Evidences showing association of interleukin-1B polymorphisms with increased risk of gastric cancer in an Indian population

Decoding the Ability of Helicobacter pylori to Evade Immune Recognition and Cause Disease

Helicobacter pylori (H pylori) successfully and chronically colonizes the gastric mucosa of approximately 43% of the world's population. Infection with this organism is the strongest known risk factor for the development of gastric cancer, and disease development is dependent on several interactive components. One H pylori determinant that augments cancer risk is the strain-specific cag type IV secretion system, which not only translocates a pro-inflammatory and oncogenic protein, CagA, into host cells but also DNA, peptidoglycan, and a lipopolysaccharide intermediate, heptose-1,7-bisphosphate. However, cognate interactions between certain microbial and host constituents can also attenuate pro-inflammatory responses, and H pylori harbors multiple effectors that function differently than the respective counterparts in other mucosal pathogens. In this review, we discuss current data related to mechanisms utilized by H pylori to evade the immune response, sustain its longevity in the host, and further disease progression, as well as implications for developing targeted, immune-based eradication strategies.

First insights into the molecular basis association between promoter polymorphisms of the IL1B gene and Helicobacter pylori infection in the Sudanese population: computational approach

BACKGROUND

Helicobacter pylori (H. pylori) infects nearly half of the world's population with a variation in incidence among different geographic regions. Genetic variants in the promoter regions of the IL1B gene can affect cytokine expression and creates a condition of hypoacidity which favors the survival and colonization of H. pylori. Therefore, the aim of this study was to characterize the polymorphic sites in the 5'- region [-687_ + 297] of IL1B in H. pylori infection using in silico tools.

RESULTS

A total of five nucleotide variations were detected in the 5'-regulatory region [-687_ + 297] of IL1B which led to the addition or alteration of transcription factor binding sites (TFBSs) or composite regulatory elements (CEs). Genotyping of IL1B - 31 C > T revealed a significant association between -31 T and susceptibility to H. pylori infection in the studied population (P = 0.0363). Comparative analysis showed conservation rates of IL1B upstream [-368_ + 10] region above 70% in chimpanzee, rhesus monkey, a domesticated dog, cow and rat.

CONCLUSIONS

In H. pylori-infected patients, three detected SNPs (- 338, - 155 and - 31) located in the IL1B promoter were predicted to alter TFBSs and CE, which might affect the gene expression. These in silico predictions provide insight for further experimental in vitro and in vivo studies of the regulation of IL1B expression and its relationship to H. pylori infection. However, the recognition of regulatory motifs by computer algorithms is fundamental for understanding gene expression patterns.

Unveiling the Crucial Role of Type IV Secretion System and Motility of Helicobacter pylori in IL-1β Production via NLRP3 Inflammasome Activation in Neutrophils

Helicobacter pylori is a gram-negative, microaerophilic, and spiral-shaped bacterium and causes gastrointestinal diseases in human. IL-1β is a representative cytokine produced in innate immune cells and is considered to be a key factor in the development of gastrointestinal malignancies. However, the mechanism of IL-1β production by neutrophils during H. pylori infection is still unknown. We designed this study to identify host and bacterial factors involved in regulation of H. pylori-induced IL-1β production in neutrophils. We found that H. pylori-induced IL-1β production is abolished in NLRP3-, ASC-, and caspase-1/11-deficient neutrophils, suggesting essential role for NLRP3 inflammasome in IL-1β response against H. pylori. Host TLR2, but not TLR4 and Nod2, was also required for transcription of NLRP3 and IL-1β as well as secretion of IL-1β. H. pylori lacking cagL, a key component of the type IV secretion system (T4SS), induced less IL-1β production in neutrophils than did its isogenic WT strain, whereas vacA and ureA were dispensable. Moreover, T4SS was involved in caspase-1 activation and IL-1β maturation in H. pylori-infected neutrophils. We also found that FlaA is essential for H. pylori-mediated IL-1β production in neutrophils, but not dendritic cells. TLR5 and NLRC4 were not required for H. pylori-induced IL-1β production in neutrophils. Instead, bacterial motility is essential for the production of IL-1β in response to H. pylori. In conclusion, our study shows that host TLR2 and NLRP3 inflammasome and bacterial T4SS and motility are essential factors for IL-1β production by neutrophils in response to H. pylori.

