Effects of selective COX-2 inhibitor and Helicobacter pylori eradication on precancerous gastric lesions

A possible role of GDDR in the development of Helicobacter pylori-associated gastric cancer

Helicobacter pylori (H. pylori) infection plays an important part in the development of gastric carcinoma. GDDR has been confirmed as a tumor suppressor gene in gastric tumorigenesis. However, the underlying mechanism of GDDR in H. pylori-induced carcinogenesis is not well known. The aim of this study is to investigate the clinicopathological significance and possible molecular mechanism of GDDR in gastric cancer associated with H. pylori. Western blot, real-time quantitative PCR (qRT-PCR), and immunohistochemistry were used to detect the expression level of GDDR with or without H. pylori infection. The function and possible related molecular mechanisms of GDDR were further explored in vitro and in vivo. The variability of GDDR expression appeared in the early stage of gastric carcinogenesis with positive H. pylori infection status. GDDR might inhibit the progression of normal gastric epithelial cells to cancer cells by suppressing NF-kappaB signaling pathway, which in turn could be regulated by H. pylori infection. Our results suggested, for the first time, that the gradual change in GDDR expression might not only be directly related to H. pylori infection but also be an early molecular event in the development of gastric carcinoma.

Helicobacter pylori associated gastric intestinal metaplasia: Treatment and surveillance

Gastric cancer (GC) is one of the leading causes of cancer related death in the world, particularly in East Asia. According to the Correa’s cancer cascade, non-cardia GC is usually developed through a series of mucosal changes from non-atrophic gastritis to atrophic gastritis (AG), intestinal metaplasia (IM), dysplasia and adenocarcinoma. Atrophic gastritis and IM are therefore generally considered to be pre-neoplastic gastric lesions. Helicobacter pylori (H. pylori) infection is an important initiating and promoting step of this gastric carcinogenesis cascade. Emerging long-term data showed that eradication of H. pylori reduced the risk of subsequent cancer development. It however remains confusing whether eradication of the bacterium in individuals with pre-neoplastic gastric lesions could regress these changes as well as in preventing cancer. Whilst H. pylori eradication could likely regress AG, the presence of IM may be a point of no return in this cascade. Hence, surveillance by endoscopy may be indicated in those with extensive IM or those with incomplete IM, particularly in populations with high GC risk. The optimal interval and the best tool of surveillance endoscopy remains to be determined in future studies.

A large randomised controlled intervention trial to prevent gastric cancer by eradication of Helicobacter pylori in Linqu County, China: baseline results and factors affecting the eradication

OBJECTIVE

To clarify the full range of benefits and adverse consequences of Helicobacter pylori eradication as a strategy for gastric cancer prevention, the community-based intervention trial was launched in Linqu County, China.

DESIGN

A total of 184,786 residents aged 25-54 years were enrolled in this trial and received (13)C-urea breath test. H. pylori positive participants were assigned into two groups, either receiving a 10-day quadruple anti-H. pylori treatment or lookalike placebos together with a single dosage of omeprazole and bismuth.

RESULTS

The prevalence of H. pylori in trial participants was 57.6%. A total of 94,101 subjects completed the treatment. The overall H. pylori eradication rate was 72.9% in the active group. Gender, body mass index, history of stomach disease, baseline delta over baseline-value of (13)C-urea breath test, missed medication doses, smoking and drinking were independent predictors of eradication failure. The missed doses and high baseline delta over baseline-value were important contributors in men and women (all Ptrend<0.001). However, a dose-response relationship between failure rate and smoking or drinking index was found in men (all Ptrend<0.001), while high body mass index (Ptrend<0.001) and history of stomach disease were significant predictors in women. The treatment failure rate increased up to 48.8% (OR 2.87, 95% CI 2.24 to 3.68) in men and 39.4% (OR 2.67, 95% CI 1.61 to 4.42) in women with multiple factors combined.

CONCLUSIONS

This large community-based intervention trial to eradicate H. pylori is feasible and acceptable. The findings of this trial lead to a distinct evaluation of factors influencing eradication that should be generally considered for future eradication therapies.

TRIAL REGISTRATION NUMBER

ChiCTR-TRC-10000979 in accordance with WHO ICTRP requirements.

Helicobacter pylori eradication cannot reduce the risk of gastric cancer in patients with intestinal metaplasia and dysplasia: evidence from a meta-analysis

BACKGROUND

The effect of Helicobacter pylori (H. pylori) eradication on gastric cancer (GC) prevention is controversial. Intestinal metaplasia (IM) seems to be a "point of no return" in the precancerous cascade. We performed a meta-analysis of randomized controlled trials (RCTs) to illustrate this issue.

MATERIALS AND METHODS

The MEDLINE, EMBASE, Cochrane Library were searched for relevant RCTs that were published in any language up to March 2014. By dividing participants into subgroups based on their baseline diagnoses as group <IM (normal, non-atrophic gastritis, atrophic gastritis) and group ≥ IM(intestinal metaplasia, dysplasia), the relative risk (RR) of GC in each study compared treatment group with control group were pooled using Mantel-Haenszel fixed-effect model and publication bias analyses were performed.

