Molecular Classification of Gastric Cancer among Alaska Native People

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.

Role of lncRNAs in Helicobacter pylori and Epstein-Barr virus associated gastric cancers

Helicobacter pylori infection is a risk factor for the development of gastric cancer (GC), and the role of co-infection with viruses, such as Epstein-Barr virus, in carcinogenesis cannot be ignored. Furthermore, it is now known that genetic factors such as long non-coding RNAs (lncRNAs) are involved in many diseases, including GC. On the other side, they can also be used as therapeutic goals. Modified lncRNAs can cause aberrant expression of genes encoding proximal proteins, which are essential for the development of carcinoma. In this review, we present the most recent studies on lncRNAs in GC, concentrating on their roles in H. pylori and EBV infections, and discuss some of the molecular mechanisms of these GC-related pathogens. There was also a discussion of the research gaps and future perspectives.

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

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

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.

Current progress and challenges of immunotherapy in gastric cancer: A focus on CAR-T cells therapeutic approach

Gastric cancer (GC) is a severe malignancy, accounting for the third most common cancer death worldwide. Despite the development of chemo-radiation therapy, there has not been sufficient survival advantage in patients with GC who were treated by these methods. GC immunogenicity is hampered by a highly immunosuppressive microenvironment; therefore, further understanding of the molecular biology of GC is the potential to achieve new therapeutic strategies in GC therapy, including specific immunotherapy. Current immunotherapies are mainly based on cytokines, immune checkpoints, monoclonal antibodies (mAb), bispecific antibodies (BisAbs), antibody-drug conjugates (ADCs), and chimeric antigen receptor (CAR). Immunotherapy has made significant progress in the treatment of GC, so that studies show that nivolumab as a programmed death 1 (PD1) inhibitor has proper safety and effectiveness as a third-line treatment for GC patients. Multiple monoclonal antibodies like ramucirumab and claudiximab were effective in treating GC patients, especially in combination with other treatments. Despite the challenges of CAR therapy in solid tumors, CAR therapy targets various GC cells targets; among them, intercellular adhesion molecule (ICAM)-1 CAR-T cell and CLDN18.2 CAR-T cell have shown promising results. Although responses to all these treatments are encouraging and in some cases, durable, these successes are not seen in all treated patients. The present review represents the development of various immunotherapies especially CAR-T cell therapy, its current use, clinical data in GC, and their limitations.

The Alaska Native Tumour Registry: fifty years of cancer surveillance data for Alaska Native people

Like other Indigenous Circumpolar populations, Alaska Native (AN) people experience different patterns of cancer than their non-Indigenous counterparts. Every 5 years, the Alaska Native Tumour Registry releases a comprehensive report on cancer among AN people; this study provides 50 years of cancer surveillance data. Five-year annual-average age-adjusted incidence rates were calculated for time-periods ranging 1969-2018. AN data were compared with data for US whites (SEER 9). Mortality rates were calculated for 1994-2018 using data from the National Center for Health Statistics. During 2014-2018, there were 2,401 cases of invasive cancer among AN people. Among these, the most commonly diagnosed cancers were colorectal (405 cases, 17% of all cancers), lung and bronchus (373 cases, 16% of all cancers), and female breast (340 cases, 14% of all cancers). Lung cancer was the leading cause of cancer death, followed by colorectal and female breast cancers. These leading cancers are screenable, and preventable through lifestyle modifications including tobacco cessation, healthy eating and engaging in physical activity. These data provide important information to support cancer prevention and control among AN people. Cancer surveillance has been a valuable tool throughout the Circumpolar North to support reducing the burden of cancer among Indigenous populations.Abbreviations: ANAI: Alaska Native/American Indian; AN: Alaska Native; USW: U.S. White(s); ANMC: Alaska Native Medical Center; ANTR: Alaska Native Tumour Registry; IR: Incidence Rate; CI: Confidence Interval; RR: Rate Ratio; ICD-O-3: International Classification of Diseases for Oncology - Third Edition; SEER: Surveillance, Epidemiology and End Results.

Association of single nucleotide polymorphisms (SNPs) with gastric cancer susceptibility and prognosis in population in Wuwei, Gansu, China

BACKGROUND

Gastric cancer (GC) is the sixth most common cancer. China is one of the most frequent GC occurred countries, and Wuwei, Gansu, is one of the highest incidence area in China. Possible biomarkers of GC susceptibility and prognosis among the population in Wuwei are urgently needed.

