Prognostic perspectives of PD-L1 combined with tumor-infiltrating lymphocytes, Epstein-Barr virus, and microsatellite instability in gastric carcinomas

The tumor immune composition of mismatch repair deficient and Epstein-Barr virus-positive gastric cancer: A systematic review

BACKGROUND

Gastric cancer (GC), known for its unfavorable prognosis, has been classified in four distinct molecular subtypes. These subtypes not only exhibit differences in their genome and transcriptome but also in the composition of their tumor immune microenvironment. The microsatellite instable (MSI) and Epstein-Barr virus (EBV) positive GC subtypes show clear clinical benefits from immune checkpoint blockade, likely due to a neoantigen-driven and virus-driven antitumor immune response and high expression of immune checkpoint molecule PD-L1. However, even within these subtypes response to checkpoint inhibition is variable, which is potentially related to heterogeneity in the tumor immune microenvironment (TIME) and expression of co-inhibitory molecules. We conducted a systematic review to outline the current knowledge about the immunological features on the TIME of MSI and EBV + GCs.

METHODS

A systematic search was performed in PubMed, EMBASE and Cochrane Library. All articles from the year 1990 and onwards addressing immune features of gastric adenocarcinoma were reviewed and included based on predefined in- and exclusion criteria.

RESULTS

In total 5962 records were screened, of which 139 were included that reported immunological data on molecular GC subtypes. MSI and EBV + GCs were reported to have a more inflamed TIME compared to non-MSI and EBV- GC subtypes. Compared to microsatellite stable (MSS) tumors, MSI tumors were characterized by higher numbers of CD8 + and FoxP3 + T cells, and tumor infiltrating pro- and anti-inflammatory macrophages. HLA-deficiency was most common in MSI tumors compared to other molecular GC subtypes and associated with lower T and B cell infiltrates compared to HLA-proficient tumors. EBV + was associated with a high number of CD8 + T cells, Tregs, NK cells and macrophages. Expression of PD-L1, CTLA-4, Granzyme A and B, Perforin and interferon-gamma was enriched in EBV + tumors. Overall, MSI tumors harbored a more heterogeneous TIME in terms of immune cell composition and immune checkpoints compared to the EBV + tumors.

DISCUSSION AND CONCLUSION

MSI and EBV + GCs are highly Handbook for Conducting a Literature-Based Health Assessment Using OHAT Approach for Systematic Review and Evidence Integration.; 2019pro-inflammatory immune cell populations. Although studies on the direct comparison of EBV + and MSI tumors are limited, EBV + tumors show less intra-subgroup heterogeneity compared to MSI tumors. More studies are needed to identify how Intra-subgroup heterogeneity impacts response to immunotherapy efficacy.

Porphyromonas gingivalis, a bridge between oral health and immune evasion in gastric cancer

Porphyromonas gingivalis (P. gingivalis) is a gram-negative oral pathogen associated with chronic periodontitis. Previous studies have linked poor oral health and periodontitis with oral cancer. Severe cases of periodontal disease can result in advanced periodontitis, leading to tissue degradation, tooth loss, and may also correlate with higher gastric cancer (GC) risk. In fact, tooth loss is associated with an elevated risk of cancer. However, the clinical evidence for this association remains inconclusive. Periodontitis is also characterized by chronic inflammation and upregulation of members of the Programmed Death 1/PD1 Ligand 1 (PD1/PDL1) axis that leads to an immunosuppressive state. Given that chronic inflammation and immunosuppression are conditions that facilitate cancer progression and carcinogenesis, we hypothesize that oral P. gingivalis and/or its virulence factors serve as a mechanistic link between oral health and gastric carcinogenesis/GC progression. We also discuss the potential impact of P. gingivalis' virulence factors (gingipains, lipopolysaccharide (LPS), and fimbriae) on inflammation and the response to immune checkpoint inhibitors in GC which are part of the current standard of care for advanced stage patients.

Investigating the relationship between Epstein-Barr virus infection and gastric cancer: A systematic review and meta-analysis

Background and Aims

Gastric cancer (GC) is a common cancer type worldwide, and various factors can be involved in its occurrence. One of these factors is Epstein-Barr virus (EBV) infection. In this regard, a systematic review and meta-analysis was conducted to achieve a better understanding of the EBV prevalence in GC samples.