RESULTS

Ten studies from eight RCTs were included in this analysis, for a total of 7,955 participants. H. pylori treatment compared with control significantly reduced the risk of GC, with a pooled RR of 0.64 (95% CI, 0.48-0.85). Subgroup analysis for patients with non-atrophic gastritis, atrophic gastritis (<IM) yielded a similar results (RR = 0.25, 95% CI, 0.08-0.81). But this difference was not observed in patients with intestinal metaplasia, dysplasia (≥ IM) (RR = 0.88; 95% CI, 0.59-1.31).

CONCLUSIONS

Our results suggested that patients with Intestinal metaplasia or dysplasia could not benefit from the H. pylori treatment on the risk of GC.

Chemoprevention trials of GI cancers in Asia

Cancers are among the leading causes of morbidity and mortality worldwide, with gastrointestinal (GI) luminal cancers accounting for a large proportion of cancer incidence. Chemoprevention of GI luminal cancers is important to reduce this cancer burden. Screening for and eradication of Helicobacter pylori (H. pylori) in areas with high gastric cancer incidence is a safe and effective strategy to decrease the incidence of gastric cancer. Eradication of H. pylori also seems to be effective in preventing metachronous cancer development after endoscopic resection of early gastric cancer. For the average risk individual, COX inhibitors may have a role in reducing the incidence of adenoma formation as well as colorectal cancer, bearing in mind its inherent risks. There is currently insufficient evidence to recommend a chemoprevention agent against esophageal and small intestine cancer.

Helicobacter pylori, cyclooxygenase-2 and evolution of gastric lesions: results from an intervention trial in China

To investigate the role of cyclooxygenase (COX)-2/prostaglandin E2 (PGE2) in the process of Helicobacter pylori-induced gastric carcinogenesis, a prospective study based on an intervention trial was conducted in Linqu County, China. A total of 1401 subjects with histopathologic diagnosis were investigated at baseline, among those, 919 completed subsequent interventions (anti-H.pylori and/or celecoxib treatment). Expressions of COX-2 and Ki-67 were assessed by immunohistochemistry, and PGE2 levels were measured by enzyme immunoassay before and after interventions, respectively. We found a grade-response relationship between COX-2 expression level and risk of advanced gastric lesions at baseline. Stratified analysis indicated an additive interaction between COX-2 expression and H.pylori infection on the elevated risk of advanced gastric lesions. The odds ratios (ORs) for both factors combined were 9.31 [95% confidence interval (CI): 4.13-20.95] for chronic atrophic gastritis, 16.26 (95% CI: 7.29-36.24) for intestinal metaplasia and 21.13 (95% CI: 7.87-56.75) for dysplasia, respectively. After interventions, COX-2 expression and Ki-67 labeling index (LI) were decreased in anti-H.pylori group (OR: 1.65, 95% CI: 1.36-1.99 for COX-2; OR: 1.78, 95% CI: 1.49-2.12 for Ki-67) or anti-H.pylori followed by celecoxib group (OR: 1.41, 95% CI: 1.17-1.70 for COX-2; OR: 1.63, 95% CI: 1.37-1.94 for Ki-67). PGE2 levels were decreased in all treatment groups. Furthermore, the regression of gastric lesions was associated with the decrease of COX-2 expression or Ki-67 LI after interventions. Our findings indicate that H.pylori-induced COX-2/PGE2 pathways play an important role on the progression of precancerous gastric lesions in a Chinese population.

Molecular cancer prevention: Current status and future directions

The heterogeneity and complexity of advanced cancers strongly support the rationale for an enhanced focus on molecular prevention as a priority strategy to reduce the burden of cancer. Molecular prevention encompasses traditional chemopreventive agents as well as vaccinations and therapeutic approaches to cancer-predisposing conditions. Despite challenges to the field, we now have refined insights into cancer etiology and early pathogenesis; successful risk assessment and new risk models; agents with broad preventive efficacy (eg, aspirin) in common chronic diseases, including cancer; and a successful track record of more than 10 agents approved by the US Food and Drug Administration for the treatment of precancerous lesions or cancer risk reduction. The development of molecular preventive agents does not differ significantly from the development of therapies for advanced cancers, yet it has unique challenges and special considerations given that it most often involves healthy or asymptomatic individuals. Agents, biomarkers, cohorts, overall design, and endpoints are key determinants of molecular preventive trials, as with therapeutic trials, although distinctions exist for each within the preventive setting. Progress in the development and evolution of molecular preventive agents has been steadier in some organ systems, such as breast and skin, than in others. In order for molecular prevention to be fully realized as an effective strategy, several challenges to the field must be addressed. Here, the authors provide a brief overview of the context for and special considerations of molecular prevention along with a discussion of the results from major randomized controlled trials.

Helicobacter pylori eradication for the prevention of gastric neoplasia

BACKGROUND

Gastric cancer is the third most common cause of cancer death worldwide. Individuals infected with Helicobacter pylori have a higher likelihood of developing gastric cancer than individuals who are not infected. Eradication of H. pylori in healthy asymptomatic individuals in the general population may reduce the incidence of gastric cancer, but the magnitude of this effect is unclear.

OBJECTIVES

To assess the effectiveness of eradication of H. pylori in healthy asymptomatic individuals in the general population in reducing the incidence of gastric cancer.

