant chemotherapy between 2000 and 2018 were eligible. MSI status, determined by next-generation sequencing or mismatch repair protein immunohistochemistry, was determined in 535 patients. Associations among MSI status, chemotherapy administration, overall survival (OS), disease-specific survival, and disease-free survival were assessed.

RESULTS

In 535 patients, 82 (15.3%) had an MSI-high tumor and ∼20% better OS, disease-specific survival, and disease-free survival. Grade 1 (90%-100%) pathological response to neoadjuvant chemotherapy was found in 0 of 40 (0%) MSI-high tumors versus 43 of 274 (16%) MSS. In the MSI-high group, the 3-year OS rate was 79% with chemotherapy versus 88% with surgery alone ( P =0.48). In the MSS group, this was 61% versus 59%, respectively ( P =0.96). After multivariable interaction analyses, patients with MSI-high tumors had superior survival compared with patients with MSS tumors whether given chemotherapy (hazard ratio=0.53, 95% confidence interval: 0.28-0.99) or treated with surgery alone (hazard ratio=0.15, 95% confidence interval: 0.02-1.17).

CONCLUSIONS

MSI-high locally advanced gastric cancer was associated with superior survival compared with MSS overall, despite worse pathological chemotherapy response. In patients with MSI-high gastric cancer who received chemotherapy, the survival rate was ∼9% worse compared with surgery alone, but chemotherapy was not significantly associated with survival.

Estimating the Global Burden of Epstein-Barr Virus-Associated Gastric Cancer: A Systematic Review and Meta-Analysis

BACKGROUND & AIMS

Evidence suggests that a fraction of new gastric cancer cases may be etiologically associated with Epstein-Barr virus (EBV), a known carcinogenic agent. We aimed to systematically explore the proportion of EBV-positive gastric cancer.

METHODS

We did a systematic review (PROSPERO CRD42020164473) from January 1990 to August 2021. For each country and geographical region with available data, pooled prevalence and corresponding 95% confidence intervals (CIs) of EBV in gastric tumors were calculated for 3 subtypes of gastric adenocarcinoma (conventional adenocarcinoma, lymphoepithelioma-like gastric carcinoma, and remnant/stump carcinoma). For conventional adenocarcinoma, prevalence ratios (PRs) were presented for sex, Lauren's classification, gastric cancer stage, and anatomical location of the stomach.

RESULTS

In 220 eligible studies including over 68,000 cases of conventional gastric adenocarcinoma, EBV prevalence in tumor cells was 7.5% (95% CI, 6.9%-8.1%) and was higher in men compared with women (PR, 2.1; 95% CI, 1.9-2.4), in diffuse type compared with intestinal type (PR, 1.3; 95% CI, 1.1-1.5), and in the proximal region compared with the distal region (PR, 2.5; 95% CI, 2.0-3.1). There was no difference in EBV prevalence by gastric cancer stage. EBV prevalence was 75.9% (95% CI, 62.8%-85.5%) among lymphoepithelioma-like gastric carcinoma and 26.3% (95% CI, 22.2%-32.0%) among remnant or stump carcinoma.

CONCLUSIONS

Assuming a causal association between EBV and gastric cancer, our findings, when applied to the GLOBOCAN 2020 gastric cancer incidence, suggest that primary prevention such as the development of an effective EBV vaccine might prevent 81,000 EBV-associated gastric cancer cases worldwide annually.

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.

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.

Impact of mature tertiary lymphoid structures on prognosis and therapeutic response of Epstein-Barr virus-associated gastric cancer patients

Background

Epstein-Barr virus-associated gastric cancer (EBVaGC) exhibits unique histological characteristics within the immune-cell-rich microenvironment, but the role of tertiary lymphoid structure (TLS) in EBVaGC is not yet fully understood.

Methods

We retrospectively identified EBVaGC from 8517 consecutive GC cases from the two top cancer centers in China. Furthermore, we evaluated the prognostic value of TLS in 148 EBVaGC patients from our institute and then validated it in an external cohort (76 patients). TLS was quantified and its relationships with overall survival (OS) and therapeutic response were further analyzed. Multiplex immunofluorescence staining and targeted sequencing were used to characterize the composition of TLS and the genomic landscape, respectively.

Results

In our study, EBVaGC was observed in 4.3% (190/4436) and 2.6% (109/4081) of GCs in the training and validation cohorts, respectively. TLS was identified in the intratumor (94.6%) and peritumor (77.0%) tissues with lymphoid aggregates, primary and secondary (i.e., mature TLSs) follicles in EBVaGC. Kaplan-Meier analysis showed that mature TLS in intratumoral tissues was associated with a favorable OS in the training and validation cohorts (p < 0.0001; p = 0.0108). Multivariate analyses demonstrated that intratumoral TLS maturation, pTNM, and PD-L1 expression were independent prognostic factors for OS (p < 0.05). Furthermore, the mature TLS was significantly associated with a good response to treatment in EBVaGC patients. Interestingly, the mutation frequency of SMARCA4 was significantly lower in the mature TLS groups.

Conclusions

Intratumoral mature TLS was associated with a favorable prognosis and good therapeutic response, suggesting that it is a potential prognostic biomarker and predicts a good therapeutic response in EBVaGC patients.

Familial Esophageal Cancer in Taihang Mountain, China: An Era of Personalized Medicine Based on Family and Population Perspective

In the Taihang Mountain areas, known as the “esophageal cancer zone” in China, the incidence of esophageal cancer (ESCA) ranks the first in the country and shows a familial and regional clustering trend. Taihang Mountain areas are located in a mountainous area, with inconvenient transportation, limited living conditions, unbalanced diet, and poor nutrition. Ninety percent of the pathological types of ESCA in Taihang Mountain areas are squamous cell carcinoma, among which the risk factors have not been well understood. These areas are usually remote villages and mountains with low population mobility, large family members, similar environmental factors, and a clear and stable genetic background. Therefore, according to the current situation, second-generation sequencing and multigroup analysis technology are used to analyze the familial ESCA patients; disease-related genetic variation are located; and then disease-related susceptibility genes associated with ESCA are screened and analyzed. Health education, tobacco control, endoscopic screening, and other health management projects for suspected and high-risk patients in areas with a high incidence of ESCA can be carried out for screening and early diagnosis, and the incidence of ESCA in Taihang Mountain areas can be reduced. A comprehensive continuous care pattern based on traditional medical nursing to track, monitor, evaluate, and intervene with patients diagnosed with ESCA to facilitate them with medications guidance, dietary guidance, and timely health problem-solving is established. Furthermore, statistical analysis of epidemiology, gene sequencing, and family genetics information can be performed on patients with ESCA in the Taihang Mountains areas to clarify the relationship between genetic phenotype and genotype during the occurrence of ESCA.

Expression of DNA Mismatch Repair Proteins, PD1 and PDL1 in Barrett's Neoplasia

BACKGROUND/AIM

Cancers with a microsatellite instability-high (MSI-H) or deficient mismatch repair (dMMR) status respond to immune checkpoint inhibition (ICI). Regardless of the tumor type, MSI-H/dMMR status is a reliable biomarker for ICI responsiveness. This study aimed at determining the MSI-H status in precursor lesions to esophageal adenocarcinoma (EAC) such as Barrett's esophagus (BE) and BE with either low-grade dysplasia (LGD) or high-grade dysplasia (HGD).

PATIENTS AND METHODS

We performed immunohistochemical staining (IHC) for PMS2, MSH6, PD1, and PD-L1.

