Recent development of gastric cancer prevention

Racial disparities of gastric cancer in the USA: an overview of epidemiology, global screening guidelines, and targeted screening in a heterogeneous population

Gastric cancer is the fifth most common cancer diagnosis and fourth leading cause of cancer-related death globally. The incidence of gastric cancer in the USA shows significant racial and ethnic disparities with gastric cancer incidence in Korean Americans being over five times higher than in non-Hispanic whites. Since gastric cancer is not common in the USA, there are no current screening guidelines. In countries with higher incidences of gastric cancer, screening guidelines have been implemented for early detection and intervention and this has been associated with a reduction in mortality. Immigrants from high incidence countries develop gastric cancer at lower rates once outside of their country of origin, but continue to be at higher risk for developing gastric cancer. This risk does seem to decrease with subsequent generations. With increasing availability of endoscopy, initiating gastric cancer screening guidelines for high-risk groups can have the potential to improve survival by diagnosing and treating gastric cancer at an earlier stage. This article aims to provide context to gastric cancer epidemiology globally, review risk factors for developing gastric cancer, highlight racial and ethnic disparities in gastric cancer burden in the USA, examine current guidelines that exist in high incidence countries, and suggest future studies examining the efficacy of additional screening in high-risk populations to reduce gastric cancer mortality and disparate burden on ethnic minorities in the USA.

Pathology and Clinical Relevance of Gastric Epithelial Dysplasia

Gastric dysplasia is defined as an unequivocally neoplastic epithelium. Dysplastic lesions are characterized by cellular atypia reflective of abnormal differentiation and disorganized glandular architecture. The last few years have been marked by a refinement of the prognosis and risk of progression of gastric dysplasia and the recognition of novel morphologic patterns of dysplasia. Determination of the correct diagnosis and grade of dysplasia are critical steps since it will be predicting the risk of malignant transformation and help tailor appropriate surveillance strategy. This review describes the morphologic characteristics of conventional dysplasia and nonconventional gastric dysplasia that have been more recently characterized.

Advancements in Understanding Gastric Cancer: A Comprehensive Review

As a complex and difficult condition, gastric cancer (GC) continues to have a big impact on the world's health. The goal of this review article is to give a thorough summary of the most recent developments and research discoveries in the field of stomach cancer. The review discusses a wide range of topics, such as the epidemiology and risk factors for GC, molecular insights into its pathogenesis, the use of biomarkers in diagnosis and prognosis, current and novel therapeutic approaches, and the intriguing potential of immunotherapy. In addition, procedures for surgery, therapy strategies, and imaging modalities for diagnosis and staging are examined. The paper emphasizes how crucial it is to comprehend the tumor microenvironment and how it affects the course of the disease. Overall, this review provides a comprehensive assessment of the current body of knowledge, highlights research gaps, and suggests future lines of inquiry to enhance the treatment of GC.

Clinical value of serum pepsinogen in the diagnosis and treatment of gastric diseases

Pepsinogen, secreted from the gastric mucosa, is the precursor of pepsin. It is categorized as pepsinogen 1 and pepsinogen 2 based on its immunogenicity. The pepsinogen content that can enter the blood circulation through the capillaries of the gastric mucosa is approximately 1% and remains stable all the time. The pepsinogen content in serum will change with the pathological changes of gastric mucosa. Therefore, the level of pepsinogen in serum can play a role in serologic biopsy to reflect the function and morphology of different regions of gastric mucosa and serve as an indicator of gastric disease. This study conducts relevant research on serum pepsinogen 1, pepsinogen 2, and the ratio of pepsinogen 1 to pepsinogen 2, and reviews their important value in clinical diagnosis of Helicobacter pylori infection, gastric ulcer, and even gastric carcinoma, providing ideas for other researchers.

Age-related twin-peak prevalence profiles of H. pylori infection, gastritis, GIN and gastric cancer: Analyses of 70,534 patients with gastroscopic biopsies

Objectives

H. pylori (Hp) infection has been indicated in the pathogenesis of gastric diseases including gastric cancer (GC). This study aimed at exploring the relationships between Hp infection and gastric diseases including GC in a large dataset of routine patients undergoing gastroscopy.

Methods

From November 2007 to December 2017, 70,534 first-time visiting patients aged 18–94 years with gastroscopic biopsies were histologically diagnosed and analyzed. Patients’ data were entered twice in an Excel spreadsheet database and analyzed using the SPSS (version 22.0) software package and statistical significance was defined as P<0.05 for all analyses.

Results

The first interesting observation was age-related twin-peak prevalence profiles (TPPs) for Hp infection, gastritis, and advanced diseases with different time spans (TS) between the first and second occurring peaks. Hp infection and gastritis had TPPs occurring at earlier ages than TPPs of gastric introepithelial neoplasia (GIN) and GC. More patients were clustered at the second occurring TPPs. The time spans (TS) from the first occurring peak of Hp infection to the first occurring peaks of other gastric diseases varied dramatically with 0–5 years for gastritis; 5–15 years for GINs, and 5–20 years for GC, respectively. The number of males with Hp infection and gastric diseases, excluding non-atrophic gastritis (NAG), was more than that of females (P<0.001).

Conclusions

We have first observed age-related twin-peak prevalence profiles for Hp infection, gastritis, GIN, and GC, respectively, among a large population of patients undergoing gastroscopy. The second prevalence peak of GC is at ages of 70–74 years indicating that many GC patients would be missed during screening because the cut-off age for screening is 69 years old in China.