SEARCH METHODS

We identified trials by searching the Cochrane Central Register of Controlled Trials (CENTRAL; 2013, Issue 11), MEDLINE (1946 to December 2013), and EMBASE (1974 to December 2013). We handsearched reference lists from trials selected by electronic searching to identify further relevant trials. We handsearched published abstracts from conference proceedings from the United European Gastroenterology Week (published in Gut) and Digestive Disease Week (published in Gastroenterology) between 2001 and 2013. We contacted members of the Cochrane Upper Gastrointestinal and Pancreatic Diseases Review Group and experts in the field and asked them to provide details of outstanding clinical trials and any relevant unpublished materials.

SELECTION CRITERIA

We analysed randomised controlled trials comparing at least one week of H. pylori therapy with placebo or no treatment in preventing subsequent development of gastric cancer in otherwise healthy and asymptomatic H. pylori-positive adults. Trials had to follow up participants for at least two years and needed to have at least two participants with gastric cancer as an outcome. We defined gastric cancer as any gastric adenocarcinoma, including intestinal (differentiated) or diffuse (undifferentiated) type, with or without specified histology.

DATA COLLECTION AND ANALYSIS

We collected data on incidence of gastric cancer, incidence of oesophageal cancer, deaths from gastric cancer, deaths from any cause, and adverse effects arising due to therapy.

MAIN RESULTS

Six trials met all our eligibility criteria and provided extractable data. Three trials were at low risk of bias, one trial was at unclear risk, and two trials were at high risk of bias. Five trials were conducted in Asian populations. In preventing development of subsequent gastric cancer, H. pylori eradication therapy was superior to placebo or no treatment (6 trials, 6497 participants, risk ratio (RR) of developing subsequent gastric cancer 0.66; 95% confidence interval (CI) 0.46 to 0.95; moderate-quality evidence). Only one trial reported effect of eradication of H. pylori on development of subsequent oesophageal cancer (2 (0.2%) among 817 participants assigned to eradication therapy, compared with 1 (0.1%) of 813 participants allocated to placebo; RR 1.99; 95% CI 0.18 to 21.91). The effect of H. pylori eradication on preventing death from gastric cancer compared with placebo or no treatment was uncertain due to wide confidence intervals (3 trials, 4475 participants, RR 0.67; 95% CI 0.40 to 1.11; moderate-quality evidence). There was no evidence of an effect on all-cause mortality (4 trials, 5253 participants, RR 1.09; 95% CI 0.86 to 1.38; moderate-quality evidence). Adverse events data were poorly reported.

AUTHORS' CONCLUSIONS

We found limited, moderate-quality evidence that searching for and eradicating H. pylori reduces the incidence of gastric cancer in healthy asymptomatic infected Asian individuals, but we cannot necessarily extrapolate this data to other populations.

Anti-LeY antibody enhances therapeutic efficacy of celecoxib against gastric cancer by downregulation of MAPKs/COX-2 signaling pathway: correlation with clinical study

INTRODUCTION

Helicobacter pylori (H. pylori) is a major causative agent for the induction of chronic gastritis, gastric ulcer and gastric cancer. Celecoxib (COX-2 inhibitor) inhibits gastric cancer cell proliferation, but with low treatment efficacy, limiting its applications. It is important to develop a better strategy to improve the efficacy of celecoxib. Lewis Y (LeY) is a difucosylated oligosaccharide, highly expressed in 60-90% of human epithelial cancers, including gastric cancer. We previously found that H. pylori infection was associated with high level of LeY in gastric cancer.

MATERIAL AND METHODS

Herein, we analyzed the correlation between H. pylori and cyclo-oxygenase-2 (COX-2), LeY, gastric markers (CA724 and GRN) in gastric patient's tissue and serum samples by IHC and ELISA. Furthermore, we treated the primary gastric cancer cells with celecoxib, anti-LeY antibody or the combination, and analyzed their therapeutic efficacy on CA724, GRN and COX-2 expression by Western blot, flow cytometry and ELISA.

RESULTS

We found that gastric cancer had significantly high expression of H. pylori, COX-2, CA724, and GRN compared to gastric ulcers and chronic gastritis (P < 0.0001). H. pylori level showed significant correlation with COX-2 (R--0.552), LeY (R--0.861), CA724 (R--0.714) and GRN (R--0.664) (P < 0.0001). Additionally, the combination therapy led to impressive inhibition of gastric cancer cell proliferation, with decreased expression of COX-2, CA724 and GRN through downregulation of MAPKs/COX-2 pathway (P < 0.01).

CONCLUSIONS

Our findings suggest that anti-LeY antibody enhances the cancer cell proliferation inhibitory effects of celecoxib, which might be a new feasible way for gastric cancer therapy.

Cancer Prevention Research in China

Although cancer incidence and mortality rates in the United States and some European countries have started to decrease, those in developing countries are increasing. China, the most populous developing country, is facing a serious challenge from cancer. Cancer incidence has been increasing for decades, and cancer is the leading cause of death in China. In 2012, the cancer incidence was 174.0 per 100,000, and the cancer mortality was 122.2 per 100,000 in China. In addition to the still-prevalent traditional Chinese cancers of the stomach, liver, esophagus, cervix, and nasopharynx, the incidence of "Western" cancers such those of the lung, breast, and colorectum has increased alarmingly in recent years. These increases are likely due to the lifestyle and environmental changes associated with rapid economic development and population aging. More importantly, a large portion of these cancers are preventable. Researchers in China have made important contributions to cancer prevention research, especially in the traditional Chinese cancers. More cancer prevention research and measures, especially on the major emerging cancers, are urgently needed. This review article highlights some of the past achievements and present needs in cancer prevention research in China and suggests important areas for future studies.