The Role of Host Genetic Polymorphisms in Helicobacter pylori Mediated Disease Outcome

The clinical outcome of infection with the chronic gastric pathogen Helicobacter pylori is not the same for all individuals and also differs in different ethnic groups. Infection occurs in early life (<3 years of age), and while all infected persons mount an immune response and develop gastritis, the majority of individuals are asymptomatic. However, up to 10-15% develop duodenal ulceration, up to 1% develop gastric cancer (GC) and up to 0.1% can develop gastric mucosa-associated lymphoid tissue (MALT) lymphoma. The initial immune response fails to clear infection and H. pylori can persist for decades. H. pylori has been classified as a group one carcinogen by the WHO. Interestingly, development of duodenal ulceration protects against GC. Factors that determine the outcome of infection include the genotype of the infecting strains and the environment. Host genetic polymorphisms have also been identified as factors that play a role in mediating the clinical outcome of infection. Several studies present compelling evidence that polymorphisms in genes involved in the immune response such as pro and anti-inflammatory cytokines and pathogen recognition receptors (PRRs) play a role in modulating disease outcome. However, as the number of studies grows emerging confounding factors are small sample size and lack of appropriate controls, lack of consideration of environmental and bacterial factors and ethnicity of the population. This chapter is a review of current evidence that host genetic polymorphisms play a role in mediating persistent H. pylori infection and the consequences of the subsequent inflammatory response.

Network pharmacology-based strategy to investigate pharmacological mechanisms of Zuojinwan for treatment of gastritis

BACKGROUND

Zuojinwan (ZJW), a classic herbal formula, has been extensively used to treat gastric symptoms in clinical practice in China for centuries. However, the pharmacological mechanisms of ZJW still remain vague to date.

METHODS

In the present work, a network pharmacology-based strategy was proposed to elucidate its underlying multi-component, multi-target, and multi-pathway mode of action against gastritis. First we collected putative targets of ZJW based on TCMSP and STITCH databases, and a network containing the interactions between the putative targets of ZJW and known therapeutic targets of gastritis was built. Then four topological parameters, "degree", "betweenness", "closeness", and "coreness" were calculated to identify the major targets in the network. Furthermore, the major hubs were imported to the Metacore database to perform a pathway enrichment analysis.

RESULTS

A total of 118 nodes including 59 putative targets of ZJW were picked out as major hubs in terms of their topological importance. The results of pathway enrichment analysis indicated that putative targets of ZJW mostly participated in various pathways associated with anti-inflammation response, growth and development promotion and G-protein-coupled receptor signaling. More importantly, five putative targets of ZJW (EGFR, IL-6, IL-1β, TNF-α and MCP-1) and two known therapeutic targets of gastritis (CCKBR and IL-12β) and a link target NF-κB were recognized as active factors involved in the main biological functions of treatment, implying the underlying mechanisms of ZJW acting on gastritis.

CONCLUSION

ZJW could alleviate gastritis through the molecular mechanisms predicted by network pharmacology, and this research demonstrates that the network pharmacology approach can be an effective tool to reveal the mechanisms of traditional Chinese medicine (TCM) from a holistic perspective.

Association of Interleukin-1 beta and tumor necrosis factor-alpha genetic polymorphisms with gastric cancer in India

Interleukin 1 beta (IL-1β) and Tumor necrosis factor alpha (TNF-α) are key inflammatory cytokines whose polymorphisms have been correlated with increased susceptibility to gastric cancer (GC). Since geographical and racial differences exist in cancer rates, our study was aimed to evaluate the first possible association of polymorphisms in these genes with GC risk in West Bengal, India. Polymorphisms in IL-1β and TNF-α genes were genotyped in 120 GC patients and 135 healthy individuals. Combined effect of the SNPs in both genes with GC risk was determined through allele dosage analysis (ADA) and the survival data were analyzed by Log Rank Test. The study results revealed that IL-1β rs1143627: T > C, rs16944: C > T (p = 0.001;OR = 1.85; 95% CI 1.30-2.63) and rs1143633: G > A (p < 0.0001; OR = 2.53; 95% CI 1.67-3.83) and TNF-α rs1800630: C > A, rs1799964: T > C (p < 0.0001; OR = 2.31; 95% CI 1.54-3.46) polymorphisms significantly contributed toward GC risk. Moreover, ADA showed that carriage of 7 "effective" risk alleles conferred a risk of almost 10-fold in comparison to individuals carrying less than 3 "effective" risk alleles. Our survival analysis also indicated a significant association between IL-1β rs1143627: T > C and rs16944: C > T and patient survivability. The presence of H. pylori enhanced the risk in individuals with IL-1β rs1143627:CC and rs16944:TT genotypes. Further, meta-analysis revealed significant association of IL-1β rs1143627: T > C (p = 0.026; OR = 4.165; 95% CI 1.18-14.65) and rs16944: C > T (p = 0.01; OR = 5.49; 95% CI 1.48-20.37) in presence of H. pylori with gastric cancer in Asian population though no significant difference (p > 0.05) was found when compared to absence of H. pylori Environ. Mol. Mutagen. 59:653-667, 2018. © 2018 Wiley Periodicals, Inc.

Associations between cytokine gene polymorphisms and susceptibility to Helicobacter pylori infection and Helicobacter pylori related gastric cancer, peptic ulcer disease: A meta-analysis

Objectives

The aim of this study is to clarify the associations between IL-1B31C/T, IL-1B-511C/T, IL-8-251T/A gene polymorphisms and the risk of Helicobacter pylori (H. pylori) infection together with H. pylori-related gastric cancer (GC), peptic ulcer disease (PUD).