Methods

English databases were searched and studies that reported the prevalence and etiological factors of EBV related to GC from July 2007 to November 2022 were retrieved. The reported data were selected based on the inclusion and exclusion criteria. The pooled prevalence of EBV infection with 95% confidence intervals was calculated. Quality assessment, heterogeneity testing, and publication bias assessment were also performed. The literature search showed 953 studies, of which 87 studies met our inclusion criteria and were used for meta-analysis.

Results

The pooled prevalence of EBV infection related to GC was estimated to be 9.5% (95% confidence interval [CI]: 8.2%-11%) in the general population. The prevalence of EBV infection related to GC by gender was 13.5% (95% CI: 11.1%-16.3%) in males and 7.6% (95% CI: 5.4%-10.6%) in females. No significant differences were observed in terms of geographical region. Out of the 87 studies included in the meta-analysis, the most common diagnostic test was in situ hybridization (58 cases).

Conclusions

Altogether, the results indicated that EBV infection is one of the important factors in the development of GC. However, this does not necessarily mean that EBV infection directly causes GC since other factors may also be involved in the development of GC. Therefore, it is recommended to conduct extensive epidemiological studies on various aspects of the relationship between this virus and GC, which can provide valuable information for understanding the relationship between EBV and GC.

Association of PD-L1 Expression with Clinicopathologic Characters in Gastric Cancer: A Comprehensive Meta-analysis

PURPOSE

The expression level of programmed death ligand-1(PD-L1) in patients with gastric cancer is the key to determining the use of immune drugs. The relationship between PD-L1 expression level and clinical characteristics is worth exploring.

METHODS

By setting the search terms correlated to PD-L1 and gastric cancer, a nearly comprehensive search was carried out in four major databases, and the deadline for searching was September 1, 2022. The retrieved documents were further screened by strict inclusion and exclusion criteria after removing the duplication. Next, the quality of the included studies was evaluated with the Newcastle-Ottawa Scale (NOS) scale. Finally, the STATA15.1 software was used to process data and draw plots, and the odds ratios (ORs) were adopted to assess the pooled effect size.

RESULTS

A total of 85 works of literature were included in this study through screening strictly, and detailed data were extracted after evaluating the quality of the literature. The process of analysis was conducted in the whole population, Asia-Africa population, European and American population, and Asian population with CPS≥1, amd all found that the expression of PD-L1 in gastric cancer was correlated with age, tumor size, EBV infection, Her-2 expression and microsatellite status. However, the subgroup of the region also found some differences in Asian and Western regions, which was interesting and worth studying further. The included research of this study did not have significant publish bias.

CONCLUSION

After careful analysis, this study found that age (>60 years), tumor size (>5cm), EBV infection (+), Her-2 expression (+), microsatellite status (MSI), and mismatch repair status (dMMR) were risk factors for positive expression of PD-L1 in gastric cancer.

Clinicopathological and molecular characteristics of gastric papillary adenocarcinoma

Papillary adenocarcinoma is defined as carcinoma with a well-defined papillary or villous structure. Despite sharing clinicopathological and morphological features with tubular adenocarcinomas, papillary adenocarcinomas frequently show microsatellite instability. The present study aimed to clarify the clinicopathological features, molecular classification, and programmed death-ligand 1 (PD-L1) expression characteristics of papillary adenocarcinoma, especially tumors with microsatellite instability. We examined the microsatellite status and expression of mucin core proteins and PD-L1 as well as the clinicopathological features in 40 gastric papillary adenocarcinomas. Surrogate immunohistochemical analysis of p53 and mismatch repair proteins along with Epstein-Barr virus-encoded RNA in situ hybridization were performed for molecular classification. Female predominance and frequent microsatellite instability were observed in papillary adenocarcinoma in comparison with tubular adenocarcinoma. The presence of microsatellite instability in papillary adenocarcinoma was significantly correlated with older age, tumor-infiltrating lymphocytes, and Crohn's-like lymphoid reactions. Surrogate examination demonstrated that the genomically stable type (17 cases, 42.5%) was the most common, followed by the microsatellite-unstable type (14 cases, 35%). Among the seven cases showing PD-L1-positive expression in tumor cells, four involved carcinomas with microsatellite instability. These results reveal the clinicopathological and molecular characteristics of gastric papillary adenocarcinoma.