NOD1 and NOD2 Genetic Variants in Association with Risk of Gastric Cancer and Its Precursors in a Chinese Population

BACKGROUND

Genetic variants of nucleotide-binding oligomerization domain-containing protein (NOD) may influence the outcome of Helicobacter pylori (H. pylori) infection and gastric carcinogenesis. To explore genetic variants of NOD1 and NOD2 in association with gastric cancer (GC) and its precursors, a population-based study was conducted in Linqu County, China.

METHODS

TagSNPs of NOD1 and NOD2 were genotyped by Sequenom MASS array in 132 GCs, and 1,198 subjects with precancerous gastric lesions, and were correlated with evolution of gastric lesions in 766 subjects with follow-up data.

RESULTS

Among seven tagSNPs, NOD1 rs2709800 and NOD2 rs718226 were associated with gastric lesions. NOD1 rs2709800 TG genotype carriers had a decreased risk of intestinal metaplasia (IM, OR: 0.53; 95% CI: 0.31-0.92), while NOD2 rs718226 G allele (AG/GG) showed increased risks of dysplasia (DYS, OR: 2.96; 95% CI: 1.86-4.71) and GC (OR: 2.35; 95% CI: 1.24-4.46). Moreover, an additive interaction between rs718226 and H. pylori was found in DYS or GC with synergy index of 3.08 (95% CI: 1.38-6.87) or 3.99 (95% CI: 1.55-10.22), respectively. The follow-up data indicated that NOD2 rs2111235 C allele (OR: 0.52; 95% CI: 0.32-0.83) and rs7205423 G allele (OR: 0.56; 95% CI: 0.35-0.89) were associated with decreased risk of progression in H. pylori-infected subjects.

CONCLUSIONS

NOD1 rs2709800, NOD2 rs718226, rs2111235, rs7205423 and interaction between rs718226 and H. pylori infection may be related to risk of gastric lesions.

Gastrointestinal injury associated with NSAID use: a case study and review of risk factors and preventative strategies

Nonsteroidal anti-inflammatory drugs (NSAIDs) are effective anti-inflammatory and analgesic agents and are among the most commonly used classes of medications worldwide. However, their use has been associated with potentially serious dose-dependent gastrointestinal (GI) complications such as upper GI bleeding. GI complications resulting from NSAID use are among the most common drug side effects in the United States, due to the widespread use of NSAIDs. The risk of upper GI complications can occur even with short-term NSAID use, and the rate of events is linear over time with continued use. Although gastroprotective therapies are available, they are underused, and patient and physician awareness and recognition of some of the factors influencing the development of NSAID-related upper GI complications are limited. Herein, we present a case report of a patient experiencing a gastric ulcer following NSAID use and examine some of the risk factors and potential strategies for prevention of upper GI mucosal injuries and associated bleeding following NSAID use. These risk factors include advanced age, previous history of GI injury, and concurrent use of medications such as anticoagulants, aspirin, corticosteroids, and selective serotonin reuptake inhibitors. Strategies for prevention of GI injuries include anti-secretory agents, gastroprotective agents, alternative NSAID formulations, and nonpharmacologic therapies. Greater awareness of the risk factors and potential therapies for GI complications resulting from NSAID use could help improve outcomes for patients requiring NSAID treatment.

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.

Helicobacter pylori infection, gastrin and cyclooxygenase-2 in gastric carcinogenesis

Gastric cancer is one of the most frequent neoplasms and a main cause of death worldwide, especially in China and Japan. Numerous epidemiological, animal and experimental studies support a positive association between chronic Helicobacter pylori (H. pylori) infection and the development of gastric cancer. However, the exact mechanism whereby H. pylori causes gastric carcinogenesis remains unclear. It has been demonstrated that expression of cyclooxygenase-2 (COX-2) is elevated in gastric carcinomas and in their precursor lesions. In this review, we present the latest clinical and experimental evidence showing the role of gastrin and COX-2 in H. pylori-infected patients and their possible association with gastric cancer risk.

Comparison of cancer incidence among patients with rheumatic disease: a retrospective cohort study

Introduction

Rheumatic diseases (RDs) are associated with different cancers; however, it is unclear whether particular cancers are more prevalent in certain RDs. In the present study, we examined the relative incidence of several cancers in a single homogeneous cohort of patients with different RDs.

Methods

Patients (N = 3,586) diagnosed with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), systemic sclerosis (SSc), dermatomyositis (DM) or polymyositis were included. Cancer diagnosis was based on histopathology. The 2008 Korean National Cancer Registry served as the reference for calculating standardized incidence ratios (SIRs).