METHODS

All participants in this study were recruited from the Wuwei Cancer Hospital in Gansu, including 303 patients diagnosed with GC and 200 non-cancer controls. DNA was extracted for further single nucleotide polymorphisms (SNP) genotyping. All SNPs were firstly screened by additive logistic regression model then selected SNPs were subjected to univariate Cox regression analysis and multivariate Cox regression analysis for their associations with GC occurrence.

RESULTS

The results showed that 31 SNPs were significantly related to the incidence of GC in Wuwei, Gansu, China. Genotype rs4823921 was significantly related to the overall survival of GC patients and AC/AA genotype of rs4823921 polymorphism was significantly associated with an increased risk of GC in Wuwei population.

CONCLUSIONS

Thirty-one SNPs were significantly related to the incidence of GC in Wuwei and rs4823921 genotype AC/AA was significantly associated with poor prognosis of GC patients in Wuwei, Gansu.

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.

Immunotherapy for Gastroesophageal Tumors: Is There Still Hope for Efficacy?

Abstract:

Immunotherapy represents one of the biggest break-throughs of the 21st century and redefined modern cancer treatment. Despite this new approach changed the treatment paradigm in various cancer entities including lung and head-and-neck cancer, the efficacy of these treatment regimens varies in different patient subgroups and so far, failed to meet these high expectations in gastroesophageal cancer patients. This review discusses new treatment approaches concerning immunotherapy in gastroesophageal cancer patients and sheds some light on ongoing trials and new treatment combinations.

Overexpressed LINC00467 promotes the viability and proliferation yet inhibits apoptosis of gastric cancer cells via raising ITGB3 level

Long non-coding RNA (lncRNA) LINC00467 plays a proto-oncogenic role in non-small cell lung cancer. However, its effect and modulatory mechanism in gastric cancer (GC) are unknown. Thereby, we elucidated the mechanism of LINC00467 in GC. LINC00467 level in GC tissues was assessed by bioinformatic analysis, and clinicopathological parameters from GC patients were collected. The levels of LINC00467, integrin subunit beta 3 (ITGB3), proliferating cell nuclear antigen (PCNA), cleaved caspase-3 and cleaved poly (ADP-ribose) polymerase 1 (PARP1) in tissue samples or treated GC cells were assessed by quantitative real-time polymerase chain reaction (qRT-PCR), fluorescence in situ hybridization (FISH), or Western blot. The viability, proliferation and apoptosis of GC cells were detected by methyl thiazolyl tetrazolium assay, colony formation assay, and flow cytometry. Levels of LINC00467 and ITGB3 were up-regulated in GC, and highly expressed LINC00467 was positively associated with tumor size, differentiation, N stage, and T stage in GC patients. LINC00467 was enriched in cytoplasm of GC cells, and overexpressed LINC00467 promoted the viability and proliferation as well as levels of ITGB3 and PCNA, while suppressing the apoptosis and levels of cleaved caspase-3 and cleaved PARP1 in GC cells. Besides, the effects of shLINC00467 on inhibiting cell viability, proliferation of GC cells and PCNA level and promoting apoptosis as well as levels of cleaved caspase-3 and cleaved PARP1 were all partially reversed by overexpressed ITGB3. Overexpressed LINC00467 enhanced the viability and proliferation but inhibited apoptosis of GC cells via increasing ITGB3 level.

Recent advances in immune therapies for gastric cancer

Gastric cancer (GC) is an aggressive malignancy that is the third leading cause of cancer mortality worldwide. Localized GC can be cured with surgery, but most patients present with more advanced non-operable disease. Until recently, treatment options for relapsed and refractory advanced GC have been limited to combination chemotherapy regimens, HER-2 directed therapy, and radiation, which lead to few durable responses. Over the past decade, there have been significant advances in our understanding of the molecular and immune pathogenesis of GC. The infectious agents Epstein-Barr virus and Helicobacter pylori perturb the gastric mucosa immune equilibrium, which creates a microenvironment that favors GC tumorigenesis and evasion of immune surveillance. Insights into immune mechanisms of GC have translated into novel therapeutics, including immune checkpoint inhibitors, which have become a treatment option for select patients with GC. Furthermore, chimeric antigen receptor T-cell therapies have emerged as a breakthrough treatment for many cancers, with recent studies showing this to be a potential therapy for GC. In this review, we summarize the current state of knowledge on immune mechanisms of GC and the status of emerging immunotherapies to treat this aggressive cancer, as well as outline current challenges and directions for future research.