Comprehensive biomarker analysis of long-term response to trastuzumab in patients with HER2-positive advanced gastric or gastroesophageal adenocarcinoma

BACKGROUND

A subgroup of patients with HER2-positive metastatic gastric and gastroesophageal junction cancers shows long-term response under trastuzumab maintenance monotherapy. Obviously, HER2 status alone is not able to identify these patients. We performed this study to identify potential new prognostic biomarkers for this long-term responding patient group.

PATIENTS AND METHODS

Tumour samples of 19 patients with HER2-positive metastatic gastric and gastroesophageal junction cancer who underwent trastuzumab treatment were retrospectively collected from multiple centres. Patients were divided into long-term responding (n = 7) or short-term responding group (n = 12) according to progression-free survival (PFS≥12 months vs. PFS < 12 months). Next-generation sequencing and microarray-based gene expression analysis were performed along with HER2 and PD-L1 immunohistochemistry.

RESULTS

Long-term responding patients had significantly higher PD-L1 combined positive scores (CPS) and CPS correlated with longer progression-free survival. PD-L1 positivity (CPS ≥ 1) was further associated with an increased CD4+ memory T-cell score. The ERBB2 copy number as well as the tumour mutational burden could not discriminate between short-term and long-term responding patients. Genetic alterations and coamplifications in HER2 pathway associated genes such as EGFR, which were connected to trastuzumab resistance, were present in 10% of the patients and equally distributed between the groups.

CONCLUSION

The study highlights the clinical relevance of PD-L1 testing also in the context of trastuzumab treatment and offers a biological rational by demonstrating elevated CD4+ memory T-cells scores in the PD-L1-positive group.

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.

Prognostic roles of leptin-signaling proteins, PD-L1, and tumor-infiltrating lymphocytes in surgically-resected biliary tract cancers

BACKGROUND

Biliary tract cancers are rare, with a poor patient prognosis. Leptin and programmed death-ligand 1 (PD-L1) influence CD8⁺ and forkhead box P3 (FOXP3)⁺ lymphocytes, and thus, cancer cell growth. We aimed to define the prognostic implications of these variables and the clinicopathological features of biliary tract cancers.

METHODS

Immunohistochemistry for leptin signaling-related proteins (leptin, leptin receptor, pSTAT3, extracellular-regulated kinase, mammalian target of rapamycin), PD-L1, CD8, and FOXP3 and in situ hybridization for Epstein-Barr virus-encoded small RNAs were performed in 147 cases of surgically-resected biliary tract cancers.

RESULTS

Immune cell PD-L1-positivity, tumor size < 3 cm, adjuvant chemotherapy, no recurrence, and early-stage tumors were correlated with better 5-year survival in the tumoral PD-L1^(-) and leptin^(-) subgroups, and extrahepatic cholangiocarcinoma through multivariate analysis (all p < 0.05). Immune cell PD-L1 and adjuvant chemotherapy lost its prognostic significance in the tumoral PD-L1⁺ and leptin⁺ subgroups.

CONCLUSIONS

The prognostic implication of the variables may depend upon tumoral protein expression and the anatomical site. Immune cell PD-L1-positivity and the administration of adjuvant chemotherapy may indicate the favorable survival of patients with surgically-resected biliary tract cancers, specifically, in the tumoral PD-L1^(-) or tumor leptin^(-) subgroups and extrahepatic cholangiocarcinoma. PD-L1- or leptin-targeted therapy combined with conventional chemotherapy may benefit the tumoral PD-L1⁺ or leptin⁺ subgroups.

Clinicopathological features of PD-L1 protein expression, EBV positivity, and MSI status in patients with advanced gastric and esophagogastric junction adenocarcinoma in Japan