Methods

All eligible literature published up to July 2016 were identified by searching Pubmed, Embase, Web of Science and CNKI. Pooled odds ratio (OR) and 95% confidence interval (95% CI) were calculated using a fixed or random effects model.

Results

29 case-control studies were eligible, and each of them may focus on more than one gene polymorphism. Ultimately, there were 21 studies (3159 cases and 2816 controls) for IL-1B-31C/T, 16 studies (2486 cases and 1989 controls) for IL-1B-511C/T polymorphisms, 9 studies (1963 cases and 1205 controls) for IL-8-251T/A polymorphisms. Overall, an increased risk of H. pylori infection was found for IL-1B-31C/T polymorphisms in total population [OR = 1.134, 95%CI = 1.008–1.275 for recessive model; OR = 1.145, 95%CI = 1.007–1.301 for TT vs CC model]. While, for IL-1B-511C/T and IL8-251T/A polymorphisms, no evidence indicated that they were associated with the risk of H. pylori infection in all genetic models. Furthermore, we found an increased risk of H. pylori-related GC with IL-1B-511C/T polymorphisms [OR = 1.784, 95%CI = 1.289–2.469 for recessive model; OR = 1.772, 95%CI = 1.210–2.594 for TT vs CC model] and IL8-251A/T polymorphisms [OR = 1.810, 95%CI = 1.229–2.667 for recessive model; OR = 1.717, 95%CI = 1.143–2.580 for TT vs AA model], an increased risk of H. pylori-related PUD with IL8-251T/A polymorphisms [OR = 1.364, 95%CI = 1.010–1.843 for recessive model; OR = 1.427, 95%CI = 1.039–1.959 for AA vs TT model].

Conclusions

IL-1B-31C/T gene polymorphisms might increase H. pylori infection risk. IL-1B-511-C/T and IL-8-251T/A gene polymorphisms might act as a risk factor to H. pylori-related diseases including GC or PUD

Association of the IL-1RN variable number of tandem repeat polymorphism and Helicobacter pylori infection: A meta-analysis

The aim of this study was to clarify the association of IL-1RN variable number of tandem repeat (VNTR) polymorphism and H. pylori infection. We performed a meta-analysis of studies retrieved by systematic searches of Pubmed, Embase and the Cochrane Library. Data were analyzed with STATA 13.1 using pooled odds ratios (ORs) with 95% confidence intervals (CIs). A total of 18 studies were included in our meta-analysis, and IL-1RN VNTR was found to be significantly associated with H. pylori infection in the comparisons of 22+2L vs. LL (OR = 1.17, 95% CI = 1.02-1.33) and 2 allele vs. L allele (OR = 1.18, 95% CI = 1.00-1.40). Stratified analyses on study designs and ethnicities were also conducted. IL-1RN VNTR was positively correlated with H. pylori infection in Asian subgroup and Hospital-Based subgroup (i.e., study samples obtained from hospital inpatients). In conclusion, our study demonstrated that IL-1RN VNTR polymorphism might increase the risk of H. pylori infection, especially in Asians.

Helicobacter pylori with East Asian-type cagPAI genes is more virulent than strains with Western-type in some cagPAI genes

The severity of Helicobacter pylori-related disease is correlated with the presence and integrity of a cag pathogenicity island (cagPAI). cagPAI genotype may have a modifying effect on the pathogenic potential of the infecting strain. After analyzing the sequences of cagPAI genes, some strains with the East Asian-type cagPAI genes were selected for further analysis to examine the association between the diversity of the cagPAI genes and the virulence of H. pylori. The results showed that gastric mucosal inflammatory cell infiltration was significantly higher in patients with East Asian-type cagPAI genes H. pylori strain compared with mosaicism cagPAI genes H. pylori strain (p < 0.05). H. pylori strains with the East Asian-type cagPAI genes were closely associated with IL-8 secretion in vitro and in vivo compared with H. pylori strains with the mosaicism cagPAI genes (p < 0.01). H. pylori strains with East Asian-type cagPAI genes are able to strongly translocate CagA to host cells. These results suggest that H. pylori strains with East Asian-type cagPAI genes are more virulent than the strains of cagPAI gene/genes that are Western type.