RESULTS

All cases of BE (50), LGD (48), and HGD (50) had intact PMS2 and MSH6 nuclear expression; were negative for PD1; and had a PD-L1 combined positive score (CPS) score <1. One EAC case (2%) was negative for PMS2 nuclear expression. One HGD case (2%) and two EAC cases (4%) were PD1 positive (CPS score <1 applied to PD1). One EAC case (2%) had a CPS score >1, and one EAC case (2%) was MSI-H. MSI-H tumors usually show PD-L1 expression, although the MSI-H EAC in this study had a PD-L1 CPS score of <1.

CONCLUSION

Further studies investigating EAC and its precursor lesions for PD1, PD-L1, and dMMR status may be informative regarding the immunogenicity of the evolution of EAC.

Increasing frequency of gene copy number aberrations is associated with immunosuppression and predicts poor prognosis in gastric adenocarcinoma

BACKGROUND

Patients with Epstein-Barr virus-positive gastric cancers or those with microsatellite instability appear to have a favourable prognosis. However, the prognostic value of the chromosomal status (chromosome-stable (CS) versus chromosomal instable (CIN)) remains unclear in gastric cancer.

METHODS

Gene copy number aberrations (CNAs) were determined in 16 CIN-associated genes in a retrospective study including test and validation cohorts of patients with gastric cancer. Patients were stratified into CS (no CNA), CINlow (1-2 CNAs) or CINhigh (3 or more CNAs). The relationship between chromosomal status, clinicopathological variables, and overall survival (OS) was analysed. The relationship between chromosomal status, p53 expression, and tumour infiltrating immune cells was also assessed and validated externally.

RESULTS

The test and validation cohorts included 206 and 748 patients, respectively. CINlow and CINhigh were seen in 35.0 and 15.0 per cent of patients, respectively, in the test cohort, and 48.5 and 20.7 per cent in the validation cohort. Patients with CINhigh gastric cancer had the poorest OS in the test and validation cohorts. In multivariable analysis, CINlow, CINhigh and pTNM stage III-IV (P < 0.001) were independently associated with poor OS. CIN was associated with high p53 expression and low immune cell infiltration.

CONCLUSION

CIN may be a potential new prognostic biomarker independent of pTNM stage in gastric cancer. Patients with gastric cancer demonstrating CIN appear to be immunosuppressed, which might represent one of the underlying mechanisms explaining the poor survival and may help guide future therapeutic decisions.

Immunotherapy for Esophageal Cancer: State-of-the Art in 2021

The management of esophageal cancer (EC) has experienced manifold changes during the last decades. Centralization of EC treatment has been introduced in many countries, subsequently allowing the development of specialized high-volume centers. Minimal invasive surgery has replaced open surgery in many centers, whereas more potent systemic treatments have been introduced in clinical practice. Newer chemotherapy regimens increase long-term survival. Nevertheless, the overall survival of EC patients remains dismal for advanced tumor stages. In this direction, a wide range of targeted biologic agents (immunotherapy) is currently under assessment. Anti- Human Epidermal Growth Factor Receptor-2 (HER-2) monoclonal antibodies are used in HER2 (+) tumors, predominantly well-differentiated adenocarcinomas, and are currently assessed in the neoadjuvant setting (TRAP, INNOVATION trials). Immune checkpoint inhibitors Nivolumab (ATTRACTION-03) and pembrolizumab (KEYNOTE-181), have demonstrated a survival benefit compared with conventional chemotherapy in heavily pre-treated progressive disease. More recently, CheckMate-577 showed very promising results for nivolumab in a curative adjuvant setting, improving disease-free survival mainly for esophageal squamous cell carcinoma. Several ongoing trials are investigating novel targeted agents in the preoperative setting of locally advanced EC. In addition, other immunomodulatory approaches such as peptide vaccines and tumor infiltrating lymphocytes (TILs) are currently under development and should be increasingly integrated into clinical practice.

Optimal First-Line Therapy for Metastatic Adenocarcinoma of the Esophagus

OPINION STATEMENT

Treatment strategies for esophageal adenocarcinoma patients continue to advance with the generation of more data from clinical trials that are permitting us to refine the use of immunotherapy in combination with other treatment modalities. While the frontline therapy for metastatic esophageal adenocarcinoma has become more complicated with the approval of combination regimens, it is also yielding better outcomes. These treatment strategies can now be individualized to fit patient circumstances and goals as well as the biomarker profile of their individual tumors leading to an increased likelihood of treatment related remissions and extended median survivals. Comprehensive genomic profiling at diagnosis should now be standard to allow the management team to customize each patient's treatment plan based on the genetic abnormalities discovered in their tumor. By refining these targeted approaches, we will see decreased toxicities and increased survival.

Diverse 'just-right' levels of chromosomal instability and their clinical implications in neoadjuvant treated gastric cancer

BACKGROUND

The Cancer Genome Atlas (TCGA) consortium described EBV positivity(+), high microsatellite instability (MSI-H), genomic stability (GS) and chromosomal instability (CIN) as molecular subtypes in gastric carcinomas (GC). We investigated the predictive and prognostic value of these subtypes with emphasis on CIN in the context of neoadjuvant chemotherapy (CTx) in GC.

METHODS

TCGA subgroups were determined for 612 resected adenocarcinomas of the stomach and gastro-oesophageal junction (291 without, 321 with CTx) and 143 biopsies before CTx. EBV and MSI-H were analysed by standard assays. CIN was detected by multiplex PCRs analysing 22 microsatellite markers. Besides the TCGA classification, CIN was divided into four CIN-subgroups: low, moderate, substantial, high. Mutation profiling was performed for 52 tumours by next-generation sequencing.

RESULTS

EBV(+) (HR, 0.48; 95% CI, 0.23-1.02), MSI-H (HR, 0.56; 95% CI, 0.35-0.89) and GS (HR, 0.72; 95% CI, 0.45-1.13) were associated with increased survival compared to CIN in the resected tumours. Considering the extended CIN-classification, CIN-substantial was a negative prognostic factor in uni- and multivariable analysis in resected tumours with CTx (each p < 0.05). In biopsies before CTx, CIN-high predicted tumour regression (p = 0.026), but was not prognostically relevant.

CONCLUSION

A refined CIN classification reveals tumours with different biological characteristics and potential clinical implications.

The Impact of Mismatch Repair Status on Prognosis of Patients With Gastric Cancer: A Multicenter Analysis

BACKGROUND

The clinical role of deficient DNA mismatch repair (dMMR)/microsatellite instability-high (MSI-H) in gastric cancer (GC) is still controversial. We aimed to analyze the relationship between dMMR/MSI-H and clinicopathological features along with survival.

METHODS

Patients who were diagnosed with GC at the three big cancer centers in China from 2015 to 2020 were evaluated retrospectively. MMR/MSI status was assessed using immunohistochemistry/PCR. Clinical and pathological data were collected from the medical record system.

RESULTS

A total of 196 patients with dMMR/MSI-H status were enrolled for analysis. The prevalence of MSI-H/dMMR in GC was 6.6%. Another 694 proficient MMR (pMMR) GC patients were enrolled for comparison. Compared with pMMR patients, dMMR/MSI-H patients were associated with older age, female predominance, distal location in the stomach, earlier TNM stage, intestinal subtype, better differentiation, and more negative HER2 status. The median overall survival (OS) of the dMMR/MSI-H group was better than that of the pMMR/microsatellite stability (MSS) group (not reached vs. 53.9 months, p = 0.014). Adjuvant chemotherapy had no impact in both disease-free survival (DFS) and OS of dMMR/MSI-H patients (p = 0.135 and 0.818, respectively). dMMR/MSI-H patients had poorer response and progression-free survival (PFS) of first-line chemotherapy, though they were statistically significant (p = 0.361 and 0.124, respectively).

