Risks of interleukin-1 genetic polymorphisms and Helicobacter pylori infection in the development of gastric cancer

Role of polymorphisms in genes that encode cytokines and Helicobacter pylori virulence factors in gastric carcinogenesis

The Helicobacter pylori (H. pylori) infection is a determinant factor in gastric cancer (GC) development. However, the infection outcomes are variable and depend on both host and bacterial characteristics. Some host cytokines such as interleukin (IL)-1β, IL-1Ra, IL-8, IL-10 and tumor necrosis factor-α play important roles in the host immune system response to the pathogen, in the development of gastric mucosal lesions and in cell malignant transformation. Therefore, these host factors are crucial in neoplastic processes. Certain polymorphisms in genes that encode these cytokines have been associated with an increased risk of GC. On the other hand, various virulence factors found in distinct H. pylori bacterial strains, including cytotoxin-associated antigen A, vacuolating cytotoxin, duodenal ulcer promoting gene A protein, outer inflammatory protein and blood group antigen binding adhesin, have been associated with the pathogenesis of different gastric diseases. The virulent factors mentioned above allow the successful infection by the bacterium and play crucial roles in gastric mucosa lesions, including malignant transformation. Moreover, the role of host polymorphisms and bacterial virulence factors in gastric carcinogenesis seems to vary among different countries and populations. The identification of host and bacterium factors that are associated with an increased risk of GC development may be useful in determining the prognosis of infection in patients, what could help in clinical decision-making and in providing of an optimized clinical approach.

Combination of Interleukin 1 Polymorphism and Helicobacter pylori Infection: an Increased Risk of Gastric Cancer in Pakistani Population

Helicobacter pylori is one of the major risk factors involved in the development ofgastritis and gastric cancer (GC). H. pylori infection leads to increased production of pro-inflammatory cytokines by the host. Carriage of specific polymorphisms in cytokine genes may be associated with host susceptibility to the development of GC. We investigated the role of host genetic factors including polymorphisms of IL-1B and IL-1RN in correlation with gastritis and GC in H. pylori infected Pakistani population. A total of 230 gastritis cases and 100 GC cases were genotyped for IL 1B-511 and IL-1RN penta-allelic variable number of tandem repeats (VNTRs). A combination of IL-1B-511*T and IL-1RN*2 alleles (OR 19.064; 95% CI 2.319-156.7; p = 0.001) in H. pylori infected individuals had markedly increased risk of GC development. In Pakistani population, an increased risk of GC development is associated with the carriage of IL-1B-511*T and IL-1RN*2 alleles. Synergistic effect of H. pylori infection and IL-1B-511*T/IL-1RN*2 genotypes was also observed in association with significantly higher risk of developing GC. Further prospective and large scale studies are needed to establish the clinical impact of these findings.

Interaction between Helicobacter pylori and host genetic variants in gastric carcinogenesis

Helicobacter pylori (H. pylori) is the definite carcinogen of gastric cancer. H. pylori infection induces chronic inflammation, causes DNA damage and aberrant methylation of genes and these pathways are involved in H. pylori-related gastric carcinogenesis. Polymorphisms of the genes involved in these pathways could alter susceptibility to gastric cancer. In this mini review, we focused on the role of polymorphisms in these genes on the susceptibility to gastric cancer, with a particular emphasis on their possible interactions with H. pylori infection. We found that many studies on this theme did not simultaneously report H. pylori infection and the interactions remained inconclusive.

Correlation Between Interleukin-1β-511 C/T Polymorphism and Gastric Cancer in Chinese Populations: A Meta-Analysis

Background

Several studies have indicated that interleukin (IL)-1β-511 C/T polymorphism may contribute to individual susceptibility to gastric cancer, but the results vary among regions and races. No relevant meta-analysis has been conducted in a Chinese population. Therefore, we performed the current meta-analysis to investigate the possible correlation between IL-1β-511 C/T polymorphism and gastric cancer susceptibility in Chinese subjects.

Material/Methods

PubMed, EmBase, Cochrane Library, Chinese Biology Medicine (CBM), Chinese National Knowledge Infrastructure (CNKI), and Wanfang databases were searched for case-control studies published before 21 January 2015 and investigating a correlation between IL-1β-511 C/T polymorphism and gastric cancer susceptibility. Two investigators independently screened the studies, extracted data, and evaluated the quality of included studies with the Newcastle-Ottawa scale. Meta-analysis was conducted with STATA 12.0.

Results

A total of 27 articles from 28 case-control studies were collected. Meta-analysis showed that IL-1β-511C/T polymorphism was related to increased susceptibility to gastric cancer in Chinese subjects [T vs. C: OR=1.21, 95%CI (1.07–1.37), P<0.01; TT vs. CC: OR=1.41, 95%CI (1.11–1.80), P<0.01; CT vs. CC: OR=1.26, 95% CI (1.05–1.50), P<0.01; TT+CT vs. CC: OR=1.31, 95%CI (1.08–1.58), P<0.01; and TT vs. CT+CC: OR=1.24, 95%CI (1.05–1.47), P<0.01]. Subgroup analysis showed a significant correlation between IL-1β-511C/T polymorphism and susceptibility to gastric cancer in residents of southern China and in patients with intestinal-type gastric cancer, but not in residents of northern China or in patients with diffuse gastric cancer. Moreover, H. pylori-infected subjects carrying T (CT+TT) exhibited a relatively higher risk of GC [OR=2.4, 95% CI (1.2–5.1), P=0.02].

Conclusions

IL-1β-511C/T polymorphism is significantly associated with increased susceptibility to gastric cancer in residents of southern China and in intestinal-type gastric cancer. We also found a synergistic interaction between IL-1β-511C/T polymorphism and H. pylori infection in the development of GC.

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.

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.

IL1 receptor antagonist gene IL1-RN variable number of tandem repeats polymorphism and cancer risk: a literature review and meta-analysis

IL1 receptor antagonist (IL1RA) and IL1beta (IL1β), members of the pro-inflammatory cytokine interleukin-1 (IL1) family, play a potential role against infection and in the pathogenesis of cancers. The variable number of tandem repeats (VNTR) polymorphism in the second intron of the IL1 receptor antagonist gene (IL1-RN) and a polymorphism in exon 5 of IL1B (IL1B+3954C>T, rs1143634) have been suggested in predisposition to cancer risk. However, studies have shown inconsistent results. To validate any association, a meta-analysis was performed with 14,854 cases and 19,337 controls from 71 published case–control studies for IL1-RN VNTR and 33 eligible studies contained 7,847 cases and 8917 controls for IL1B +3954. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated from comparisons to assess the strength of the association. There was significant association between the IL1-RN VNTR polymorphism and the risk of cancer for any overall comparison. Furthermore, cancer type stratification analysis revealed that there were significantly increased risks of gastric cancer, bladder cancer and other cancer groups. Infection status analysis indicated that the H. pylori or HBV/HCV infection and IL1-RN VNTR genotypes were independent factors for developing gastric or hepatocellular cancers. In addition, a borderline significant association was observed between IL1B+3954 polymorphism and the increased cancer risk. Although some modest bias could not be eliminated, this meta-analysis suggested that the IL1-RN VNTR polymorphisms may contribute to genetic susceptibility to gastric cancer. More studies are needed to further evaluate the role of the IL1B+3954 polymorphism in the etiology of cancer.