From inflammation to gastric cancer: Role of Helicobacter pylori

Gastric cancer is a multifactorial disease and a leading cause of mortality and the risk factors for this include environmental factors and factors that influence host-pathogen interaction and complex interplay between these factors. Gastric adenocarcinomas are of two types, namely intestinal and diffuse type, and Helicobacter pylori (H. pylori) infection has been suspected of being causally linked to the initiation of chronic active gastritis, which leads to adenocarcinoma of the intestinal type. Even though most individuals with H. pylori infection do not show any clinical symptoms, long-term infection leads to inflammation of gastric epithelium and approximately 10% of infected patients develop peptic ulcers and 1–3% of patients develop gastric adenocarcinoma. Among the several mechanisms involved in tumorigenesis, CagA and peptidoglycan of H. pylori, which enter the infected gastric epithelial cells play an important role by triggering oncogenic pathways. Inflammation induced by H. pylori in gastric epithelium, which involves the cyclooxygenase-2/prostaglandin E2 pathway and IL-1β, is also an important factor that triggers chronic active gastritis and adenocarcinoma. H. pylori infection induced oxidative stress and dysregulated E-cadherin/β-catenin/p120 interactions and function also play a critical role in tumorigenesis. Environmental and dietary factors, in particular salt intake, are known to modify the pathogenesis induced by H. pylori. Gastric cancer induced by H. pylori appears to involve several mechanisms, making this mode of tumorigenesis a highly complicated process. Nevertheless, there are many events in this tumorigenesis that remain to be clarified and investigated.

Interleukin-1B 31 C>T polymorphism combined with Helicobacter pylori-modified gastric cancer susceptibility: evidence from 37 studies

Gastric cancer is one of the most common malignancies worldwide. Interleukin‐1‐beta (IL‐1β) is a pro‐inflammatory cytokine and potent inhibitor of gastric acid secretion. Some studies provided evidence of the association between IL‐1B 31 polymorphism and gastric cancer risk while other studies did not. Therefore, we conducted a comprehensive meta‐analysis to reassess the association. A systematic literature search of the PubMed and EMBASE databases identified 37 studies with 6108 cases and 8980 controls for this meta‐analysis. The crude odd ratios (ORs) and the 95% confidence intervals (CIs) were calculated to evaluate the strength of the association. Meta‐regression was used to determine the major source of heterogeneity across the studies. The pooled analysis did not suggest the significant association of IL‐1B 31 C>T polymorphism with gastric cancer risk. Stratified analysis was performed by ethnicity, source of control, genotype method, and indicated a significantly increased gastric cancer risk associated with IL‐1B 31T variant in the population‐based subgroup (heterozygous model: OR = 1.22, 95% CI = 1.03–1.45). Moreover, stratified analysis by Helicobacter pylori infection status indicated that IL‐1B 31 polymorphism increased gastric cancer risk in infection‐positive subgroup (homozygous model: OR = 1.35, 95% CI = 1.02–1.78; heterozygous model: OR = 1.31, 95% CI = 1.04–1.66; recessive model: OR = 1.29, 95% CI = 1.04–1.61). The study suggested that IL‐1B 31 polymorphism might confer susceptibility to gastric cancer in the presence of H. pylori infection, indicating a gene–environment interaction in gastric carcinogenesis.

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.

Withaferin A Inhibits Helicobacter pylori-induced Production of IL-1β in Dendritic Cells by Regulating NF-κB and NLRP3 Inflammasome Activation

Helicobacter pylori infection is associated with chronic gastritis, peptic ulcer, and gastric cancer. There is evidence that IL-1β is associated with the development of gastric cancer. Therefore, downregulation of H. pylori-mediated IL-1β production may be a way to prevent gastric cancer. Withaferin A (WA), a withanolide purified from Withania somnifera, is known to exert anti-inflammatory and anti-tumor effects. In the present study, we explored the inhibitory activity of WA on H. pylori-induced production of IL-1β in murine bone marrow-derived dendritic cells (BMDCs) and the underlying cellular mechanism. Co-treatment with WA decreased IL-1β production by H. pylori in BMDCs in a dose-dependent manner. H. pylori-induced gene expression of IL-1β and NLRP3 (NOD-like receptor family, pyrin domain containing 3) were also suppressed by WA treatment. Moreover, IκB-α phosphorylation by H. pylori infection was suppressed by WA in BMDCs. Western blot analysis revealed that H. pylori induced cleavage of caspase-1 and IL-1β, as well as increased procaspase-1 and pro IL-1β protein levels, and that both were suppressed by co-treatment with WA. Finally, we determined whether WA can directly inhibit ac tivation of the NLRP3 inflammasome. NLRP3 activators induced IL-1β secretion in LPS-primed macrophages, which was inhibited by WA in a dose-dependent manner, whereas IL-6 production was not affected by WA. Moreover, cleavage of IL-1β and caspase-1 by NLRP3 activators was also dose-dependently inhibited by WA. These findings suggest that WA can inhibit IL-1β production by H. pylori in dendritic cells and can be used as a new preventive and therapeutic agent for gastric cancer.

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.

