Helicobacter pylori Seropositivity Is Associated with Gastric Cancer Regardless of Tumor Subtype in Korea

The impact of physical disability on the risk of gastric cancer incidence in elderly patients with diabetes: a focus on regional disparity

PURPOSE

Elderly patients with type 2 diabetes mellitus (T2DM) may have a higher risk of physical disability. This study investigated the incidence of gastric cancer according to physical disability status in elderly patients with T2DM.

METHODS

The National Health Insurance Service claims data were used. A total of 76,162 participants aged 60 years or above, diagnosed with T2DM, were included. The association between physical disability status and gastric cancer incidence was evaluated using the Cox regression analysis. Additionally, subgroup analysis was performed according to region.

RESULTS

A total of 9,154 (12.0%) individuals had physical disability. Gastric cancer incidence was more common in participants with physical disability (3.3%) than those without (2.4%). A higher risk of gastric cancer incidence was found in elderly T2DM patients with physical disability (Hazard Ratio (HR) 1.18, 95% Confidence Interval (95% CI) 1.04-1.34). Such tendencies were maintained regardless of region, although the effect of physical disability status on gastric cancer incidence was particularly significant in individuals residing in non-metropolitan areas (HR: 1.19, 95% CI: 1.01-1.40).

CONCLUSION

Elderly patients with T2DM who had physical disability showed a higher risk of gastric cancer incidence. The findings suggest a need to monitor elderly T2DM patients with disability as they may be susceptible to difficulties in accessing cancer-related healthcare.

Gastric Intestinal Metaplasia: Challenges and the Opportunity for Precision Prevention

GIM is a persistent, premalignant lesion whereby gastric mucosa is replaced by metaplastic mucosa resembling intestinal tissue, arising in the setting of chronic inflammation, particularly in the context of Helicobacter pylori. While the overall rates of progression to gastric adenocarcinoma are low, estimated at from 0.25 to 2.5%, there are features that confer a much higher risk and warrant follow-up. In this review, we collate and summarise the current knowledge regarding the pathogenesis of GIM, and the clinical, endoscopic and histologic risk factors for cancer. We examine the current state-of-practice with regard to the diagnosis and management of GIM, which varies widely in the published guidelines and in practice. We consider the emerging evidence in population studies, artificial intelligence and molecular markers, which will guide future models of care. The ultimate goal is to increase the detection of early gastric dysplasia/neoplasia that can be cured while avoiding unnecessary surveillance in very low-risk individuals.

Cardia and non-cardia gastric cancer risk associated with Helicobacter pylori in East Asia and the West: A systematic review, meta-analysis, and estimation of population attributable fraction

OBJECTIVES

To assess the region-specific relative risk of cardia/non-cardia gastric cancer (CGC/NCGC) associated with Helicobacter pylori (H. pylori) and quantify its contribution to gastric cancer burden using population attributable fraction (PAF).

METHODS

PubMed, EMBASE, Web of Science, and Cochrane Central databases were searched by two reviewers until April 20, 2022. The association between H. pylori infection and NCGC/CGC was assessed using pooled odds ratios (ORs) with 95% confidence intervals (CIs). PAF was calculated using the formula of H. pylori prevalence and the pooled OR.

RESULTS

One hundred and eight studies were included. A significant association was observed between H. pylori infection and NCGC in East Asia (OR, 4.36; 95% CI: 3.54-5.37) and the West (OR, 4.03; 95% CI: 2.59-6.27). Regarding CGC, a significant association was found only in East Asia (OR, 2.86; 95% CI: 2.26-3.63), not in the West (OR, 0.80; 95% CI: 0.61-1.05). For studies with a follow-up time of ≥10 years, pooled ORs for NCGC and CGC in East Asia were 5.58 (95% CI: 4.08-7.64) and 3.86 (95% CI: 2.69-5.55), respectively. Pooled OR for NCGC was 6.80 (95% CI: 3.78-12.25) in the West. PAFs showed that H. pylori infection accounted for 71.2% of NCGC, 60.7% of CGC in East Asia, and 73.2% of NCGC in the West.

CONCLUSIONS

Gastric cancer burden associated with H. pylori infection exhibits important geographical differences. Prolonged follow-up period could overcome the underestimation of the magnitude of the association between H. pylori infection and CGC/NCGC. Customized strategies for H. pylori screening and eradication should be implemented to prevent gastric cancer.