A complex diagnostics of early gastric cancer associated with <i>Helicobacter pylori</i> infection in the adult population of the Krasnoyarsk Territory

The aim of our study was to evaluate the clinical-anamnestic, serological, immunological and biochemical tests used for early diagnostics of gastric cancer associated with Helicobacter pylori infection in the adult population of the Krasnoyarsk Territory. Materials and methods. The control group consisted of 104 apparently healthy blood donors, the comparison group – 97 patients with chronic atrophic gastritis as well as a group of patients with early gastric cancer comprising 98 subjects. Assessment of monocyte and neutrophil spontaneous and induced chemiluminescence (CL) was carried out on a 36-channel biochemiluminometer BLM-3607. Phagocytosis was measured by using a Beckman Coulter FC 500 flow cytometer. A Varian Cary Eclipse spectrofluorometer was used to study lipid peroxidation and factors of the antioxidant defense system. Results and discussion. While studying the phagocytic arm of immunity, it was found that all patients with early gastric cancer were reported to have parameters of the maximum intensity for neutrophil spontaneous CL from 17 831 c.u. and lower, whereas induced CL reached at least 30 000 c.u. Phagocytic activity of neutrophilic granulocytes in patients with early gastric cancer was 36% or less. While studying the indicators of monocytes, it was found that spontaneous and induced CL decreased from 454 c.u. and 1186 c.u., respectively, in the patients with early gastric cancer. Monocytic activity in early gastric cancer was 34% or less. In the study of lipid peroxidation, an antioxidant defense in patients with chronic atrophic gastritis and gastric cancer had increased malondialdehyde (MDA) level. Patients with gastric cancer had decreased activity of the enzyme catalase (CAT), whereas subjects with chronic atrophic gastritis had reduced glutathione peroxidase (GPO) level. In contrast, patients with early gastric cancer were featured with increased GPO activity. We have proposed coefficients for assessing the factors of the antioxydant defence system in patients: the ratio for superoxide dismutase to catalase activity (SOD/CAT) as well as the ratio for superoxide dismutase to glutathione peroxidase activity (SOD/GPO). Conclusion. During the study, threshold values of parameters were obtained for assigning groups at high risk of developing early gastric cancer, which can be used for screening in adult population.

Artificial Intelligence in Gastric Cancer: Identifying Gastric Cancer Using Endoscopic Images with Convolutional Neural Network

Simple Summary

Gastric cancer (GC) is one of the most newly diagnosed cancers and the fifth leading cause of death globally. Previous studies reported that the detection rate of gastric cancer (EGC) at an earlier stage is low, and the overall false-negative rate with esophagogastroduodenoscopy (EGD) is up to 25.8%, which often leads to inappropriate treatment. Accurate diagnosis of EGC can reduce unnecessary interventions and benefits treatment planning. Convolutional neural network (CNN) models have recently shown promising performance in analyzing medical images, including endoscopy. This study shows that an automated tool based on the CNN model could improve EGC diagnosis and treatment decision.

Abstract

Gastric cancer (GC) is one of the most newly diagnosed cancers and the fifth leading cause of death globally. Identification of early gastric cancer (EGC) can ensure quick treatment and reduce significant mortality. Therefore, we aimed to conduct a systematic review with a meta-analysis of current literature to evaluate the performance of the CNN model in detecting EGC. We conducted a systematic search in the online databases (e.g., PubMed, Embase, and Web of Science) for all relevant original studies on the subject of CNN in EGC published between 1 January 2010, and 26 March 2021. The Quality Assessment of Diagnostic Accuracy Studies-2 was used to assess the risk of bias. Pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were calculated. Moreover, a summary receiver operating characteristic curve (SROC) was plotted. Of the 171 studies retrieved, 15 studies met inclusion criteria. The application of the CNN model in the diagnosis of EGC achieved a SROC of 0.95, with corresponding sensitivity of 0.89 (0.88–0.89), and specificity of 0.89 (0.89–0.90). Pooled sensitivity and specificity for experts endoscopists were 0.77 (0.76–0.78), and 0.92 (0.91–0.93), respectively. However, the overall SROC for the CNN model and expert endoscopists was 0.95 and 0.90. The findings of this comprehensive study show that CNN model exhibited comparable performance to endoscopists in the diagnosis of EGC using digital endoscopy images. Given its scalability, the CNN model could enhance the performance of endoscopists to correctly stratify EGC patients and reduce work load.

Endoscopic Screening and Surveillance for Gastric Cancer

Gastric cancer is one of the most common cancers worldwide. Gastric cancer is a multifactorial disease, and the incidence varies widely by geographic region, with half of new cases occurring in East Asia. Population-based nationwide screening for gastric cancer has been implemented in some Eastern Asian countries such as South Korea and Japan. In these countries, endoscopic screening decreased gastric cancer mortality. Endoscopic screening seems to be a cost-effective modality in countries with high incidence of gastric cancer. However, the usefulness of population-based screening has not yet been proved in countries with low incidence of gastric cancer.

Bioinformatic and integrated analysis identifies an lncRNA-miRNA-mRNA interaction mechanism in gastric adenocarcinoma

BACKGROUND

lncRNAs-miRNAs-mRNAs networks play an important role in Gastric adenocarcinoma (GA). Identification of these networks provide new insight into the role of these RNAs in gastric cancer.

OBJECTIVES

Biological information databases were screened to characterize and examine the regulatory networks and to further investigate the potential prognostic relationship this regulation has in GA.

METHODS

By mining The Cancer Genome Atlas (TCGA) database, we gathered information on GA-related lncRNAs, miRNAs, and mRNAs. We identified differentially expressed (DE) lncRNAs, miRNAs, and mRNAs using R software. The lncRNA-miRNA-mRNA interaction network was constructed and subsequent survival examination was performed. Representative genes were selected out using The Biological Networks Gene Ontology plug-in tool on Cytoscape. Additional analysis of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) terms were used to screen representative genes for functional enrichment. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) were used to identify the expression of five candidate differential expressed RNAs.

RESULTS

Information of samples from 375 cases of gastric cancer and 32 healthy cases (normal tissues) were downloaded from the TCGA database. A total of 1632 DE-mRNAs, 1008 DE-lncRNAs and 104 DE-miRNAs were identified and screened. Among them, 65 DE-lncRNAs, 10 DE-miRNAs, and 10 DE-mRNAs form lncRNAs-miRNAs-mRNAs regulatory network. Additionally, 10 lncRNAs and 2 mRNAs were associated with the prognosis of GA. Multivariable COX analysis revealed that AC018781.1 and VCAN-AS1 were independent risk factors for GA. GO functional enrichment analysis found DE-mRNA was significantly enriched TERM (P < 0.05). The KEGG signal regulatory network analysis found 11 significantly enrichment networks, the most prevailing was for the AGE-RAGE signaling pathway associated with Diabetic complications. Results of RT-qPCR was consistent with the in silico results.

CONCLUSIONS

The results of the present study represent a view of GA from a analysis of lncRNA, miRNA and mRNA. The network of lncRNA-miRNA-mRNA interactions revealed here may potentially further experimental studies and may help biomarker development for GA.