Molecular genetics of gastric adenocarcinoma in clinical practice

The molecular genetics of gastric carcinoma (GC) dictates their biology and clinical behavior. The two morphologically distinct types of gastric carcinoma by Lauren classification, i.e., intestinal and diffuse cell types, have a significant difference in clinical outcome. These two types of GC have different molecular pathogenetic pathways with unique genetic alterations. In addition to environmental and other etiologies, intestinal type GC is associated with Helicobacter pylori (H. pylori) infection and involves a multistep molecular pathway driving the normal epithelium to intestinal metaplasia, dysplasia, and malignant transformation by chromosomal and/or microsatellite instability (MSI), mutation of tumor suppressor genes, and loss of heterozygosity among others. Diffuse type shows no clear causal relationship with H. pylori infection, but is commonly associated with deficiency of cell-cell adhesion due to mutation of the E-cadherin gene (CDH1), and a manifestation of the hereditary gastric cancer syndrome. Thus, detection of CDH1 mutation or loss of expression of E-cadherin may aid in early diagnosis or screening of diffuse type GC. Detection of certain genetic markers, for example, MSI and matrix metalloproteinases, may provide prognostic information, particularly for intestinal type. The common genetic alterations may offer therapeutic targets for treatment of GC. Polymorphisms in Thymidylate synthase to metabolize 5-fluorouracil, glutathione S-transferase for degradation of Cisplatin, and amplification/overexpression of human epidermal growth factor receptor 2 targeted by monoclonal antibody Trastuzumab, are a few examples. P13K/Akt/mTOR pathway, c-Met pathways, epidermal growth factor receptor, insulin-like growth factor receptor, vascular endothelial growth factor receptor fibroblast growth factor receptor, and micro RNAs are several potential therapeutic biomarkers for GC under investigation.

Association of interleukin-1β -511 C/T polymorphism with tobacco-associated cancer in northeast India: a study on oral and gastric cancer

The IL-1β -511 C/T polymorphism is associated with increased IL-1 production and with increased risk of developing cancers. In this study, 251 patients (125 with gastric cancer [GC] and 126 with oral cancer [OC]) and 207 normal controls from northeast (NE) India were genotyped for the IL-1β -511 C/T polymorphism by PCR-restriction fragment length polymorphism (RFLP) and sequencing. Analysis of results showed betel-quid chewing to be a major risk factor (OR = 2.01, 95% CI = 1.05-3.87; P = 0.035) for OC. Inheritance of the IL-1β -511 CT or TT resulted in a 2.6- to 3.05-fold increase in the risk of developing OC relative to that of participants who possessed the reference genotype (OR = 2.57, 95% CI = 1.06-6.22; P = 0.036 and OR = 3.05, 95% CI = 1.22-7.63; P = 0.017), after adjusting for potential confounders. The dominant genetic model also confirmed the presence of the T allele as a significant risk factor for OC (OR = 2.72, 95% CI = 1.15-6.42; P = 0.02). In GC, interaction of the CT genotype with tobacco and betel-quid chewing habits conferred a significant 78% and 89% reduced risk of cancer, respectively. In conclusion, for the NE Indian population, the IL-1β -511 CC and CT genotypes were significantly associated with increased risk of OC. However, the interaction of the CT genotype with risk habits may play a preventive role for GC but not for OC.

Interleukin-1β induced by Helicobacter pylori infection enhances mouse gastric carcinogenesis

Interleukin-1β (Il1b) is considered to be involved in Helicobacter pylori (HP)-induced human gastric carcinogenesis, while the role of its polymorphisms in gastric cancer susceptibility remains controversial. Here, we aimed to clarify the role of HP infection-induced IL1B in gastric inflammation and carcinogenesis using Il1b(-/-) (Il1b-null) mice. In gastric mucosa of the Il1b(+/+) (WT) mice, HP infection induced Il1b expression and severe inflammation. In contrast, in Il1b-null mice, recruitment of neutrophils and macrophages by HP infection was markedly suppressed. In a carcinogenicity test, the multiplicity of gastric tumors was significantly suppressed in theIl1b-null mice (58% of WT; P<0.005). Mechanistically, HP infection induced NF-κB activation both in the inflammatory and epithelial cells in gastric mucosae, and the activation was attenuated in the Il1b-null mice. Accordingly, increased proliferation and decreased apoptosis of gastric epithelial cells induced by HP infection in the WT mice were attenuated in the Il1b-null mice. These results demonstrated that the IL1B physiologically induced by HP infection enhanced gastric carcinogenesis by affecting both inflammatory and epithelial cells.

Systematic review and meta-analysis on the association between IL-1B polymorphisms and cancer risk

BACKGROUND

Interleukin-1 beta (IL-1β), a pro-inflammatory cytokine, is emerging as a key mediator of carcinogenesis that characterizes host-environment interactions. Epidemiological studies investigating the association between two polymorphisms of IL-1B (-511C/T and +3954C/T) and cancer susceptibility have shown conflicting results. The aim of this study is to derive a more precise estimation of the relationship.

METHODS

Related studies were identified through a systematic literature search of PubMed and Web of Science from their inception to September 15, 2012. Summary odds ratios (ORs) and 95% confidence intervals (CIs) for the IL-1B -511C/T and +3954C/T polymorphisms and cancer risk were calculated. Heterogeneity among studies and publication bias were also tested.