Dynamic variations of the gastric microbiota: Key therapeutic points in the reversal of Correa's cascade

Correa's cascade is a dynamic process in the development of intestinal-type gastric cancer (GC), and its pathological features, gastric microbiota and interactions between microorganisms and their hosts vary at different developmental stages. The characteristics of cells, tissues and gastric microbiota before or after key therapeutic points are critical for monitoring malignant transformation and early tumour reversal. This review summarises the pathological features of gastric mucosa, characteristics of gastric microbiota, specific microbial markers, microbe-microbe interactions and microbe-host interactions at different stages in Correa's cascade. The markers related to each Correa's cascade point were analysed in detail. We attempted to identify key therapeutic points for early cancer reversal and provide a novel approach to reduce the incidence of GC and improve precise treatment.

Tumorigenic mechanisms of estrogen and Helicobacter pylori cytotoxin-associated gene A in estrogen receptor α-positive diffuse-type gastric adenocarcinoma

BACKGROUND

Diffuse-type gastric cancer (DGC), for which Helicobacter pylori infection is a causal factor, is associated with poor prognosis among young women, possibly due to female hormones such as estrogen. We aimed to identify the carcinogenesis induced by estrogen and H. pylori in DGC.

METHODS

We screened and selected estrogen receptor alpha (ERα)-positive (MKN45) and ERα-negative (SNU5) DGC cell lines. H. pylori strain 60190 and its isogenic mutant strain lacking cytotoxin-associated gene A (60190ΔCagA) were used to infect MKN45 cells. And the cytotoxin-related gene A (CagA) cDNA which was cloned into pSP65-SR-HA (cagA-pSP65SRa) vector was used to transfect MKN45 cells. Tumor samples were used for DGC organoid culture.

RESULTS

In MKN45 cells, we found that estradiol promotes epithelial-mesenchymal transition (EMT) and stemness phenotypes via HOTAIR expression. These effects were further enhanced by the addition of CagA secreted by H. pylori but were reversed by co-treatment with fulvestrant (ICI 182,780), a selective ER degrader. We also validated the effect of estrogen on DGC organoids. ERα expression was associated with tumor invasion and HOTAIR expression in DGC patients with overt H. pylori infection.

CONCLUSIONS

These findings may explain the rapid DGC progression in young women with physiologically high levels of estrogen and suggest that fulvestrant with ovarian function suppression could serve as a tumor-suppressive agent in premenopausal patients with DGC.

The dawn of precision medicine in diffuse-type gastric cancer

Gastric cancer (GC) is one of the most common malignancies worldwide. The histology- and morphology-based Lauren classification of GC has been widely used for over 50 years in clinical practice. The Lauren classification divides GC into intestinal and diffuse types, which have distinct etiology, molecular profiles, and clinicopathological features. Diffuse-type GC (DGC) accounts for approximately 30% of GCs. Tumor cells lack adhesion and infiltrate the stroma as single cells or small subgroups, leading to easy dissemination in the abdominal cavity. Clinically, DGC has aggressive traits with a high risk of recurrence and metastasis, which results in unfavorable prognosis. Although systemic chemotherapy is the main therapeutic approach for recurrent or metastatic GC patients, clinical benefits are limited for patients with DGC. Therefore, it is urgent to develop effective therapeutic strategies for DGC patients. Considerable research studies have characterized the molecular and genomic landscape of DGC, of which tight junction protein claudin-18 isoform 2 (CLDN18.2) and fibroblast growing factors receptor-2 isoform IIIb (FGFR2-IIIb) are the most attractive targets because of their close association with DGC. Recently, the impressive results of two phase II FAST and FIGHT trials demonstrate proof-of-concept, suggesting that anti-CLDN18.2 antibody (zolbetuximab) and FGFR2-IIIb antibody (bemarituzumab) are promising approaches for patients with CLDN18.2-positive and FGFR2-IIIb-positive GC, respectively. In this review, we summarize the clinicopathological features and molecular profiles of DGC and highlight a potential therapeutic target based on the findings of pivotal clinical trials.

Helicobacter pylori in gastric cancer: Features of infection and their correlations with long-term results of treatment

BACKGROUND

Helicobacter pylori (H. pylori) is a spiral-shaped bacterium responsible for the development of chronic gastritis, gastric ulcer, gastric cancer (GC), and MALT-lymphoma of the stomach. H. pylori can be present in the gastric mucosa (GM) in both spiral and coccoid forms. However, it is not known whether the severity of GM contamination by various vegetative forms of H. pylori is associated with clinical and morphological characteristics and long-term results of GC treatment.