Chronic atrophic gastritis detection with a convolutional neural network considering stomach regions

BACKGROUND

The risk of gastric cancer increases in patients with Helicobacter pylori-associated chronic atrophic gastritis (CAG). X-ray examination can evaluate the condition of the stomach, and it can be used for gastric cancer mass screening. However, skilled doctors for interpretation of X-ray examination are decreasing due to the diverse of inspections.

AIM

To evaluate the effectiveness of stomach regions that are automatically estimated by a deep learning-based model for CAG detection.

METHODS

We used 815 gastric X-ray images (GXIs) obtained from 815 subjects. The ground truth of this study was the diagnostic results in X-ray and endoscopic examinations. For a part of GXIs for training, the stomach regions are manually annotated. A model for automatic estimation of the stomach regions is trained with the GXIs. For the rest of them, the stomach regions are automatically estimated. Finally, a model for automatic CAG detection is trained with all GXIs for training.

RESULTS

In the case that the stomach regions were manually annotated for only 10 GXIs and 30 GXIs, the harmonic mean of sensitivity and specificity of CAG detection were 0.955 ± 0.002 and 0.963 ± 0.004, respectively.

CONCLUSION

By estimating stomach regions automatically, our method contributes to the reduction of the workload of manual annotation and the accurate detection of the CAG.

Expression and biological function of rhotekin in gastric cancer through regulating p53 pathway

Background/aim

Gastric cancer (GC) is one of a most threatening cancer globally. Rhotekin (RTKN), a Rho effector, has been reported to be upregulated in GC tissues. This study aimed to investigate the underlying regulatory roles of RTKN in the biological behavior of GC.

Methods

Real-time PCR and Western blotting were carried out to detect the mRNA and protein expression, respectively. Cell Counting Kit-8 and xenograft nude mice model were used to evaluate cell proliferation. Flow cytometry analysis was performed to assess cell cycle distribution and cell apoptosis.

Results

RTKN had high expression level in GC compared with normal tissues. RTKN expression strongly associated with tumor size, TNM stage, lymphnode metastasis and the poor prognosis of patients with GC. Downregulation of RTKN significantly repressed GC cell proliferation, but increased cell population in G1/S phase and induced cell apoptosis. Moreover, the RTKN expression level was related to the p53 signaling pathway and histone deacetylase (HDAC) Class I pathway. RTKN knockdown caused a notable increment in the acetylation level of p53 (Lys382), and the expression of p53-target genes (p21, Bax, and PUMA), as well as a reduction in the expression of a potential deacetylase for p53, HDAC1. Notably, downregulation of HDAC1 had similar effects as RTKN knockdown, and RTKN overexpression could hardly abrogate the effects of HDAC1 knockdown on GC cells.

Conclusion

RTKN could work as an oncogene via regulating HDAC1/p53 and may become a promising treatment strategy for GC.

Regulatory effect of traditional Chinese medicine on brain-gut peptides in chronic atrophic gastritis

Chronic atrophic gastritis (CAG) is a common digestive system disease, which belongs to a type of precancerous lesion of gastric cancer (PLGC). Modern medical research has shown that brain-gut peptides, such as ghrelin, gastrin, somatostatin, and motilin, play an important role in the pathogenesis of CAG and PLGC. In particular, brain-gut peptides can help to judge the traditional Chinese medicine (TCM) syndrome of CAG and thereby evaluate CAG progression and the therapeutic effect. Based on TCM theory and brain gut interaction, this paper discusses the regulatory effect of TCM intervention on brain-gut peptides in CAG, with an aim to provide a theoretical basis for TCM prevention and treatment of CAG.

ERp29 inhibits tumorigenicity by suppressing epithelial mesenchymal transition in gastric cancer

ERp29 is a novel endoplasmic reticulum (ER) protein that plays an important role in protein unfolding and secretion. Recently, it has been reported to be widely implicated in control of tumorigenesis in some tumors. However, the potential function of ERp29 in gastric cancer remains poorly understood. In this study, we found that the positive rate of ERp29 in gastric cancer tissues was significantly lower than that in adjacent non-tumor tissues. And tumor with high ERp29 expression had inclinations towards smaller tumor size and earlier TNM stage. The in vitro experiments indicated that over-expression of ERp29 in gastric cancer cells significantly suppressed the proliferation and migration of tumor cells, which is consistent with the result of the in vivo animal experiments. Furthermore, our mechanistic investigations revealed that ERp29 reversed EMT process in gastric carcinoma, and its effect was related to the inactivation of ERK1/2 and AKT phosphorylation. Thus, we conclude that ERp29 acts as a tumor suppressor gene in gastric cancer, and is expected to become a novel target of the treatment of GC.

Gastric adenocarcinoma

Gastric cancers, with gastric adenocarcinoma (GAC) as the most common histological type, impose a considerable global health burden. Although the screening strategies for early detection have been shown to be successful in Japan and South Korea, they are either not implemented or not feasible in most of the world, leading to late diagnosis in most patients. Helicobacter pylori infection contributes to the development of many endemic GACs, and pre-emptive eradication or early treatment of this bacterial infection might provide effective primary prevention. GACs are phenotypically and genotypically heterogeneous. Localized (clinical stage I) GAC is best treated either endoscopically or with limited surgical resection, but clinical stage II or stage III tumours require multidisciplinary adjunctive approaches in addition to surgery. Although GAC is highly treatable in its early stages, advanced (clinical stage IV) GAC has a median survival of just ∼9-10 months. However, detailed molecular and immune profiling of GAC is yielding promise; early studies with immune checkpoint inhibitors suggest that GAC is amenable to immune modulation. Molecular studies have yielded a vast quantity of new information for potential exploitation. Nevertheless, advances against GACs have lagged compared with other tumours of similar incidence, and more research is necessary to overcome the obstacles to prolong survival.

