Increased risk of noncardia gastric cancer associated with proinflammatory cytokine gene polymorphisms

Helicobacter pylori vacA Genotypes in Chronic Gastritis and Gastric Carcinoma Patients from Macau, China

Helicobacter pylori is the major triggering factor for gastric carcinoma, but only a small proportion of infected patients develop this disease. Differences in virulence observed among H. pylori strains, namely in the vacuolating cytotoxin vacA gene, may contribute to this discrepancy. Infection with vacA s1, i1 and m1 strains increases the risk for progression of gastric premalignant lesions and for gastric carcinoma. However, in East Asian countries most of the H. pylori strains are vacA s1, regardless of the patients’ clinical status, and the significance of the vacA i1 and m1 genotypes for gastric carcinoma in this geographic area remains to be fully elucidated. The aim of the present study was to investigate this relationship in 290 patients from Macau, China. Using very sensitive and accurate genotyping methods, we detected infection with vacA i1 and with vacA m1 strains in, respectively, 85.2% and 52.6% of the patients that were infected with single genotypes. The prevalence of cagA-positive strains was 87.5%. No significant associations were observed between vacA genotypes or cagA and gastric carcinoma. It is worth noting that 37.5% of the infected patients had coexistence of H. pylori strains with different vacA genotypes. Additional studies directed to other H. pylori virulence factors should be performed to identify high risk patients in East Asia.

Local Immune Response in Helicobacter pylori Infection

There have been few studies concerning the cytokine profiles in gastric mucosa of Helicobacter pylori-infected patients with normal mucosa, chronic gastritis, and gastric carcinoma (GAC).In the present study, we aimed to elucidate the genomic expression levels and immune pathological roles of cytokines-interferon (IFN)-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-4, IL-6, IL-10, transforming growth factor (TGF)-β, IL-17A, IL-32-in H pylori-infected patients with normal gastric mucosa (NGM; control), chronic active gastritis (CAG), and GAC. Genomic expression levels of these cytokines were assayed by real-time PCR analysis in gastric biopsy specimens obtained from 93 patients.We found that the genomic expression levels of IFN-γ, TNF-α, IL-6, IL-10, IL-17A mRNA were increased in the CAG group and those of TNF-α, IL-6, IL-10, IL-17A, TGF-β mRNA were increased in the GAC group with reference to H pylori-infected NGM group.This study is on the interest of cytokine profiles in gastric mucosa among individuals with normal, gastritis, or GAC. Our findings suggest that the immune response of gastric mucosa to infection of H pylori differs from patient to patient. For individual therapy, levels of genomic expression of IL-6 or other cytokines may be tracked in patients.

Oesophageal adenocarcinoma and gastric cancer: should we mind the gap?

Over recent decades we have witnessed a shift in the anatomical distribution of gastric cancer (GC), which increasingly originates from the proximal stomach near the junction with the oesophagus. In parallel, there has been a dramatic rise in the incidence of oesophageal adenocarcinoma (OAC) in the lower oesophagus, which is associated with antecedent Barrett oesophagus (BO). In this context, there has been uncertainty regarding the characterization of adenocarcinomas spanning the area from the lower oesophagus to the distal stomach. Most relevant to this discussion is the distinction, if any, between OAC and intestinal-type GC of the proximal stomach. It is therefore timely to review our current understanding of OAC and intestinal-type GC, integrating advances from cell-of-origin studies and comprehensive genomic alteration analyses, ultimately enabling better insight into the relationship between these two cancers.

Genetic association between interluekin-4 rs2243250 polymorphism and gastric cancer susceptibility: evidence based on a meta-analysis

Purpose

Numerous studies have suggested that the interleukin-4 (IL-4) rs2243250 polymorphism is associated with gastric cancer susceptibility. However, the results were inconsistent. Hence, we carried out a meta-analysis to confirm the conclusion.

Methods

We searched PubMed, Embase, CBM, CNKI, and Wanfang Data to identify relevant studies up to August 20, 2015. Odds ratio (OR) and 95% confidence interval (CI) were used to estimate the association between IL-4 rs2243250 polymorphism and gastric cancer susceptibility. All the statistical analyses were performed with Stata 12.0 software.

Results

A total of eleven published case–control studies were identified, including 2,247 gastric cancer patients and 3,370 controls. Overall, no significant association between IL-4 rs2243250 polymorphism and gastric cancer susceptibility was observed in this meta-analysis (T vs C: OR =1.05, 95% CI =0.95–1.17; TT vs CC: OR =1.20, 95% CI =0.89–1.63; CT vs CC: OR =1.14, 95% CI =0.87–1.48; TT + CT vs CC: OR =1.13, 95% CI =0.89–1.44; TT vs CT + CC: OR =1.02, 95% CI =0.88–1.20). Similar results were found in subgroup analyses according to ethnicity and Hardy–Weinberg equilibrium in controls.

Conclusion

This meta-analysis suggests that IL-4 rs2243250 polymorphism may not be associated with gastric cancer susceptibility. Further studies are needed to validate this conclusion.

The Protective Effects of 18β-Glycyrrhetinic Acid on Helicobacter pylori-Infected Gastric Mucosa in Mongolian Gerbils

18β-Glycyrrhetinic acid (GRA), a major component of Glycyrrhiza glabra, is widely used therapeutically in clinic. In this study, the effect of GRA on Helicobacter pylori- (H. pylori-) infected gastritis was investigated in Mongolian gerbils in vivo. The gerbils were randomly divided into groups: uninfected; H. pylori-infected; H. pylori + antibiotics (clarithromycin, amoxicillin, and esomeprazole); and H. pylori + GRA. The gastric intraluminal pH value, histopathological changes, and the expression levels of inflammation-related cytokines (IL-1β, TNF-α, COX-2, and iNOS) were investigated. The results showed that, in the H. pylori + GRA group, the intraluminal gastric pH value was lower (2.14 ± 0.08 versus 3.17 ± 0.23, P < 0.05), erosion and hyperplasia were alleviated, the infiltration of neutrophils and mononuclear cells was attenuated (P < 0.05), and the expression levels of TNF-α, IL-1β, COX-2, and iNOS were decreased (P < 0.05) compared with the H. pylori-infected group. There was no significant difference in results between the H. pylori + GRA group and the H. pylori + antibiotics group. This study indicated that GRA significantly attenuated H. pylori-infected gastritis in gerbils and has the potential to be developed as a new therapeutic drug.

Role of Helicobacter pylori in gastric cancer: Updates

Helicobacter pylori (H. pylori) infection is highly prevalent in human, affecting nearly half of the world’s population; however, infection remains asymptomatic in majority of population. During its co-existence with humans, H. pylori has evolved various strategies to maintain a mild gastritis and limit the immune response of host. On the other side, presence of H. pylori is also associated with increased risk for the development of various gastric pathologies including gastric cancer (GC). A complex combination of host genetics, environmental agents, and bacterial virulence factors are considered to determine the susceptibility as well as the severity of outcome in a subset of individuals. GC is one of the most common cancers and considered as the third most common cause of cancer related death worldwide. Many studies had proved H. pylori as an important risk factor in the development of non-cardia GC. Although both H. pylori infection and GC are showing decreasing trends in the developed world, they still remain a major threat to human population in the developing countries. The current review attempts to highlight recent progress in the field of research on H. pylori induced GC and aims to provide brief insight into H. pylori pathogenesis, the role of major virulence factors of H. pylori that modulates the host environment and transform the normal gastric epithelium to neoplastic one. This review also emphasizes on the mechanistic understanding of how colonization and various virulence attributes of H. pylori as well as the host innate and adaptive immune responses modulate the diverse signaling pathways that leads to different disease outcomes including GC.