Polymorphisms in inflammatory response genes and their association with gastric cancer: A HuGE systematic review and meta-analyses

To evaluate the association between gastric cancer susceptibility and inflammation-related gene polymorphisms, the authors conducted a series of meta-analyses using a predefined protocol. Genes investigated were those coding for the interleukin (IL) proteins (IL1B, IL1RN, IL8, and IL10) and for tumor necrosis factor-alpha. Gastric cancers were stratified by histologic subtype and anatomic subsite, by Helicobacter pylori infection status, by geographic location (Asian or non-Asian study population), and by a quantitative index of study quality. All published literature and meeting abstracts from the period 1990-2006 were considered. Results consistently supported increased cancer risk for IL1RN2 carriers; the increased risk was specific to non-Asian populations and was seen for intestinal and diffuse cancers, distal cancers, and, to a lesser extent, cardia cancers. Analyses restricted to high-quality studies or H. pylori-positive cases and controls also showed significant associations with both carrier status and homozygosity status. In Asian populations, reduced risk was observed in association with IL1B-31C carrier status. This effect was also observed in analyses restricted to high-quality studies. These results indicate the importance of stratification by anatomic site, histologic type, H. pylori infection, and country of origin. Study quality considerations, both laboratory and epidemiologic, can also affect results and may explain, in part, the variability in results published to date.

Gastric juice acidity in upper gastrointestinal diseases

AIM: To search the independent factors determining gastric juice acidity and to investigate the acidity of gastric juices in various benign and malignant upper gastrointestinal diseases.

METHODS: Fasting gastric juice acidity of 165 healthy subjects and 346 patients with esophageal ulcer (n = 21), gastric ulcer (n = 136), duodenal ulcer (n = 100) or gastric cancer (n = 89) were measured and compared. Additionally, gastric specimens were taken from the antrum and body for rapid urease test and histological examination.

RESULTS: Multivariate analysis revealed that bile stain of gastric juice, high acute inflammatory score of the corpus, and atrophy of the corpus were independent risk factors for the development of gastric hypoacidity with odds ratios of 3.1 (95% CI: 1.3-7.3), 3.1 (95% CI: 1.2-7.9) and 3.5 (95% CI: 1.3-9.2). Esophageal ulcer and duodenal ulcer patients had a lower pH level (1.9 and 2.1 vs 2.9, both P < 0.05) of gastric juices than healthy subjects. In contrast, gastric ulcer and gastric cancer patients had a higher pH level (3.4 and 6.6 vs 2.9, both P < 0.001) than healthy controls. Hypoacidity existed in 22%, 5%, 29%, 5% and 88% of healthy subjects, esophageal ulcer, gastric ulcer, duodenal ulcer and gastric cancer patients, respectively.

CONCLUSION: Bile reflux, atrophy and dense neutrophil infiltrate of the corpus are three independent factors determining the acidity of gastric juice.

Interleukin-1B and interleukin-1 receptor antagonist gene polymorphisms are not associated with premalignant gastric conditions: a combined haplotype analysis

OBJECTIVE

Contradictory results have been reported about the role of interleukin-1B (IL1B) and IL1 receptor antagonist (IL1RN) alleles in gastric carcinogenesis. Here, IL1B and IL1RN polymorphisms were analyzed as genotypes and haplotypes in relation to the presence of atrophic gastritis (AG) and intestinal metaplasia in the stomach.

METHODS

Two hundred and seventy-eight patients (212 Caucasians and 66 Asians) aged 50 years and above, referred for upper endoscopy because of dyspeptic symptoms, were included in the study. Gastric biopsies were histologically assessed according to the updated Sydney classification. Genomic DNA was typed for polymorphisms at position -3737, -1464, -511, -31 for the IL1B gene and the allele 2 of IL1RN using restriction fragment length polymorphism of amplified PCR fragments and intron-spanning PCR analysis, respectively.

RESULTS

IL1B-1464-C/C genotype was associated with higher presence of AG in antrum of the stomach in Caucasians [odds ratio: 4.8 (95% confidence interval=1.7-14.3); P=0.028]. IL1B-1464-G/C genotype was associated with lower incidence of AG in corpus of the stomach in Asians [odds ratio: 0.7 (95% confidence interval=0.5-0.8); P=0.02]. IL1RN*2 allele was not linked with AG or intestinal metaplasia in all parts of the stomach both among Asians and Caucasians. Overall, data show that none of the major four IL1B polymorphisms (IL1B-3737C>T, -1464G>C, -511C>T, -31T>C) and the IL1RN*2 is individually, or in its haplotype configuration, linked to the presence of premalignant lesions in Caucasians.

CONCLUSION

The determination of these IL1-related loci does not have any predictive value for stratification of subgroups with respect to gastric cancer risk.

Interleukin-1B and interleukin-1 RN polymorphisms and gastric carcinoma risk: a meta-analysis

BACKGROUND AND AIM

We aimed to explore the role of interleukin (IL)-1B cluster gene polymorphisms at positions -511, -31, and +3954 and the receptor IL-1RN variable number tandem repeat polymorphisms in the susceptibility to gastric carcinoma through a systematic review and meta-analysis.

METHODS

Each initially included article was scored for quality appraisal. The desirable data were extracted and registered into databases. Studies that deviated from Hardy-Weinberg equilibrium were excluded. Eighteen studies were ultimately eligible for the meta-analysis of IL1B-511, 21 studies for IL1B-31, 10 studies for IL1B+3954, and 20 studies for IL1RN variable number tandem repeat genetic polymorphisms, respectively. Original groups were collapsed and re-grouping was adopted in line with the most probably appropriate genetic models. Potential sources of heterogeneity were sought out via stratification and sensitivity analyses, and biases across studies were estimated.