The role of Notch signaling in gastric carcinoma: molecular pathogenesis and novel therapeutic targets

Notch signaling, an evolutionarily conserved signaling cascade system, is involved in promoting the progression of different types of cancers. Within the past decades, the Notch signaling pathway has increasingly been shown to have a primary role in deciding the fate of cancer cells and cancer stem cells in the stomach. Most components of Notch signaling are strongly expressed at different levels in gastric carcinoma tissue samples and are associated with a considerable number of clinical parameters. Moreover, crosstalk signaling between the Notch pathway and the Wnt, Ras, and NF-κB pathways promotes the process of gastric carcinogenesis. Consequently, this increases proliferation and prevents apoptosis in gastric cancer cells, and it contributes to the induction of angiogenesis and accelerates the progression of the epithelial-to-mesenchymal transition. Although the Notch signaling pathway presents novel therapeutic targets for cancer therapeutic intervention, there is still a dearth of in-depth understanding of the molecular mechanisms of Notch signaling in gastric carcinoma. In this review, we summarize the landscape of the Notch signaling pathway and recent findings on Notch signaling in gastric cancer. Furthermore, advanced studies and clinical treatments targeting the Notch signaling pathway arediscussed.

Screening and Preventive Strategies in Esophagogastric Cancer

Gastric adenocarcinoma, esophageal adenocarcinoma, and esophageal squamous cell carcinoma are among the most prevalent and deadly of malignancies worldwide. Screening and prevention programs will be critical to finally improving outcomes in these diseases. For gastric adenocarcinoma, screening in high-risk populations has significantly reduced mortality. More research is needed on screening high-risk individuals in low-risk populations. For esophageal adenocarcinoma, work is needed to develop efficient and effective techniques in mass screening programs. For most Western populations, current screening is not cost effective. Avoiding environmental risk factors is critical to reducing the incidence of this deadly illness.

Helicobacter Pylori infection detection from gastric X-ray images based on feature fusion and decision fusion

In this paper, a fully automatic method for detection of Helicobacter pylori (H. pylori) infection is presented with the aim of constructing a computer-aided diagnosis (CAD) system. In order to realize a CAD system with good performance for detection of H. pylori infection, we focus on the following characteristic of stomach X-ray examination. The accuracy of X-ray examination differs depending on the symptom of H. pylori infection that is focused on and the position from which X-ray images are taken. Therefore, doctors have to comprehensively assess the symptoms and positions. In order to introduce the idea of doctors' assessment into the CAD system, we newly propose a method for detection of H. pylori infection based on the combined use of feature fusion and decision fusion. As a feature fusion scheme, we adopt Multiple Kernel Learning (MKL). Since MKL can combine several features with determination of their weights, it can represent the differences in symptoms. By constructing an MKL classifier for each position, we can obtain several detection results. Furthermore, we introduce confidence-based decision fusion, which can consider the relationship between the classifier's performance and the detection results. Consequently, accurate detection of H. pylori infection becomes possible by the proposed method. Experimental results obtained by applying the proposed method to real X-ray images show that our method has good performance, close to the results of detection by specialists, and indicate that the realization of a CAD system for determining the risk of H. pylori infection is possible.

Screening and surveillance for gastric cancer in the United States: Is it needed?

BACKGROUND AND AIMS

Although the incidence of gastric cancer in the United States is relatively low, the incidence of gastric cancer is higher than for esophageal cancer, for which clear guidelines for screening and surveillance exist. With the increasing availability of endoscopic therapy, such as endoscopic submucosal dissection, for treating advanced dysplasia and early gastric cancer, establishing guidelines for screening and surveillance of patients who are at high risk of developing gastric cancer has the potential to diagnose and treat gastric cancer at an earlier stage and improve mortality from gastric cancer. The aims of this article were to review the data regarding the risk factors for developing gastric cancer, methods for gastric cancer screening, and results of national screening programs.

METHODS

A review of the existing literature related to the aims was performed.

RESULTS

Risk factors for gastric cancer that were identified include race/ethnicity (East Asian, Russian, or South American), first-degree relative diagnosed with gastric cancer, positive Helicobacter pylori status, and presence of atrophic gastritis or intestinal metaplasia. Endoscopy has the highest rate of detecting gastric cancer compared with other gastric cancer screening methods. The national screening program in Japan has demonstrated a mortality reduction from gastric cancer based on cohort data.

CONCLUSIONS

Gastric cancer screening with endoscopy should be considered in individuals who are immigrants from regions associated with a high risk of gastric cancer (East Asia, Russia, or South America) or who have a family history of gastric cancer. Those with findings of atrophic gastritis or intestinal metaplasia on screening endoscopy should undergo surveillance endoscopy every 1 to 2 years. Large prospective multicenter studies are needed to further identify additional risk factors for developing gastric cancer and to assess whether gastric cancer screening programs for high-risk populations in the United States would result in improved mortality.

Incidence of and risk factors for metachronous gastric cancer after endoscopic resection and successful Helicobacter pylori eradication: results of a large-scale, multicenter cohort study in Japan

BACKGROUND

A previous multicenter prospective randomized study from Japan showed that Helicobacter pylori eradication reduced the development of metachronous gastric cancer (MGC) after endoscopic resection for early gastric cancer. MGC risk, however, is not eliminated; yet few studies have evaluated its long-term incidence and risk factors. In this study, we investigated the incidence of and risk factors for MGC in patients who underwent endoscopic resection for early gastric cancer with successful H. pylori eradication.

METHODS

A total of 594 patients who underwent endoscopic resection for early gastric cancer and successful H. pylori eradication at three institutions (National Cancer Center Hospital, University of Tokyo Hospital, and Wakayama Medical University Hospital) were analyzed retrospectively. Annual endoscopic surveillance was performed after initial endoscopic resection. MGC was defined as a gastric cancer newly detected at least 1 year after successful H. pylori eradication.

RESULTS

Ninety-four MGCs were detected in 79 patients during the 4.5-year median follow-up period. Kaplan-Meier analysis showed the cumulative incidence of MGC 5 years after successful H. pylori eradication was 15.0 %; the incidence of MGC calculated by use of the person-year method was 29.9 cases per 1000 person-years. Multivariate analysis using the Cox proportional hazards model revealed that male sex, severe gastric mucosal atrophy, and multiple gastric cancers before successful H. pylori eradication were independent risk factors for MGC. Eleven percent of MGCs (10 of 94) were detected more than 5 years after successful H. pylori eradication.

CONCLUSION

Surveillance endoscopy for MGC in patients who have undergone endoscopic resection for early gastric cancer should be performed even after successful H. pylori eradication.