Results

During the follow-up period of 31,064 person-years, 187 patients developed cancer. RA and SLE patients showed an increased risk of non-Hodgkin’s lymphoma (SIR for RA patients = 3.387, 95% confidence interval (CI) = 1.462 to 6.673; SIR for SLE patients = 7.408, 95% CI = 2.405 to 17.287). SLE patients also had a higher risk of cervical cancer (SIR = 4.282, 95% CI = 1.722 to 8.824). SSc patients showed a higher risk of lung cancer (SIR = 4.917, 95% CI = 1.977 to 10.131). Endometrial cancer was increased only in patients with DM (SIR = 30.529, 95% CI = 3.697 to 110.283). RA patients had a lower risk for gastric cancer (SIR = 0.663, 95% CI = 0.327 to 0.998). The mean time between the RD and cancer diagnoses ranged from 0.1 to 16.6 years, with the shortest time observed in patients with DM (2.0 ± 2.1 years).

Conclusions

Different RDs are associated with particular cancers. Thus, cancer surveillance tailored to specific RDs might be beneficial.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-014-0428-x) contains supplementary material, which is available to authorized users.

At the bedside: Helicobacter pylori, dysregulated host responses, DNA damage, and gastric cancer

Clinical trials performed in populations at high GC risk have demonstrated that eradication of Helicobacter pylori from the stomach with a course of combination antimicrobials helps prevent gastric carcinogenesis when they are administered before precancerous lesions have yet developed. In this review, we consider the insights into H. pylori-associated gastric carcinogenesis that have been gained from these and many other clinical studies in the field to highlight priority areas for basic research and clinical investigation. Among these are defining the magnitude of the risk reduction that may be achieved in clinical practice and at a population level by H. pylori eradication and investigating when, during the slow multistep progression to GC, intervention will be of the most benefit. Additional strategies to prevent GC induced by H. pylori, including chemoprevention, dietary modification, and close endoscopic surveillance, may also have value in augmenting the risk reduction. Why only a small subpopulation of those infected by H. pylori go on to develop GC may be partially explained by genetic susceptibility related to SNPs in several genes regulating the intensity of the gastric inflammatory response to H. pylori. Investigation of the basic mechanisms underlying the promotion of GC by H. pylori and the associated inflammatory response will likely continue to improve clinical strategies for the prevention of one of the most common causes of cancer death globally. See related review, At the Bench: H. pylori, dysregulated host responses, DNA damage, and gastric cancer.

Methylation status of blood leukocyte DNA and risk of gastric cancer in a high-risk Chinese population

BACKGROUND

To evaluate the relationship between methylation status of blood leukocyte DNA and risk of gastric cancer, a population-based study was conducted in Linqu County.

METHODS

Methylation levels of IGFII and N33 were determined by quantitative methylation-specific PCR. The temporal trend of methylation levels during gastric cancer development was investigated in 133 gastric cancer cases from two cohorts with pre- and/or post-gastric cancer samples. As the references of pre-GCs, 204 intestinal metaplasia (IM) or dysplasia (DYS) subjects who did not progress to gastric cancer during the follow-up period were selected. Meanwhile, 285 subjects with superficial gastritis/chronic atrophic gastritis (SG/CAG) were also selected as controls.

RESULTS

IGFII median methylation level was significantly higher in gastric cancer cases than those with SG/CAG (61.47% vs. 49.73%; P < 0.001). IGFII and N33 methylation levels were elevated at least 5 years ahead of clinical gastric cancer diagnosis comparing with SG/CAG (63.38% vs. 49.73% for IGFII, 9.12% vs. 5.70% for N33; all P < 0.001). Furthermore, the frequency of hypermethylated IGFII was markedly increased in IM or DYS subjects who progressed to gastric cancer in contrast to those who remained with IM and DYS, and adjusted ORs were 12.52 [95% confidence interval (CI), 3.81-41.15] for IM and 10.12 (95% CI, 2.68-38.22) for DYS. Similar results were also found for N33 in subjects with IM (OR, 3.77; 95% CI, 1.20-11.86).

CONCLUSIONS

Our findings suggested that hypermethylated IGFII and N33 in blood leukocyte DNA were associated with risk of gastric cancer in a Chinese population.

IMPACT

IGFII and N33 methylation status may be related to gastric carcinogenesis.

Recent advances and future trends in the targeted therapy of metastatic gastric cancer

The better understanding of the molecular mechanisms behind gastric cancer has led to the development of new therapeutic strategies that are likely to improve patient outcomes in the near future. Recently, targeting the HER2 and the VEGF pathways with trastuzumab and ramucirumab, respectively, have been found to improve survival, while directed therapies against a number of other pathways are under clinical evaluation. These include the hepatocyte growth factor and its receptor c-MET, the insulin-like growth factor 1, the fibroblast growth factor, the mammalian target of rapamycin (mTOR), the epidermal growth factor receptor, and other pathways, as well as relevant immunotherapeutic strategies. This article reviews recent advances and future trends of these concepts for gastric cancer and adenocarcinoma of the gastroesophageal junction.

Helicobacter pylori eradication therapy to prevent gastric cancer in healthy asymptomatic infected individuals: systematic review and meta-analysis of randomised controlled trials

OBJECTIVES

To determine whether searching for Helicobacter pylori and treating with eradication therapy leads to a reduction in incidence of gastric cancer among healthy asymptomatic infected individuals.