RESULTS

The pooled odds ratios (95% confidence intervals, P-value) associated with IL-1B -511 T carriers versus CC genotypes and with RN *2 carriers versus L/L were 1.23 (1.04-1.45, P = 0.015) and 1.26 (1.06-1.51, P = 0.010), respectively, for overall gastric carcinoma; 1.31 (1.04-1.64, P = 0.020) and 1.47 (1.21-1.79, P = 0.000), respectively, for non-cardia gastric cancer; 1.55 (1.05-2.28, P = 0.026) and 1.66 (1.23-2.25, P = 0.001), respectively, for intestinal type gastric carcinoma; and 1.33 (1.04-1.71, P = 0.023) and 1.31 (1.07-1.61, P = 0.010), respectively, in Caucasians for overall gastric carcinoma. The pooled odds ratio (95% confidence interval, P-value) regarding IL-1B-31 CC plus TT versus CT was 0.73 (0.60-0.89, P = 0.002) for intestinal type gastric carcinoma. Genotyping methods and publication time could constitute the sources of heterogeneity across studies. Publication biases were not found.

CONCLUSION

IL-1B -511 T allele and IL-1 RN *2 VNTR are significantly associated with an increased risk of developing gastric carcinoma and even more significantly with non-cardia gastric carcinoma or with intestinal-type gastric carcinoma. Both are significantly associated with an increased risk of developing gastric carcinoma among Caucasians, but not among Asians or Hispanics.

Role of interleukin polymorphisms in gastric cancer: "Pros and cons"

Helicobacter pylori (H. pylori) infection is the leading cause of gastric cancer worldwide. Infection with this bacterium causes a chronic active immune response that persists for the life of the host. The combination of bacterial factors, environmental insults, and the host immune response drives the initiation and progression of mucosal atrophy, metaplasia, and dysplasia toward GC. Among the host factors, IL-1 gene cluster polymorphisms (IL-1B encoding IL-1β and IL-1RN encoding IL-1ra, its naturally occurring receptor antagonist) play a decisive role in modulating the risk of developing hypochlorhydria, gastric atrophy and GC in the presence of H. pylori infection. In particular, one single nucleotide polymorphism in the IL-1B promoter (IL-1B-511C⁄T), and the short allele of a 86-bp variable number of tandem repeats polymorphism in the IL-1RN second intron (IL-1RN*2) are associated with an increased risk for GC. However this hypothesis is still to be fully confirmed. This review focuses on the divergent results obtained by several epidemiological and functional in vitro and in vivo studies and show that IL-1 genotyping has still no role in the clinical management of patients with H. pylori infection.

Interleukin-1 and TNF-alpha polymorphisms and Helicobacter pylori in a Brazilian Amazon population

AIM

To study the association between Interleukin-1 (IL-1) and tumor necrosis factor (TNF)-alpha polymorphisms, infection by Helicobacter pylori (H pylori) and the development of gastrointestinal diseases.

METHODS

Genomic DNA was extracted from the peripheral blood of 177 patients with various gastrointestinal diseases and from 100 healthy volunteers. The polymorphisms in IL-1beta and TNF-alpha genes were analyzed using the polymerase chain reaction-restriction fragment length polymorphism method (PCR-RFLP) and those from IL-1RN with PCR. The presence of infection due to H pylori and the presence of the CagA toxin were detected by serology. The histopathological parameters in the gastric biopsies of the patients were according to the Sydney classification.

RESULTS

A comparison of the frequencies of the different polymorphisms studied among the patients and the control group demonstrated that the allele IL-1RN*2 was more frequent among patients with gastric ulcers and adenocarcinoma. Carriers of the allele IL-RN*2 and those with reactive serology for anti-CagA IgG had a greater risk of developing peptic ulcer and gastric adenocarcinoma, as well as a higher degree of inflammation and neutrophilic activity in the gastric mucosa.

CONCLUSION

Our results indicate a positive association between IL-1RN gene polymorphism and infection by positive H pylori CagA strains and the development of gastric ulcers and adenocarcinoma.

Interleukin 1-beta gene polymorphisms and risk of gastric cancer in Sweden

OBJECTIVE

Helicobacter pylori (H. pylori) infection stimulates the production of interleukin (IL)-1 beta, a pro-inflammatory cytokine and suppressor of gastric acid secretion. As both inflammation and hypochlorhydria, which might facilitate proximal colonization of H. pylori and other bacterial species alike, have been implicated in gastric carcinogenesis, much attention has been directed to functional genetic polymorphisms that affect the production of IL-1 beta. The purpose of this study was to clarify the role of these polymorphisms.

MATERIAL AND METHODS

We analysed a population-based, case-control study in 5 Swedish counties and a hospital-based, case-control study conducted in 8 Swedish hospitals, with a total of 351 gastric cancer cases and 539 controls. The IL1B-31, IL1B-511 and IL1B+3954 biallelic polymorphisms were genotyped using pyrosequencing. The variable number of tandem repeats (VNTR) polymorphism of IL1-RN was analysed using polymerase chain reaction (PCR) followed by gel electrophoresis. Relative risks were estimated by odds ratios with 95% confidence intervals, derived from unconditional logistic regression.

RESULTS

The risk of gastric cancer was unrelated to genotype in all of the studied polymorphic loci, and the absence of any association was confirmed in both the population-based and hospital-based case-control studies. Analyses confined to histological subtypes (intestinal or diffuse) and site-specific tumours (cardia or distal stomach), as well as analyses stratified by H. pylori infection status and family history of gastric cancer, did not reveal any significant increases or decreases in risk.

CONCLUSION

Our results do not lend support to the hypothesis that human genetic polymorphisms related to the production of IL-1 beta are associated with the risk of gastric cancer.

Interleukin-1 and TNF-α polymorphisms and Helicobacter pylori in a Brazilian Amazon population

AIM: To study the association between Interleukin-1 (IL-1) and tumor necrosis factor (TNF)-α polymorphisms, infection by Helicobacter pylori (H pylori) and the development of gastrointestinal diseases.

METHODS: Genomic DNA was extracted from the peripheral blood of 177 patients with various gastrointestinal diseases and from 100 healthy volunteers. The polymorphisms in IL-1β and TNF-α genes were analyzed using the polymerase chain reaction-restriction fragment length polymorphism method (PCR-RFLP) and those from IL-1RN with PCR. The presence of infection due to H pylori and the presence of the CagA toxin were detected by serology. The histopathological parameters in the gastric biopsies of the patients were according to the Sydney classification.

RESULTS: A comparison of the frequencies of the different polymorphisms studied among the patients and the control group demonstrated that the allele IL-1RN*2 was more frequent among patients with gastric ulcers and adenocarcinoma. Carriers of the allele IL-RN*2 and those with reactive serology for anti-CagA IgG had a greater risk of developing peptic ulcer and gastric adenocarcinoma, as well as a higher degree of inflammation and neutrophilic activity in the gastric mucosa.