A Causal Role of Genetically Elevated Circulating Interleukin-10 in the Development of Digestive Cancers: Evidence from Mendelian Randomization Analysis Based on 29,307 Subjects

Recent studies have observed a high level of circulating interleukin-10 (IL-10) in patients with digestive cancers, yet whether elevated IL-10 is causally associated with digestive cancers so far remained unresolved. We therefore meta-analyzed available observational studies with Mendelian randomization method to explore this causal association by employing IL-10 gene 3 variants (-592C>A, -819C>T, and -1082A>G) as instruments. Data were available from 52 articles encompassing 29,307 subjects. Subgroup analysis by cancer type indicated that -1082A>G was associated with increased risk of gastric cancer (odds ratio [OR] = 1.19; 95% confidence interval [CI]: 1.05-1.35; P = 0.006), and the association was reinforced for intestinal type gastric cancer (OR = 1.26; 95%CI: 1.09-1.44; P = 0.001). By ethnicity, risk estimate for -1082G allele carriers was increased by 21% for digestive cancers in East Asians (95%CI: 1.05-1.40; P = 0.009). As for the genotype-phenotype association, carriers of -1082G allele had an overall 20.21 pg/mL higher IL-10 level than those with -1082AA genotype (P = 0.023). In further Mendelian randomization analysis, the predicted OR for 10 pg/mL increment in IL-10 was 1.14 (95%CI: 1.01-16.99) in gastric cancer. Our findings provided evidence for a causal role of genetically elevated IL-10 in the development of gastric cancer, especially in East Asians and for intestinal type gastric cancer.

Immunotherapy in upper GI malignancies

OPINION STATEMENT

A comprehensive analysis of the interactions that can occur amongst three complex systems-the tumor cell, tissue microenvironment, and the immune response, is required if we are to realize the potential of immunotherapeutics in gastroesophageal cancer. For many years, epithelial cancers were believed to originate due to the transformation of tissue stem cells. Recently however, it has suggested that bone marrow-derived cells (BMDCs), which are frequently recruited to sites of tissue injury and inflammation, might also represent a potential source of malignancy. The link between infection, chronic inflammation, and cancer has long been recognized in gastric cancer with its close association with Helicobacter pylori as a class I carcinogen. The long-term consequences of recruiting pluripotent cells to areas of chronic inflammation which can result in altered cell signaling and differentiation needs to be defined, but this work provides a fascinating insight into the pivotal role played by the immune system in the development of upper GI tumors. Here, we discuss many of the immunotherapeutic strategies that have been assessed in gastroesophageal cancer in the last two decades. At the time of writing, the use of checkpoint inhibitors represents the most exciting approach and displays the greatest potential for widespread adoption in the clinic. Preliminary data suggest that programmed death ligand-1 (PD-L1) expression ranges from approximately 18 to 42% in gastroesophageal cancer. Phase II and phase III clinical trials involving either single agent PD-1/PD-L1 inhibition or combined with CTLA-4 inhibitors are currently enrolling, and it is expected that checkpoint inhibition will become a new standard of care in the management of advanced disease in the near future.

Helicobacter pylori Diversity and Gastric Cancer Risk

Gastric cancer is a leading cause of cancer-related death worldwide. Helicobacter pylori infection is the strongest known risk factor for this malignancy. An important goal is to identify H. pylori-infected persons at high risk for gastric cancer, so that these individuals can be targeted for therapeutic intervention. H. pylori exhibits a high level of intraspecies genetic diversity, and over the past two decades, many studies have endeavored to identify strain-specific features of H. pylori that are linked to development of gastric cancer. One of the most prominent differences among H. pylori strains is the presence or absence of a 40-kb chromosomal region known as the cag pathogenicity island (PAI). Current evidence suggests that the risk of gastric cancer is very low among persons harboring H. pylori strains that lack the cag PAI. Among persons harboring strains that contain the cag PAI, the risk of gastric cancer is shaped by a complex interplay among multiple strain-specific bacterial factors as well as host factors. This review discusses the strain-specific properties of H. pylori that correlate with increased gastric cancer risk, focusing in particular on secreted proteins and surface-exposed proteins, and describes evidence from cell culture and animal models linking these factors to gastric cancer pathogenesis. Strain-specific features of H. pylori that may account for geographic variation in gastric cancer incidence are also discussed.

New Biology to New Treatment of Helicobacter pylori-Induced Gastric Cancer

BACKGROUND

Helicobacter pylori is a bacterial carcinogen that is supposed to have the highest known level of risk for the development of gastric cancer, a disease that claims hundreds of thousands of lives per year. Approximately 89% of the global gastric cancer burden and 5.5% of malignancies worldwide are attributed to H. pylori-induced inflammation and injury. However, only a fraction of colonized persons ever develop neoplasia, and disease risk involves well-choreographed interactions between pathogen and host, which are dependent upon strain-specific bacterial factors, host genotypic traits, and/or environmental conditions.

KEY MESSAGES

One H. pylori strain-specific virulence determinant that augments the risk for gastric cancer is the cag pathogenicity island, a secretion system that injects the bacterial oncoprotein CagA into host cells. Host polymorphisms within genes that regulate immunity and oncogenesis also heighten the risk for gastric cancer, in conjunction with H. pylori strain-specific constituents. Further, conditions such as iron deficiency and high salt intake can influence H. pylori phenotypes that lower the threshold for disease.

CONCLUSIONS

Delineation of bacterial, host, and environmental mediators that augment gastric cancer risk has profound ramifications for both physicians and biomedical researchers as such findings will not only focus prevention approaches that target H. pylori-infected human populations at increased risk for stomach cancer, but will also provide mechanistic insights into inflammatory carcinomas that develop beyond the gastric niche.

Pathobiology of Helicobacter pylori-Induced Gastric Cancer

Colonization of the human stomach by Helicobacter pylori and its role in causing gastric cancer is one of the richest examples of a complex relationship among human cells, microbes, and their environment. It is also a puzzle of enormous medical importance given the incidence and lethality of gastric cancer worldwide. We review recent findings that have changed how we view these relationships and affected the direction of gastric cancer research. For example, recent data have indicated that subtle mismatches between host and microbe genetic traits greatly affect the risk of gastric cancer. The ability of H pylori and its oncoprotein CagA to reprogram epithelial cells and activate properties of stemness show the sophisticated relationship between H pylori and progenitor cells in the gastric mucosa. The observation that cell-associated H pylori can colonize the gastric glands and directly affect precursor and stem cells supports these observations. The ability to mimic these interactions in human gastric organoid cultures as well as animal models will allow investigators to more fully unravel the extent of H pylori control on the renewing gastric epithelium. Finally, our realization that external environmental factors, such as dietary components and essential micronutrients, as well as the gastrointestinal microbiota, can change the balance between H pylori's activity as a commensal or a pathogen has provided direction to studies aimed at defining the full carcinogenic potential of this organism.

Interleukin-1B signalling leads to increased survival of gastric carcinoma cells through a CREB-C/EBPβ-associated mechanism

BACKGROUND

Polymorphisms in inflammation-related genes have been associated with a risk of gastric carcinoma (GC). However, the biological mechanisms underlying these associations are still elusive. Our objective was to determine whether chronic inflammation-associated IL1Β signalling, as seen in the context of Helicobacter pylori infection, could be linked to gastric carcinogenesis by modulating the behaviour of gastric epithelial cells.

METHODS

The effect of IL1B was assessed by studying the expression and activation status of the IL1Β-activated transcription factors C/EBPβ and CREB in GC cell lines. Interaction between CREB and C/EBPβ was explored through interference RNA, chromatin immunoprecipitation and chemical inhibition. CREB and C/EBPβ expression was analysed in 66 samples of primary GC and in normal gastric mucosa. GC cell growth was analysed in vitro by BrdU incorporation and in vivo employing a chicken embryo chorioallantoic membrane model.