CONCLUSIONS

dMMR/MSI-H GC patients have specific clinicopathological characteristics and better prognosis than pMMR patients.

PD-1 antibody camrelizumab for Epstein-Barr virus-positive metastatic gastric cancer: a single-arm, open-label, phase 2 trial

Gastric cancer (GC) patients with Epstein-Barr virus (EBV) positivity have demonstrated promising response with immunotherapy. We assessed the efficacy and safety of camrelizumab as salvage treatment in EBV-positive mGC. In this single-arm, phase 2 prospective clinical trial (NCT03755440), stage IV EBV-positive GC patients who failed/could not tolerate previous lines of chemotherapy were given intravenous camrelizumab 200 mg every 2 weeks until disease progression or unacceptable toxicity. The primary endpoint was objective response rate. Secondary endpoints were progression-free survival (PFS), overall survival (OS), disease control rate (DCR), duration of response, and toxicity. Exploratory analysis included the associations between treatment response and tumor mutation burden (TMB), programmed cell death ligand-1 (PD-L1) expression. Six eligible patients were enrolled in the first stage of the study. No patient achieved an objective response; thus, the study did not proceed to the second stage. The DCR was 67% (4/6). The median PFS rate was 2.2 months (95% CI: 1.5-not reached [NR]) and median OS was 6.8 months (95% CI: 1.7-NR). All treatment-related adverse events were grade 1-2, with reactive cutaneous capillary endothelial proliferation (n=4 [67%]) being the most commonly observed event. The only patient with PD-L1 combined positive score >1 had disease progression. Two stable disease and one disease progression were observed in three patients with TMB >10 Mut/Mb. EBV positivity may not be a good predictor for response to camrelizumab in mGC. Newer biomarkers are needed to identify EBV-positive mGC respondents who might benefit from immunotherapy.

Genomic and Transcriptomic Characteristics of Esophageal Adenocarcinoma

Esophageal adenocarcinoma (EAC) is a deadly disease with limited options for targeted therapy. With the help of next-generation sequencing studies over the last decade, we gained an understanding of the genomic architecture of EAC. The tumor suppressor gene TP53 is mutated in 70 to 80% of tumors followed by genomic alterations in CDKN2A, KRAS, ERBB2, ARID1A, SMAD4 and a long tail of less frequently mutated genes. EAC is characterized by a high burden of point mutations and genomic rearrangements, resulting in amplifications and deletions of genomic regions. The genomic complexity is likely hampering the efficacy of targeted therapies. Barrett's esophagus (BE), a metaplastic response of the esophagus to gastro-esophageal reflux disease, is the main risk factor for the development of EAC. Almost all EACs are derived from BE. The sequence from BE to EAC provides an opportunity to study the genomic evolution towards EAC. While the overlap of point mutations between BE and EAC within the same patient is, at times, surprisingly low, there is a correlation between the complexity of the genomic copy number profile and the development of EAC. Transcriptomic analyses separated EAC into a basal and a classical subtype, with the basal subtype showing a higher level of resistance to chemotherapy. In this review, we provide an overview of the current knowledge of the genomic and transcriptomic characteristics of EAC and their relevance for the development of the disease and patient care.

Occurrence of High Microsatellite-Instability/Mismatch Repair Deficiency in Nearly 2,000 Human Adenocarcinomas of the Gastrointestinal Tract, Pancreas, and Bile Ducts: A Study From a Large German Comprehensive Cancer Center

INTRODUCTION

Knowledge of the high microsatellite-instability (MSI-H)/mismatch repair deficiency (MMRd) status is of increasing interest for personalized neoadjuvant or adjuvant therapy planning. Only a few studies are available on MSI-H distribution in the Northern European Caucasian patient population. In this study, we focused on a large cohort of tumors of the upper gastrointestinal tract.

MATERIALS AND METHODS

Surgical material from a total of 1,965 patients was analyzed for MSI-H/MMRd status (including 1,267 carcinomas of the esophagus or stomach). All tumors were analyzed with an internationally recommended immunohistochemical panel consisting of four antibodies (MLH1, MSH2, PMS2, and MSH6). The results were molecularly objectified.

RESULTS

Adenocarcinomas with MSI-H/MMRd were detected with the following distribution: esophagus (1.4%), stomach (8.3%), small intestine (18.2%), large intestine (8.5%), intrahepatic bile ducts (1.9%), and pancreas (0%). In case of gastric tumors with MSI-H/MMRd, neoadjuvant therapy did not influence the prognosis of patients (p = 0.94). Within all tumor entities with MSI-H/MMRd, patients with a UICC stage 4 were also represented. In this advanced stage, 11.7% of patients with MSS tumors were diagnosed compared to 0.5% of patients with MSI-H tumors relative to the entire tumor collective.

DISCUSSION

In this study, the proportion of MSI-H/MMRd tumors in the stomach is smaller than would have been expected in knowledge of the data published by TCGA or AGRC. Negative prognostic effects regarding MSI-H status and neoadjuvant therapy as described by the MAGIC study group were not seen in our cohort. The extent to which the MSI-H/MMRd status should be known for neoadjuvant therapy planning must be clarified in prospective studies in the future. At present, there is no convincing data to dispense the neoadjuvant therapy for gastric carcinoma. Due to the very convincing, positive data regarding the response rates of MSI-H tumors to treatment with PD1/PD-L1 inhibitors, every metastatic carcinoma of the gastrointestinal tract should be tested for its MSI-H status.

Computational Image Analysis of T-Cell Infiltrates in Resectable Gastric Cancer: Association with Survival and Molecular Subtypes

Background

Gastric and gastro-esophageal junction cancers (GCs) frequently recur after resection, but markers to predict recurrence risk are missing. T-cell infiltrates have been validated as prognostic markers in other cancer types, but not in GC because of methodological limitations of past studies. We aimed to define and validate the prognostic role of major T-cell subtypes in GC by objective computational quantification.

Methods

Surgically resected chemotherapy-naïve GCs were split into discovery (n = 327) and validation (n = 147) cohorts. CD8 (cytotoxic), CD45RO (memory), and FOXP3 (regulatory) T-cell densities were measured through multicolor immunofluorescence and computational image analysis. Cancer-specific survival (CSS) was assessed. All statistical tests were two-sided.

Results

CD45RO-cell and FOXP3-cell densities statistically significantly predicted CSS in both cohorts. Stage, CD45RO-cell, and FOXP3-cell densities were independent predictors of CSS in multivariable analysis; mismatch repair (MMR) and Epstein–Barr virus (EBV) status were not statistically significant. Combining CD45RO-cell and FOXP3-cell densities into the Stomach Cancer Immune Score showed highly statistically significant (all P ≤ .002) CSS differences (0.9 years median CSS to not reached). T-cell infiltrates were highest in EBV-positive GCs and similar in MMR-deficient and MMR-proficient GCs.

Conclusion

The validation of CD45RO-cell and FOXP3-cell densities as prognostic markers in GC may guide personalized follow-up or (neo)adjuvant treatment strategies. Only those 20% of GCs with the highest T-cell infiltrates showed particularly good CSS, suggesting that a small subgroup of GCs is highly immunogenic. The potential for T-cell densities to predict immunotherapy responses should be assessed. The association of high FOXP3-cell densities with longer CSS warrants studies into the biology of regulatory T cells in GC.