This real-world study examined the prevalence of programmed death ligand-1 (PD-L1) expression and assessed the frequency of microsatellite instability-high (MSI-H) status and Epstein-Barr virus (EBV) positivity in Japanese patients with advanced gastric and gastroesophageal junction (GEJ) adenocarcinoma. This multicenter (5 sites), retrospective, observational study (November 2018–March 2019) evaluated Japanese patients with advanced gastric and GEJ adenocarcinoma after surgical resection (Stage II/III at initial diagnosis) or unresectable advanced cancer (Stage IV). The primary objectives were prevalence of PD-L1 expression (combined positive score [CPS] ≥1), MSI status, and EBV positivity. Tumor specimens of 389/391 patients were analyzed (male, 67.1%; mean age, 67.6 ± 12.2 years); 241/389 (62%) were PD-L1 positive, 24/379 (6.3%) had MSI-H tumors, and 13/389 (3.3%) were EBV positive. PD-L1 expression was higher in tumor-infiltrating immune cells than in tumor cells for lower CPS cutoffs. Among patients with MSI-H tumors and EBV-positive tumors, 19/24 (79.2%) and 9/13 (69.2%), respectively, were PD-L1 positive. A greater proportion of patients with MSI-H tumors (83.3% [20/24]) were PD-L1 positive than those with MSI-low/stable tumors (60.8% [216/355]; p = .0297); similarly, an association was observed between history of H pylori infection and PD-L1 expression. A higher proportion of patients with MSI-H tumors demonstrated PD-L1 expression with a CPS ≥10 (66.7% [16/24]) vs those with MSI-low/stable tumors (24.8% [88/355]; p < .0001). The prevalence of PD-L1 positivity among Japanese patients was comparable to that in previous pembrolizumab clinical trials and studies in gastric cancer. Particularly, higher PD-L1 expression was observed in MSI-H tumors.

Changes in the Gustave Roussy Immune Score as a Powerful Prognostic Marker of the Therapeutic Sensitivity of Nivolumab in Advanced Gastric Cancer: A Multicenter, Retrospective Study

BACKGROUND

Identification of positive biomarkers for the effects of nivolumab on patients with advanced gastric cancer (AGC) is significant. The Gustave Roussy Immune Score (GRIm-s) is associated with therapeutic resistance of immune checkpoint inhibitors (ICIs) in other cancers. This multicenter, retrospective study was designed to analyze the association of GRIm-s with therapeutic sensitivity of nivolumab in patients with AGC.

METHODS

We reviewed 58 patients with AGC treated with nivolumab from October 2017 to November 2018 at five participating institutions. We performed blood tests before the start of nivolumab and after administration of two courses. We evaluated the correlation between the best overall response and GRIm-s. Additionally, we focused on the changes in GRIm-s before the start of nivolumab and after administration of two courses.

RESULTS

Of the 58 patients, 21 (36.2%) were classified into the disease control (DC) group and 37 (63.8%) into the progressive disease (PD) group. GRIm-s before nivolumab treatment did not correlate with the best therapeutic response (p = 0.086). However, GRIm-s after two courses of nivolumab showed that significantly more PD cases were in the high-risk group (p < 0.0001). After two courses of nivolumab, overall survival was significantly worse in the high-risk group (p < 0.0001). For progression-free survival, the high-risk group had a significantly worse prognosis both before (p = 0.04) and after two courses of nivolumab treatment (p < 0.0001).

CONCLUSIONS

GRIm-s after two courses of nivolumab and its changes compared to pretreatment values proved beneficial in predicting nivolumab sensitivity.

Influence of Helicobacter pylori infection on PD-1/PD-L1 blockade therapy needs more attention

BACKGROUND AND OBJECTIVE

The tumor microenvironment and tumor immunity are crucially involved in tumor therapy. Immune checkpoint inhibitors targeting PD-1/PD-L1 signal transduction have been widely used in tumor therapy and have shown ideal clinical efficacy. However, some kinds of cancers still do not respond to PD-1/PD-L1 blockade therapy effectively, including gastric cancer. The related factors should be explored.

METHODS AND RESULTS

This review summarizes the recent progression of understanding the influence of Helicobacter pylori infection on PD-1/PD-L1 blockade therapy. Current pieces of evidence have indicated that H. pylori infection might affect the curative effect of tumor therapy associating with the induced immunomodulation.

CONCLUSION

It is necessary to understand the overall integration of PD-1/PD-L1 blockade therapy, the tumor microenvironment, and H. pylori infection. Much attention on the influence of H. pylori infection on the efficacy of tumor immunotherapy should be paid.