RESULTS

We found that IL1B regulates the expression/activation status of both C/EBPβ and CREB in GC cells through an ERK1/2-dependent mechanism. Our results show that CREB is a direct transactivator of CEBPB, acting as an upstream effector in this regulatory mechanism. Furthermore, we found CREB to be overexpressed in 94 % of GC samples and significantly associated with C/EBPβ expression (P < 0.05). Finally, we demonstrated both in vitro and in vivo that CREB can mediate IL1B-induced GC cell proliferation.

CONCLUSIONS

Our results support the hypothesis that the effect of chronic inflammation on gastric carcinogenesis, as seen in the context of genetically susceptible individuals infected with Helicobacter pylori, includes the modulation of signalling pathways that regulate survival mechanisms in epithelial cells. IL1B is able to increase the expression/activation status of CREB and its target gene C/EBPβ, which are mandatory for GC cell survival. Our results may help inform new strategies for the prevention and treatment of GC, including the control of chronic inflammation.

Helicobacter pylori Infection Synergistic with IL-1β Gene Polymorphisms Potentially Contributes to the Carcinogenesis of Gastric Cancer

Helicobacter pylori (H. pylori) infection is the most common chronic bacterial infection in the world and the etiological agent for most gastric cancer (GC). Interleukin-1β (IL-1β) is a potent proinflammatory cytokine, and its deregulation is closely associated with the tumorigenesis of several cancers. Recent studies have revealed that the IL-1β-31 and -511T alleles are closely associated with gastric carcinogenesis due to their roles in the induction of gastric precancerous lesions and hypochlorhydria. Furthermore, H. pylori infection has a synergistic effect on the development of GC with IL-1β gene polymorphisms, and the highest prevalence of severe gastric abnormalities are found in patients with both host and bacterial high-risk genotypes (cagA(+)/vacAs1(+)/IL-1β-511T). Therefore, these recent advances demonstrate that H. pylori synergistic with IL-1β gene polymorphisms contribute to the gastric carcinogenesis by their involvement in precancerous gastric lesions and low gastric acid secretion.

Lack of association among TNF-α gene expression, -308 polymorphism (G > A) and virulence markers of Helicobacter pylori

Background

Tumor necrosis factor plays a critical role in the pathogenesis of gastric diseases such as gastric cancer, and an abnormal inflammatory response has frequently been observed in dyspeptic patients. Helicobacter pylori infection can induce a gastric mucosal inflammatory response that may be influenced by -308 (G > A) polymorphisms and gene expression of the TNF-α gene.

Methods

One hundred and thirty-four gastric biopsy samples were collected from patients of both genders (61♂ and 73♀, mean age 40.3 ± 24.2 years) with gastric symptoms. The -308 (G > A) polymorphism of TNF-α was characterized using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). The expression level was measured using real-time PCR, and relative quantification (RQ) was calculated using the comparative CT method (2^-ΔΔCT).

Results

The analysis revealed an increase in TNF-α gene expression in patients with gastritis; on the other hand, no statistical differences were observed in patients with gastric cancer. In addition, no association was found among -308 polymorphism genotypes, virulence markers, or TNF-α gene expression.

Conclusions

Helicobacter pylori induces a large increase in TNF-α expression in patients with gastritis, regardless of tissue inflammation, but after the tissue becomes neoplastic, the presence of bacteria did not influence expression. These results suggest that the TNF-α pathway may play an important role in the progression from gastritis to gastric cancer

Mannose-binding lectin protein and its association to clinical outcomes in COPD: a longitudinal study

BACKGROUND

Functional deficiency of mannose-binding lectin (MBL) may contribute to the pathogenesis of chronic obstructive pulmonary disease. We hypothesized that specific MBL2 gene polymorphisms and circulating MBL protein levels are associated with clinically relevant outcomes in the Predicting Outcome using systemic Markers In Severe Exacerbations of COPD PROMISE-COPD cohort.

METHODS

We followed 277 patients with stable COPD GOLD stage II-IV COPD over a median period of 733 days (IQR 641-767) taking survival as the primary outcome parameter. Patients were dichotomized as frequent (≥ 2 AECOPD/year) or infrequent exacerbators. Serum MBL levels and single nucleotide polymorphisms of the MBL2 gene were assessed at baseline.

RESULTS

The MBL2-HYPD haplotype was significantly more prevalent in frequent exacerbators (OR: 3.33; 95% CI, 1.24-7.14, p = 0.01). The median serum MBL concentration was similar in frequent (607 ng/ml, [IQR; 363.0-896.0 ng/ml]) and infrequent exacerbators (615 ng/ml, [IQR; 371.0-942.0 ng/ml]). Serum MBL was not associated with lung function characteristics or bacterial colonization in sputum. However, high serum MBL at stable state was associated with better survival compared to low MBL (p = 0.046, log rank test).

CONCLUSIONS

In COPD, the HYPD haplotype of MBL2 gene is associated with frequent exacerbations and high serum MBL is linked to increased survival. The PROMISE-COPD study was registered at www.controlled-trials.com under the identifier ISRCTN99586989.

Safety of proton pump inhibitors and risk of gastric cancers: review of literature and pathophysiological mechanisms

INTRODUCTION

Despite being an overall safe drug, several long-term adverse effects are associated with proton pump inhibitors (PPIs). The link between PPI use and gastric neuroendocrine tumors (NETs), gastric adenocarcinomas and Barrett's esophagus progression gastric cancers has been investigated due to PPI-induced hypergastrinemia.

AREAS COVERED

The pathophysiological mechanisms underlying PPI exposure and gastric NETs, gastric adenocarcinomas and Barrett's esophagus progression are discussed. The quality of randomized control studies, cohort studies and case reports investigating the link between gastric cancers and PPIs are examined. Recommendations for clinicians are provided.

EXPERT OPINION

PPIs cause a hypergastrinemic state, increasing enterochromaffin-like cell dysplasia and risk of gastric NET development, increasing gastritis severity in the context of Helicobacter pylori infection, and progression of carcinogenesis in a certain predisposed subset of Barrett's esophagus patients. There are case reports of PPI-induced gastric NETs and adenocarcinomas as consequences of these effects. In pernicious anemia and chronic gastritis, clinicians should be aware of potential increased risk of gastric NET development with chronic PPI use in these patients. Eradication status of H. pylori prior to commencing long-term PPI therapy should be established to reduce the risk of severe atrophic gastritis and development of gastric dysplasia.

IL-1β polymorphism and expression associated with decreased risk of gastric carcinoma: a case control study in the ethnic Kashmiri population, India

The aim of this research was to investigate the possible association between gastric carcinoma (GC) and polymorphisms of the IL-1β gene in the Kashmiri population using peripheral blood DNA from 150 gastric carcinoma cases and 250 population controls with detailed data for clinicopathological characteristics of the disease. Two SNPs in the IL-1β gene were selected for this study. Expression of IL-1β was studied in 50 gastric carcinoma cases using immunohistochemistry and RT-PCR and then correlated with genotype. The frequency of the IL-1β-511 C allele was significantly higher in the GC case group (53.3%) than in controls (45.4%) with an odds ratio (OR) of 0.73 and a P value of 0.03. Multivariate regression analysis showed associations of gastric carcinoma with mutant form of IL-1β-511 TT (OR 0.309; P value <0.001) and the CC genotype of IL-1β-31 (OR 0.313; P value of 0.002). Haplotype analysis of IL-1β-31 and IL-1β-511 showed decreased association of IL- 1β-31 T with IL-1β-511 C with gastric carcinoma (OR 0.728; P value 0.03). Expression study of 50 samples by immunohistochemistry (IHC) and RT-PCR showed association with grade III and stage III+IV. After correlating the expression with polymorphism no association was found.