RESULTS

The meta-analysis included 91 case-control studies in 85 publications, 81 studies for the -511C/T (19547 cases and 23935 controls) and 26 studies for the +3954C/T polymorphisms (8083 cases and 9183). The pooled results indicated that IL-1B +3954C/T (dominant model: OR = 1.15, 95% CI: 1.01-1.30) was significantly associated with increased overall cancer risk, especially among hospital-based case-control studies (dominant model: OR = 1.30, 95% CI: 1.02-1.66). As for -511C/T, we observed an inverse relationship in cervical cancer (dominant model: OR = 1.74, 95% CI: 1.35-2.23) and hepatocellular carcinoma (dominant model: OR = 0.68, 95% CI: 0.47-0.99). Moreover, -511C/T was associated with risk of specific subtypes of gastric carcinoma.

CONCLUSION

This meta-analysis suggested that both the IL-1B -511C/T and +3954C/T polymorphisms might modulate cancer susceptibility. Further well-designed studies based on larger sample sizes should be performed to confirm the findings.

E-selectin rs5361 and FCGR2A rs1801274 variants were associated with increased risk of gastric cancer in a Chinese population

Host immune responses are critical steps for carcinogenesis. Single nucleotide polymorphisms (SNPs) in immunoregulatory genes may influence gastric cancer risk. We performed a genotyping analysis for immunoregulatory genes in 311 gastric cancer cases and 425 controls from a Chinese population. We found that there were significant differences of E-selectin variant rs5361 (A>C) and FCGR2A variant rs1801274 (T>C) between cases and controls (P = 0.022 and P = 0.0001, respectively). Logistic regression analysis indicated that genotype of E-selectin rs5361AC increased the risk of gastric cancer significantly (P = 0.026, adjusted Odds ratio (OR) = 2.84, 95% confidence interval (CI) = 1.13-7.12). C allele of E-selectin rs5361 showed a significant increased frequency in cases (P = 0.023). However, the E-selectin variant did not affect the protein expression. E-selectin protein was observed not only in tumor interstitial vascular endothelial cells, but also in gastric cancer cells at primary and metastatic sites. The protein was associated with clinicopathological characteristics of gastric cancer, such as age (P = 0.008), tumor size (P = 0.027), differentiation (P = 0.000), and tumor-node-metastasis (TNM) stage (P = 0.006). CT and CC + CT genotypes of FCGR2A variant rs1801274 increased gastric cancer risk (P = 0.000, adjusted OR = 1.92, 95%CI = 1.36-2.72; P = 0.003, adjusted OR = 1.68, 95%CI = 1.20-2.35, respectively). Interleukin-4 receptor (IL-4R) variant rs2107356 presented negative correlations to E-selectin variant rs5361 and FCGR2A variant rs1801274 (P = 0.035 and P = 0.023) in conferring susceptibility to gastric cancer. We concluded E-selectin variant rs5361 and FCGR2A variant rs1801274 were significantly associated with gastric cancer risk. Expression of E-selectin protein would promote progression of gastric cancer.

Polymorphisms of the TLR2 and TLR4 genes are associated with risk of gastric cancer in a Brazilian population

AIM: To investigate toll-like receptor 2 (TLR2) -196 to -174 del, and TLR4 (+896A/G rs4986790 and +1196C/T rs4986791) polymorphisms at risk of chronic gastritis and gastric cancer in a Brazilian population and association of gastric lesions with risk factors such as smoking, alcohol intake and Helicobacter pylori infection.

METHODS: In this case-control study, polymorphism at TLR2 -196 to -174 del was investigated by using the allele-specific polymerase chain reaction (PCR) method, while the PCR-restriction fragment length polymorphism technique was carried out to identify the TLR4 (rs4986790 and rs4986791) genotypes in 607 Brazilian individuals (208 with chronic gastritis-CG, 174 with gastric cancer-GC and 225 controls -C).

RESULTS: The single nucleotide polymorphisms TLR4+1196C/T was not associated with risk of chronic gastritis or gastric cancer and the homozygous genotypes TLR4+896GG and TLR4+1196TT were absent in the studied population. However, the frequency of TLR2 -196 to -174 ins/del + del/del and TLR4+896AG genotypes was significantly higher (P < 0.01 and P = 0.01, respectively) in the cancer group (33.4% and 11.5%, respectively) than in the control group (16.9% and 4.5%, respectively). It was also observed that the G-C haplotype of the TLR4+896A/G+1196C/T (P = 0.02) and the combination of variant alleles of the TLR2/TLR4+896G (P = 0.02) are associated with susceptibility to gastric cancer. In addition, the multiple logistic regression showed that male gender [odds ratio (OR) = 2.70; 95% CI: 1.66-4.41; P < 0.01], alcohol intake (OR = 2.93; 95% CI: 1.76-4.87; P < 0.01), TLR2 -196 to -174 del (OR = 2.64; 95% CI: 1.56-4.44; P < 0.01) and TLR4+896G (OR = 3.19; 95% CI: 1.34- 7.61; P < 0.01) polymorphisms were associated with a higher susceptibility to developing this neoplasm.