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

OBJECTIVES

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

The Epstein-Barr Virus Hacks Immune Checkpoints: Evidence and Consequences for Lymphoproliferative Disorders and Cancers

The Epstein-Barr Virus (EBV) is a gammaherpesvirus involved in the etiopathogenesis of a variety of human cancers, mostly of lymphoid and epithelial origin. The EBV infection participates in both cell transformation and tumor progression, also playing an important role in subverting immune responses against cancers. The homeostasis of the immune system is tightly regulated by inhibitory mechanisms affecting key immune effectors, such as T lymphocytes and NK cells. Collectively known as immune checkpoints, these mechanisms rely on a set of cellular receptors and ligands. These molecules may be candidate targets for immune checkpoints blockade-an emergent and promising modality of immunotherapy already proven to be valuable for a variety of human cancers. The EBV was lately suspected to interfere with the expression of immune checkpoint molecules, notably PD-1 and its ligands, found to be overexpressed in cases of Hodgkin lymphoma, nasopharyngeal, and gastric adenocarcinomas associated with the viral infection. Even though there is compelling evidence showing that the EBV interferes with other immune checkpoint regulators (e.g., CTLA-4, LAG-3, TIM-3, and VISTA), the published data are still scarce. Herein, we discuss the current state of the knowledge on how the EBV interferes with the activity of immune checkpoints regulators, as well as its implications considering the immune checkpoints blockade for clinical management of the EBV-associated malignancies, notably lymphomas.

Recent insights into the use of immune checkpoint inhibitors in gastric cancer

Gastric cancer (GC) is the fifth most incident and the fourth deadliest cancer worldwide. GC is a heterogeneous disease from the histological and molecular standpoints. This malignancy is mostly diagnosed at advanced stages of the disease, where the available therapeutic interventions are not effective. The emergence of immunotherapy has transformed the landscape of cancer treatment, including GC, and currently immune checkpoint inhibitors have been approved for the treatment of patients with recurrent/metastatic GC. This review summarizes the main clinical trials evaluating the use of immune checkpoint inhibitors in GC. It also highlights the potential of biomarkers for patient selection for GC immune checkpoint inhibition therapy, including programmed cell death ligand 1 expression and tumor mutational burden, and characteristics of the GC molecular classification, such as microsatellite instability status and Epstein-Barr virus infection, as predictors of response to blockade of the programmed cell death 1/programmed cell death ligand 1 axis.

Molecular Classification of Gastric Cancer With Emphasis on PDL-1 Expression: The First Report From Iran

BACKGROUND

Gastric cancer is one of the lethal cancers and there is no effective treatment for these patients and still, 5-year survival rate is about 25% to 30%. Finding reliable biomarkers for early-stage diagnosis, targeted therapy, and survival prediction is a priority in this cancer.

OBJECTIVES

In this study we were trying to know about the molecular classification of gastric cancers in a group of patients from the South of Iran.

PATIENTS AND METHODS

In a cross sectional study, 50 specimens of gastric cancer were selected that have enough tissue to be stained by immunohistochemistry (IHC). IHC was performed for Her-2, mismatch repair genes (MLH-1, MSH-2, MSH-6, and PMS-2), and PDL-1. Frequency of positive makers was compared with survival and outcome.

RESULTS AND CONCLUSION

In our study, deficient MMR (dMMR) was detected in 4 patients (8.0%). PD-L1 expression in tumor cells (TC) was observed in 1 of 4 cases (25%) with PMS2 loss. However, PD-L1 in TCs and TILs (tumor infiltrating lymphocytes) was negative in 1 case with MLH1 loss and in 3 of 4 cases with PMS2 loss, which was not statistically significant. All of our 50 cases were positive for MSH2 and MSH6, 24% of which showed TCs with PDL-1 expression and 32% of them in TIL. HER2 was positive in 2 (2/50, 4.0%) cases, among which all of the cases were positive for PD-L1 expression in TCs and TILs, respectively. However, in HER2-negative group, 26.2% (11/42) and 28.6% (12/42) of tumors were positive for PD-L1 in TCs and TILs, respectively. The expression rate of PD-L1 in HER2 negative TCs was significantly higher than that in HER2 positive TCs (P = .033). Immunohistochemistry for Her-2 was equivocal in 6 cases (12.0%) none of which expressed PD-L1 in tumor cells. In our study minimum and maximum survival times from detection of gastric cancer were 1 and 87 months, respectively. The mean ± SD and median ± SD of overall survival time were 30.69 ± 4.88 and 18 ± 1.45 months, respectively. One and 3-year survival rates of 40% and 24%, respectively. PD-L1 expression was not associated with survival, but its expression was associated with intestinal type Lauren classification and negative HER-2. PD-L1 positivity in tumor cells or tumor infiltrating lymphocytes was not an independent prognostic factor in gastric cancer.