CONCLUSION: Our results indicate a positive association between IL-1RN gene polymorphism and infection by positive H pylori CagA strains and the development of gastric ulcers and adenocarcinoma.

Mechanism for gastric cancer development by Helicobacter pylori infection

Helicobacter pylori (H. pylori) infection plays a crucial role in the development of gastric cancer. There are two major pathways for the development of gastric cancer by H. pylori infection: the indirect action of H. pylori on gastric epithelial cells through inflammation, and the direct action of the bacteria on epithelial cells through the induction of protein modulation and gene mutation. Both pathways work together to promote gastric carcinogenesis.

Is interleukin-1 genotyping useful for the clinical management of patients with atrophic body gastritis?

BACKGROUND

Atrophic body gastritis patients are at increased risk for gastric cancer. IL-1B/IL-1RN polymorphisms have been associated with gastric cancer susceptibility. The relationship between these polymorphisms and the long-term outcome of atrophic body gastritis patients is not known.

AIM

To investigate whether the genotyping of IL-1B-511/IL-1RN polymorphisms is useful to characterize atrophic body gastritis patients at increased risk for gastric neoplasms.

METHODS

IL-1B-511/IL-1RN polymorphisms were compared between 110 atrophic body gastritis patients and 110 age- and gender-matched controls, and patients were followed up (median 4.1 years) according to a cohort study design.

RESULTS

Genotype frequencies of IL-1B-511/IL-1RN were similar between patients and controls. Atrophic body gastritis patients harbouring the wild type of IL-1B-511/IL-1RN polymorphisms were not different from those harbouring the proinflammatory pattern as far as regards gender, age, gastric cancer family history and metaplastic atrophy. Sixteen atrophic body gastritis patients developed a gastric neoplastic lesion at follow-up: eight were IL-1B-511-T carriers and eight were IL-1RN-allele-2 carriers. Harbouring the proinflammatory genotypes was not significantly associated with developing gastric neoplastic lesions.

CONCLUSIONS

In atrophic body gastritis patients, IL-1B-511 and IL-1RN polymorphisms do not appear to be associated either with specific clinical, biochemical or histological features or with the development of gastric neoplastic lesions at long-term follow-up.

Gastric cancer susceptibility is not linked to pro-and anti-inflammatory cytokine gene polymorphisms in whites: a Nationwide Multicenter Study in Spain

BACKGROUND AND AIMS

Recent studies have reported an association between cytokine gene polymorphisms and GC risk. However, results are inconsistent among studies from different geographic regions and ethnic groups. Our goal was to evaluate the influence of Helicobacter pylori (H. pylori) infection and host genetic factors on GC susceptibility in a population of Spanish white GC patients.

METHODS

DNA from 404 unrelated patients with GC and 404 sex- and age-matched healthy controls was typed for several functional polymorphisms in pro- (IL-1B, TNFA, LTA, IL-12p40) and anti-inflammatory (IL-4, IL-1RN, IL-10, TGFB1) genes by PCR, RFLP, and TaqMan assays. H. pylori infection and CagA/VacA antibody status were also determined by western blot serology.

RESULTS

Logistic regression analysis identified H. pylori infection with cagA strains (OR 2.54, 95% CI 1.77-3.66), smoking habit (OR 1.91, 95% CI 1.25-2.93), and positive family history of GC (OR 3.67, 95% CI 2.01-6.71) as independent risk factors for GC. None of the cytokine gene polymorphisms analyzed in this study were associated with susceptibility to GC development, whether GC patients were analyzed as a group or categorized according to anatomic location or histological subtype. Some simultaneous combinations of proinflammatory genotypes reportedly associated with greater GC risk yielded no significant differences between patients and controls.

CONCLUSIONS

Our results show that, at least in some white populations, the contribution of the cytokine gene polymorphisms evaluated in this study (IL-1B, IL-1RN, IL-12p40, LTA, IL-10, IL-4, and TGF-B1) to GC susceptibility may be less relevant than previously reported.

Interleukin-1B polymorphisms and gastric cancer risk--a meta-analysis

Some studies have reported that proinflammatory polymorphisms in interleukin-1B (IL-1B) and IL-1 receptor antagonist (IL-1RN) genes are associated with increased gastric cancer risk. However, other studies have shown null or inverse associations. This meta-analysis reviews and summarizes published evidence for these associations. Searching the PubMed Database yielded 35 studies that reported on the association between IL-1B -511 C>T, IL-1B -31 T>C, or IL-1RN variable number tandem repeat polymorphisms and gastric cancer risk. Q-statistics and I(2) statistics were calculated to examine heterogeneity. Summary odds ratios (OR) and 95% confidence intervals (95% CI) were calculated in the random-effects model using the DerSimonian-Laird method. For all gastric cancers, the overall ORs (95% CIs) for IL-1B -511 CT versus CC and TT versus CC genotypes were 1.07 (0.91-1.25) and 1.16 (0.95-1.42), respectively. ORs (95% CIs) for the association between IL-1B -31 CT versus TT and CC versus TT genotypes were 0.99 (0.83-1.19) and 0.98 (0.78-1.21), respectively. For the associations between IL-1RN and gastric cancer, ORs (95% CIs) for *2/L versus LL and *2/*2 versus L/L were 1.15 (0.96-1.38) and 1.23 (0.79-1.92). For each of the examined associations, there was significant heterogeneity among studies; P(heterogeneity) < or = 0.001 and I(2) ranged from 0.54 to 0.71. Noncardia cancers showed stronger associations with IL-1B -511 CT or TT and IL1-RN *2/*2 genotypes, but limiting the analysis to intestinal-type cancers, studies conducted in Western countries, or studies in which polymorphisms were in Hardy-Weinberg equilibrium, made no material difference in the results. The overall associations between IL-1B or IL-1RN proinflammatory polymorphisms and gastric cancer were null but several studies showed an association. The sources of this variation are unclear.

Alpha1-antitrypsin precursor in gastric juice is a novel biomarker for gastric cancer and ulcer

PURPOSE

To search for novel disease-specific markers in gastric juice by investigating the protein concentrations and components in gastric juice from patients with various gastroduodenal diseases.

EXPERIMENTAL DESIGN

Protein concentrations and pH values in fasting gastric juice were examined in 120 healthy subjects and 39 gastric ulcer, 38 duodenal ulcer, and 31 gastric cancer patients. The protein components in gastric juice were studied by two-dimensional PAGE and mass spectrometric analysis.