CONCLUSION: Our data indicate that TLR2 -196 to -174 del and TLR4+896G may increase the risk of gastric cancer in a Brazilian population.

Capsaicin consumption, Helicobacter pylori CagA status and IL1B-31C>T genotypes: a host and environment interaction in gastric cancer

Gastric cancer (GC) has been associated with a complex combination of genetic and environmental factors. In contrast to most countries, available information on GC mortality trends showed a gradual increase in Mexico. Our aim was to explore potential interactions among dietary (chili pepper consumption), infectious (Helicobacter pylori) and genetic factors (IL1B-31 genotypes) on GC risk. The study was performed in three areas of Mexico, with different GC mortality rates. We included 158 GC patients and 317 clinical controls. Consumption of capsaicin (Cap), the pungent active substance of chili peppers, was estimated by food frequency questionnaire. H. pylori CagA status was assessed by ELISA, and IL1B-31 genotypes were determined by TaqMan assays and Pyrosequencing in DNA samples. Multivariate unconditional logistic regression was used to estimate potential interactions. Moderate to high Cap consumption synergistically increased GC risk in genetically susceptible individuals (IL1B-31C allele carriers) infected with the more virulent H. pylori (CagA+) strains. The combined presence of these factors might explain the absence of a decreasing trend for GC in Mexico. However, further research on gene-environment interactions is required to fully understand the factors determining GC patterns in susceptible populations, with the aim of recommending preventive measures for high risk individuals.

IL-1ra anti-inflammatory cytokine polymorphism is associated with risk of gastric cancer and chronic gastritis in a Brazilian population, but the TNF-β pro-inflammatory cytokine is not

Genetic polymorphisms in genes that codify inflammatory cytokines have been associated with gastric carcinogenesis. This study evaluated polymorphisms IL-1RN VNTR and TNFB+252A/G in a population from Southeast Brazil with regard to the risk of chronic gastritis and gastric cancer and the presence of an association of gastric lesions with risk factors such as gender, age, smoking, drinking and Helicobacter pylori infection. In this case-control study, polymorphism at IL-1RN VNTR was investigated using the allele-specific polymerase chain reaction method, while the polymerase chain reaction-restriction fragment length polymorphism technique was used to identify the TNFB+252A/G genotype in 675 Brazilian individuals [229 with chronic gastritis (CG), 200 with gastric cancer (GC) and 246 healthy individuals as controls (C)]. Multiple logistic regression analysis (log-additive, dominant, and recessive models) have not showed association of the genotype frequencies for the SNP TNFB + 252A/G with risk of CG or GC. However, as for IL-1RN VNTR it was observed significant differences in all three analysis models, with higher values of OR in recessive model, both in the GC group (OR = 3.04, 95% CI = 1.41-6.56, p < 0.01) and CG (OR = 2.32, 95% CI = 1.10-4.90, p = 0.02) compared to the C group. In addition, the multiple logistic regression showed also an association with risk factors such as male gender, older age and alcohol intake regarded GC group. So, our results indicated that the IL-1RN*2 allele may increase the risk of gastric cancer and precancerous lesions in the Southeast Brazilian population, reinforcing the importance of host genetic factors in the susceptibility to gastric cancer and the participation of cytokines in both the inflammation and the carcinogenic process.

Polymorphisms in interleukin-1B (IL-1B) and interleukin 1 receptor antagonist (IL-1RN) genes associate with gastric cancer risk in the Chinese population

BACKGROUND

Gastric cancer is one of the most common malignancies afflicting the Chinese population. Polymorphisms in interleukin-1B (IL-1B) and interleukin-1 receptor antagonist (IL-1RN) genes have been associated with increased gastric cancer risk.

AIMS

A case-control study enrolled 392 gastric cancer patients and 508 healthy were carried out to investigate the association between polymorphisms in IL-1B and IL-1RN and gastric cancer risk.

METHODS

Polymerase chain reaction (PCR)-restriction fragment length polymorphism was used for detection of two potentially functional polymorphisms (IL-1B-31 and IL-1B-511) in the IL-1B gene promoter and PCR was used for detection of the variable tandem repeat in the second intron of IL-1RN.

RESULTS

The data showed that the IL-1B-31CC genotype increased gastric cancer risk to an adjusted odd of 2.27 (95% CI, 1.49-3.46), IL-1B-31CT to 1.48 (95% CI, 1.01-2.16) and IL-1B-31CT/CC to 1.68 (95% CI, 1.17-2.40), while IL-1B-51TT genotype associated with increased gastric cancer risk to an adjusted odd of 2.53 (95% CI, 1.67-3.84), IL-1B-511TC to 1.45 (95% CI, 1.02-2.06), and IL-1B-511TC TT/TC to 1.72 (95% CI, 1.23, 2.39). Furthermore, IL-1RN heterogeneity genotype (IL-1RN2L) was associated with gastric cancer risk to an adjusted odd of 1.70 (95% CI, 1.05-2.74) compared to the wild-type homozygote (IL-1RNLL). In addition, H. pylori infection enhanced gastric cancer risk through these SNPs.