AIM

To establish the features of H. pylori infection in patients with GC and their correlations with clinical and morphological characteristics of diseases and long-term results of treatment.

METHODS

Of 109 patients with GC were included in a prospective cohort study. H. pylori in the GM and tumor was determined by rapid urease test and by immunohistochemically using the antibody to H. pylori. The results obtained were compared with the clinical and morphological characteristics and prognosis of GC. Statistical analysis was performed using the Statistica 10.0 software.

RESULTS

H. pylori was detected in the adjacent to the tumor GM in 84.5% of cases, of which a high degree of contamination was noted in 50.4% of the samples. Coccoid forms of H. pylori were detected in 93.4% of infected patients, and only coccoid-in 68.9%. It was found that a high degree of GM contamination by the coccoid forms of H. pylori was observed significantly more often in diffuse type of GC (P = 0.024), in poorly differentiated GC (P = 0.011), in stage T3-4 (P = 0.04) and in N1 (P = 0.011). In cases of moderate and marked concentrations of H. pylori in GM, a decrease in 10-year relapse free and overall survival from 55.6% to 26.3% was observed (P = 0.02 and P = 0.07, respectively). The relationship between the severity of the GM contamination by the spiral-shaped forms of H. pylori and the clinical and morphological characteristics and prognosis of GC was not revealed.

CONCLUSION

The data obtained indicates that H. pylori may be associated not only with induction but also with the progression of GC.

Population Attributable Fraction of Helicobacter pylori Infection-Related Gastric Cancer in Korea: A Meta-Analysis

PURPOSE

This study aimed to determine the proportion of gastric cancer attributable to Helicobactor pylori in the Korean population. Infection with H. pylori has been recognized as the most significant risk factor for gastric cancer. In Korea, gastric cancer is the most common cancer that accounted for 13.3% of all cancers in 2016. In particular, men are most commonly diagnosed with gastric cancer; the age-standardized incidence rate in men is 49.6 per 100,000, which is more than twice the incidence in women.

MATERIALS AND METHODS

The population attributable fraction (PAF) was calculated as a function of the relative risk (RR) of gastric cancer associated with H. pylori infections. To estimate PAF of gastric cancer due to H. pylori, the prevalence of H. pylori infections was extrapolated for the year of 1990 and a pooled RR was obtained by conducting a meta-analysis of studies recently published in Korea.

RESULTS

The estimated prevalence of H. pylori was 76.4% in men and 71.9% in women. The RRs (95% confidence interval) pooled from case-control studies using a random effects model was 1.69 (1.29-2.22) for overall gastric cancer and 2.17 (1.04-4.55) for non-cardia gastric cancer. Using the RR for overall gastric cancer, the estimated PAFs due to H. pylori were 34.5% in men and 33.2% in women.

CONCLUSION

The occurrence of gastric cancer in Koreans may be affected by other risk factors in addition to H. pylori infection, which may contribute to increasing baseline risk for gastric cancer.

Predictive Effect of Helicobacter pylori in Gastric Carcinoma Development: Systematic Review and Quantitative Evidence Synthesis

Helicobacter pylori (H. pylori) is a bacterial pathogen implicated in gastritis, gastric ulceration, and gastric carcinoma. This study aimed to synthesize literature in providing evidence on the causative role of H. pylori in gastric carcinoma development. This study is based on assessing public literature using an applied meta-analysis, namely, quantitative evidence synthesis (QES). The analytic procedure uses DerSimonian-Laird, including assessing heterogeneity. The QES also utilizes meta-regression and the environmental effect associated with H. pylori in gastric cancer development. Eighteen studies are included in the QES. There is increased prevalence of H. pylori exposure among the cases. The heterogeneity between the CES and individual effect sizes is also significant. Despite controlling for the confoundings, there is increased exposure to H. pylori among the gastric cancer cases, regardless of the differences in the geographic location. H. pylori in this synthesized literature illustrates the contributory role of this microbe in gastric carcinoma. Additionally, regardless of geographic locale, namely, South Korea or Spain, H. pylori is implicated in gastric cancer development.

Microbiological evidences for gastric cardiac microflora dysbiosis inducing the progression of inflammation

BACKGROUND AND AIM

Nowadays, anti-inflammation treatment is a promising approach for preventing tumorigenesis, and human microflora is closely related to inflammation. This study aimed to investigate the gastric cardiac microbiome and identify inflammation-related microorganisms for gastric cardiac inflammation.