Long non-coding RNAs in Epstein-Barr virus-related cancer

Epstein Barr-virus (EBV) is related to several cancers. Long non-coding RNAs (lncRNAs) act by regulating target genes and are involved in tumourigenesis. However, the role of lncRNAs in EBV-associated cancers is rarely reported. Understanding the role and mechanism of lncRNAs in EBV-associated cancers may contribute to diagnosis, prognosis and clinical therapy in the future. EBV encodes not only miRNAs, but also BART lncRNAs during latency and the BHLF1 lncRNA during both the latent and lytic phases. These lncRNAs can be targeted regulate inflammation, invasion, and migration and thus tumourigenesis. The products of EBV also directly and indirectly regulate host lncRNAs, including LINC00312, NORAD CYTOR, SHNG8, SHNG5, MINCR, lncRNA-BC200, LINC00672, MALATI1, LINC00982, LINC02067, IGFBP7-AS1, LOC100505716, LOC100128494, NAG7 and RP4-794H19.1, to facilitate tumourigenesis using different mechanisms. Additionally, lncRNAs have been previously validated to interact with microRNAs (miRNAs), and lncRNAs and miRNAs mutually suppress each other. The EBV-miR-BART6-3p/LOC553103/STMN1 axis inhibits EBV-associated tumour cell proliferation. Additionally, H. pylori-EBV co-infection promotes inflammatory lesions and results in EMT. HPV-EBV co-infection inhibits the transition from latency to lytic replication. KSHV-EBV co-infection aggravates tumourigenesis in huNSG mice. COVID-19-EBV co-infection may activate the immune system to destroy a tumour, although this situation is rare and the mechanism requires further confirmation. Hopefully, this information will shed some light on tumour therapy strategies tumourigenesis. Additionally, this strategy benefits for infected patients by preventing latency to lytic replication. Understanding the role and expression of lnRNAs in these two phases of EBV is critical to control the transition from latency to the lytic replication phase. This review presents differential expressed lncRNAs in EBV-associated cancers and provides resources to aid in developing superior strategies for clinical therapy.

Understanding the immuno-biology of oesophageal adenocarcinoma: Towards improved therapeutic approaches

With an incidence that is constantly rising, oesophageal adenocarcinoma (OAC) is becoming an increasing health burden worldwide. Although significant advances in treatment regimens have improved patient outcomes, survival rates for this deadly cancer remain unsatisfactory. This highlights the need to improve current therapeutic approaches and develop novel therapeutic strategies for treating OAC patients. The advent of immunotherapy has revolutionised treatment across a range of malignancies, however outcomes in OAC show modest results. The inherent resistance of OAC to treatment reflects the complex genomic landscape of this cancer, which displays a lack of ubiquitous driver mutations and large-scale genomic alterations along with high tumour and immune heterogeneity. Research into the immune landscape of OAC is limited, and elucidation of the mechanisms surrounding the immune responses to this complex cancer will result in improved therapeutic approaches. This review explores what is known about the immuno-biology of OAC and explores promising therapeutic avenues that may improve responses to immunotherapeutic regimens.

Prediction Model of Tumor Regression Grade for Advanced Gastric Cancer After Preoperative Chemotherapy

Background

Preoperative chemotherapy (PCT) has been considered an important treatment for advanced gastric cancer (AGC). The tumor regression grade (TRG) system is an effective tool for the assessment of patient responses to PCT. Pathological complete response (TRG = 0) of the primary tumor is an excellent predictor of better prognosis. However, which patients could achieve pathological complete response (TRG = 0) after chemotherapy is still unknown. The study aimed to find predictors of TRG = 0 in AGC.

Methods

A total of 304 patients with advanced gastric cancer from July 2009 to November 2018 were enrolled retrospectively. All patients were randomly assigned (2:1) to training and internal validation groups. In addition, 124 AGC patients receiving PCT from December 2018 to June 2020 were included prospectively in the external validation cohort. A prediction model for TRG = 0 was established based on four predictors in the training group and was validated in the internal and external validation groups.

Results

Through univariate and multivariate analyses, we found that CA199, CA724, tumor differentiation and short axis of the largest regional lymph node (LNmax) were independent predictors of TRG = 0. Based on the four predictors, we established a prediction model for TRG = 0. The AUC values of the prediction model in the training, internal and external validation groups were 0.84, 0.73 and 0.82, respectively.

Conclusions

We found that CA199, CA724, tumor differentiation and LNmax were associated with pathological response in advanced gastric cancer. The prediction model could provide guidance for clinical work.

Preservation of Epstein-Barr virus status and mismatch repair protein status along the metastatic course of gastric cancer

AIMS

Epstein-Barr virus (EBV) in-situ hybridisation and mismatch repair (MMR) protein immunohistochemistry identifies two subgroups of gastric cancer (GC) with high immunogenicity and likelihood for response to immune check-point inhibition. As tumour biology may change during the metastatic course, which can negatively influence the success of therapeutic decisions made on primary tissue, we investigated the consistency of GC EBV and MMR status within primary tumours and metastases.

METHODS AND RESULTS

We investigated a cohort of 415 primary resected GC, including 111 cases with corresponding distant metastases and 297 cases with lymph node metastases. Tumours were analysed by EBV in-situ hybridisation and MLH1, PMS2, MSH2 and MSH6 immunohistochemistry using tissue microarray technique. Primary tumours were grouped as EBV-positive MMR-proficient, EBV-negative MMR-deficient and EBV-negative MMR-proficient. Eleven of 415 (2.7%) of primary tumours were EBV-positive MMR-proficient, whereas 49 of 415 (11.8%) of tumours were EBV-negative MMR-deficient. EBV and MMR protein status showed full concordance with that of the primary tumours. MMR-deficient tumours were of lower pT-category (P < 0.001), had fewer lymph node metastases [24 of 49 (49%) versus 273 of 361 (75.6%) cases; P < 0.001] and a lower rate of distant metastases [six of 49 (12.2%) versus 105 of 366 (28.7%) cases; P = 0.015].

CONCLUSION

We demonstrate a strong correlation of EBV and MMR status between primary tumours, lymph node and distant metastases in a large series of primary resected GC. The cases showed the expected frequency of EBV-positive MMR-deficient and EBV-negative MMR-proficient tumours. We conclude that tissue testing for molecular subtyping for therapeutic decision-making can be reliably performed on primary tumours and metastases in GC.

Distribution of tumor-infiltrating-T-lymphocytes and possible tumor-escape mechanisms avoiding immune cell attack in locally advanced adenocarcinomas of the esophagus

Introduction

The inflammatory microenvironment has emerged as one of the focuses of cancer research. Little is known about the immune environment in esophageal adenocarcinoma (EAC) and possible tumor-escape mechanisms to avoid immune cell attack.

Patients and methods

We measured T cell inflammation (CD3, CD8) in the microenvironment using a standardized software-based evaluation algorithm considering different predefined tumor areas as well as expression of MHC class 1 and PD-L1 on 75 analyzable primarily resected and locally advanced (≥ pT2) EACs. We correlated these findings statistically with clinical data.

Results

Patients with high amounts of T cell infiltration in their tumor center showed a significant survival benefit of 41.4 months compared to 16.3 months in T cell poor tumors (p = 0.025), although CD3 fails to serve as an independent prognostic marker in multivariate analysis. For the invasion zone, a correlation between number of T-cells and overall survival was not detectable. Loss of MHC1 protein expression on tumor cells was seen in 32% and PD-L1 expression using the combined positive score (CPS) in 21.2%. Most likely due to small numbers of cases, both markers are not prognostically relevant, even though PD-L1 expression correlates with advanced tumor stages.