Screening of gastric cancer in Asia

In North-Eastern Asian countries, where incidence and mortality of gastric cancer remain very high, population-based gastric cancer screenings have been conducted under governmental subsidy in Japan and Korea. Reduction of gastric cancer mortality by the screening was documented in Japan, but the Japanese gastric cancer screening with the X-ray photofluorography is criticized for its high cost and a low uptake rate. Although the Korean program seems to achieve a high-rate of uptake with increasing use of endoscopy, the work load is substantial. In the meantime, more attention in the world turns to primary prevention through eradication of Helicobacter pylori. Indeed, fairly large-scale studies to examine the feasibility of mass-eradication to prevent gastric cancer are underway in China and Taiwan. In the future, gastric cancer screening should incorporate 'screen to treat' of H. pylori infection at younger age followed by endoscopic surveillance for subjects at risk.

Is screening and surveillance for early detection of gastric cancer needed in Korean Americans?

The incidence rate of gastric cancer in Korean Americans is over five times higher than that in non-Hispanic whites, and is similar to the incidence of colorectal cancer in the overall United States population. In Korea, the National Cancer Screening Program recommends endoscopy or upper gastrointestinal series for people aged 40 years and older every 2 years. However, the benefit of gastric cancer screening in Korean Americans has not been evaluated. Based on epidemiologic studies, Korean Americans appear to have more similar gastric cancer risk factors to Koreans as opposed to Americans of European descent, though the risk of gastric cancer appears to decrease for subsequent generations. Therefore, in accordance with recent recommendations regarding screening for gastric cancer in Korea, endoscopic screening for gastric cancer in Korean Americans should be considered, especially in those with known atrophic gastritis/intestinal metaplasia or a family history of gastric cancer. In the future, additional studies will needed to assess whether a screening program for gastric cancer in Korean Americans will result in a survival benefit.

Characteristics of gastric cancer in Asia

Gastric cancer (GC) is the fourth most common cancer in the world with more than 70% of cases occur in the developing world. More than 50% of cases occur in Eastern Asia. GC is the second leading cause of cancer death in both sexes worldwide. In Asia, GC is the third most common cancer after breast and lung and is the second most common cause of cancer death after lung cancer. Although the incidence and mortality rates are slowly declining in many countries of Asia, GC still remains a significant public health problem. The incidence and mortality varies according to the geographic area in Asia. These variations are closely related to the prevalence of GC risk factors; especially Helicobacter pylori (H. pylori) and its molecular virulent characteristics. The gradual and consistent improvements in socioeconomic conditions in Asia have lowered the H. pylori seroprevalence rates leading to a reduction in the GC incidence. However, GC remains a significant public health and an economic burden in Asia. There has been no recent systemic review of GC incidence, mortality, and H. pylori molecular epidemiology in Asia. The aim of this report is to review the GC incidence, mortality, and linkage to H. pylori in Asia.

Low dose capsule based 13c-urea breath test compared with the conventional 13c-urea breath test and invasive tests

CONTEXT

One of the limitations of 13C-urea breath test for Helicobacter pylori infection diagnosis in Brazil is the substrate acquisition in capsule presentation.

OBJECTIVES

The purpose of this study was to evaluate a capsule-based 13C-urea, manipulated by the Pharmacy Division, for the clinical practice.

METHODS

Fifty patients underwent the conventional and the capsule breath test. Samples were collected at the baseline and after 10, 20 and 30 minutes of 13C-urea ingestion. Urease and histology were used as gold standard in 83 patients.

RESULTS

In a total of 50 patients, 17 were positive with the conventional 13C-urea (75 mg) breath test at 10, 20 and 30 minutes. When these patients repeated breath test with capsule (50 mg), 17 were positive at 20 minutes and 15 at 10 and 30 minutes. The relative sensitivity of 13C-urea with capsule was 100% at 20 minutes and 88.24% at 10 and at 30 minutes. The relative specificity was 100% at all time intervals. Among 83 patients that underwent capsule breath test and endoscopy the capsule breath test presented 100% of sensitivity and specificity.

CONCLUSIONS

Capsule based breath test with 50 mg 13C-urea at twenty minutes was found highly sensitive and specific for the clinical setting.

A registry program for familial gastric cancer patients referred to Cancer Institute of Iran

BACKGROUND

Gastric cancer is the second most common cause of cancer death. It has a poor prognosis with only 5-10% of hereditary etiology. If it is diagnosed, it could be helpful for screening the other susceptible members of a family for preventive procedures. Usually it is identified by symptoms such as presence of cancer in different members of family, some special type of pathology such as diffused adenocarcinoma, having younger age and multiple cancer syndromes. Hence, designing a registry program can be a more practical way to screen high risk families for a preventive program.

MATERIALS AND METHODS

Based on the inclusion criteria, a questionnaire was prepared. After pilot on a small number of patients, the actual data was collected from 197 patients and processed in SPSS 16.0.

RESULTS

Totally, 11.8% of the patients were younger than 45 years old. Blood type 'A' was dominant and males had a higher risk behavior with higher consumption of unhealthy food. Adenocarcinoma was reported in majority of cases. 21.8% of the patients had the including criteria for familial gastric cancer (FGC).

CONCLUSIONS

The high percentage of FGC population compared to the other studies have revealed a need to design an infrastructural diagnostic protocol and screening program for patients with FGC, plus preventive program for family members at risk which could be done by a precise survey related to frequency and founder mutations of FGC in a national registry program.

Gastric cancer: prevention, screening and early diagnosis

Gastric cancer continues to be an important healthcare problem from a global perspective. Most of the cases in the Western world are diagnosed at late stages when the treatment is largely ineffective. Helicobacter pylori (H. pylori) infection is a well-established carcinogen for gastric cancer. While lifestyle factors are important, the efficacy of interventions in their modification, as in the use of antioxidant supplements, is unconvincing. No organized screening programs can be found outside Asia (Japan and South Korea). Although several screening approaches have been proposed, including indirect atrophy detection by measuring pepsinogen in the circulation, none of them have so far been implemented, and more study data is required to justify any implementation. Mass eradication of H. pylori in high-risk areas tends to be cost-effective, but its adverse effects and resistance remain a concern. Searches for new screening biomarkers, including microRNA and cancer-autoantibody panels, as well as detection of volatile organic compounds in the breath, are in progress. Endoscopy with a proper biopsy follow-up remains the standard for early detection of cancer and related premalignant lesions. At the same time, new advanced high-resolution endoscopic technologies are showing promising results with respect to diagnosing mucosal lesions visually and targeting each biopsy. New histological risk stratifications (classifications), including OLGA and OLGIM, have recently been developed. This review addresses the current means for gastric cancer primary and secondary prevention, the available and emerging methods for screening, and new developments in endoscopic detection of early lesions of the stomach.