Helicobacter pylori vs immune system or antibiotics

Helicobacter pylori (H. pylori) infection has often no clinical signs and is one of the most common bacterial infections. All infected subjects have histology of active chronic gastritis. In some cases patients develop peptic ulcer and minority of them develop gastric cancer. Gastric cancer is multifactorial disease, thus various progressions of H. pylori infection and disease are dependent on the host genetic factors, the characteristics of the individual’s immune response, environmental factors, and different bacterial virulence factors of the individual bacterial strains. Eradication of the bacteria plays a crucial role in the treatment of these cases however antibiotic therapy does not always help. Bacteria often develop resistance to antibiotics so we recommend that not only screening for H. pylori also the strain determination should have some diagnostic value, especially in the patients who already developed gastritis. Furthermore, for such patients assessment of disease progression (atrophic or metaplastic gastritis) could be followed by polymorphism determination. Until now we cannot predict the disease based only on single polymorphism. Bacteria successfully neutralize the responses of the immune systems using different enzymes or even components of the host immune response. However, the influence of immune system and its components could represent new ways of treatments and could help to eradicate the infection.

STAT3: a critical component in the response to Helicobacter pylori infection

STAT3 imparts a profound influence on both the epithelial and immune components of the gastric mucosa, and through regulation of key intracellular signal transduction events, is well placed to control inflammatory and oncogenic outcomes in the context of Helicobacter (H.) pylori infection. Here we review the roles of STAT3 in the host immune response to H. pylori infection, from both gastric mucosal and systemic perspectives, as well as alluding more specifically to STAT3-dependent mechanisms that might be exploited as drug targets.

Polymorphisms of Tumor Necrosis Factor Alpha in Moroccan Patients with Gastric Pathology: New Single-Nucleotide Polymorphisms in TNF-α(-193) (G/A)

Polymorphisms in tumor necrosis factor alpha (TNF-α) gene are emerging as key determinants of gastric diseases. The TNF-α⁻³⁰⁸ (G/A) and TNF-α⁻²³⁸ (G/A) single-nucleotide polymorphisms SNPs are the most extensively studied. However, all these studies are conducted in Caucasian and Asian populations. Thus, for the first time in Africa, we sought to investigate whether polymorphisms in TNF-α gene were associated with the development of gastric pathology in Morocco. Two SNPs located in the promoter region (positions −308 and −238) in TNF-α gene were genotyped in 244 individuals (170 patients and 74 healthy controls). Odds ratios (ORs) and 95% confidence intervals (CI) were estimated using logistic regression analysis. The TNF-α⁻²³⁸ (G/A) genotype was significantly associated with a high risk of gastritis and gastric cancer (GC) (P = 0.001 and P = 0.002, resp.). Furthermore, a new polymorphism located in the promoter region at position −193 in TNF-α gene was identified. The distribution of this SNP was markedly different in patients suffering from ulcers. The association between TNF-α⁻¹⁹³ (G/A) genotype and high risk of ulcer was significant (P = 0.03). These results suggest that the TNF-α⁻¹⁹³ (G/A) allele has a protective function against gastric cancer by developing ulcer.

Genetics and Molecular Pathogenesis of Gastric Adenocarcinoma

Gastric cancer (GC) is globally the fifth most common cancer and third leading cause of cancer death. A complex disease arising from the interaction of environmental and host-associated factors, key contributors to GC's high mortality include its silent nature, late clinical presentation, and underlying biological and genetic heterogeneity. Achieving a detailed molecular understanding of the various genomic aberrations associated with GC will be critical to improving patient outcomes. The recent years has seen considerable progress in deciphering the genomic landscape of GC, identifying new molecular components such as ARID1A and RHOA, cellular pathways, and tissue populations associated with gastric malignancy and progression. The Cancer Genome Atlas (TCGA) project is a landmark in the molecular characterization of GC. Key challenges for the future will involve the translation of these molecular findings to clinical utility, by enabling novel strategies for early GC detection, and precision therapies for individual GC patients.

Case–control study of Epstein–Barr virus and Helicobacter pylori serology in Latin American patients with gastric disease

Background:

Chronic tissue damage induced by Helicobacter pylori (HP)-driven inflammation is considered the main risk of gastric carcinoma (GC). Epstein–Barr virus (EBV) infection has also been associated with GC. In this study, we aim to address the role of EBV in inflammatory GC precursor lesions and its added risk to HP infection.

Methods:

Antibodies against EBV, HP and the bacterial virulence factor CagA were measured in sera from 525 Mexican and Paraguayan patients with gastric disease. Gastric samples were characterised according to the updated Sydney classification and associations were estimated between antibody responses and severity of both tissue damage and inflammation.

Results:

We found significant associations (odd ratios and trends) between EBV and HP copositivity and premalignant lesions and intestinal-type GC. The EBV and HP coinfection was also significantly associated with increased infiltration of immune cells. No association was found between EBV and the less inflammation-driven diffuse-type GC.

Conclusions:

Our study suggests that EBV co-participates with HP to induce severe inflammation, increasing the risk of progression to intestinal-type GC.

Hereditary diffuse gastric cancer--An overview

The incidence of gastric cancer varies by up to ten fold throughout the world, and the geographic distribution of hereditary cases is not well explored. Familial clustering is seen in 10% of cases, and approximately 3% of all gastric cancers develop due to hereditary diffuse gastric cancer (HDGC). In this review, the characteristics of HDGC are presented according to molecular particularities, geographic distribution, and other parameters. Based on our experience and the data from the literature, we discuss the possibility of applying a mutation signature (spectrum) study and adductomic approaches to a comparative carcinogenesis of HDGC. We also provide a comprehensive, up-to-date review of genetic counseling and criteria for screening and surveillance of eligible families.

Molecular Pathogenesis of Helicobacter pylori-Related Gastric Cancer

Helicobacter pylori infection plays a crucial role in gastric carcinogenesis. H pylori exerts oncogenic effects on gastric mucosa through complex interaction between bacterial virulence factors and host inflammatory responses. On the other hand, gastric cancer develops via stepwise accumulation of genetic and epigenetic alterations in H pylori-infected gastric mucosa. Recent comprehensive analyses of gastric cancer genomes indicate a multistep process of genetic alterations as well as possible molecular mechanisms of gastric carcinogenesis. Both genetic processes of gastric cancer development and molecular oncogenic pathways related to H pylori infection are important to completely understand the pathogenesis of H pylori-related gastric cancer.

Association between pro-(IL-8) and anti-inflammatory (IL-10) cytokine variants and their serum levels and H. pylori-related gastric carcinogenesis in northern India

BACKGROUND

Interleukin (IL)-8 -251 T/A and IL-10 (-1082 G/A and -819/592 C/T) polymorphisms and their expression may influence gastritis, atrophy, intestinal metaplasia (IM) and gastric cancer (GC) following H. pylori infection.

METHODS

Genotyping of these genes was performed (ASO-PCR) in 200, 182 and 250 with GC, functional dyspepsia (FD) and healthy controls (HC), respectively. Anti-H. pylori IgG-antibody was tested in all and serums IL-8 and IL-10 were measured randomly in 60 subjects of each group by ELISA.

RESULTS

Pro-(IL-8)-251 AA and anti-inflammatory (IL-10)-819 TT genotypes were commoner among GC than HC (p = 0.023, OR 1.86 [1.09-3.2] and p = 0.020, OR 2.0 [1.11-3.5]) but comparable with FD. IL-8 AA and IL-10-819 T allele carriage was also commoner in H. pylori-infected GC than HC (p = 0.011, OR 2.47 [1.23-5.0], and p = 0.018, OR 2.3 (1.16-4.59). IL-10-1082 G/A genotype and haplotypes (ACC, GCC, ATA and GTA) were comparable in all groups. Circulating levels of IL-8 and IL-10 were higher among GC than HC but comparable to FD (IL-8; 57.64 [6.44-319.46] vs. 54.35 [4.24-318.96] and 26.33 [4.67-304.54] pg/ml, p < 0.001 and IL-10; 15.47 [1.01-270.87] vs. 12.28 [0.96-64.88] and 3.79 [1.24-56.65], p < 0.001 for GC vs. HC). IL-8/IL-10 ratio was lower among GC than HC but higher than FD (3.7 [0.18-38.41] vs. 6.59 [0.98-130.2], p < 0.001 and 4.22 [0.15-61.4], p < 0.01). Circulating levels of IL-8, IL-10 and IL-8/lL-10 ratios were different among H. pylori-infected and non-infected GC than HC (p < 0.001, p < 0.001 and p < 0.01).