Gastric Cancer in Alaska Native and American Indian People Living in Alaska, 1990-2017

INTRODUCTION

Alaska Native (AN) people experience a high burden of gastric cancer compared with other US Native and non-Native populations. Previous reports have suggested that gastric cancer in AN people occurs at a younger age and is a more aggressive pathologic type. We evaluated all cases of gastric cancer in AN people from 1990 to 2017 and compared the epidemiologic and pathologic characteristics with the gastric cancers that occurred in the same time in the US white (USW) population.

METHODS

Cancer data were collected by the Alaska Native Tumor Registry and National Cancer Institute's Surveillance, Epidemiology, and End Results Program. Comparisons were performed looking at the age and sex distribution of the affected AN and USW people, as well as the cancer characteristics, including the location, stage, and pathology.

RESULTS

The age distribution was significantly different between AN and USW patients (P < 0.001), with a greater proportion of AN people diagnosed younger than 40 years (11% vs 3%, P < 0.0001) and 40-59 years (37% vs 20%, P < 0.0001). In addition, a greater proportion of AN people were diagnosed with distant stage cancer (AN: 48% and USW: 35%, P < 0.0001). The age-adjusted rate of gastric cancer in the AN population was significantly higher than the USW population (20.8 vs 6.7 per 100,000 persons, P < 0.0001). Although there has been a significant decrease in the gastric cancer incidence rate in the USW population, no significant change in incidence was seen in the AN population.

DISCUSSION

This study highlights the disproportionate burden of gastric cancer in the AN population. Further work is needed to address and understand this disparity.

Her2-Positive and Microsatellite Instability Status in Gastric Cancer-Clinicopathological Implications

Gastric cancer (GC) is one of the leading causes of cancer-related death. The combination of new molecular classifications with clinicopathological data could contribute to the individualization of patients and to the development of new therapeutic strategies. We examined the various associations in two molecular types of GC: HER2-positive (human epidermal growth factor receptor 2) and microsatellite instability (MSI), assessing their influence on treatment and prognosis. A retrospective study of 142 GC patients was performed with molecular characterization through HER2 overexpression and DNA repair protein expression for MSI. The percentage of HER2-positive tumors was 13.4%, predominantly in men. Correlations were found with intestinal type, metastases, advanced stages and chemotherapy. Almost 75% of HER2-positive patients died. MSI occurred in 16.2%, associated with advanced age, female sex, distal location and intestinal type. These patients had few metastases and low stages. The percentage of deaths was higher among MSI patients who received perioperative chemotherapy. The determination of HER2 and MSI status in GC is important for their association with specific clinicopathological features and for their prognostic and predictive value.

Clinicopathological features of tumor mutation burden, Epstein-Barr virus infection, microsatellite instability and PD-L1 status in Chinese patients with gastric cancer

Objectives

Gastric cancer (GC) is the 4th most common type of cancer worldwide. Different GC subtypes have unique molecular features that may have different therapeutic methods. The aim of the present study was to investigate Epstein-Barr virus (EBV) infection, microsatellite instability (MSI) status, the expression of programmed death-ligand 1 (PD-L1) and gene mutations in GC patients.

Methods

The data of 2504 GC patients, who underwent curative gastrectomy with lymphadenectomy at Peking University Cancer Hospital between 2013 and 2018, were reviewed. We analyzed the clinicopathological factors associated with the immunohistochemistry (IHC) profiles of these patients, and genetic alterations were analyzed using next generation sequencing (NGS).