RESULTS

Protein concentrations in gastric juice of patients with gastric ulcers and gastric cancer were significantly higher than those in healthy subjects (1.06 and 2.61 mg/mL versus 0.48 mg/mL; P=0.001 and P<0.001, respectively), and duodenal ulcer patients had lower gastric juice protein concentrations compared with healthy subjects (0.26 versus 0.48 mg/mL; P<0.05). Gastric hypoacidity and advanced age were independent factors affecting the protein concentrations in gastric juice with odds ratios of 32.9 (95% confidence interval, 11.8-90.9) and 3.2 (95% confidence interval, 1.3-8.3), respectively. Each electrophoresis images of gastric juice could be classified into one of three patterns: basic band, specific band, or nonspecific band. The frequencies of specific band pattern in healthy subjects, gastric ulcer, duodenal ulcer, and gastric cancer patients were 6%, 42%, 6%, and 93%, respectively. Proteomic analysis revealed that alpha1-antitrypsin precursor was the principal peptide in the specific band.

CONCLUSIONS

alpha1-antitrypsin precursor in gastric juice is a novel biomarker for gastric cancer and ulcer. A noninvasive method to obtain gastric juice followed by proteomic analysis may serve as a new tool to screen for gastric malignancies.

Novel interleukin-4 and interleukin-1 receptor antagonist gene variations associated with non-cardia gastric cancer in Japan: comprehensive analysis of 207 polymorphisms of 11 cytokine genes

BACKGROUND AND AIM

Helicobacter pylori (H. pylori)-induced chronic atrophic gastritis is a high-risk factor for gastric cancer. Immune responses to H. pylori are involved in gastric mucosal inflammation, and might affect clinical outcome, including the development of gastric cancer. The present study examines the significance of gene polymorphisms of various cytokines in the development of gastric cancer following H. pylori infection.

METHODS

One hundred Japanese non-cardia gastric cancer patients and 93 dyspeptic patients as controls were enrolled in the study (age range 50-75 years). All patients were positive for H. pylori. Genomic DNA was extracted from peripheral whole blood leukocytes, and we comprehensively analyzed 207 single nucleotide polymorphisms (SNP) in 11 cytokine genes; interleukin (IL)-1alpha, IL-1beta, IL-1 receptor antagonist (RN), IL-4, IL-4R, IL-8, IL-10, IL-12, TNF-alpha, TNF-beta, and IFN-gamma, using either invader assay (163 SNP), direct sequencing (22 SNP), or PCR-restriction fragment length polymorphism (22 SNP).

RESULTS

Among the 207 SNP examined, the IL-4 gene diplotypes (984 and 2983 AA/GA) had a significant negative association with gastric cancer development (odds ratio =0.3, 95% confidence interval =0.1-0.9). When we adopted the dyspeptic patients over 66 years of age as the controls, the IL-1RN gene diplotypes (-1102 and 6110 CG/GA) also had a significant negative association (odds ratio =0.2, 95% confidence interval =0.1-0.7).

CONCLUSION

A comprehensive analysis of 207 SNP of 11 cytokine genes revealed that variations in IL-4 and IL-1RN genes are negatively associated with the risk of developing gastric cancer following H. pylori infection. Distinct host cytokine responses in the gastric mucosa might have a role in H. pylori-induced carcinogenesis.

Helicobacter pylori infection and the risk of gastric malignancy

OBJECTIVE

This prospective cohort study investigated the impact of Helicobacter pylori infection on the development of various gastric malignancies.

METHODS

We prospectively followed up 1,225 dyspeptic Taiwanese who had nonulcer dyspepsia, gastric ulcers, or duodenal ulcers at enrollment. Among them, 618 (50.4%) had H. pylori infection and 607 (49.6%) did not. Patients underwent endoscopy at enrollment and at 1- to 3-yr intervals thereafter.

RESULTS

During a mean follow-up of 6.3 yr, gastric adenocarcinoma developed in 7 of the 618 H. pylori-infected patients, but in none of the 607 uninfected patients (1.1%vs 0.0%, P= 0.015). The incidence of gastric lymphoma was 0.2% (1/618) and 0% in H. pylori-infected and uninfected patients. Taken together, the development rate of gastric malignancy in H. pylori-infected patients was significantly higher than that in uninfected patients (1.3%vs 0%, P= 0.007). Among H. pylori-infected subjects, the incidence of gastric malignancy was similar between those receiving and not receiving eradication therapy (1.4%vs 1.2%). Multivariate analysis showed that intestinal metaplasia was the only independent factor predicting subsequent development of gastric malignancy in H. pylori-infected subjects with an odds ratio of 4.5 (95% CI 1.1-19.1).

CONCLUSIONS

In this prospective cohort study, all gastric malignancies, including adenocarcinoma and lymphoma, developed in H. pylori-infected patients. The finding implies that H. pylori is a necessary cause of most gastric malignancies. Follow-up for H. pylori-infected patients who have intestinal metaplasia is indicated.

Interleukin-1beta gene (IL-1B) and interleukin 1 receptor antagonist gene (IL-1RN) polymorphisms and gastric cancer risk in an Omani Arab population

BACKGROUND

Gastric cancer (GC) is the most common malignancy in Oman. Interleukin-1beta gene (IL-1B) and interleukin-1 receptor antagonist gene (IL-1RN) polymorphisms have been associated with increased GC risk. No previous studies have examined their role in an Arab population. We tested the associations between polymorphisms of IL1B at positions -31, -511, and +3954 and the IL-1RN polymorphism [variable number of tandem repeats (VNTR) and TC polymorphism at the -2018 position] and GC in Omani Arab patients.

METHODS

Genomic DNA was extracted from peripheral blood of 245 control subjects and 118 gastric cancer patients. The DNA samples were analyzed using the TaqMan allelic discrimination test for IL-1B -31, -511, and +3954 polymorphisms and IL-1RN -2018 polymorphism. The VNTR of IL-1RN was genotyped using the polymerase chain reaction followed by agarose gel electrophoresis.

RESULTS

There was an association between the presence of IL-1RN*2 allele and gastric cancer [odds ratio (OR) = 2.2, 95% confidence interval (CI) = 1.0-3.3, P = 0.04). The GC risk further increased to OR = 3.5 (95% CI = 1.0-11.9) in Helicobacter pylori-positive patients. No association was found between any of the other polymorphisms studied and GC.

CONCLUSION

IL-1RN polymorphism increased the risk of GC in an Omani Arab population, consistent with previous reports. In contrast, the IL-1B -31 polymorphism was not associated with an increased GC risk. These findings underscore the role of cytokine gene polymorphisms in the development of GC and further support the ethnic differences in the effect of IL-1B polymorphism on GC carcinogenesis.