CONCLUSIONS

Pro-(IL-8)-251 T/A and anti-inflammatory (IL-10)-819 C/T gene polymorphisms and their circulating levels may play a role in H. pylori-associated gastric carcinogenesis in northern India.

The influence of cytokine gene polymorphisms on the risk of developing gastric cancer in patients with Helicobacter pylori infection

BACKGROUND

Helicobacter pylori infection is the main cause of gastric cancer. The disease progression is influenced by the host inflammatory responses, and cytokine single nucleotide polymorphisms (SNPs) may have a role in the course of the disease. The aim of our study was to investigate proinflammatory cytokine polymorphisms, previously associated with the development of gastric cancer, in a Slovenian population.

PATIENTS AND METHODS

In total 318 patients and controls were selected for the study and divided into three groups: (i) patients with gastric cancer (n = 58), (ii) patients with chronic gastritis (n = 60) and (iii) healthy control group (n = 200). H. pylori infection in patient groups was determined by serology, histology and culture. Four proinflammatory gene polymorphisms were determined (IL-1β, IL-1ra, TNF-α, TLR-4) in all subjects.

RESULTS

We found a statistically significant difference between males and females for the groups (p = 0.025). Odds ratio (OR) for gastric cancer risk for females was 0.557 (95% confidence interval [CI]: 0.233-1.329) and for chronic gastritis 2.073 (95% CI: 1.005-4.277). IL-1B-511*T/T homozygous allele for cancer group had OR = 2.349 (95% CI: 0.583-9.462), heterozygous IL-1B-511*T had OR = 1.470 (95% CI: 0.583-3.709) and heterozygotes in TNF-A-308 genotype for chronic gastritis had OR = 1.402 (95% CI: 0.626-3.139). Other alleles had OR less than 1.

CONCLUSIONS

We could not prove association between gastric cancer and chronic gastritis due to H. pylori in any cytokine SNPs studied in Slovenian population. Other SNPs might be responsible besides infection with H. pylori for the progression from atrophy to neoplastic transformation.

A Comprehensive Study of Tumor Necrosis Factor-Alpha Genetic Polymorphisms, its Expression in Skin and Relation to Histopathological Features in Psoriasis

BACKGROUND

Tumor necrosis factor-alpha (TNFα) is an important inflammatory mediator in psoriasis and several genetic polymorphisms of this cytokine have been reported. Majority of studies have focused on the increased G- A polymorphism at the -308 position in psoriasis. There has been no comprehensive study evaluating the genetic polymorphisms, TNFα expression in the skin and histopathology. We are undertaking this study to outline TNFα genetic polymorphisms, its skin expression and histopathological correlation to help determine its role at the genetic and protein level.

MATERIALS AND METHODS

112 patients of psoriasis and 243 healthy controls were included in this prospective study. 5 ml of peripheral blood was collected to study the TNFα genetic polymorphisms by polymerase chain reaction and restriction fragment length polymorphism analysis. Histopathological analysis of biopsies from the 112 patients were done using visual analogue scale and correlated with the findings. 61 of these cases were analyzed for TNFα expression by immunohistochemistry. The results of study were statistically analyzed using SPSS 13.0 statistical package program.

RESULTS

A strong association of TNFα -308 G/A polymorphism in psoriasis cases was detected. The A allele of the TNFα -308 G/A polymorphism occurs rarely in the Indian population, however there is an over representation of this allele in psoriatic patients. There was no association seen between TNFα genotype and histopathological severity of psoriasis.

CONCLUSION

The study emphasized the central role of TNFα in the pathogenesis of psoriasis. TNFα genotyping may be helpful in identifying subjects in whom anti-TNFα therapeutic strategies may be tried.

Differential inflammatory response to Helicobacter pylori infection: etiology and clinical outcomes

The bacterial pathogen Helicobacter pylori commonly colonizes the human gastric mucosa during early childhood and persists throughout life. The organism has evolved multiple mechanisms for evading clearance by the immune system and, despite inducing inflammation in the stomach, the majority of infections are asymptomatic. H. pylori is the leading cause of peptic ulcer disease and gastric cancer. However, disease outcomes are related to the pattern and severity of chronic inflammation in the gastric mucosa, which in turn is influenced by both bacterial and host factors. Despite over 2 decades of intensive research, there remains an incomplete understanding of the circumstances leading to disease development, due to the fascinating complexity of the host-pathogen interactions. There is accumulating data concerning the virulence factors associated with increased risk of disease, and the majority of these have pro-inflammatory activities. Despite this, only a small proportion of those infected with virulent strains develop disease. Several H. pylori virulence factors have multiple effects on different cell types, including the induction of pro- and anti-inflammatory, immune stimulatory, and immune modulatory responses. The expression of multiple virulence factors is also often linked, making it difficult to assess the meaning of their effects in isolation. Overall, H. pylori is thought to usually modulate inflammation and limit acute damage to the mucosa, enabling the bacteria to persist. If this delicate balance is disturbed, disease may then develop.

STAT3 polymorphism and Helicobacter pylori CagA strains with higher number of EPIYA-C segments independently increase the risk of gastric cancer

Background

Because to date there is no available study on STAT3 polymorphism and gastric cancer in Western populations and taking into account that Helicobacter pylori CagA EPIYA-C segment deregulates SHP-2/ERK-JAK/STAT3 pathways, we evaluated whether the two variables are independently associated with gastric cancer.

Methods

We included 1048 subjects: H. pylori-positive patients with gastric carcinoma (n = 232) and with gastritis (n = 275) and 541 blood donors. Data were analyzed using logistic regression model.

Results

The rs744166 polymorphic G allele (p = 0.01; OR = 1.76; 95 % CI = 1.44-2.70), and CagA-positive (OR = 12.80; 95 % CI = 5.58-19.86) status were independently associated with gastric cancer in comparison with blood donors. The rs744166 polymorphism (p = 0.001; OR = 1.64; 95 % CI = 1.16-2.31) and infection with H. pylori CagA-positive strains possessing higher number of EPIYA-C segments (p = 0.001; OR = 2.28; 95 % CI = 1.41-3.68) were independently associated with gastric cancer in comparison with gastritis. The association was stronger when host and bacterium genotypes were combined (p < 0.001; OR = 3.01; 95 % CI = 2.29-3.98). When stimulated with LPS (lipopolysaccharide) or Pam3Cys, peripheral mononuclear cells of healthy carriers of the rs744166 GG and AG genotypes expressed higher levels of STAT3 mRNA than those carrying AA genotype (p = 0.04 for both). The nuclear expression of phosphorylated p-STAT3 protein was significantly higher in the antral gastric tissue of carriers of rs744166 GG genotype than in carriers of AG and AA genotypes.

Conclusions

Our study provides evidence that STAT3 rs744166 G allele and infection with CagA-positive H. pylori with higher number of EPIYA-C segments are independent risk factors for gastric cancer. The odds ratio of having gastric cancer was greater when bacterium and host high risk genotypes were combined.