Pathogenetic mechanisms in gastric cancer

Gastric cancer (GC) is a major public health issue as the fourth most common cancer and the second leading cause of cancer-related death. Recent advances have improved our understanding of its molecular pathogenesis, as best exemplified by elucidating the fundamental role of several major signaling pathways and related molecular derangements. Central to these mechanisms are the genetic and epigenetic alterations in these signaling pathways, such as gene mutations, copy number variants, aberrant gene methylation and histone modification, nucleosome positioning, and microRNAs. Some of these genetic/epigenetic alterations represent effective diagnostic and prognostic biomarkers and therapeutic targets for GC. This information has now opened unprecedented opportunities for better understanding of the molecular mechanisms of gastric carcinogenesis and the development of novel therapeutic strategies for this cancer. The pathogenetic mechanisms of GC are the focus of this review.

[New guidelines for Helicobacter pylori treatment: comparisons between Korea and Japan]

Korea and Japan show the highest incidence of gastric cancer and Helicobacter pylori infection. New 2013 guidelines on H. pylori infection differ between the two countries with regard to the indications for H. pylori eradication, diagnostic methods, and treatment regimens. Indications for eradication in Korean guideline focus on specific diseases such as peptic ulcer disease, low-grade gastric mucosa-associated lymphoid tissue lymphoma, and after resection of early gastric cancer, while Japanese guideline includes all H. pylori-associated gastritis for the prevention of dissemination. With regard to the diagnosis, either noninvasive or invasive method (except for bacterial culture) is recommended in Korea, while two noninvasive tests including serum anti-H. pylori IgG antibody level are preferred in Japan. As for the treatment regimens, second-line treatment (quadruple bismuth-containing regimen) is recommended without first-line triple therapy in areas of high clarithromycin resistance in Korea. However, there is no bismuth-based second-line treatment in Japan, and the Japanese regimen consists of a lower dose of antibiotics for a shorter duration (7 days). Such discrepancies between the two countries are based not only on the differences in the literature search and interpretation, but also on the different approvals granted by the national health insurance system, manufacturing process of the antibiotics, and diagnostic techniques in each country. Collaborations are required to minimize the discrepancies between the two countries based on cost-effectiveness.

Helicobacter pylori eradication for preventing gastric cancer

Helicobacter pylori (H. pylori) infection is a major risk factor for gastric cancer (GC) development, which is one of the most challenging malignant diseases worldwide with limited treatments. In the multistep pathogenesis of GC, H. pylori infection slowly induces chronic active gastritis, which progresses through the premalignant stages of atrophic gastritis, intestinal metaplasia, and dysplasia, and then finally to GC. Although eradication of H. pylori is a reasonable approach for the prevention of GC, there have been some contradictory reports, with only some long-term follow-up data showing efficacy of this approach. The inconsistencies are likely due to the insufficient number of participants, relatively short follow-up periods, poor quality of study designs, and the degree and extent of preneoplastic changes at the time of H. pylori eradication. This review analyzes recent high-quality studies to resolve the discrepancies regarding the eradication of H. pylori for GC prevention. The relationship between H. pylori eradication and GC/precancerous lesions/metachronous GC is examined, and the cost-effectiveness of this strategy in the prevention of GC is assessed. Although it is assumed that eradication of H. pylori has the potential to prevent GC, the feasibility and appropriate timing of this strategy for cancer prevention remain to be determined. As a result, additional well-designed trials with longer follow-up periods are needed to clarify this issue.

Maternal embryonic leucine zipper kinase enhances gastric cancer progression via the FAK/Paxillin pathway

Background

Elevated MELK expression is featured in multiple tumors and correlated with tumorigenesis and tumor development. This study is aimed to investigate the mechanisms of MELK-mediated development of gastric cancer.

Methods

MELK expression levels in human gastric cancer were determined by quantitative-PCR and immunohistochemistry. The effect of MELK on cell activity was explored by knockdown and overexpression experiments. Cell growth was measured using the CCK-8 assay. Apoptosis and cell cycle distributions were analyzed by flow cytometry. Migration and invasion were tested using a transwell migration assay. Cytoskeletal changes were analyzed by immunofluorescence. To explore the molecular mechanism and effect of MELK on migration and invasion, Western blotting was used to analyze the FAK/Paxillin pathway and pull down assays for the activity of small Rho GTPases. In vivo tumorigenicity and peritoneal metastasis experiments were performed by tumor cell engraftment into nude mice.

Results

MELK mRNA and protein expression were both elevated in human gastric cancer, and this was associated with chemoresistance to 5-fluorouracil (5-FU). Knockdown of MELK significantly suppressed cell proliferation, migration and invasion of gastric cancer both in vitro and in vivo, decreased the percentages of cells in the G1/G0 phase and increased those in the G2/M and S phases. Moreover, knockdown of MELK decreased the amount of actin stress fibers and inhibited RhoA activity. Finally, knockdown of MELK decreased the phosphorylation of the FAK and paxillin, and prevented gastrin-stimulated FAK/paxillin phosphorylation. By contrast, MELK overexpression had the opposite effect.

Conclusions

MELK promotes cell migration and invasion via the FAK/Paxillin pathway, and plays an important role in the occurrence and development of gastric cancer. MELK may be a potential target for treatment against gastric cancer.