METHODS

We performed 16S rRNA sequencing on a total of 11 healthy individuals and 89 individuals with different degree of gastric cardiac inflammation. Immunohistochemistry was used for verifying candidate bacteria. Phylogenetic reconstruction of unobserved states (picrust) was used for predicting the pathways involved by cardiac microflora.

RESULTS

The resident phyla in normal were Proteobacteria, Firmicutes, Bacteroides, and Actinobacteria, and the dominant genus in normal were Halomonas, shewanella, and Comamonas. In the progression of gastric cardiac inflammation, the diversity of cardiac microflora did not change (P > 0.05). However, the composition structure of cardiac microflora varied between healthy and inflamed tissues (P < 0.05). Meanwhile, there were 64 species parallel increased with inflammation degree, especially Helicobacter pylori, Lactobacillus spp. Additionally, inflammation-related species were detected (P < 0.05), including H. pylori, Acinetobacter ursingii, and Streptococcus agalactiae. Higher H. pylori colonization was positively related to the progression of cardiac inflammation (γ coefficient = 0.678, P < 0.001), and it also influenced the cardiac microbial community structure. Cardiac microflora also participated in DNA repair pathways and is affected by the relative abundance of H. pylori (P < 0.0001).

CONCLUSIONS

Cardiac microflora dysbiosis, especially the increasing of the relevant abundance of H. pylori, promotes the progression of cardiac inflammation.

Helicobacter pylori Is Associated With Precancerous and Cancerous Lesions of the Gastric Cardia Mucosa: Results of a Large Population-Based Study in China

Background: Helicobacter pylori (H. pylori) is widely accepted to be the most important cause of gastric non-cardia adenocarcinoma (GNCA), while its role in the development of gastric cardia adenocarcinoma (GCA) is not well-defined. We aimed to investigate current H. pylori infection in relation to the severity of both precancerous and cancerous lesions of the gastric cardia in an Asian population at high risk of GCA. Methods: A population-based cross-sectional study was conducted in Linzhou County, Henan Province, China. Two thousand three (2,003) randomly selected participants with data on current H. pylori infection, assayed by 13C-urea breath test (13C-UBT), and a sequence of histological diagnoses of the gastric cardia mucosa were analyzed. Results: Of 2,003 subjects, 828 (41.33%) were currently infected with H. pylori. The prevalence of current H. pylori infection increased with increasing severity of histological lesions, from 34.12% in subjects with normal gastric cardia mucosa to 52.17% in subjects with gastric cardia high-grade intraepithelial neoplasia (CHIN)/ gastric cardia adenocarcinoma (GCA) (P for trend <0.001). With H. pylori-negative subjects as the reference category, H. pylori-positive subjects had statistically significant elevated adjusted prevalence odds ratios (PORs) for each of the histological lesions. The PORs (95% CI) were 2.15 (1.74-2.64), 3.46 (2.08-5.75), 2.78 (1.90-4.07), and 3.05 (1.30-7.17) for subjects with carditis, cardia intestinal metaplasia (CIM), cardia low-grade intraepithelial neoplasia (CLIN), and CHIN/GCA), respectively. The associations remained when subjects with abnormal stomach non-cardia mucosa were excluded. Conclusions: This large epidemiologic study demonstrates a positive association between current H. pylori infection and the severity of both precancerous and cancerous lesions of the gastric cardia in an Asian population at high risk of GCA. These findings suggest that H. pylori infection may play a role throughout both early- and late-stage development of GCA.

KMT2C Mutations in Diffuse-Type Gastric Adenocarcinoma Promote Epithelial-to-Mesenchymal Transition

PURPOSE

Lauren diffuse-type gastric adenocarcinomas (DGAs) are generally genomically stable. We identified lysine (K)-specific methyltransferase 2C (KMT2C) as a frequently mutated gene and examined its role in DGA progression.

EXPERIMENTAL DESIGN

We performed whole exome sequencing on tumor samples of 27 patients with DGA who underwent gastrectomy. Lysine (K)-specific methyltransferase 2C (KMT2C) was analyzed in DGA cell lines and in patient tumors.