Association Between IL-4 and IL-6 Expression Variants and Gastric Cancer Among Portuguese Population

Introduction

Multiple studies have reported strong associations between Helicobacter pylori (Hp) inflammation and gastric cancer (GC) development. Altered expressions of pro/anti-inflammatory cytokines have a crucial role in Hp and GC proliferation. Although there are many studies related to cytokines polymorphisms involvement in GC risk, the role of Interleukin-4 (IL-4) and Interleukin-6 (IL-6) in gastric inflammation process is not yet clarified.

Aim

This study aimed to investigate the impact of common IL-4 and IL-6 polymorphisms in GC development risk among Portuguese population.

Methods

A total of 100 GC biopsies (50 with intestinal type, IGC, 50 with diffuse type, DGC) and 50 chronic gastritis cases, used as control group, were included in this case-control study. IL-4 and IL-6 common polymorphisms were genotyped by PCR-SSP, using commercially available kits.

Results

IL-4 low producer genotypes, IL-4-590TT (OR = 6.7; 95% CI 1.4–32.4) and IL-4-1098GG (OR = 4.4; 95% CI 1.7–16.9) were found associated with IGC and DGC, respectively. We also verified that IL-4 TTT haplotype was linked with both IGC (OR = 5.8; 95% CI 2.3–14.4) and DGC (OR = 2.3; 95% CI 1.0–5.5) groups. Concerning IL-6 results, IL-6-174CG genotype showed a higher prevalence among IGC cases (OR = 7.3; 95% CI 2.7–20.3), and IL-6-174CC (OR = 3.8; 95% CI 1.7–8.7) showed upper prevalence within DGC subjects. Finally, IL-6-174/nt565CG haplotype showed a significant association with both IGC (OR = 7.3; 95% CI 2.7–20.3) and DGC (OR = 7.9; 95% CI 4.2–14.9).

Conclusion

IL-6 and IL-4 expression variants seem to have an important role in GC risk mechanisms. This study provides preliminary evidence that IL-4 and IL-6 polymorphisms, although not directly linked to the disease, may be useful tools in the study of this multifactorial disease.

Circulating interleukin-6 and cancer: A meta-analysis using Mendelian randomization

Interleukin-6 (IL-6) plays a contributory role in the progression and severity of many forms of cancer; it however remains unclear whether the relevance between circulating IL-6 and cancer is causal. We therefore meta-analyzed published articles in this regard using IL-6 gene -174G/C variant as an instrument. Seventy-eight and six articles were eligible for the association of -174G/C variant with cancer and circulating IL-6, respectively. Overall analyses failed to identify any significance between -174G/C and cancer risk. In Asians, carriers of the -174CC genotype had an 1.95-fold increased cancer risk compared with the -174GG genotype carriers (P = 0.009). By cancer type, significance was only attained for liver cancer with the -174C allele conferring a reduced risk under allelic (odds ratio or OR = 0.74; P = 0.001), homozygous genotypic (OR = 0.59; P = 0.029) and dominant (OR = 0.67; P = 0.004) models. Carriers of the -174CC genotype (weighted mean difference or WMD = −4.23 pg/mL; P < 0.001) and -174C allele (WMD = −3.43 pg/mL; P < 0.001) had circulating IL-6 reduced significantly compared with the non-carriers. In further Mendelian randomization analysis, a reduction of 1 pg/mL in circulating IL-6 was significantly associated with an 12% reduced risk of liver cancer. Long-term genetically-reduced circulating IL-6 might be causally associated with a lower risk of liver cancer.

Is Campylobacter to esophageal adenocarcinoma as Helicobacter is to gastric adenocarcinoma?

Esophageal adenocarcinoma develops through a cascade of cellular changes that shares similarities to the etiology of Helicobacter pylori-associated intestinal-type gastric adenocarcinoma. While host genetics and immune response have been implicated in the progression to esophageal adenocarcinoma, studies investigating esophageal microbial communities suggest that bacteria may also play an important role in driving the inflammation that leads to disease. Of these, emerging Campylobacter species have been found to be more prevalent and abundant in patients progressing through the esophageal adenocarcinoma cascade compared to controls. Given that these bacteria possess several virulence mechanisms such as toxin production, cellular invasion, and intracellular survival, emerging Campylobacter species should be investigated as etiological agents of the chronic esophageal inflammation that leads to cancer.

Influence of prostate stem cell antigen gene polymorphisms on susceptibility to Helicobacter pylori-associated diseases: a case-control study

BACKGROUND

Patients with duodenal ulcer have a reduced risk of developing gastric cancer compared to those without. Recently, the prostate stem cell antigen (PSCA) rs2294008 C>T polymorphism was found to be associated with different pathogenesis of duodenal ulcer and gastric cancer developments. However, whether PSCA rs2294008 C>T polymorphism is associated with severity of gastric mucosal atrophy is unclear. We examined the influence of the PSCA rs2294008 C>T polymorphism on susceptibility to H. pylori-related diseases and the relationships between PSCA polymorphism and gastric mucosal atrophy.

METHODS

PSCA rs2294008 C>T polymorphism was assessed in H. pylori-positive Japanese patients (n = 488) with noncardia gastric cancer (n = 193), gastric ulcer (n = 84), duodenal ulcer (n = 61), and atrophic gastritis (n = 150), as well as in H. pylori-negatives (n = 266).

RESULTS

Frequency of PSCA rs2294008 C/C genotype in duodenal ulcer was 36.1%, which was significantly higher than those with gastric cancer (12.4%), gastric ulcer (19.0%), gastritis (10.7%), and H. pylori-negatives (19.5%) (p < .001). Compared with duodenal ulcer, having the T allele significantly increased the risk of gastric cancer (OR: 3.97, 95% CI: 2.02-7.80; p < .001), gastric ulcer (2.40, 1.13-5.10; p = .023), and gastritis (4.72, 2.26-9.86; p < .001). Mean pepsinogen (PG) I/PG II ratio in T allele carriers (2.17 ± 0.75) was significantly lower than that in C/C genotype (3.39 ± 1.27, p < .001).

CONCLUSIONS

The PSCA rs2294008 C>T polymorphism is associated with differing susceptibilities to H. pylori-associated diseases. The PSCA rs2294008 C>T polymorphism may be acting through induction of gastric mucosal atrophy, finally leading to development of gastric ulcer and gastric cancer in PSCA rs2294008 T allele carriers, but not duodenal ulcer.

To be or not to be: The host genetic factor and beyond in Helicobacter pylori mediated gastro-duodenal diseases

Helicobacter pylori (H. pylori) have long been associated with a spectrum of disease outcomes in the gastro-duodenal system. Heterogeneity in bacterial virulence factors or strains is not enough to explain the divergent disease phenotypes manifested by the infection. This review focuses on host genetic factors that are involved during infection and eventually are thought to influence the disease phenotype. We have summarized the different host genes that have been investigated for association studies in H. pylori mediated duodenal ulcer or gastric cancer. We discuss that as the bacteria co-evolved with the host; these host gene also show much variation across different ethnic population. We illustrate the allelic distribution of interleukin-1B, across different population which is one of the most popular candidate gene studied with respect to H. pylori infections. Further, we highlight that several polymorphisms in the pathway gene can by itself or collectively affect the acid secretion pathway axis (gastrin: somatostatin) thereby resulting in a spectrum of disease phenotype

Variations of gastric corpus microbiota are associated with early esophageal squamous cell carcinoma and squamous dysplasia

Observational studies revealed a relationship between changes in gastric mucosa and risk of esophageal squamous cell carcinoma (ESCC) which suggested a possible role for gastric microbiota in ESCC carcinogenesis. In this study we aimed to compare pattern of gastric corpus microbiota in ESCC with normal esophagus. Cases were included subjects with early ESCC (stage I-II) and esophageal squamous dysplasia (ESD) as the cancer precursor. Control groups included age and sex-matched subjects with mid-esophagus esophagitis (diseased-control), and histologically normal esophagus (healthy-control). DNA was extracted from snap-frozen gastric corpus tissues and 16S rRNA was sequenced on GS-FLX Titanium. After noise removal, an average of 3004 reads per sample was obtained from 93 subjects. We applied principal coordinate analysis to ordinate distances from beta diversity data. Pattern of gastric microbiota using Unifrac (p = 0.004) and weighted Unifrac distances (p = 0.018) statistically varied between cases and healthy controls. Sequences were aligned to SILVA database and Clostridiales and Erysipelotrichales orders were more abundant among cases after controling for multiple testing (p = 0.011). No such difference was observed between mid-esophagitis and healthy controls. This study is the first to show that composition of gastric corpus mucosal microbiota differs in early ESCC and ESD from healthy esophagus.