Association of interleukin-1 gene polymorphisms with gastric cancer: a meta-analysis

Previous studies on the association between interleukin-1 (IL-1) genetic polymorphisms and the risk of gastric cancer have produced conflicting results. The purpose of this study was to examine the association between IL-1 genotype and gastric cancer by systematically reviewing the risk of the original studies. Thirty-nine studies, which included 6,863 gastric cancer cases and 8,434 controls, met the inclusion criteria and were included in the meta-analysis. By pooling all the studies identified, the summary odds ratio (OR) of gastric cancer risk associated with IL-1B-511T, -31C, +3954T and IL-1RN*2 was 1.26 (95% confidence interval (CI): 1.03-1.55), 1.00 (95% CI: 0.82-1.22), 1.37 (95% CI: 0.94-2.00) and 1.20 (95% CI: 1.01-1.41), respectively. A stratified analysis showed that IL-1B-511T was associated with an increased risk of gastric cancer (intestinal type) (OR = 1.76, 95% CI: 1.12-2.57). Moreover, IL-1RN*2 was also associated with an increased risk of gastric cancer among Caucasians (OR = 1.30, 95% CI: 1.09-1.54). In conclusion, IL-1B-511 and IL-1RN genetic polymorphisms are associated with an increased risk of developing gastric cancer.

Interleukin-1beta and interleukin-1 receptor antagonist gene polymorphisms and gastric cancer: a meta-analysis

BACKGROUND

Polymorphisms of interleukin-1B (IL1B) and its receptor antagonist (IL1RN) genes have been inconsistently associated with gastric cancer risk. We examined these associations by performing meta-analyses.

MATERIALS AND METHODS

Twenty-five studies testing the association between IL1B and/or IL1RN gene polymorphisms and gastric cancer were examined: 14 studies of IL1B-511, 14 studies of IL1B-31, 8 studies of IL1B+3954, and 23 studies of IL1RN. Overall and ethnicity-specific summary odds ratios and corresponding 95% confidence intervals for gastric cancer associated with these polymorphisms were estimated using fixed- and random-effects models. Heterogeneity and publication bias were evaluated.

RESULTS

IL1B-511T and IL1RN*2 were associated with gastric cancer risk in Caucasians, but not in Asians. For IL1B-511T, the association in Caucasians was stronger when intestinal-subtype and noncardia gastric cancer cases were examined. A nonsignificant trend was observed between IL1B-31C and gastric cancer in Caucasians. No significant association of IL1B+3954T and gastric cancer risk was detected. Studies with better methodologic characteristics reported stronger effects. There was no evidence of publication bias.

CONCLUSION

IL1B-511T is associated with gastric cancer susceptibility in Caucasians. The meta-analyses suggest that the conflicting results among studies may be explained by variation in allele frequencies among the ethnic groups and variation in tumor types, as well as by the methodologic quality of the studies.

H pylori and gastric cancer: Shifting the global burden

Infection with H pylori leads to a persistent chronic inflammation of the gastric mucosa, thereby increasing the risk of distal gastric adenocarcinoma. Numerous studies have determined a clear correlation between H pylori infection and the risk of gastric cancer; however, general eradication is not recommended as cancer prophylaxis and time points for treatment remain controversial in different areas of the world. Prevalence rates in Western countries are decreasing, especially in younger people (< 10%); and a decline in distal gastric adenocarcinoma has been observed. Risk groups in Western countries still show considerably higher risk of developing cancer, especially in patients infected with cagA⁺ strains and in persons harboring genetic polymorphism of the IL-1B promoter (-511T/T) and the corresponding IL-1 receptor antagonist (IL-1RN*2). Thus, general eradication of all infected persons in Western countries not recommended and is limited to risk groups in order to achieve a risk reduction. In contrast, infection rates and cancer prevalence are still high in East Asian countries. A prevention strategy to treat infected persons may avoid the development of gastric cancer to a large extent and with enormous clinical importance. However, studies in China and Japan indicate that prevention of gastric cancer is effective only in those patients that do not display severe histological changes such as atrophy and intestinal metaplasia. Thus, prophylactic strategies to prevent gastric cancer in high risk populations such as China should therefore especially aim at individuals now at younger age when the histological alterations caused by the bacterial infection was still reversible. In countries with a low prevalence of gastric cancer, risk groups carrying cagA⁺ strains and IL-1 genetic polymorphisms should be identified and treated.

Latest insights into the effects of Helicobacter pylori infection on gastric carcinogenesis

There appears to be the strong association between Helicobacter pylori (H pylori) and gastric cancer. We reviewed the latest evidences about the effects of H pylori infection on gastric carcinogenesis, classified into epidemiology, dynamics of gastric mucosal changes, DNA damages, virulence factors, host factors, and source of gastric malignancy. Through the considerable progress made in research into virulence factors resulting from differences between H pylori strains, such as cagA positivity, as well as into host factors, such as gene polymorphisms, a diverse spectrum of H pylori-associated diseases, including gastric cancer, is beginning to lend itself to elucidation. The impact of the novel hypothesis advanced by Houghton et al proposing bone-marrow derived stem cells (BMDC) as a potential source of gastric malignancy on evolving research remains to be seen with interest. Further progress in research into H pylori eradication as a viable prophylaxis of gastric cancer, as well as into the mechanisms of gastric carcinogenesis, is to be eagerly awaited for the current year and beyond.

The effects of genetic polymorphisms of IL-1 and TNF-A on Helicobacter pylori-induced gastroduodenal diseases in Korea

OBJECTIVE

To evaluate whether or not genetic polymorphism of IL-1B, IL-1RN, and TNF-Alpha is an important factor in the different expression of gastroduodenal diseases after Helicobacter pylori infection.

METHODS

This study consisted of 1360 subjects: control, gastric cancer (GC, intestinal type, and diffuse type), benign gastric ulcer (BGU), duodenal ulcer, and first-degree gastric cancer relative (GCR). IL-1Beta-511 and TNF-A-308 biallelic polymorphism were genotyped by 5' nuclease polymerase chain reaction (PCR) assays, and PCR-restriction fragment length polymorphism (PCR-RFLP). IL-1RN penta-allelic variable number of tandem repeats was genotyped by PCR.