DESIGN

Systematic review and meta-analysis of randomised controlled trials.

DATA SOURCES

Medline, Embase, and the Cochrane central register of controlled trials were searched through to December 2013. Conference proceedings between 2001 and 2013 were hand searched. A recursive search was performed with bibliographies of relevant studies. There were no language restrictions.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised controlled trials examining the effect of at least seven days of eradication therapy on subsequent occurrence of gastric cancer in adults who tested positive for Helicobacter pylori but otherwise healthy and asymptomatic were eligible. The control arm had to receive placebo or no treatment. Subjects had to be followed for ≥ 2 years.

MAIN OUTCOME MEASURES

Primary outcome, defined a priori, was the effect of eradication therapy on the subsequent occurrence of gastric cancer expressed as a relative risk of gastric cancer with 95% confidence intervals.

RESULTS

The search strategy identified 1560 citations, of which six individual randomised controlled trials were eligible. Fifty one (1.6%) gastric cancers occurred among 3294 individuals who received eradication therapy versus 76 (2.4%) in 3203 control subjects (relative risk 0.66, 95% confidence interval 0.46 to 0.95), with no heterogeneity between studies (I(2)=0%, P=0.60). If the benefit of eradication therapy was assumed to persist lifelong the number needed to treat was as low as 15 for Chinese men and as high as 245 for US women.

CONCLUSIONS

These data provide limited, moderate quality evidence that searching for and eradicating H pylori reduces the incidence of gastric cancer in healthy asymptomatic infected Asian individuals, but these data cannot necessarily be extrapolated to other populations.

Inflammation-related factors predicting prognosis of gastric cancer

Gastric cancer (GC), which is mainly induced by Helicobacter pylori (H. pylori) infection, is one of the leading causes of cancer-related death in the developing world. Active inflammation initiated by H. pylori infection and maintained by inherent immune disorders promotes carcinogenesis and postoperative recurrence. However, the presence with H. pylori in tumors has been linked to a better prognosis, possibly due to the induction of antitumor immunity. Tumor infiltrations of tumor-associated macrophages, myeloid-derived suppressor cells, neutrophils, Foxp3⁺ regulatory T cells are correlated with poor prognosis. Tumor infiltrating CD8⁺ cytotoxic T lymphocytes, dendritic cells, and CD45RO T cells are generally associated with good prognosis of GC, although some subsets of these immune cells have inverse prognosis prediction values. High ratios of Foxp3⁺/CD4⁺ and Foxp3⁺/CD8⁺ in tumors are associated with a poor prognosis; whereas high Th1/Th2 ratio in tumors predicts a good prognosis. High levels of interleukin (IL)-6, IL-10, IL-32, and chemokine C-C motif ligands (CCL)7 and CCL21 in circulation, high expression of CXC chemokine receptor 4, chemokine C-C motif receptor (CCR)3, CCR4, CCR5, CCR7, hypoxia-inducible factor-1α, signal transducer activator of transcription-3, cyclooxygenase-2, and orphan nuclear receptor 4A2 in tumors are associated with an unfavorable prognosis. Increased serum levels of matrix metalloproteinases (MMP)-3, MMP-7, and MMP-11 and increased levels of MMP-9, MMP-12, and MMP-21 in tumors are consistently associated with poor survival of GC. Further emphasis should be put on the integration of these biomarkers and validation in large cohorts for personalized prediction of GC postoperative prognosis.

Helicobacter pylori antibody responses and evolution of precancerous gastric lesions in a Chinese population

Helicobacter pylori-specific proteins are involved in gastric carcinogenesis. To investigate the seroprevalence of six H. pylori-specific antibodies in patients with different gastric histology, and the impact of seropositivities on the evolution of precancerous gastric lesions, a follow-up study was conducted in Linqu County, China. The seropositivities for CagA, VacA, GroEL, UreA, HcpC and gGT were assessed by recomLine analysis in 573 H. pylori-positive subjects and correlated with evolution of precancerous gastric lesions. We found that the score of H. pylori recomLine test was significantly increased in subjects with chronic atrophic gastritis (CAG, p < 0.0001) or intestinal metaplasia (IM, p = 0.0125), and CagA was an independent predictor of advanced gastric lesions, adjusted odds ratios (ORs) were 2.54 (95% CI = 1.42-4.55) for IM and 2.38 (95% CI = 1.05-5.37) for dysplasia (DYS). Moreover, seropositivities for CagA and GroEL were identified as independent predictors for progression of gastric lesions in a longitudinal study, and ORs were 2.89 (95% CI = 1.27-6.59) and 2.20 (95% CI = 1.33-3.64), respectively. Furthermore, the risk of progression was more pronounced in subjects with more than three positive antigens (p(for) trend = 0.0003). This population-based study revealed that seropositivities for CagA and GroEL might be potential markers to identify patients infected with high-risk H. pylori strains, which are related to the development of GC in a Chinese high-risk population, and recomLine test might serve as a tool for risk stratification.