Advances of Tumorigenesis, Diagnosis at Early Stage, and Cellular Immunotherapy in Gastrointestinal Malignancies

Globally, in 2018, 4.8 million new patients have a diagnosis of gastrointestinal (GI) cancers, while 3.4 million people died of such disorders. GI malignancies are tightly relevant to 26% of the world-wide cancer incidence and occupies 35% of all cancer-associated deaths. In this article, we principally investigated molecular and cellular mechanisms of tumorigenesis in five major GI cancers occurring at esophagus, stomach, liver, pancreas, and colorectal region that illustrate high morbidity in Eastern and Western countries. Moreover, through this investigation, we not only emphasize importance of the tumor microenvironment in development and treatment of malignant tumors but also identify significance of M2PK, miRNAs, ctDNAs, circRNAs, and CTCs in early detection of GI cancers, as well as systematically evaluate contribution of personalized precision medicine including cellular immunotherapy, new antigen and vaccine therapy, and oncolytic virotherapy in treatment of GI cancers.

Microsatellite instability and Epstein-Barr virus combined with PD-L1 could serve as a potential strategy for predicting the prognosis and efficacy of postoperative chemotherapy in gastric cancer

Background

Microsatellite instability (MSI) and Epstein-Barr virus (EBV)-positive molecular subtypes exhibit complex immune responses in gastric cancer (GC), and PD-L1 has emerged as a prognostic biomarker associated with the cancer immune microenvironment. This study aimed to determine the prognostic value of molecular subtypes and whether the addition of PD-L1 would accurately predict the prognosis and guide postoperative chemotherapy for GC patients.

Methods

We performed molecular subtyping of tissue microarray slides from 226 GC patients who were treated with radical gastrectomy. The MSI status and PD-L1 expression were evaluated through immunohistochemistry (IHC) and EBV status through situ hybridization. Multiplex polymerase chain reaction (PCR) was also performed on 50 cases to validate the accuracy of IHC in defining MSI status. Differences in overall survival (OS) were assessed using the Kaplan-Meier method, log-rank test and Cox proportional hazards regression model.

Results

Among the 226 GC patients, 52 (23.2%) patients were classified as the MSI subtype, 11 (4.9%) were EBV⁺ subtype, and 161 (71.9%) were MSS (Microsatellite stable) /EBV subtype according to TCGA analysis. Two patients were both positive for MSI and EBV infection. EBV⁺ cases showed higher PD-L1 positivity than MSI cases and MSS/EBV cases (81.8% vs. 50.0% vs. 35.4%, P = 0.003). Compared with the non-MSS/EBV (MSI or EBV⁺ cases) subgroup, GC patients with MSS/EBV were associated with the worst outcomes (HR = 1.610, 95% CI [1.0462.479], P = 0.031). MSS/EBV GCs alone could benefit from postoperative chemotherapy (HR = 0.452, 95% CI [0.2990.682], P<0.001), and PD-L1-positive expression could also predict a better prognosis (HR = 0.612, 95% CI [0.3890.962], P = 0.033) in this subgroup. Considering both chemotherapy efficacy and PD-L1 expression in the MSS/EBV subgroup, chemotherapy could improve the prognosis for PD-L1-negative MSS/EBV GCs (HR = 0.357, 95% CI [0.2170.587], P <0.001) but not PD-L1-positive MSS/EBV GCs.

Conclusions

Molecular subtyping combined with PD-L1 expression could serve as a potential strategy to better predict prognosis and guide postoperative chemotherapy of GC patients.

Cytotoxic T-lymphocyte infiltration and chemokine predict long-term patient survival independently of tumor mutational burden in triple-negative breast cancer

Background:

Cytotoxic T-lymphocyte (CTL) infiltration into tumor is a positive prognostic factor in breast cancer. High tumor mutational burden (TMB) is also considered as a predictor of tumor immunogenicity and response to immunotherapy. However, it is unclear whether the infiltration of functional CTL simply reflects the TMB or represents an independent prognostic value.

Methods:

Utilizing The Cancer Genome Atlas (TCGA) breast cancer cohort, we established the Functional Hotness Score (FHS). The associations of FHS and breast cancer patient prognosis as well as distinct immunity markers were analyzed in a total of 3011 breast cancer patients using TCGA, METABRIC and metastatic breast cancer (MBC) cohort GSE110590.