Characteristics of gastric cancer in Asia

Gastric cancer (GC) is the fourth most common cancer in the world with more than 70% of cases occur in the developing world. More than 50% of cases occur in Eastern Asia. GC is the second leading cause of cancer death in both sexes worldwide. In Asia, GC is the third most common cancer after breast and lung and is the second most common cause of cancer death after lung cancer. Although the incidence and mortality rates are slowly declining in many countries of Asia, GC still remains a significant public health problem. The incidence and mortality varies according to the geographic area in Asia. These variations are closely related to the prevalence of GC risk factors; especially Helicobacter pylori (H. pylori) and its molecular virulent characteristics. The gradual and consistent improvements in socioeconomic conditions in Asia have lowered the H. pylori seroprevalence rates leading to a reduction in the GC incidence. However, GC remains a significant public health and an economic burden in Asia. There has been no recent systemic review of GC incidence, mortality, and H. pylori molecular epidemiology in Asia. The aim of this report is to review the GC incidence, mortality, and linkage to H. pylori in Asia.

Therapy of Helicobacter pylori: present medley and future prospective

The increasing prevalence of antimicrobial resistance has warned clinicians to adopt new strategies for dealing with the H. pylori infection. The success of various therapeutic regimens has recently declined to unacceptable levels. To date, first line therapies (including concomitant therapy and hybrid therapy), second line therapies (including bismuth-containing quadruple therapy and levofloxacin-containing therapy), and third line therapy (culture-guided therapy) had been introduced. In the near future, treatment of H. pylori is entering into a completely new resistance era. In this setting, despite the recent progress, we may only be targeting the patients with problematic H. pylori. Local preference for antibiotic selection should be an inevitable article in each therapeutic regimen worldwide. Meanwhile, improving the patients' compliance protocols and observed side effects in suggested therapeutic regimens should be considered cautiously. The new strategies in treatment should be adopted based upon local resistance patterns, which requires physician's resistance about the recommended guidelines. Designing new therapeutic regimen, which contains most effective available antibiotics with less possible side effects and high patient compliance, represents a challenging task in treatment of H. pylori infections.

Systematic review: serum autoantibodies in the early detection of gastric cancer

Antibodies against tumor-associated antigens have been found in serum of patients with various types of cancers and may serve as biomarkers for early detection of gastric cancer as well. This systematic review aims to give an overview about known autoantibodies and their diagnostic value in gastric cancer. We conducted a systematic literature search in two databases to identify studies which performed serological testing for autoantibodies in gastric cancer patients and controls. Data on study characteristics and results were extracted independently by two reviewers. Overall, 39 articles reporting the detection of 34 different autoantibodies met the inclusion criteria for this review. The most common antibody detection method was enzyme-linked immunosorbent assay and the most frequently assessed autoantibody was anti-p53, which was tested in 13 studies. Most antibodies were assessed in only one study and only few authors have evaluated the diagnostic value of combinations of multiple autoantibodies. For single autoantibodies, specificity was generally very high (median: 99.15%), but sensitivity was mostly rather low (median: 12.35%). For some autoantibody combinations, substantially higher sensitivity at reasonably high levels of specificity could be achieved. Development of extended and optimized multimarker panels of autoantibodies might be a promising approach for gastric cancer early detection.

Current progress toward eradicating Helicobacter pylori in East Asian countries: Differences in the 2013 revised guidelines between China, Japan, and South Korea

New 2013 guidelines on Helicobacter pylori (H. pylori) infection have been published in China, Japan, and South Korea. Like the previous ones, these new guidelines differ between the three countries with regard to the indications for H. pylori eradication, diagnostic methods, and treatment regimens. The most profound change among all of the guidelines is that the Japanese national health insurance system now covers the expenses for all infected subjects up to second-line treatment. This makes the Japanese indications for eradication much wider than those in China and South Korea. With regard to the diagnosis, a serum H. pylori antibody test is not recommended in China, whereas it is considered to be the most reliable method in Japan. A decrease relative to the initial antibody titer of more than 50% after 6-12 mo is considered to be the most accurate method for determining successful eradication in Japan. In contrast, only the urea breath test is recommended after eradication in China, while either noninvasive or invasive methods (except the bacterial culture) are recommended in South Korea. Due to the increased rate of antibiotics resistance, first-line treatment is omitted in China and South Korea in cases of clarithromycin resistance. Notably, the Japanese regimen consists of a lower dose of antibiotics for a shorter duration (7 d) than in the other countries. There is neither 14 d nor bismuth-based regimen in the first-line and second-line treatment in Japan. Such differences among countries might be due to differences in the approvals granted by the governments and national health insurance system in each country. Further studies are required to achieve the best results in the diagnosis and treatment of H. pylori infection based on cost-effectiveness in East Asian countries.

The role of inflammation in gastric cancer

Gastric cancer, despite its declining incidence rate, is still the second cause of cancer-related death worldwide, killing 750,000 people each year and remaining the second common type of cancer. The best examples of inflammation-associated cancer in human beings may be gastric cancer. Understanding the molecular mechanism of the inflammation in gastric carcinogenesis is important for developing new strategies against gastric cancer.

Abnormal DNA-PKcs and Ku 70/80 expression may promote malignant pathological processes in gastric carcinoma

AIM

To determine the expression of the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs) and the Ku70/Ku80 heterodimer (Ku 70/80) in gastric carcinoma.

METHODS

Gastric biopsies were obtained from 146 gastric carcinoma patients [Helicobacter pylori (H. pylori)-negative: 89 and H. pylori-positive: 57] and 34 from normal subjects (H. pylori-negative: 16 and H. pylori-positive: 18) via surgery and endoscopic detection from April 2011 to August 2012 at the First Affiliated Hospital of Nanchang University. Pathological diagnosis and classification were made according to the criteria of the World Health Organization and the updated Sydney system. An ''in-house'' rapid urease test and modified Giemsa staining were employed to detect H. pylori infection. The expression of DNA-PKcs and the Ku 70/80 protein was detected by immunohistochemistry.