Impact of non-steroidal anti-inflammatory drugs on gastrointestinal cancers: current state-of-the science

Growing evidence from epidemiologic and preclinical studies suggests that nonsteroidal anti-inflammatory drugs (NSAIDs) reduce the risk of gastrointestinal (GI) cancers, including esophageal, gastric, pancreatic, colorectal cancer, and hepatocellular carcinoma. However, there is also evidence indicating the absence of this benefit. The exact mechanism of NSAIDs' action on GI tumors is not known. Although some studies have suggested inhibition of carcinogenesis by NSAIDs through suppression effect on inflammation-associated cyclooxygenase-2 (COX-2) expression, other studies have suggested COX-2-independent mechanisms. Herein, we summarize the current state of-the-science regarding NSAID benefit for patients with GI cancers.

The Effect of Helicobacter pylori on Epidermal Growth Factor Receptor-Induced Signal Transduction and the Preventive Effect of Celecoxib in Gastric Cancer Cells

Background/Aims

Helicobacter pylori infection induces cyclooxygenase-2 (COX-2) and epidermal growth factor receptor (EGFR) overexpression, and these factors may engage in cross-talk. The aim of the present study was to evaluate the effect of H. pylori on EGFR signaling pathways and to determine whether celecoxib has an inhibitory effect on this pathway.

Methods

The AGS cell line was cocultured with H. pylori G27 and the isogenic cagE- mutant. The expression of COX-2, EGFR, heparin binding-epidermal growth factor (HB-EGF), and transforming growth factor-β (TGF-β) was measured by real time-polymerase chain reaction (RT-PCR). Next, Western blot analyses of COX-2, EGFR, total Akt, phosphorylated Akt (pAkt), and phosphorylated glycogen synthase kinase-3β (pGSK3β) were performed after incubating H. pylori-treated AGS cells for 24 hours with various concentrations of celecoxib (0, 10, 20, and 30 µmol/L).

Results

H. pylori infection upregulated the mRNA levels of COX-2, EGFR, HB-EGF, and TGF-β, as detected by RT-PCR. However, AGS cells treated with cagE- mutants, which have a defective type IV secretion system, did not exhibit EGFR upregulation. Celecoxib had inhibitory effects on the H. pylori-induced overexpression of COX-2 (p=0.015), EGFR (p=0.025), pAkt (p=0.025), and pGSK3β (p=0.029) by Western blot analysis.

Conclusions

H. pylori with an intact type IV secretion system activated the COX-2 and EGFR-Akt pathways in the AGS cell line. As celecoxib exhibited inhibitory effects on the EGFR signaling pathway, the cross-talk of COX-2 and EGFR likely mediates H. pylori-induced gastric cancer.

Eradication of gastric cancer is now both possible and practical

In 1994, Helicobacter pylori was declared a human carcinogen. Evidence has now accumulated to show that at least 95% of gastric cancers are etiologically related to H. pylori. An extensive literature regarding atrophic gastritis and its effects on acid secretion, gastric microflora, and its tight association with gastric cancer has been rediscovered, confirmed, and expanded. Methods to stratify cancer risk based on endoscopic and histologic findings or serologic testing of pepsinogen levels and H. pylori testing have been developed producing practical primary and secondary gastric cancer prevention strategies. H. pylori eradication halts progressive mucosal damage. Cure of the infection in those with non-atrophic gastritis will essentially prevent subsequent development of gastric cancer. For all, the age-related progression in cancer risk is halted and likely reduced as eradication reduces or eliminates mucosal inflammation and reverses or reduces H. pylori-associated molecular events such aberrant activation-induced cytidine deaminase expression, double strand DNA breaks, impaired DNA mismatch repair and aberrant DNA methylation. Those who have developed atrophic gastritis/gastric atrophy however retain some residual risk for gastric cancer which is proportional to the extent and severity of atrophic gastritis. Primary and secondary cancer prevention starts with H. pylori eradication and cancer risk stratification to identify those at higher risk who should also be considered for secondary cancer prevention programs. Japan has embarked on population-wide H. pylori eradication coupled with surveillance targeted to those with significant remaining risk. We anticipate that countries with high gastric cancer burdens will follow their lead. We provide specific recommendations on instituting practical primary and secondary gastric cancer prevention programs as well identifying research needed to make elimination of gastric cancer both efficient and cost effective.

Expression of orphan nuclear receptor NR4A2 in gastric cancer cells confers chemoresistance and predicts an unfavorable postoperative survival of gastric cancer patients with chemotherapy

BACKGROUND

NR4A2, an orphan nuclear receptor essential in the generation of dopaminergic neurons, has been recently linked to inflammation and cancer. This study sought to identify the role of NR4A2 on chemoresistance and postoperative prognosis of gastric cancer (GC).

METHODS

NR4A2 was transfected into GC cells to investigate its effects on chemoresistance to 5-fluorouracil and the tumorigenicity in nude mice. This study also investigated prostaglandin E2 (PGE2 )-induced NR4A2 expression and its effect on chemoresistance. Surgical specimens from patients with stage I through III GC were examined immunohistochemically for NR4A2 expression. Median follow-up time was 76 months for 245 patients.