RESULTS

There was no difference in the genetic polymorphism of IL-1Beta-511, IL-1RN and TNF-A in the patients with gastric cancer regardless of H. pylori positivity compared with control. However, the frequencies of IL-1B-511 C/T (OR: 0.5, 95% CI: 0.3-0.7) and T carrier (OR: 0.6, 95% CI: 0.4-0.8) were lower in the H. pylori-positive BGU patients. The IL-1RN 2/2 was higher (OR: 5.5, 95% CI: 1.1-28.5) in the H. pylori-positive GCR. There was no significance in the polymorphism of TNF-Alpha-308 regardless of H. pylori-induced gastroduodenal diseases.

CONCLUSIONS

The IL-1Beta-511 T-carrier polymorphism has a negative effect on the development of H. pylori-positive BGU, and high frequency of IL-1RN 2/2 was found in the H. pylori-positive relatives of GC patients, which suggest that this genetic polymorphism could play some role in the H. pylori-induced gastroduodenal diseases in Korea.

Gastric cancer risk in a Mexican population: role of Helicobacter pylori CagA positive infection and polymorphisms in interleukin-1 and -10 genes

Several polymorphisms of the IL1B and IL10 gene promoters have been reported to be associated with gastric cancer risk in Caucasians. However, studies in other populations have shown differing results. We aimed to test for associations between polymorphisms in IL1B (-31 and +3954), IL10-592 and IL1RN variable number of tandem repeats (VNTR) and risk of gastric cancer in a Mexican population. DNA was extracted from sera of 183 gastric adenocarcinoma patients and 377 controls. The IL1B-31, IL1B+3954 and IL10-592 biallelic polymorphisms were discriminated using 5' Nuclease (TaqMan) assays and Pyrosequencing. The IL1RN penta-allelic VNTR polymorphism was genotyped using PCR followed by GeneScan analysis. A significant interaction was found between IL1B-31 and CagA status for the risk of intestinal-type gastric cancer (p = 0.023). Among CagA positive subjects, those with IL1B-31CC genotype had an increased risk of intestinal-type gastric cancer (OR 3.19, 95%CI = 1.05-9.68), compared to carriers of IL1B-31TT genotype. In contrast, among CagA negative subjects, no significant association of IL1B-31CC genotype with gastric cancer was observed. The IL10-592CC genotype was associated with more than doubling of the risk of the intestinal-type gastric cancer (OR, 2.20, 95%CI = 1.04-4.65). A nonsignificantly increased risk for intestinal-type gastric cancer was found in IL1RN*2 carriers (OR 1.49, 95%CI = 0.89-2.50). None of these polymorphisms was significantly related to the risk of diffuse-type gastric cancer. No significant association was found between risk of gastric cancer and the IL1B+3954 polymorphism. Individuals carrying 2 or more of the risk-associated alleles (IL1B-31C, IL1RN *2 and IL10-592C) were at increased risk for intestinal-type gastric cancer, compared to those with 0 or 1 risk-associated allele. The risk from multiple risk-associated alleles was especially high in subjects infected with CagA positive H. pylori. Our results support the identification of the IL1B-31 promoter polymorphism as a useful marker for risk of intestinal type gastric cancer in persons with CagA positive H. pylori infections.

Interleukin 1 genetics, inflammatory mechanisms, and nutrigenetic opportunities to modulate diseases of aging

Inflammation plays a central role in many diseases of aging, and genetic differences in the inflammatory response appear to influence different disease courses among individuals. Variations in the genes for the family of interleukin 1 (IL-1) proteins are inherited together in a small set of patterns and provide an example of the role of inflammatory genetics as a modifier of diseases of aging. The IL-1 genetic variations are associated with variation in both the inflammatory response and the clinical presentation of a range of diseases, including coronary artery disease, Alzheimer disease, gastric cancer, and periodontitis. This growing understanding of the role of genetic variation in inflammation and chronic disease presents opportunities to identify healthy persons who are at increased risk of disease and to potentially modify the trajectory of disease to prolong healthy aging. Nutrition represents one of the promising approaches to modulation of the risk of diseases of aging because of the effects of certain nutrients on gene expression. One of the most practical applications of nutritional modulation of chronic disease may be nutrients that regulate the expression of key inflammatory genes.

Familial gastric cancer - clinical management

The clinical management of familial gastric cancer is the same as that for sporadic gastric cancer at the current time. As the causative mutations for these cases are identified this should lead to the development of specific treatments which target the molecular abnormality. The only germline mutations identified so far occur within the E-cadherin gene (CDHI) and they account for approximately 30% of familial gastric cancer cases. When index patients fulfilling the clinical criteria for hereditary diffuse gastric cancer syndrome have a CDHI mutation identified then genetic testing of asymptomatic relatives should be considered. The clinical sequelae of testing positive for such a mutation are profound and therefore it is essential that counselling is given prior to genetic testing. The management options are surveillance endoscopy and prophylactic gastrectomy. In this chapter the practicalities of genetic testing are discussed as well as the pros and cons of the two management options. It is essential that experience of these rare families is pooled so that surveillance and treatment can be optimised in the future.

Role of cytokine polymorphisms in the risk of distal gastric cancer development

We review the current information concerning the role of cytokine polymorphisms and the risk of develop distal gastric cancer in different populations. We have included populations colonized with Helicobacter pylori as well as populations without colonization. We found that the study of polymorphisms alone seems insufficient to assess gastric cancer risk and it is necessary to examine environmental factors in different ethnic groups and geographic areas along with the study of H. pylori strains to define better the risk factors associated with distal gastric cancer.

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Interleukin-1 gene polymorphisms and gastric cancer risk in a high-risk Italian population

OBJECTIVES

Host genetic factors, including the IL1 gene cluster, play a key role in determining the long-term outcome of Helicobacter pylori infection. The aim of the study was to investigate the relationship between selected IL1 loci polymorphisms and gastric cancer risk in an Italian population.

METHODS

In a case-control study we compared the IL1B-31 and IL1B+3954 biallelic and IL1RN pentaallelic variable number of tandem repeats (VNTR) polymorphisms in 185 gastric cancer patients and 546 controls randomly sampled from the general population of an area at high gastric cancer risk (Tuscany, Central Italy).

RESULTS

Genotype frequencies of the IL1B-31 T/C, IL1B+3954 C/T, and IL1RN polymorphisms among our population controls were in Hardy-Weinberg equilibrium. In multivariate analyses, no increase in gastric cancer risk was observed for the IL1B-31*C- and IL1B+3954*T- carriers; a significant 50% increase emerged for IL1RN*2 allele carriers (OR = 1.49; 95% CI: 1.01-2.21). Analyses based on combined genotypes showed also that the association with IL1RN*2 allele was limited to two-variant allele carriers who were also homozygous for the IL1B-31*T allele (OR = 2.23; 95% CI: 1.18-4.23) with a statistically significant interaction between these two genotypes (p= 0.043). Haplotype analysis showed an increased risk for the haplotype IL1RN*2/IL1B-31*T.