H. pylori infection, inflammation and gastric cancer

INTRODUCTION

A strong association between chronic infection, inflammation, and cancer has been suggested.

DISCUSSION

Helicobacter pylori, a microaerophilic gram negative bacterium, infects about half the world's population. It has been defined as a definitive carcinogen in the pathogenesis of gastric cancer. H. pylori evades the host immune responses and persists in the stomach leading to gastritis gastric atrophy and sometimes gastric cancer.

CONCLUSION

Chronic H. pylori infection causes gastric cancer via two mechanisms: the presence of virulence factors and the induction of chronic inflammation which ultimately leads to neoplastic transformation.

The course of gastric cancer following surgery is associated with genetic variations of the interleukin-1 receptor antagonist and interleukin-1β

BACKGROUND

Inflammation, especially the cytokine response of the IL-1 family, has been shown to influence susceptibility to gastric cancer. In addition, several other pro-inflammatory cytokines have been demonstrated to influence metastasis and resistance to chemotherapy. Therefore, genetic variations within these genes may not only affect susceptibility but also influence the outcome of gastric cancer patients. A limited number of studies showed indeed an association of IL-1β and IL-1RN variations with survival of gastric cancer patients. However, results are inconsistent, possibly because of different patient cohorts and different therapies.

METHODS

In this retrospective cohort study we genotyped 154 patients with gastric cancer for IL-1β and IL-1RN variations. Patients had undergone pathologically proven R0 resection and had received no additional adjuvant treatment.

RESULTS

We show here a protective association with disease-free survival for both heterozygous genotypes, IL-1β SNP C-511T (rs16944) and IL-1RN VNTR. The combination of both heterozygous genotypes is the strongest predictor independent of UICC stage.

CONCLUSION

Genetic variations in the IL-1β and IL-1RN genes influence disease progression in gastric cancer. Screening for these genetic variations might help to stratify therapies for gastric cancer patients in the future.

At the crossroad between obesity and gastric cancer

Obesity has reached epidemic proportions worldwide with disproportionate prevalence in different communities and ethnic groups. Recently, the American Medical Association recognized obesity as a disease, which is a significant milestone that opens the possibilities of treating obesity under standardized health plans. Obesity is an inflammatory disease characterized by elevated levels of biomarkers associated with abnormal lipid profiles, glucose levels, and blood pressure that lead to the onset of metabolic syndrome. Interestingly, inflammatory biomarkers, in particular, have been implicated in the risk of developing several types of cancer. Likewise, obesity has been linked to esophageal, breast, gallbladder, kidney, pancreatic, and colorectal cancers. Thus, there exists a link between obesity status and tumor appearance, which may be associated to the differential levels and the circulating profiles of several inflammatory molecules. For example, mediators of the inflammatory responses in both obesity and gastric cancer risk are the same: pro-inflammatory molecules produced by the activated cells infiltrating the inflamed tissues. These molecules trigger pathways of activation shared by obesity and cancer. Therefore, understanding how these different pathways are modulated would help reduce the impact that both diseases, and their concomitant existence, have on society.

Clinical relevance of Helicobacter pylori vacA and cagA genotypes in gastric carcinoma

Helicobacter pylori infection is the major etiological factor of gastric carcinoma. This disease is the result of a long, multistep, and multifactorial process, which occurs only in a small proportion of patients infected with H. pylori. Gastric carcinoma development is influenced by host genetic susceptibility factors, environmental factors, and H. pylori virulence. H. pylori is genetically highly variable, and variability that affects H. pylori virulence factors may be useful to identify strains with different degrees of pathogenicity. This review will focus on VacA and CagA that have polymorphic regions that impact their functional properties. The characterization of H. pylori vacA and cagA-associated could be useful for identifying patients at highest risk of disease, who could be offered H. pylori eradication therapy and who could be included in programs of more intensive surveillance in an attempt to reduce gastric carcinoma incidence.

Helicobacter pylori: perspectives and time trends

The discovery of Helicobacter pylori three decades ago is a modern medical success story. It markedly changed our understanding of the pathophysiology of gastroduodenal diseases and led to an improvement in the treatment of diseases related to H. pylori infection. Many of these diseases (such as ulcer disease and mucosal associated lymphoid tissue lymphoma) have become curable, and others (gastric cancer) might be preventable with the application of H. pylori eradication therapy. Since its discovery, H. pylori has also been identified as a trigger for some extragastric diseases. Promising results in this exciting field might have a clinical effect in the near future. This Timeline gives an overview of the success of clinical research on H. pylori to date and highlights some future trends in this area.

Effects of the interleukin-1β-511 C/T gene polymorphism on the risk of gastric cancer in the context of the relationship between race and H. pylori infection: a meta-analysis of 20,000 subjects

The interleukin (IL)-1β-511 C/T polymorphism has been shown to be functional and to contribute to the risk of gastric cancer. However, the relationship between the IL-1β-511 C/T polymorphism and gastric carcinogenesis remains inconclusive. A systematical electronic search was conducted of the MEDLINE, EMBASE, and CENTRAL databases. A random and a fixed effects model were exploited to estimate summary odds ratios and 95 % confidence intervals. Subgroup and sensitivity analyses were carried out with respect to ethnicity, quality assessment scores, control sources, genotyping methods, cancer histopathology and location, and Helicobacter pylori (H. pylori) infection. A total of 45 studies containing 9,066 cases of gastric cancer and 11,192 control subjects satisfied the inclusion criteria. The IL-1β-511 C/T polymorphism was found to enhance the risk of stomach cancer for overall and HWE-satisfying studies. Asians showed a positive relationship in both the overall and HWE-satisfying groups, whereas Caucasians did not. Based on subgroup analysis, H. pylori infection and genotype analysis using PCR-RFLP methods increase the association between IL-1β-511 T allele carrier and risk of stomach cancer. A positive relationship was found between the IL-1β-511 C/T SNP and stomach carcinoma susceptibility, and the results suggest that Asian ethnicity, H. pylori infection and methodologically, PCR-RFLP genotyping strengthen this relationship. Reflecting on prevalence of H. pylori in Asian countries, additional studies on the IL-1β-511 C/T SNP in the context of ethnicity and H. pylori infection may provide key insights into the mechanism underlying gastric cancer carcinogenesis. It was found PCR-RFLP is the most reliable genotyping method, and thus, it is recommendable to adopt it to determine the presence of the IL-1β-511 C/T SNP.