CONCLUSIONS

The data from the current study demonstrated that the genotype CC or CT of IL-1B-31, TT or CT of IL-1B-511, and 2L of IL-1RN increased risk of gastric cancer in this Chinese population and the risk was further enhanced by H. pylori.

Epidemiological review of gastric cancer in India

Stomach cancer is the one of the leading cause of cancer in southern region of India. Its incidence is decreasing worldwide yet on global scale stomach cancer remains one of the most common causes of cancer death. Etiology of gastric cancer includes Helicobacter pylori infection, diet and lifestyle, tobacco, alcohol and genetic susceptibility. In this review, we tried to find the contribution of Indian scientist in understanding the descriptive and observational epidemiology of stomach cancer. PubMed was used as a search platform using key words such as "stomach cancer, treatment, clinical characteristics, stomach cancer outcome, epidemiology, etiological factor and their corresponding Mesh terms were used in combination with Boolean operators OR, AND". Most of the reported studies on gastric cancer from India are case report or case series and few are case-control studies. Indian studies on this topic are limited and have observed H. pylori infection, salted tea, pickled food, rice intake, spicy food, soda (additive of food), tobacco and alcohol as risk factors for gastric cancer. More research is required to understand the etiology, develop suitable screening test, to demarcate high-risk population and to develop and evaluate the effect of primary prevention programs.

Molecular characterization and susceptibility testing of Helicobacter pylori strains isolated in western Argentina

OBJECTIVE

To characterize Helicobacter pylori isolates from western Argentina using virulence markers and antimicrobial susceptibility patterns in order to assess the association between virulent genotypes, antimicrobial resistance, and disease. DNA fingerprinting was also evaluated for the segregation of virulent or resistant strain clusters.

METHODS

Genotyping of 299 H. pylori isolates was performed by PCR using specific primers for the cagA, vacA and iceA genes. Random amplification of polymorphic DNA (RAPD)-PCR and rep-PCR genetic clustering were assessed using five random primers and BOXA1R and ERIC primers, respectively. Resistance to clarithromycin (Cla) and metronidazole (Mtz) was assessed by the agar dilution method.

RESULTS

It was observed that 40.8% of the genotypes were cagA-positive; 66.9% were vacA s1m1 genotype and the iceA1 allele was found in 40.8%. A significant correlation (p=0.0000) was observed between cagA positivity and vacA s1m1/iceA1 genotypes. Triple virulent genotypes were statistically associated with peptic ulcer (PU) (p=0.0001) and Cla resistance (p=0.0000). RAPD fingerprints obtained with AO2 primers identified clusters that were strongly associated with PU, virulence markers, and resistance to Cla and Mtz.

CONCLUSIONS

The H. pylori isolates that harbored two or three virulence markers were more resistant to Cla and Mtz. Combined analysis of virulent genotypes and resistance patterns may permit identification of high-risk patients to prevent PU later in life or to avoid antimicrobial treatment failure.

Diversity in the cag pathogenicity island of Helicobacter pylori isolates in populations from North and South India

The cag pathogenicity island (cagPAI) has been reported to be the major virulence determinant in Helicobacter pylori-related diseases. In the present study, the diversity of the cagA gene and the integrity of the cagPAI in 158 H. pylori strains from Varanasi (North India) and Hyderabad (South India) were studied by amplifying the cagA gene (approximately 3.5 kb), followed by PCR-RFLP analysis. The results revealed significant differences in the cagA gene and the integrity of the cagPAI between North and South Indian isolates. Of 158 isolates, 40 (34.8 %) from Varanasi and 20 (46.5 %) from Hyderabad were found to carry an intact cagPAI. A partially deleted cagPAI was present in 75 (65.2 %) isolates from Varanasi and 23 (53.5 %) from Hyderabad. None of the isolates showed complete deletion of the cagPAI. Differences in the cagA 5' and 3' regions were also noted, and 11 isolates (8 from Varanasi and 3 from Hyderabad) that were cagA negative with primers for the 5' region turned out to be cagA positive with primers for the 3' variable region. It is tentatively concluded that the 3' variable region may be a better marker for cagA typing. The results also showed that the majority of the isolates harboured the Western-type EPIYA motif. PCR-RFLP analysis of the cagA gene showed 29 distinguishable digestion patterns, and cluster analysis of RFLP types from a random selection of 32 isolates placed all of the isolates into 5 groups. These results demonstrate that significant differences in the cagPAI occur among isolates from North and South India, and that RFLP of cagA could be employed for elucidating genetic variations among various isolates of H. pylori.