Discussion

Our analyses reveal an outstanding, though not statistically independent, prognostic relevance of T-cell-rich inflammation in our group of EACs, in particular driven by the tumor center. For the first time, we describe that the inner part of the invasion zone in EACs shows significantly fewer T-cells than other tumor segments and is prognostically irrelevant. We also demonstrate that the loss of antigen presenting ability via MHC1 downregulation by the carcinoma cells is a common escape mechanism in EACs. Future work will need to show whether tumors with MHC class 1 loss respond less well to immunotherapy.

How Should We Test for Lynch Syndrome? A Review of Current Guidelines and Future Strategies

International guidelines for the diagnosis of Lynch syndrome (LS) recommend molecular screening of colorectal cancers (CRCs) to identify patients for germline mismatch repair (MMR) gene testing. As our understanding of the LS phenotype and diagnostic technologies have advanced, there is a need to review these guidelines and new screening opportunities. We discuss the barriers to implementation of current guidelines, as well as guideline limitations, and highlight new technologies and knowledge that may address these. We also discuss alternative screening strategies to increase the rate of LS diagnoses. In particular, the focus of current guidance on CRCs means that approximately half of Lynch-spectrum tumours occurring in unknown male LS carriers, and only one-third in female LS carriers, will trigger testing for LS. There is increasing pressure to expand guidelines to include molecular screening of endometrial cancers, the most frequent cancer in female LS carriers. Furthermore, we collate the evidence to support MMR deficiency testing of other Lynch-spectrum tumours to screen for LS. However, a reliance on tumour tissue limits preoperative testing and, therefore, diagnosis prior to malignancy. The recent successes of functional assays to detect microsatellite instability or MMR deficiency in non-neoplastic tissues suggest that future diagnostic pipelines could become independent of tumour tissue.

Sex-specific prognostic effect of CD66b-positive tumor-infiltrating neutrophils (TANs) in gastric and esophageal adenocarcinoma

BACKGROUND

Tumor-associated neutrophils (TANs) have recently been identified as a relevant component of the tumor microenvironment (TME) in solid tumors. Within the TME TANs mediate either tumor-promoting or tumor-inhibiting activities. So far, their prognostic relevance remains to be determined. This study aims to evaluate the prognostic relevance of TANs in different molecular subtypes of gastric and esophageal adenocarcinoma.

METHODS

We analyzed a total of 1118 Caucasian patients divided into gastric adenocarcinoma (n = 458) and esophageal adenocarcinoma cohort (n = 660) of primarily resected and neoadjuvant-treated individuals. The amount of CD66b + TANs in the tumor stroma was determined using quantitative image analysis and correlated to both molecular, as well as clinical data.

RESULTS

An accumulation of TANs in the tumor stroma of gastric carcinomas was associated to a significant favorable prognosis (p = 0.026). A subgroup analysis showed that this effect was primarily related to the molecular chromosomal instable subtype (CIN) of gastric carcinomas (p = 0.010). This was only observed in female patients (p = 0.014) but not in male patients (p = 0.315). The same sex-specific effect could be confirmed in adenocarcinomas of the esophagus (p = 0.027), as well as in female individuals after receiving neoadjuvant therapy (p = 0.034).

CONCLUSIONS

Together, we show a sex-specific prognostic effect of TANs in gastric cancer within a Caucasian cohort. For the first time, we showed that this sex-specific prognostic effect of TANs can also be seen in esophageal cancer.

Cross-testing of major molecular markers indicates distinct pathways of tumorigenesis in gastric adenocarcinomas and synchronous gastrointestinal stromal tumors

Small subtype of the gastrointestinal stromal tumor (micro-GIST, MG) is usually asymptomatic and is frequently found incidentally in association with gastric adenocarcinoma (GAC). The background of this coincidence is still an open question. This study comprehensively characterized nine MGs and GACs present in the same surgical specimen by cross-testing the markers of the major pathogenetic pathways of both tumor types. All of the MGs were immunohistochemically positive for CD117/KIT, CD34, and DOG1. DOG1 was also detected in four GACs. Four MGs carried mutations in c-KIT (exons 9, 11, and 13) and two cases in PDGFRα (exon 18). None of the GACs carried activating mutations in c-KIT or PDGFRα. MMR immunopanel identified one GAC as microsatellite unstable tumor. No EBV-positive tumor was found. According to the TCGA molecular classification, one GAC was categorized in the MSI subgroup, three GACs in the genomically stable subgroup, and the rest into the chromosomal instability subgroup. Although a common carcinogenic effect cannot be ruled out, our data suggest a distinct molecular background in the evolvement of the synchronous MGs and GACs. The presence of a MG in gastric resection specimens may be indicative of the development of synchronous malignant tumors in or outside the stomach.

Which is the optimal management for locally advanced gastric cancer patients with TRG 0 and 1 after R0 resection?

Background

Neoadjuvant chemotherapy (NAC) followed by surgery currently offers promise as a strategy for patients with locally advanced gastric cancer (GC). However, there is limited evidence to guide treatment for TRG 0 and 1 patients with locally advanced GC after R0 resection. This study set out to explore the optimal management for TRG 0 and 1 patients with locally advanced GC after R0 resection.

Methods

The retrospective data of 154 TRG 0 and 1 patients with locally advanced GC following R0 resection who were treated between January 2012 and December 2018 were collected and analyzed. The Kaplan-Meier method was used to estimate the survival rate. Multivariate analysis was performed using the Cox proportional hazards model.

Results

The median follow-up was 34.1 (range, 6.6–90.9) months. Six patients (3.9%) were lost during follow-up. Of the 27 patients who experienced relapse, 12 died, including 2 patients who died of non-neoplastic causes. The 5-year recurrence-free survival (RFS) and 5-year overall survival (OS) were 71.6% (95% CI: 68.5–79.6) and 82.9% (95% CI: 76.9–86.1) for the whole cohort, respectively. Univariate analysis revealed that patients with carcinoembryonic antigen (CEA) <5.0 ng/ml after NAC (77.7% vs. 20.1%, P<0.001), distal gastrectomy (91.7% vs. 67.5%, P=0.046) had higher 5-year RFS. Meanwhile, combined resection (55.6% vs. 73.1%, P=0.042), major complications (42.7% vs. 80.50%, P<0.001), and lymph node metastasis (ypN+) (52.0% vs. 83.7%, P<0.001) had lower 5-year RFS. The multivariate analysis showed that CEA level after NAC (HR =2.876, 95% CI: 1.051–7.872, P=0.040), major complications (HR =2.432, 95% CI: 1.062–5.567, P=0.035), and lymph node metastasis (ypN+) (HR =3.183, 95% CI: 1.242–8.161, P=0.016) were independent prognostic factors.

Conclusions

TRG 0 and 1 patients with local GC after R0 resection following NAC had a good prognosis, especially patients with CEA <5.0 ng/mL after NAC, and those without major complications or lymph node metastasis. Monotherapy or no chemotherapy may offer options for treating TRG 0 and 1 patients without adverse prognostic factors.

Observational cohort study of clinical outcome in Epstein-Barr virus associated gastric cancer patients

Background:

Epstein–Barr virus-associated gastric cancer (EBVaGC) has unique clinicopathologic features and our present understanding of its treatment outcome is limited. Here, we investigated the clinical outcomes of resectable and metastatic EBVaGC cases with regards to their respective treatment.

Methods:

We retrieved the data of EBVaGC patients treated at our center from October 2014 to June 2019. The primary endpoint was overall survival (OS). Secondary endpoints were disease-free survival (DFS) for stage I–III patients, progression-free survival (PFS) and objective response rate (ORR) for stage IV patients.