RESULTS

KMT2C was the most frequently mutated gene (11 of 27 tumors [41%]). KMT2C expression by immunohistochemistry in tumors from 135 patients with DGA undergoing gastrectomy inversely correlated with more advanced tumor stage (P = 0.023) and worse overall survival (P = 0.017). KMT2C shRNA knockdown in non-transformed HFE-145 gastric epithelial cells promoted epithelial-to-mesenchymal transition (EMT) as demonstrated by increased expression of EMT-related proteins N-cadherin and Slug. Migration and invasion in gastric epithelial cells following KMT2C knockdown increased by 47- to 88-fold. In the DGA cell lines MKN-45 and SNU-668, which have lost KMT2C expression, KMT2C re-expression decreased expression of EMT-related proteins, reduced cell migration by 52% to 60%, and reduced cell invasion by 50% to 74%. Flank xenografts derived from KMT2C-expressing DGA organoids, compared with wild-type organoids, grew more slowly and lost their infiltrative leading edge. EMT can lead to the acquisition of cancer stem cell (CSC) phenotypes. KMT2C re-expression in DGA cell lines reduced spheroid formation by 77% to 78% and reversed CSC resistance to chemotherapy via promotion of DNA damage and apoptosis.

CONCLUSIONS

KMT2C is frequently mutated in certain populations with DGA. KMT2C loss in DGA promotes EMT and is associated with worse overall survival.

Characteristics of non-cardia gastric cancer with a high serum anti-Helicobacter pylori IgG titer and its association with diffuse-type histology

Background

Data on implications of a high positive titer of serum anti-Helicobacter pylori antibody on gastric cancer (GC) is limited. This study aimed to investigate the characteristics of GC with a high serum anti-H. pylori IgG (Hp-IgG) titer, and its association with diffuse-type GC.

Methods

We analyzed clinical and histological characteristics of 917 non-cardia GC patients who underwent gastrectomy. H. pylori infection was determined serologically by measuring Hp-IgG titer with immunoassay. Seropositive patients were divided into three groups (low-positive, mid-positive, and high-positive) according to the Hp-IgG titer value. Tumors were classified according to the Lauren criteria as diffuse or intestinal types.

Results

The median age of the patients was 59.0 years, and 33.8% were female. The patents were grouped as follows: seronegative, 188 (20.5%); low-positive, 288 (31.4%); mid-positive, 290 (31.6%); and high-positive 151 (16.5%). The high-positive group was significantly younger (median age, 55.0 years), with a higher proportion of female (45.0%) and non-smokers (58.9%). The proportion of diffuse-type GC increased in the order low-, mid-, and high-positive groups (p<0.001). In univariate analysis, the factors associated with diffuse-type GC were younger age, female sex, non-smokers, and a high-positive Hp-IgG titer. Younger age, female sex, and non-smokers remained significant on multivariate analysis whereas the high-positive Hp-IgG titer showed only a tendency toward the association (p = 0.078).

Conclusions

Non-cardia GC patients with a high Hp-IgG titer have distinct clinicopathologic characteristics. A high-positive Hp-IgG titer should be interpreted together with patients’ age, sex, and smoking status.

Clinicopathological Features and Increased Expression of Toll-Like Receptor 4 of Gastric Cardia Cancer in a High-Risk Chinese Population

The incidence of gastric cardia cancer (GCC) is high in China. However, the clinicopathological characteristics and the carcinogenesis of GCC are unclear. Toll-like receptor 4 (TLR4) is an important innate immunity receptor and has a role in non-GCC (NGCC). We compared the clinicopathological characteristics of GCC patients from a high-risk area in China to esophageal cancer (EC) patients. Immunohistochemistry for TLR4 was performed in 201 histological samples of normal gastric cardia mucosa (n = 11), gastric cardia inflammation (n = 87), and GCC (n = 103). We included 84 patients with EC and 99 with GCC. GCC tissue was more poorly differentiated than EC tissue and more invasive, with more histomorphologic variation. Lymph node metastasis was more frequent in GCC than in EC. The Helicobacter pylori infection rate was higher but not significantly with GCC than EC. Survival was shorter with lymph node metastasis. We found a statistically significant trend for progressive increase of TLR4 expression from normal mucosa to inflammation in GCC. GCC in this high-risk area displays clinicopathologic characteristics different from those of EC and different from those of gastroesophageal junction carcinomas in other countries, although this was not analyzed statistically. Increased TLR4 expression in gastric cardia lesions may be associated with GCC tumorigenesis.

Helicobacter pylori Infection and Risk of Gastric Cancer in Korea: A Quantitative Systematic Review

Objectives:

In the context of the global decrease in mortality due to gastric cancer, previous studies have reported that the effect of chronic Helicobacter pylori (H. pylori) infection on the incidence of gastric cancer varies among regions. This systematic review was conducted to investigate H. pylori as a risk factor for gastric cancer in Korea, where the incidence of gastric cancer is among the highest in the world.