Results

Mismatch repair-deficient (d-MMR) GC patients were found to have a higher probability of expressing PD-L1 (p = 0.000, PD-L1 cutoff value = 1%). In addition, 4 and 6.9% of the 2504 gastric cancer patients were EBV-positive and d-MMR, respectively. The number of MLH1/PMS2-negative cases was 126 (6%), and the number of MSH2/MSH6-negative cases was 14 (0.9%). d-MMR status was associated with a intestinal group (p = 0.012), but not with tumor differentiation. Furthermore, MSI and d-MMR GC status (detected by NGS and IHC, respectively) were consistently high, and the rate of MSI was higher in patients with d-MMR GC. A number of genes associated with DNA damage repair were detected in GC patients with MSI, including POLE, ETV6, BRCA and RNF43. In patients with a high tumor mutation burden, the most significantly mutated genes were LRP1B (79.07%), ARID1A (74.42%), RNF43 (69.77%), ZFHX3 (65.12%), TP53 (58.14%), GANS (51.16%), BRCA2 (51.16%), PIK3CA (51.16%), NOTCH1 (51.16%), SMARCA4 (48.84%), ATR (46.51%), POLE (41.86%) and ATM (39.53%).

Conclusions

Using IHC and NGS, MSI status, protein expression, tumor mutation burden (TMB) and genetic alterations were identified in patients with GC, which provides a theoretical basis for the future clinical treatment of GC.

[Update on gastric cancer. New molecular classifications]

Gastric cancer (GC) is an aggressive tumor, which is usually diagnosed at an advanced stage and shows high mortality rates. Several GC classifications have been published, based on features such as tumor location, endoscopic features or microscopic architecture. However, TNM stage remains the mainstay of GC management and treatment. In the last years, technical advances have allowed us to investigate the biological heterogeneity of GC and develop new molecular classifications. This knowledge may enhance current classifications, and has the potential to refine GC management and aid in the identification of new molecular targets. In this literature review we have summarized the main findings in epidemiology, screening, classification systems and treatment of GC, focusing on the molecular alterations and new molecular classifications published in the last years.

Anticancer activities of TCM and their active components against tumor metastasis

Traditional Chinese Medicine (TCM) has the characteristics of multiple targets, slight side effects and good therapeutic effects. Good anti-tumor effects are shown by Traditional Chinese Medicine prescription, Chinese patent medicine, single Traditional Chinese Medicine and Traditional Chinese medicine monomer compound. Clinically, TCM prolonged the survival time of patients and improved the life quality of patients, due to less side effects. Cancer metastasis is a complex process involving numerous steps, multiple genes and their products. During the process of tumor metastasis, firstly, cancer cell increases its proliferative capacity by reducing autophagy and apoptosis, and then the cancer cell capacity is stimulated by increasing the ability of tumors to absorb nutrients from the outside through angiogenesis. Both of the two steps can increase tumor migration and invasion. Finally, the purpose of tumor metastasis is achieved. By inhibiting autophagy and apoptosis of tumor cells, angiogenesis and EMT outside the tumor can inhibit the invasion and migration of cancer, and consequently achieve the purpose of inhibiting tumor metastasis. This review explores the research achievements of Traditional Chinese Medicine on breast cancer, lung cancer, hepatic carcinoma, colorectal cancer, gastric cancer and other cancer metastasis in the past five years, summarizes the development direction of TCM on cancer metastasis research in the past five years and makes a prospect for the future.

CAR-T Cell Therapy-An Overview of Targets in Gastric Cancer

Gastric cancer (GC) is one of the most commonly diagnosed malignancies and, unfortunately, still has a high mortality rate. Recent research points to CAR-T immunotherapy as a promising treatment for this disease. Using genetically engineered T cells designed to target a previously selected antigen, researchers are able to harness the natural anti-tumor activity of T cells. For therapy to be successful, however, it is essential to choose antigens that are present on tumor cells but not on healthy cells. In this review, we present an overview of the most important targets for CAR-T therapy in the context of GC, including their biologic function and therapeutic application. A number of clinical studies point to the following as important markers in GC: human epidermal growth factor receptor 2, carcinoembryonic antigen, mucin 1, epithelial cell adhesion molecule, claudin 18.2, mesothelin, natural-killer receptor group 2 member D, and folate receptor 1. Although these markers have been met with some success, the search for new and improved targets continues. Key among these novel biomarkers are the B7H6 ligand, actin-related protein 2/3 (ARP 2/3), neuropilin-1 (NRP-1), desmocollin 2 (DSC2), anion exchanger 1 (AF1), and cancer-related antigens CA-72-4 and CA-19-9.