Results:

We established FHS, based on CD8A, GZMB and CXCL10 gene expression levels of bulk tumors, which delivered the best prognostic value among some gene combinations. Breast cancer patients with the high-FHS tumors showed significantly better survival. FHS was lower in the MBCs. Triple-negative breast cancer (TNBC) showed the highest FHS among subtypes. FHS predicted patient survival in hormone receptor (HR)-negative, especially in TNBC, but not in HR-positive breast cancer. FHS predicted patient prognosis independently in TNBC. The high-FHS TNBCs showed not only higher CD8+ T cell infiltration, but also enhanced broader type-1 anti-cancer immunity. The patients with the high-FHS tumors showed better prognosis not only in high-TMB tumors but also in low-TMB TNBCs. The combination of high-TMB with high-FHS identified a unique subset of patients who do not recur over time in TNBC.

Conclusion:

TNBCs with high FHS based on the expression levels of CD8A, GZMB and CXCL10 showed improved prognosis with enhanced anti-cancer immunity regardless of TMB. FHS constitutes an independent prognostic marker of survival, particularly robustly when combined with TMB in TNBC.

[Neoadjuvant and perioperative treatment of gastric cancer, current studies and new biomarkers]

According to current German and European clinical practice guidelines perioperative chemotherapy is the recommended standard of care for localized gastric cancer beyond early cancers, i.e. in stage IB (T2 N0 M0 and T1 N1 M0) or greater. For patients who are able to tolerate intensive chemotherapy, the FLOT regimen (5-fluorouracil, folinic acid, oxaliplatin, docetaxel) should be administered preoperatively and postoperatively for four cycles each. Locally advanced nonmetastatic adenocarcinoma of the esophagogastric junction (AEG) should be treated with perioperative chemotherapy as for gastric cancer or alternatively with neoadjuvant chemoradiotherapy. The best approach for AEG is currently being investigated in ongoing clinical trials. The recommendation of perioperative treatment applies to all histopathological subtypes of gastric cancer. The article summarizes the contemporary data and provides an outlook on current progress in the field of medicinal perioperative treatment.

Whole-Exome Sequencing of Rare Site Endometriosis-Associated Cancer

Malignant transformation of extraovarian endometriosis is rare, with the carcinogenesis mechanism unclear. To clarify the actionable variants of rare-site endometriosis-associated cancer (RSEAC), we performed whole-exome sequencing for the tumor, in two patients. The intestine was affected in both cases, although the histology was that of clear cell carcinoma and undifferentiated carcinoma, respectively. Therefore, the cases were referred to as endometriosis-associated intestinal tumors (EIATs). Actionable variants (all frameshift mutations) were identified in tumor suppressor genes ARID1A, PTEN, and p53; however, no oncogenic variants were identified. Both cases were microsatellite stable. The patient with undifferentiated carcinoma exhibited hypermutator and homologous recombination deficiency phenotypes. The dominant mutation signatures were signature 30 (small subset of breast cancers) and 19 (pilocytic astrocytoma) in patient 1, and signature 5 (small subset of breast cancers) and 3 (breast, ovarian, and pancreatic cancers) in patient 2. Immunohistochemistry revealed positive CD8 and PD-1 expression in both patients; patient 1 also showed positive PDL-1 expression. Our results suggest that RSEAC is associated with variants of tumor suppressor genes as epigenetic alterations. Mutation signature-based whole-exome sequencing could be useful to select an adjuvant chemotherapy regimen. High CD8 and PD-1 expression in RSEAC suggests that immune checkpoint inhibitors are useful for treatment.

Lipid Metabolism and Immune Checkpoints

Immune checkpoints are essential for the regulation of immune cell functions. Although the abrogation of immunosurveillance of tumor cells is known, the regulators of immune checkpoints are not clear. Lipid metabolism is one of the important metabolic activities in organisms. In lipid metabolism, a large number of metabolites produced can regulate the gene expression and activation of immune checkpoints through various pathways. In addition, increasing evidence has shown that lipid metabolism leads to transient generation or accumulation of toxic lipids that result in endoplasmic reticulum (ER) stress and then regulate the transcriptional and posttranscriptional modifications of immune checkpoints, including transcription, protein folding, phosphorylation, palmitoylation, etc. More importantly, the lipid metabolism can also affect exosome transportation of checkpoints and the degradation of checkpoints by affecting ubiquitination and lysosomal trafficking. In this chapter, we mainly empathize on the roles of lipid metabolism in the regulation of immune checkpoints, such as gene expression, activation, and degradation.