Methods:

A search strategy was established to identify articles published in Korean as well as in English. Ultimately, we included observational studies conducted among Korean patients that designed with an age-matched and sex-matched control group that reported the odds ratio associated with H. pylori. Gastric cancer cases were subdivided into overall (OGC), cardia (CGC), non-cardia (NGC), early (EGC), advanced, intestinal (IGC), and diffuse forms of gastric cancer. Summary odds ratios (SORs) with 95% confidence intervals (CIs) were calculated in the meta-analysis using a random-effect model.

Results:

Eleven case-control studies were ultimately selected. H. pylori was associated with an SOR of 1.81 (95% CI, 1.29 to 2.54) for OGC. Additionally, statistically significant risks were observed for CGC, NGC, EGC, and IGC.

Conclusions:

Chronic H. pylori infection was found to raise the risk of gastric cancer among Koreans, with the highest risk observed for CGC and EGC (SOR=2.88 for both). Follow-up clinical epidemiologic studies are needed to assess the effects of current treatments aimed at eradicating H. pylori infections.

Long-Term Low-Dose Aspirin Use Reduces Gastric Cancer Incidence: A Nationwide Cohort Study

Purpose

The aim of this study was to investigate whether aspirin use can reduce the incidence of gastric cancer in patients with hypertension or type 2 diabetes.

Materials and Methods

A total of 200,000 patients with hypertension or type 2 diabetes were randomly selected from the Korean National Health Insurance claim database. Of these, 3,907 patients who used 100 mg of aspirin regularly (regular aspirin users) and 7,808 patients who did not use aspirin regularly (aspirin non-users) were selected at a frequency of 1:2, matched by age, sex, comorbid illnesses (type 2 diabetes and hypertension), and observation periods. The incidence of gastric cancer in this cohort was then assessed during the observation period of 2004 to 2010.

Results

In the matched cohort, the incidence rates of gastric cancer were 0.8% (31/3,907) for regular aspirin users and 1.1% (86/7,808) for aspirin non-users, but the cumulative incidence rates were not significantly different between groups (p=0.116, log-rank test). However, in multivariate analysis, regular aspirin users had a reduced risk of gastric cancer (adjusted hazard ratio [aHR], 0.71; 95% confidential interval [CI], 0.47 to 1.08; p=0.107). Duration of aspirin use showed significant association with reduction of gastric cancer risk (aHR for each year of aspirin use, 0.85; 95% CI, 0.73 to 0.99; p=0.044), particularly in patients who used aspirin for more than 3 years (aHR, 0.40; 95% CI, 0.16 to 0.98; p=0.045).

Conclusion

Long-term low-dose aspirin use was associated with reduced gastric cancer risk in patients with hypertension or type 2 diabetes.

Characteristics of gastric cancer according to Helicobacter pylori infection status

BACKGROUND AND AIMS

The definition and incidence of gastric cancer (GC) without Helicobacter pylori (Hp) infection varies between studies. The aim of our study was to compare the characteristics of GC according to Hp infection status.

METHODS

We evaluated the presence of Hp infection in 1833 GC patients with rapid urease tests, serology examinations, and histological evaluations. GC was classified as GC with current Hp infection (HpC-GC), GC with past Hp infection (HpP-GC), and GC not associated with Hp infection (HpN-GC). HpP-GC was defined as GC without current infection but with a positive serology test, glandular atrophy, and/or intestinal metaplasia. HpN-GC was defined as GC with negative Hp test results and no histological changes.

RESULTS

The numbers of HpC-GC, HpP-GC, and HpN-GC were 1378 (75.2%), 412 (22.5%), and 43 (2.3%), respectively. Among GCs without current infection, 90.5% (412/455) were associated with HpP-GC. HpP-GCs were more common in older and male patients, had an increased incidence of synchronous cancer, and less frequently had a diffuse-type histology than HpC-GCs. HpN-GCs were more common in younger, female patients; had a higher proportion of diffuse-type cancers; and more frequently showed distant metastasis than HpP-GCs. In the 40s, the proportion of HpP-GCs with diffuse-type histology (41.9%) was lower than that of HpC-GCs (60.3%) (P = 0.016). The difference was also significant in the 50s (29.1% vs 40.1%, respectively, P = 0.004).