RESULTS

Overall, the positive rates of both DNA-PKcs and Ku 70/80 were significantly increased in gastric cancer (χ(2) = 133.04, P < 0.001 for DNA-PKcs and χ(2) = 13.06, P < 0.01 for Ku) compared with normal gastric mucosa. There was hardly any detectable expression of DNA-PKcs in normal gastric mucosa, and the positive rate of DNA-PKcs protein expression in patients with a normal gastric mucosa was 0% (0/34), whereas the rate in gastric cancer (GC) was 93.8% (137/146). The difference between the two groups was statistically significant. Additionally, the positive rate of Ku 70/80 was 79.4% (27/34) in normal gastric mucosa and 96.6% (141/146) in gastric cancer. The DNA-PKcs protein level was significantly increased in gastric cancer (Mann-Whitney U = 39.00, P < 0.001), compared with normal gastric mucosa. In addition, there was a significant difference in the expression of Ku 70/80 (Mann-Whitney U = 1117.00, P < 0.001) between gastric cancer and normal gastric mucosa. There was also a significant difference in Ku70/80 protein expression between GC patients with and without H. pylori infection (P < 0.05). Spearman analysis showed a negative correlation between tumor differentiation and DNA-PKcs expression (r = -0.447, P < 0.05). Moreover, Ku70/80 expression was negatively correlated with both clinical stage (r = -0.189, P < 0.05) and H. pylori colonization (r = -0.168, P < 0.05).

CONCLUSION

Overall, this research demonstrated that enhanced DNA-PKcs and Ku 70/80 expression may be closely associated with gastric carcinoma.

Helicobacter pylori promotes invasion and metastasis of gastric cancer cells through activation of AP-1 and up-regulation of CACUL1

Infection with Helicobacter pylori is important in the development and progression of gastric cancer. However, the mechanisms that regulate this activation in gastric tumors remain elusive. CACUL1 has been cloned and identified as a novel gene that is expressed in many types of cancer and is involved in cell cycle regulation and tumor growth. The current study aimed to examine the expression of CACUL1 in gastric cancer samples and analyze its correlation with H. pylori infection. We found that CACUL1 was highly expressed in gastric cancer tissues and negatively correlated with gastric cancer differentiation and TNM stage. In addition, CACUL1 expression was high in H. pylori-infected tissues compared with H. pylori non-infected tissue. We found that H. pylori could up-regulate CACUL1 expression through activating protein 1. The up-regulation of CACUL1 expression could promote matrix metalloproteinase 9 and Slug expression to increase invasion and metastasis of tumor cells. These results suggested that H. pylori-triggered CACUL1 production occurred in an activating protein 1-dependent manner and regulated matrix metalloproteinase 9 and Slug expression to affect the invasion and metastasis of tumor cells. Therefore, CACUL1 is a potential therapeutic target for the treatment of aggressive gastric cancer.

Current evidence of effects of Helicobacter pylori eradication on prevention of gastric cancer

Gastric cancer is the second most common cause of cancer death worldwide and is usually detected at a late stage, except in Korea and Japan where early screening is in effect. Results from animal and epidemiological studies suggest that Helicobacter pylori infection, and subsequent gastritis, promote development of gastric cancer in the infected mucosa. Relatively effective treatment regimens are available to treat H. pylori infection, and in general, mass eradication of the organism is not currently recommended as a gastric cancer prevention strategy. However, regional guidelines vary regarding the indications and recommendations for H. pylori treatment for gastric cancer prevention. In this review, we discuss the results from intervention studies, provide insight regarding current guideline recommendations, and discuss future study directions.

Rare case of Helicobacter pylori-related gastric ulcer: Malignancy or pseudomorphism?

Helicobacter pylori (H. pylori) is a pathogen and the most frequent cause of gastric ulcers. There is also a close correlation between the prevalence of H. pylori infection and the incidence of gastric cancer. We present the case of a 38-year-old woman referred by her primary care physician for screening positron emission tomography-computed tomography (PET-CT), which showed a nodular strong accumulation point with standardized uptake value 5.6 in the gastric fundus. Gastroscopy was then performed, and a single arched ulcer, 12 mm in size, was found in the gastric fundus. Histopathological examination of the lesion revealed chronic mucosal inflammation with acute inflammation and H. pylori infection. There was an obvious mitotic phase with widespread lymphoma. Formal anti-H. pylori treatment was carried out. One month later, a gastroscopy showed a single arched ulcer, measuring 10 mm in size in the gastric fundus. Histopathological examination revealed chronic mucosal inflammation with acute inflammation and a very small amount of H. pylori infection. The mitotic phase was 4/10 high power field, with some heterotypes and an obvious nucleolus. Follow-up gastroscopy 2 mo later showed the gastric ulcer in stage S2. The mucosal swelling had markedly improved. The patient remained asymptomatic, and a follow-up PET-CT was performed 6 mo later. The nodular strong accumulation point had disappeared. Follow-up gastroscopy showed no evidence of malignant cancer. H. pylori-associated severe inflammation can lead to neoplastic changes in histiocytes. This underscores the importance of eradicating H. pylori, especially in those with mucosal lesions, and ensuring proper follow-up to prevent or even reverse early gastric cancer.

Serum pepsinogen II is a better diagnostic marker in gastric cancer

AIM

To investigate screening makers for gastric cancer, we assessed the association between gastric cancer and serum pepsinogens (PGs).

METHODS

The subjects comprised 450 patients with gastric cancer, 111 individuals with gastric atrophy, and 961 healthy controls. Serum anti-Helicobacter pylori (H. pylori) immunoglobulin G (IgG), PGI and PG II were detected by enzyme-linked immunosorbent assay. Gastric atrophy and gastric cancer were diagnosed by endoscopy and histopathological examinations. Odds ratios and 95%CIs were calculated using multivariate logistic regression.

RESULTS

Rates of H. pylori infection remained high in Northeastern China. Rates of H. pylori IgG positivity were greater in the gastric cancer and gastric atrophy groups compared to the control group (69.1% and 75.7% vs 49.7%, P < 0.001). Higher levels of PG II (15.9 μg/L and 13.9 μg/L vs 11.5 μg/L, P < 0.001) and lower PGI/PG II ratio (5.4 and 4.6 vs 8.4, P < 0.001) were found in patients with gastric cancer or gastric atrophy compared to healthy controls, whereas no correlation was found between the plasma PGI concentration and risk of gastric cancer (P = 0.537). In addition, multivariate logistic analysis indicated that H. pylori infection and atrophic gastritis were independent risk factors for gastric cancer. Lower plasma PGI/PG II ratio was associated with higher risks of atrophy and gastric cancer. Furthermore, plasma PG II level significantly correlated with H. pylori-infected gastric cancer.

CONCLUSION

Serum PG II concentration and PGI/PG II ratio are potential biomarkers for H. pylori-infected gastric disease. PG II is independently associated with risk of gastric cancer.