RESULTS

Ectopic expression of NR4A2 significantly increased the chemoresistance and attenuated 5-fluorouracil-induced apoptosis. Transient treatment of GC cells with PGE2 significantly upregulated NR4A2 expression via the protein kinase A pathway and increased the chemoresistance. Ectopic expression of NR4A2 significantly increased the tumorigenicity. In clinical samples, NR4A2 was preferentially expressed in lymphocytes and epithelial cytoplasm in adjacent mucosa. High expression of NR4A2 (immunoreactive score ≥ 3) in cancer cells significantly predicted an unfavorable postoperative disease-specific survival of patients with stage I to III GC (P = .011), especially for those who received 5-fluorouracil-based chemotherapy (P = .016). This effect was not found in those without the chemotherapy. In multivariate Cox analyses, age, TNM (tumor/node/metastasis) stage, and high NR4A2 expression significantly predicted an unfavorable postoperative survival.

CONCLUSIONS

High NR4A2 expression in GC cells confers chemoresistance, attenuates 5-fluorouracil-induced apoptosis, and predicts an unfavorable survival, especially for those who received chemotherapy. NR4A2 might serve as a prognostic and predictive factor and therapeutic target for patients with GC. Cancer 2013;119:3436-3445.. © 2013 American Cancer Society.

Gastric cancer chemoprevention: the current evidence

Chemoprevention may form the cornerstone in the management of gastric adenocarcinoma of the future. Helicobacter pylori eradication and aspirin and/or nonsteroidal anti-inflammatory drug therapy have emerged as front-runner chemotherapeutic agents due to the putative pathogenic mechanisms that they address. Before a population-based chemopreventive strategy can be recommended on a large scale, randomized controlled trials with follow-up of more than 10 years of these 2 agents in populations at high gastric adenocarcinoma risk is urgently awaited.

Positive association between Toll-like receptor 4 gene +896A/G polymorphism and susceptibility to gastric carcinogenesis: a meta-analysis

Several studies have investigated the association between the Toll-like receptor 4 (TLR4) gene +896A/G polymorphism and gastric carcinogenesis, including gastric cancer and precancerous gastric lesions. However, published results are inconsistent. So, we performed a meta-analysis to assess whether the TLR4 +896A/G single-nucleotide polymorphism (SNP) is a risk factor in gastric cancer development. We searched PubMed and Embase databases for studies that reported the odds ratio (OR) and 95 % confidence interval (CI) for the association between the TLR4 +896A/G SNP and the risk of gastric cancer and/or precancerous lesions with the last update of November 2012. Data were analyzed using Review Manager (Version 5.1), and publication bias was estimated. We included 10 study populations, comprising 2,233 cases and 2,849 controls from 8 publications. The pooled OR was 2.00 (95 % CI = 1.59-2.53) for the G allelic model. Analysis stratified by different stages and anatomic sites of neoplasia resulted in a significantly increased risk associated with gastric cancer (OR = 1.87, 95 % CI = 1.44-2.44), especially the non-cardia subtype (OR = 2.03, 95 % CI = 1.51-2.72). Besides, the G allele emerged as a strong risk factor for precancerous gastric lesions (OR = 2.47, 95 % CI = 1.57-3.88). A subsequent subgroup analysis by Helicobacter pylori-positive ratio in cases (>80 %) indicated an enhancement in the association with precancerous lesions (OR = 3.43, 95 % CI = 1.92-6.13). The TLR4 +896A/G SNP is a risk factor in gastric carcinogenesis, especially in H. pylori-infected patients with precancerous lesions.

Inhibition of 15-hydroxyprostaglandin dehydrogenase by Helicobacter pylori in human gastric carcinogenesis

Helicobacter pylori (H. pylori) infection induces a chronic inflammatory response, which promotes gastric carcinogenesis. 15-Hydroxyprostaglandin dehydrogenase (15-PGDH) plays a key role as a tumor suppressor in gastrointestinal cancers. The aim of this study was to elucidate the role of 15-PGDH in gastric carcinogenesis associated with H. pylori. 15-PGDH expression in gastric biopsies from H. pylori-infected (n = 25) and noninfected (n = 15) subjects was analyzed by quantitative real-time PCR, Western blot analysis, and immunohistochemistry. 15-PGDH DNA methylation was evaluated by methylation-specific PCR and pyrosequencing. The expression of 15-PGDH, Snail, extracellular signal-regulated kinase (ERK)1/2, TLR4, and MyD88 in response to H. pylori infection was assessed by immunoblot analysis. Compared with negative specimens, H. pylori-positive specimens had 2-fold lower 15-PGDH mRNA levels and significantly less 15-PGDH protein. In four H. pylori-infected subjects with longitudinal follow-up, the suppression of 15-PGDH expression was reversed by H. pylori eradication therapy. In parallel with suppressing 15-PGDH expression, H. pylori infection activated expression of TLR4 and MyD88 expression, increased levels of phospho-ERK1/2, and increased expression of EGF receptor (EGFR)-Snail. Inhibition of Snail and MyD88 reversed suppression of 15-PGDH expression, and siMyD88 reduced phosphorylated ERK1/2. Similarly, treatment with an ERK1/2 and EGFR inhibitor also restored 15-PGDH expression. H. pylori appeared to promote gastric carcinogenesis by suppressing 15-PGDH. This process is mediated by the TLR4/MyD88 pathway via ERK1/2 or EGFR-Snail transcriptional regulation. 15-PGDH may be a useful marker and a potential therapeutic target in H. pylori-induced gastric carcinogenesis.