CONCLUSIONS

Most GCs in Korea without current Hp infection showed evidence of past Hp infection. The proportion of GCs with diffuse-type histology decreased in patients with past infection.

Peroxisome proliferator-activated receptor γ upregulates galectin-9 and predicts prognosis in intestinal-type gastric cancer

The importance of PPARγ (peroxisome proliferator-activated receptor γ) in gastric cancer (GC) is unclear. We investigated the role of PPARγ in GC cell lines and an animal model, and its prognostic significance of PPARγ in GC patients. We controlled PPARγ and galectin-9 expression by using siRNAs and lentiviral constructs. Interaction between PPARγ and galectin-9 was evaluated using luciferase and chromatin immunoprecipitation assays. PPARγ expression in GCs was determined by immunohistochemical staining of tissue microarrays and survival analysis was done. Overexpression of PPARγ was accompanied by increased galectin-9. Enhanced PPARγ or galectin-9 expression increased E-cadherin expression; decreased expression of N-cadherin, fibronectin, snail, twist and slug and reduced cell invasion and migration. PPARγ bound to the galectin-9 promoter region. Galectin-9 activity increased in PPARγ-overexpressing cells but decreased in PPARγ siRNA-treated cells. In a zebrafish xenograft model, the number of migrated cancer cells and number of fish with AGS cells in the tail vein were reduced in PPARγ-overexpressing GC cells. PPARγ was expressed in 462 of the 688 patients (69.2%) with GC. In 306 patients with intestinal-type GC, those with PPARγ-positive tumors had lower overall and cancer-specific mortalities than those with PPARγ-negative tumors. PPARγ expression was an independent prognostic factor for overall and GC-specific mortality in patients with intestinal-type GC (adjusted hazard ratio, 0.42; 95% CI, 0.22-0.81). PPARγ inhibits cell invasion, migration and epithelial-mesenchymal transition through upregulation of galectin-9 in vitro and in vivo.

Guidelines for the diagnosis and treatment of Helicobacter pylori infection in Korea, 2013 revised edition

The Korean College of Helicobacter and Upper Gastrointestinal Research first developed guidelines for the diagnosis and treatment of Helicobacter pylori (H. pylori) infection in 1998, and revised guidelines were proposed in 2009 by the same group. Although the revised guidelines were based on a comprehensive review of published articles and the consensus of expert opinions, the revised guidelines were not developed using an evidence-based process. The new guidelines presented in this study include specific changes regarding indication and treatment of H. pylori infection in Korea, and were developed through the adaptation process using an evidence-based approach. After systematic review of the literature, six guidelines were selected using the Appraisal of Guidelines for Research and Evaluation (AGREE) II process. A total of 21 statements were proposed with the grading system and revised using the modified Delphi method. After the guideline revisions, 11 statements about indication of test and treatment, four statements about diagnosis, and four statements about treatment of H. pylori infection were developed. The revised guidelines were reviewed by external experts before receiving official endorsement from the Korean College of Helicobacter and Upper Gastrointestinal Research, and disseminated to physicians and other medical professionals for use in clinical practice in Korea. The guidelines will continue to be updated and revised periodically.

OLGA and OLGIM stage distribution according to age and Helicobacter pylori status in the Korean population

BACKGROUND

The Operative Link for Gastritis Assessment (OLGA) and the Operative Link on Gastric Intestinal Metaplasia Assessment (OLGIM) staging systems have been suggested to provide risk assessment for gastric cancer. This study aimed to evaluate the distribution of OLGA and OLGIM staging by age and Helicobacter pylori status.

MATERIALS AND METHODS

We studied 632 subjects who underwent esophagogastroduodenoscopy for gastric cancer screening. Helicobacter pylori status and histologic changes were assessed using the updated Sydney system. Stage III and IV OLGA or OLGIM stages were considered as high-risk stages.

RESULTS

The rate of H. pylori infection was 59.0% (373/632). Overall, the proportion of high OLGA and OLGIM stages was significantly increased with older age (p < .001 for both). Old age (OR = 5.17, 6.97, and 12.23 for ages in the 40's, 50's, and 60's, respectively), smoking (OR = 2.54), and H. pylori infection (OR = 8.46) were independent risk factors for high-risk OLGA stages. These risk factors were the same for high-risk OLGIM stages. In the H. pylori-positive subgroup, the proportion of high-risk OLGA stages was low (6.9%) before the age of 40, but increased to 23.0%, 29.1%, and 41.1% for those in their 40s, 50s, and 60s, respectively (p < .001). High-risk OLGIM stages showed a similar trend of 2.8% before the age of 40 and up to 30.1% for those in their 60s. High-risk OLGA and OLGIM stages were uncommon in the H. pylori-negative group, with a respective prevalence of 10.3% and 3.4% even among those in their 60s.