Helicobacter pylori-induced IL-1β secretion in innate immune cells is regulated by the NLRP3 inflammasome and requires the cag pathogenicity island

Infection with the gram-negative bacterium Helicobacter pylori is the most prevalent chronic bacterial infection, affecting ∼50% of the world's population, and is the main risk factor of gastric cancer. The proinflammatory cytokine IL-1β plays a crucial role in the development of gastric tumors and polymorphisms in the IL-1 gene cluster leading to increased IL-1β production have been associated with increased risk for gastric cancer. To be active, pro-IL-1β must be cleaved by the inflammasome, an intracellular multiprotein complex implicated in physiological and pathological inflammation. Recently, H. pylori was postulated to activate the inflammasome in murine bone marrow-derived dendritic cells; however, the molecular mechanisms as well as the bacterial virulence factor acting as signal 2 activating the inflammasome remain elusive. In this study, we analyzed the inflammasome complex regulating IL-1β upon H. pylori infection as well as the molecular mechanisms involved. Our results indicate that H. pylori-induced IL-1β secretion is mediated by activation of the nucleotide-binding oligomerization domain-like receptor family, pyrin domain-containing 3 inflammasome. We also show that reactive oxygen species, potassium efflux, and lysosomal destabilization are the main cellular mechanisms responsible of nucleotide-binding oligomerization domain family, pyrin domain-containing 3 inflammasome activation upon H. pylori infection, and identify vacuolating cytotoxin A and cag pathogenicity island as the bacterial virulence determinants involved. Moreover, in vivo experiments indicate an important role for the inflammasome in the onset and establishment of H. pylori infection and in the subsequent inflammatory response of the host.

Helicobacter pylori from gastric cancer and duodenal ulcer show same phylogeographic origin in the Andean region in Colombia

Background

A recent report has shown that the phylogenetic origin of Helicobacter pylori based on multi-locus sequence typing (MLST) was significantly associated with the severity of gastritis in Colombia. However, the potential relationship between phylogenetic origin and clinical outcomes was not examined in that study. If the phylogenetic origin rather than virulence factors were truly associated with clinical outcomes, identifying a population at high risk for gastric cancer in Colombia would be relatively straightforward. In this study, we examined the phylogenetic origins of strains from gastric cancer and duodenal ulcer patients living in Bogota, Colombia.

Methods

We included 35 gastric cancer patients and 31 duodenal ulcer patients, which are considered the variant outcomes. The genotypes of cagA and vacA were determined by polymerase chain reaction. The genealogy of these Colombian strains was analyzed by MLST. Bacterial population structure was analyzed using STRUCTURE software.

Results

H. pylori strains from gastric cancer and duodenal ulcer patients were scattered in the phylogenetic tree; thus, we did not detect any difference in phylogenetic distribution between gastric cancer and duodenal ulcer strains in the hpEurope group in Colombia. Sixty-six strains, with one exception, were classified as hpEurope irrespective of the cagA and vacA genotypes, and type of disease. STRUCTURE analysis revealed that Colombian hpEurope strains have a phylogenetic connection to Spanish strains.

Conclusions

Our study showed that a phylogeographic origin determined by MLST was insufficient for distinguishing between gastric cancer and duodenal ulcer risk among hpEurope strains in the Andean region in Colombia. Our analysis also suggests that hpEurope strains in Colombia were primarily introduced by Spanish immigrants.

Association between TNF-α-308 G/A gene polymorphism and gastric cancer risk: a systematic review and meta-analysis

OBJECTIVE

Tumor necrosis factor-alpha (TNF-α) has been found to be associated with gastric carcinogenesis, but individually published results have been inconclusive. The aim of this study was to explore the relationship between the TNF-α-308 G/A polymorphism and gastric cancer risk.

METHODS

MEDLINE, EMBASE and the COCHRANE library databases were searched for relevant articles to identify all available data. The odds ratios (ORs) with 95% confidence intervals (95% CIs) from each study were used to assess the association between the TNF-α-308 G/A polymorphism and gastric cancer risk.

RESULTS

This meta-analysis included 30 studies (32 datasets) involving 7009 gastric cancer cases and 12,119 control subjects. Overall, a significant association was found between the TNF-α-308 G/A polymorphism and gastric cancer in AA+GA vs. GG (dominant contrast model) (OR=1.20, 95% CI=1.07-1.34, p=0.001). With stratification based on ethnicity, the TNF-α-308 G/A polymorphism was correlated with gastric cancer risk in Caucasians, using the dominant contrast model (OR=0.74, 95% CI=0.57-0.96, p=0.02), but not in East Asians and other ethnic groups. In the comprehensive subgroup analysis, a significant association was also found in recent articles (published after 2005), population-based high-quality studies, hospital-based high-quality studies, studies using the TaqMan method and non-cardia subgroups. However, the TNF-α-308 G/A polymorphism was not associated with specific histological types of gastric cancer risk.

CONCLUSIONS

The TNF-α-308 G/A polymorphism may contribute to susceptibility to gastric cancer in Caucasians, especially for non-cardia gastric cancer, as most strongly demonstrated in high-quality studies and in studies using the TaqMan genotyping method. Furthermore, we recommend the TaqMan method as the preferred genotyping method in DNA polymorphism studies.

The -1082A>G polymorphism in promoter region of interleukin-10 and risk of digestive cancer: a meta-analysis

The -1082A>G polymorphism is located in promoter region of interleukin-10 (IL-10) and it could affect the production of IL-10. Numerous studies have investigated the association between IL-10 -1082A>G and risk of digestive cancer. However, the conclusion is still inconsistent. Here, we have performed a meta-analysis and systematic review to determine the association between the IL-10 -1082A>G and susceptibility to digestive cancer. In this meta-analysis, we identified 40 eligible studies, involving 7195 patients of digestive cancer and 11755 controls. By pooling all eligible studies, we found the variant -1082G allele significantly increased risk of digestive cancer (G vs. A: OR = 1.181, 95% CI: 1.057-1.319). Further stratified analysis was performed to evaluate the influence of cancer types, ethnicities, study design, sample size and Hardy-Weinberg equilibrium. Stratified analysis suggested that, the -1082A>G polymorphism was only associated with increased risk for gastric cancer (G vs. A: OR = 1.281, 95% CI: 1.102-1.488) and in Asian population (G vs. A: OR = 1.399, 95% CI: 1.188-1.646). No significant publication bias was detected. Based on 40 studies and 18950 participants, we found the variant IL-10 -1082G allele significantly increased susceptibility to digestive cancer, especially for gastric cancer and in Asian population.

Review article: the epidemiology and prevention of gastric cancer

BACKGROUND

Gastric cancer can be divided into cardia and noncardia gastric adenocarcinoma (NCGA). Non cardia gastric cancer is a disease that has declined in global incidence but has remained as an extremely lethal cancer.

AIM

To review recent advances in epidemiology and strategies in prevention of non cardia gastric cancer.

METHODS

A rapid literature search strategy was developed for all English language literature published before March 2013. The search was conducted using the electronic databases PubMed and EMBASE. The search strategy included the keywords 'stomach neoplasms', 'gastric cancer', 'epidemiology', 'risk factor', 'early detection of cancer', 'mass screening', 'cancer burden', 'prevention' and 'cost-effectiveness'. The search strategy was adjusted according to different requirements for each database. The specific search was also performed in cancer-related websites for country-specific information. The search was limited to past 10 years.

RESULTS

Gastric cancer is the fifth most common cancer but the third leading cause of cancer death. The case fatality rate is 75%. Screening by radiological or endoscopic methods has limited success in prevention of gastric cancer. Helicobacter pylori has been identified as a carcinogen, accounting for 60-70% of gastric cancer globally and eradication is a potential preventive measure. A meta-analysis in 2009 demonstrated that individuals treated with H. pylori eradication therapy can reduce gastric cancer risk. The extended Shandong Intervention trial that lasted 14.3 years showed that H. pylori eradication therapy significantly reduced gastric cancer incidence by 39%. Consensus groups from Asia, Europe and Japan have recommended H. pylori eradication as primary prevention in high-risk areas. Following eradication therapy, endoscopic surveillance of pre-malignant lesions using enhanced imaging appears to be another promising preventive strategy.

CONCLUSIONS

Gastric cancer remains a major diagnostic and therapeutic challenge. There is emerging evidence that H. pylori eradication in high gastric cancer regions can lead to a decline in the incidence of this highly lethal disease.