Results:

Patients classified as stage I–III accounted for 83.7% of the total 197 cases analyzed. Two patients had mismatched repair-deficiency. The 5-year OS rate of the entire cohort was 63.51% [95% (confidence interval (CI): 52.31–72.76%]. Tumor-node-metastasis (TNM) stage and gastric stump cancer were identified as independent prognostic factors for OS. The 3- and 5-year DFS rate for stage I–III patients were 83.72% (95% CI: 75.86–89.19%) and 73.83% (95% CI: 60.39–83.32%), respectively. TNM stage III, neural invasion, lymphovascular invasion, and baseline plasma EBV-DNA positive were correlated with shorter DFS. The ORR and disease control rate (DCR) for metastatic EBVaGC patients to first-line therapy were 29.0% and 90.3% (median PFS: 9.8 months), respectively, and to second-line therapy were 25.0% and 75.0%, respectively. Seven patients received anti-PD1 therapy and had an ORR of 28.5% and a median PFS of 2.8 months.

Conclusions:

EBVaGC patients have few metastases, long DFS, and high DCR. TNM stage and gastric stump cancer were independent prognostic factors for OS.

The Cancer-Immune Set Point in Oesophageal Cancer

Immunotherapy has achieved long-term disease control in a proportion of cancer patients, but determinants of clinical benefit remain unclear. A greater understanding of antitumor immunity on an individual basis is needed to facilitate a precision oncology approach. A conceptual framework called the "cancer-immune set point" has been proposed to describe the equilibrium between factors that promote or suppress anticancer immunity and can serve as a basis to understand the variability in clinical response to immune checkpoint blockade. Oesophageal cancer has a high mutational burden, develops from pre-existing chronic inflammatory lesions and is therefore anticipated to be sensitive to immune checkpoint inhibition. However, both tumour- and patient-specific factors including the immune microenvironment, the microbiome, obesity, and host genetics contribute to an immune set point that confers a lower-than-expected response to checkpoint blockade. Immunotherapy is therefore currently confined to latter lines of treatment of advanced disease, with no reliable predictive biomarker of response. In this review, we examine oesophageal cancer in the context of the cancer-immune set point, discuss factors that contribute to response to immunotherapeutic intervention, and propose areas requiring further investigation to improve treatment response.

Mesothelin expression in esophageal adenocarcinoma and squamous cell carcinoma and its possible impact on future treatment strategies

Background

Mesothelin is expressed at very low levels by normal mesothelial cells but is overexpressed in several human cancers. This makes mesothelin a promising target for immunotherapy. Limited data exist about mesothelin expression in esophageal carcinoma. In a current clinical trial, the highly potent anti-mesothelin antibody anetumab ravtansine is used in patients with mesothelin-positive tumors. Response rates are correlated with mesothelin expression (using the Ventana antibody) in tumor cells. No data are available on expression levels using the Ventana antibody. Most data have been generated using the Novocastra antibody. As patients are selected for clinical trials based on antibody staining of tumor samples, a comparison of these two available antibodies is crucial.

Methods

We analyzed 481 esophageal carcinomas [373 esophageal adenocarcinomas (EACs), 108 esophageal squamous cell carcinomas (ESCCs)] using two different monoclonal antibodies (Novocastra and Ventana) for mesothelin expression (low-mid and high-level expression, as used in one clinical trial). We also checked for the correlation of these results with clinical and molecular data.

Results

We revealed different staining results for both antibodies in EACs: Ventana: 53.6% (low expression: 25.3%; high expression: 28.3%) and Novocastra: 35.7% (low expression: 21.2%; high expression 14.5%). In ESCC we found comparable staining results: Ventana: 13.3% (low expression: 9.5%; high expression: 3.8%) and Novocastra: 13% (low expression: 11.1%; high expression: 1.9%). ARID1a-deficient EAC patients demonstrated significantly higher rates of mesothelin-positive tumors than ARID1a intact EAC patients. No correlations were found with other molecular alterations (TP53 mutation, ERBB2 amplification) or survival rates.

Conclusion

To the best of our knowledge, this is the largest study analyzing the importance of mesothelin expression in esophageal carcinoma. This study revealed a significant number of mesothelin-positive esophageal carcinomas, especially adenocarcinomas. New therapeutic targets are urgently required to improve the outcome of patients with locally advanced or metastasized esophageal carcinoma. The inhibition of mesothelin can be a new attractive target.

Predictive Biomarkers of Immune Checkpoint Inhibition in Gastroesophageal Cancers

Immune checkpoint inhibition has transformed cancer treatment. For gastroesophageal cancer, this class of drugs have demonstrated durable responses and survival benefit in a subgroup of patients, resulting in regulatory approval. However, several recent randomized phase III studies in gastroesophageal cancer have reported negative results, blunting initial enthusiasm. Identification and validation of predictive biomarkers with appropriate patient selection for benefit from immunotherapy is an area of intense research with novel concepts rapidly emerging. In this review we describe the latest immune checkpoint inhibitor trials which have been reported in gastroesophageal cancers with a focus on predictive biomarkers. We also explore novel biomarkers being developed to improve precision oncology for immunotherapy in gastroesophageal cancers.

Claudin 18.2 expression in esophageal adenocarcinoma and its potential impact on future treatment strategies

The incidence of esophageal adenocarcinoma (EAC) has rapidly increased, particularly in the Western world. Despite improvements in perioperative treatments, the overall survival of patients remains low. Claudin 18.2 is a tight junction protein that is exclusively expressed in the gastric epithelia. However, following malignant transformation, gastric cancer metastases maintain this expression. Therefore, claudin 18.2 is a promising target for immunotherapy. Previous clinical trials have revealed improved anti-tumor activity in patients treated with an anti-claudin antibody by investigating the expression of claudin 18.2 in tumor cells. However, there is currently very limited data on the importance of claudin 18.2 expression in EAC. The present study analyzed the distribution of claudin 18.2 using immunohistochemistry in 485 patients with EAC, including their lymph node metastases. Additionally, these results were associated with clinical and molecular data. Claudin 18.2 was detected in 89/485 patients (18.4%). No correlations between expression and clinicopathological data (sex, age, pT stage, lymph node metastasis and grading) were observed. However, significantly decreased claudin 18.2 expression was observed in tumor types with upregulated human epidermal growth factor receptor 2 expression (P=0.036). Additionally, neoadjuvant treatment did not have any significant impact on claudin 18.2 expression (P=0.331). To the best of our knowledge, the present study is the largest systematic investigation of claudin 18.2 protein expression in EAC. The results obtained suggested that claudin 18.2 may serve as a promising therapeutic target in a substantial number of patients with EAC.