CONCLUSIONS

Because high-risk OLGA and OLGIM stages are uncommon under the age of 40, H. pylori treatment before that age may reduce the need for endoscopic surveillance for gastric cancer.

Randomised clinical trial: the effects of Helicobacter pylori eradication on glandular atrophy and intestinal metaplasia after subtotal gastrectomy for gastric cancer

BACKGROUND

Helicobacter pylori eradication is recommended for early gastric cancer (GC) patients after resection.

AIM

To evaluate whether H. pylori eradication improves glandular atrophy and intestinal metaplasia (IM) in GC patients undergoing subtotal gastrectomy.

METHODS

This randomised, double-blind trial was performed in tertiary care setting. Distal GC patients with H. pylori infection were randomised to receive proton pump inhibitor-based triple therapy or placebo. The histology was evaluated using the updated Sydney system before and at 36 months after surgery. The endpoints were the comparison of atrophy and IM score changes between the allocated groups and according to final H. pylori status.

RESULTS

Overall, 190 patients were randomised to the treatment and placebo groups. For lesser curvature of the corpus, mean atrophy and IM scores did not differ between the treatment and placebo groups. However, the H. pylori-eradicated patients had significantly lower mean scores than the H. pylori-persistent patients regarding atrophy (0.55 ± 0.95 vs. 1.05 ± 1.10 respectively; P = 0.0046) and IM (0.66 ± 0.99 vs. 1.05 ± 1.16 respectively; P = 0.0284). The percentage change from baseline was more marked in the H. pylori-negative than in the H. pylori-positive groups (-58.6% vs. -11.0% for atrophy and -60.5% vs. -35.6% for IM respectively). For greater curvature, mean atrophy score was lower in the H. pylori-negative group than in the H. pylori-positive group (0.14 ± 0.50 vs. 0.41 ± 0.75 respectively; P = 0.0281). The percentage change was -36.4% vs. 86.3%.

CONCLUSION

Helicobacter pylori eradication in GC patients is beneficial, as reflected by lower scores of atrophy and IM at 36 months after subtotal gastrectomy. (ClinicalTrials.gov number, NCT01002443).

Knowledge and Attitudes of Junior Medical Doctors towards Gastric Cancer

Introduction:

Gastric cancer (GC) has considerable morbidity and mortality in Singapore. As doctors play an important part in persuading patients to undergo screening, and as screening may have an important role in diagnosing early GC, we sought to determine the knowledge and attitudes of doctors towards GC and GC screening.

Methods:

Self-administered questionnaires were distributed to a cohort of junior doctors in Singapore General Hospital.

Results:

There were a total of 104 respondents; 82.5% of respondents felt that GC is common in Singapore. While most risk factors (RF) were identified correctly, knowledge of dietary RF was deficient, with only 34.3% and 36.5% realising that a high salt diet and low vegetable/fruit intake were RF, respectively. 95.1% knew that GC can be asymptomatic, but if detected early, is potentially curable (97.1%). Majority of respondents felt that GC was best diagnosed by endoscopy and the best time to diagnose it was when asymptomatic. However, only 52% of the respondents felt that screening gastroscopy was worthwhile. For those willing to pay for screening gastroscopy, the mean cost they were willing to pay was S$243.

Conclusion:

Our results show that while most RF of GC are well recognised, knowledge of dietary factors is deficient. There is ambivalence towards screening gastroscopy despite knowing that GC is common in Singapore and can be asymptomatic. This may be a barrier to tackling the problem of GC in Singapore. Before we recommend any GC screening programmes in the future, it may be important to optimise knowledge and change the mindsets of doctors in Singapore towards GC.

Gastric cancer epidemiology in Korea

Gastric cancer has been the most commonly diagnosed cancer in Korea although the age-standardized mortality and incidence has decreased gradually during last two decades. Helicobacter pylori infection and cigarette smoking are well-established risk factors, and the role of dietary factors, such as salted foods, fresh vegetables and fruits, soy foods, and processed or grilled meats on gastric carcinogenesis has been suggested. In this review, we review national and international gastric cancer statistics, studies on environmental risk factors conducted in the Korean population, and gastric cancer screening activities.