Immune profile and immunosurveillance in treatment-naive and neoadjuvantly treated esophageal adenocarcinoma

The outcome in esophageal adenocarcinoma (EAC) is still poor with only 20% of patients in Western populations surviving for more than 5 years. Almost nothing is known about the precise composition of immune cells and their gene expression profiles in primary resected EACs and also nothing compared to neoadjuvant treated EACs. This study analyzes and compares immune profiles of primary resected and neoadjuvant treated esophageal adenocarcinoma and unravels possible targets for immunotherapy. We analyzed 47 EAC in total considering a set of 30 primary treatment-naive EACs and 17 neoadjuvant pretreated (12 × CROSS, 5 × FLOT) using the Nanostring's panel-based gene expression platform including 770 genes being important in malignant tumors and their immune micromileu. Most of the significantly altered genes are involved in the regulation of immune responses, T-and B cell functions as well as antigen processing. Chemokine-receptor axes like the CXCL9, -10,-11/CXCR3- are prominent in esophageal adenocarcinoma with a fold change of up to 9.5 promoting cancer cell proliferation and metastasis. ARG1, as a regulator of T-cell fate is sixfold down-regulated in untreated primary esophageal tumors. The influence of the currently used neoadjuvant treatment revealed a down-regulation of nearly all important checkpoint markers and inflammatory related genes in the local microenvironment. We found a higher expression of checkpoint markers like LAG3, TIM3, CTLA4 and CD276 in comparison to PD-L1/PD-1 supporting clinical trials analyzing the efficacy of a combination of different checkpoint inhibitors in EACs. We found an up-regulation of CD38 or LILRB1 as examples of additional immune escape mechanism.

Loss of the SWI/SNF-ATPase subunit members SMARCF1 (ARID1A), SMARCA2 (BRM), SMARCA4 (BRG1) and SMARCB1 (INI1) in oesophageal adenocarcinoma

Background

The SWI/SNF complex is an important chromatin remodeler, commonly dysregulated in cancer, with an estimated mutation frequency of 20%. ARID1A is the most frequently mutated subunit gene. Almost nothing is known about the other familiar members of the SWI/SNF complexes, SMARCA2 (BRM), SMARCA4 (BRG1) and SMARCB1 (INI1), in oesophageal adenocarcinoma (EAC).

Methods

We analysed a large cohort of 685 patients with EAC. We used four different antibodies to detect a loss-of-protein of ARID1A BRM, BRG1 and INI1 by immunohistochemistry and correlated these findings with molecular and clinical data.

Results

Loss of ARID1A, BRG1, BRM and INI1 was observed in 10.4, 3.4, 9.9 and 2% of EAC. We found a co-existing protein loss of ARID1A and BRM in 9.9% and of ARID1A and BRG1 in 2.2%. Patients with loss of ARID1A and TP53 wildtype EACs showed a shortened overall survival compared with AIRDA1A-positive tumours [median overall survival was 60.1 months (95%CI 1.2–139.9 months)] in patients with ARIDA-1A expression and 26.2 months (95%CI 3.7–19.1 months) in cases of ARIDA-1A loss (p = 0.044). Tumours with loss or expression of ARID1A and TP53 loss were not associated with a difference in survival. Only one tumour revealed high microsatellite instability (MSI-H) with concomitant ARID1A loss. All other ARID1A loss-EACs were microsatellite-stable (MSS). No predictive relevance was seen for SWI/SNF-complex alterations and simultaneous amplification of different genes (PIK3CA, KRAS, c-MYC, MET, GATA6, ERBB2).

Conclusion

Our work describes, for the first time, loss of one of the SWI/SNF ATPase subunit proteins in a large number of adenocarcinomas of the oesophagus. Several papers discuss possible therapeutic interventions for tumours showing a loss of function of the SWI/SNF complex, such as PARP inhibitors or PI3K and AKT inhibitors. Future studies will be needed to show whether SWI/SNF complex-deficient EACs may benefit from personalized therapy.

Evaluation of the prognostic impact of pathologic response to preoperative chemotherapy using Mandard's Tumor Regression Grade (TRG) in gastric adenocarcinoma

BACKGROUND

Perioperative chemotherapy is the gold standard in gastric cancer management. The prognostic significance of pathological response has been investigated in many malignancies, using Tumor Regression Grade (TRG). Its prognostic value in gastric cancer remains poorly known.

AIMS

This study aimed to assess the prognostic value of pathological response to chemotherapy, using Mandard's TRG in gastric cancer, and to identify factors predictive of response to chemotherapy.

METHODS

We retrospectively identified patients with gastric adenocarcinoma from two institutional surgical databases, with preoperative chemotherapy and subsequent gastrectomy. Pathological response was centrally reviewed using Mandard's TRG.

RESULTS

From 325 patients resected from a gastric cancer between 1997 and 2016, 109 underwent a preoperative chemotherapy. 42% were pathologic responders (TRG1-3) and 58% non-responders (TRG4-5). Five-years overall survival (OS) was 35% for non-responders, and 73% for responders (p = 0,006). Five-years disease-free survival (DFS) was 34% for non-responders and 65% for responders (p = 0,013). In multivariate analysis, pathological response was an independent prognostic factor of poor OS: HR = 2.736 (CI95% = 1.335-5.608; p = 0.006) and DFS: HR = 2.241 (CI95% = 1.130-4.446; p = 0.021).

CONCLUSION

TRG after preoperative chemotherapy is an important prognostic factor in patients resected for a gastric adenocarcinoma. Further studies should be performed to evaluate if adjuvant therapy should be adapted to pathological response.

Mucin expression in gastric- and gastro-oesophageal signet-ring cell cancer: results from a comprehensive literature review and a large cohort study of Caucasian and Asian gastric cancer

BACKGROUND

The literature on the prognostic relevance of signet-ring cell (SRC) histology in gastric cancer (GC) is controversial which is most likely related to inconsistent SRC classification based on haematoxylin-eosin staining. We hypothesised that mucin stains can consistently identify SRC-GC and predict GC patient outcome.

METHODS

We performed a comprehensive literature review on mucin stains in SRC-GC and characterised the mucin expression in 851 Caucasian GC and 410 Asian GC using Alcian Blue (AB)-Periodic Acid-Schiff (PAS), MUC2 (intestinal-type mucin), and MUC5AC (gastric-type mucin). The relationship between mucin expression and histological phenotype [poorly cohesive (PC) including proportion of SRCs, non-poorly cohesive (non-PC), or mucinous (MC)], clinicopathological variables, and patient outcome was analysed.

RESULTS

Depending on mucin expression and cut-offs, the positivity rates of SRC-GC reported in the literature varied from 6 to 100%. Patients with MUC2 positive SRC-GC or SRC-GC with (gastro)intestinal phenotype had poorest outcome. In our cohort study, PC with ≥ 10% SRCs expressed more frequently MUC2, MUC5AC, and ABPAS (p < 0.001, p = 0.004 and p < 0.001, respectively). Caucasians with AB positive GC or combined ABPAS-MUC2 positive and MUC5AC negative had poorest outcome (all p = 0.002). This association was not seen in Asian patients.

CONCLUSIONS

This is the first study to suggest that mucin stains do not help to differentiate between SRC-GC and non-SRC-GC. However, mucin stains appear to be able to identify GC patients with different outcome. To our surprise, the relationship between outcome and mucin expression seems to differ between Caucasian and Asian GC patients which warrants further investigations.

PIK3CA and KRAS Amplification in Esophageal Adenocarcinoma and their Impact on the Inflammatory Tumor Microenvironment and Prognosis

Gene amplifications of PIK3CA or KRAS induce a downstream activation of the AKT-mTOR or RAF-ERK-pathways. Interactions of the active AKT pathway have been implicated in the inflammatory tumor microenvironment. Nothing is known about these interactions or prognostic power in esophageal adenocarcinoma (EAC). We retrospectively analyzed a large cohort of 685 EAC considering KRAS and PIK3CA gene amplification using fluorescence in situ hybridization (FISH) and immunohistochemistry. These results were correlated with clinical and molecular data as well as the inflammatory tumor microenvironment. Amplifications of KRAS were seen in 94 patients (17.1%), PIK3CA amplifications in 23 patients (5.0%). KRAS amplifications significantly correlated with nodal positive patients and poorer overall survival (OS) in the subgroup without neoadjuvant treatment (p = 0.004), coamplifications of Her2 (p = 0.027), and TP53 mutations (p = 0.016). PIK3CA amplifications significantly correlated with a high amount of tumor infiltrating T cells (p = 0.003) and showed a tendency to better OS (p = 0.068). A correlation with checkpoint makers (PD-L1, LAG3, VISTA, TIM3, IDO) could not be revealed. Our findings are the first to link the KRAS amplified genotype with lymphonodal positivity and poor prognosis and the PIK3CA-amplified genotype with a T cell–rich microenvironment in EAC. Future studies must show whether these two genotype subgroups can be therapeutically influenced. A dual inhibition of MEK and SHP2T could be effective in the subgroup of KRAS amplified EACs and an immune checkpoint blockade may prove to be particularly promising in the subgroup of PIK3CA-amplified EACs.

Novel Biomarkers for Prediction of Response to Preoperative Systemic Therapies in Gastric Cancer

Preoperative chemo- and radiotherapeutic strategies followed by surgery are currently a standard approach for treating locally advanced gastric and esophagogastric junction cancer in Western countries. However, in a large number of cases, the tumor is extremely resistant to these treatments and the patients are exposed to unnecessary toxicity and delayed surgical therapy. The current clinical trials evaluating the combination of preoperative systemic therapies with modern targeted and immunotherapeutic agents represent a unique opportunity for identifying predictive biomarkers of response to select patients that would benefit the most from these treatments. However, it is of utmost importance that these potential biomarkers are corroborated by extensive preclinical and translational research. The aim of this review article is to present the most promising biomarkers of response to classic chemotherapeutic, anti-HER2, antiangiogenic, and immunotherapeutic agents that can be potentially useful for personalized preoperative systemic therapies in gastric cancer patients.

Loss of ARID1A expression is associated with DNA mismatch repair protein deficiency and favorable prognosis in advanced stage surgically resected esophageal adenocarcinoma

Esophageal adenocarcinoma often presents at an advanced stage and has a dismal prognosis. Current prognostic markers have limited utility. ARID1A is implicated as a tumor suppressor gene in esophageal adenocarcinoma. Loss of ARID1A expression correlates with DNA mismatch repair (MMR) protein deficiency in other tumors. We hypothesized that ARID1A loss is associated with prognosis and DNA MMR protein deficiency in esophageal adenocarcinoma. Tissue microarrays representing 316 surgically resected esophageal adenocarcinomas without neoadjuvant treatment were evaluated for ARID1A and MMR proteins by immunohistochemistry. Loss of ARID1A expression (ARID1A-loss) was detected in 41 of 316 (13%) adenocarcinomas. MMR deficiency was identified in 5% (17/316) but was detected more frequently in ARID1A-loss adenocarcinomas (13/41, 32%) than in ARID1A-retained adenocarcinomas (4/275, 1%; P < .001). Morphologically, ARID1A-loss adenocarcinomas frequently demonstrated peritumoral lymphoid aggregates (90%) and tumor infiltrating lymphocytes (51%). In patients with locally advanced or metastatic disease (stages III or IV, N = 169), patients with ARID1A-loss adenocarcinomas (N = 22) had longer overall survival than patients with ARID1A-retained adenocarcinomas (median [month]: 26 vs. 16, P = .010). In these patients, ARID1A-loss correlated with a 56% reduction in mortality independent of other prognostic factors (P = .007). In summary, loss of ARID1A expression is associated with DNA MMR protein deficiency in esophageal adenocarcinoma. Furthermore, ARID1A loss is independently associated with a more favorable prognosis for patients with locally advanced or metastatic esophageal adenocarcinomas.

Prognostic implication of molecular subtypes and response to neoadjuvant chemotherapy in 760 gastric carcinomas: role of Epstein-Barr virus infection and high- and low-microsatellite instability

Epstein-Barr virus positivity (EBV(+)) and high-microsatellite instability (MSI-H) have been identified as molecular subgroups in gastric carcinoma. The aim of our study was to determine the prognostic and predictive relevance of these subgroups in the context of platinum/5-fluorouracil (5-FU) based preoperative chemotherapy (CTx). Additionally, we investigated the clinical relevance of the low-MSI (MSI-L) phenotype. We analysed 760 adenocarcinomas of the stomach or the gastro-oesophageal junction encompassing 143 biopsies before CTx and 617 resected tumours (291 without and 326 after CTx). EBV was determined by PCR and in situ hybridisation for selected cases. MSI was analysed by PCR using five microsatellite markers and classified as MSI-H and MSI-L. Frequencies of EBV(+), MSI-H and MSI-L in the biopsies before CTx were 4.2, 10.5 and 4.9% respectively. EBV(+) or MSI-H did not correlate with response, but MSI-L was associated with better response (p = 0.011). In the resected tumours, frequencies of EBV(+), MSI-H and MSI-L were 3.9, 9.6 and 4.5% respectively. Overall survival (OS) was significantly different in the non-CTx group (p = 0.014). Patients with EBV(+) tumours showed the best OS, followed by MSI-H. MSI-L was significantly associated with worse OS (hazard ratio [HR], 2.21; 95% confidence interval [CI], 1.21-4.04, p = 0.01). In the resected tumours after CTx, MSI-H was also associated with increased OS (HR, 0.54; 95% CI, 0.26-1.09, p = 0.085). In multivariable analysis, molecular classification was an independent prognostic factor in the completely resected (R0) non-CTx group (p = 0.035). In conclusion, MSI-H and EBV(+) are not predictive of response to neoadjuvant platinum/5-FU based CTx, but they are indicative of a good prognosis. In particular, MSI-H indicates a favourable prognosis irrespective of treatment with CTx. MSI-L predicts good response to CTx and its negative prognostic effect for patients treated with surgery alone suggests that MSI-L might help to identify patients with potentially high-benefit from preoperative CTx.

Assessing molecular subtypes of gastric cancer: microsatellite unstable and Epstein-Barr virus subtypes. Methods for detection and clinical and pathological implications

Background

The molecular classification of gastric cancer recognises two subtypes prone to immune checkpoint blockade: the microsatellite unstable and the Epstein-Barr virus (EBV)-related tumours. We aim to assess the concordance between immunohistochemistry and PCR for microsatellite status evaluation, and explore the value of microsatellite instability (MSI) and EBV as predictive survival factors.

Material and methods

We collected 246 consecutively diagnosed gastric cancer cases in all stages and evaluated the microsatellite status using immunohistochemistry for mismatched repair (MMR) proteins and PCR. EBV expression was studied through in situ hybridisation.

Results

Forty-five (18%) cases presented MSI and 13 (6%) were positive for EBV. MSI was associated with female sex, older age, distal location and distal non-diffuse type of the modified Lauren classification. EBV expression was most frequent in proximal location and proximal non-diffuse type. The sensitivity, specificity, positive predictive value and negative predictive value of immunohistochemistry for the microsatellite study were 91%, 98%, 91% and 98%, respectively. In the multivariate analysis, MSI was an independent predictor of favourable tumour-specific survival (TSS) in stages I–III (MSI: HR: 0.37, 95% CI 0.12 to 0.95, p=0.04).

Conclusions

The MSI status and the EBV expression should be incorporated in routine pathological report for two reasons. First, MSI defines a different pathological entity with a better outcome. Second, MSI and EBV may be useful biomarkers to identify patients who will respond to immune checkpoint blockade inhibitors. For this purpose, immunohistochemical study for MMR proteins and in situ hybridisation study for EBV evaluation are feasible and cost-effective methods.