CONCLUSIONS

Our results suggest that host genetic factors (such as the IL1RN and the IL1B-31 polymorphisms) interact in the complex process of gastric carcinogenesis in this high-risk Italian population. Overall, this effect appears more modest than previously reported in other populations, supporting the hypothesis that other still-to-be-defined factors are important in gastric carcinogenesis. These findings might be due to a haplotype effect.

IL1RN polymorphic gene and cagA-positive status independently increase the risk of noncardia gastric carcinoma

Helicobacter pylori cagA-positive strains and host cytokine proinflammatory polymorphisms have been associated with gastric carcinoma. However, the individual role of each factor has not been evaluated yet. Our aim was to evaluate whether IL-1 gene cluster and tumor necrosis factor-alpha (TNFA)-307 polymorphisms, as well as cagA-positive status, are associated with gastric carcinoma in a non-Caucasian population by analyzing the data in logistic regression models. We evaluated 166 patients with noncardia gastric carcinoma and 541 blood donors. Among them, 702 were successfully genotyped for all cytokine studied: 166 with gastric carcinoma and 536 controls. The carcinoma patients were considered to be H. pylori-positive if culture alone or 2 among preformed urease test, stained smear or histologic section, serology, polymerase chain reaction (PCR) for ureA and urea breath test were positive. In blood donors, H. pylori status was based on enzyme-linked immunosorbent assay. The cagA status was determined by PCR or serology. IL1B-511/-31, IL1RN (interleukin-1 receptor antagonist) and TNFA-307 polymorphisms were genotyped by PCR, PCR with restriction fragment length polymorphism, or PCR with confronting 2-pair primers. We found that the IL1RN2 polymorphic allele (OR = 1.93) was associated with noncardia gastric carcinoma, even after inclusion of age, gender and cagA status in the logistic models. However, the cagA-positive status was the strongest independent factor associated with gastric carcinoma (OR = 11.89). The other polymorphisms were not significantly associated with the disease when they were evaluated in logistic models. This study provides evidence supporting the independent associations of cagA-positive H. pylori status and IL1RN polymorphisms with noncardia gastric carcinoma.

Association of the myeloperoxidase-468G→A polymorphism with gastric inflammation and duodenal ulcer risk

AIM: To elucidate the relations between the myeloperoxidase^-468G→A polymorphism and the development of duodenal ulcer (DU), and to investigate the impacts of this host genetic polymorphism on the histopathological features of Helicobacter pylori (H pylori)-related gastritis.

METHODS: In a case-control study of 115 consecutive DU patients and 182 controls, the myeloperoxidase^-468G→A polymorphism was genotyped. Additionally, gastric mucosal changes were examined according to the updated Sydney System.

RESULTS: The two study groups differed in the distributions of myeloperoxidase genotypes (P = 0.008). All six individuals carrying myeloperoxidase A/A genotypes were in the DU group. The carriage of myeloperoxidase allele A and H pylori infection were associated with an increased risk of DU with odds ratios (OR) of 2.3 and 5.8, respectively. The combined risk of the carriage of myeloperoxidase allele A and H pylori infection for DU was 8.7 (95% CI, 3.5-21.8). In the H pylori-infected individuals, allele A carriers displayed higher bacterial density scores (P = 0.04) in the antrum than did non-carriers.

CONCLUSION: This work verifies for the first time the association of myeloperoxidase^-468G→A polymorphism with antral H pylori density and DU disease. The mechanisms underlying this genetic polymorphism in developing DU disease merit further investigations.

Helicobacter infection and gastric neoplasia

Chronic gastritis induced by Helicobacter pylori is the strongest known risk factor for adenocarcinoma of the distal stomach, yet only a minority of people who harbour this organism ever develop cancer. H. pylori isolates possess substantial genotypic diversity, which engenders differential host inflammatory responses that influence clinical outcome. H. pylori strains that possess the cag pathogenicity island and secrete a functional cytotoxin induce more severe gastric injury and further augment the risk for developing distal gastric cancer. However, carcinogenesis is also influenced by host genetic diversity, particularly involving immune response genes such as IL-1ss and TNF-alpha. It is important to gain insight into the pathogenesis of H. pylori-induced gastritis and adenocarcinoma, not only to develop more effective treatments for gastric cancer, but also because it might serve as a paradigm for the role of chronic inflammation in the genesis of other malignancies that arise within the gastrointestinal tract.

The interleukin-1 RN polymorphism and Helicobacter pylori infection in the development of duodenal ulcer

BACKGROUND

The host genetic factors that determine the clinical outcomes for Helicobacter pylori-infected individuals remain unclear.

AIMS

To elucidate the relations among interleukin-1 locus polymorphisms, and H. pylori infection in the development of duodenal ulcers.

MATERIALS AND METHODS

In a case-control study involving 168 control subjects and 147 patients with duodenal ulcer, biallelic polymorphisms of two interleukin-1 loci, IL-1B(-511) and IL-1B(+3954), as well as the penta-allelic variable number of tandem repeats of interleukin-1 receptor antagonist IL-1RN, were genotyped, and the H. pylori states of controls and patients were examined.

RESULTS

Helicobacter pylori infection, male gender and the carriage of IL-1RN*2 independently increased the risk of duodenal ulcer with odds ratios of 6.4 (95% confidence interval, 3.7-11.0), 1.9 (95% confidence interval, 1.1-3.4) and 2.7 (95% confidence interval, 1.1-6.8), respectively. Statistical analysis revealed an interaction between IL-1RN*2 and H. pylori infection with the duodenal ulcer risk conferred by the H. pylori infection substantially increased (odds ratios, 22.6; 95% confidence interval, 5.9-86.5) by the carriage of IL-1RN*2. In addition, a synergistic interaction between IL-1RN*2 and blood group O existed. The combined risk of H. pylori infection, the carriage of IL-1RN*2 and blood group O for duodenal ulcer was 27.5 (95% confidence interval, 3.1-243.6).

CONCLUSIONS

This work is the first to verify IL-1RN*2 as an independent factor that governs the development of duodenal ulcers. Our data indicate that H. pylori infection and IL-1RN*2 synergistically determine susceptibility to duodenal ulcer. The blood group phenotype is possibly a crucial determinant for the outcome of the impact of an interleukin-1 locus polymorphism on H. pylori-infected individuals.

Gastric cancer: who is at risk?

Gastric cancer is a multifactorial disease. Helicobacter pylori infection, host genetic factors and dietetic factors play an important role in the development of gastric cancer. Individuals with a positive family history of gastric cancer and/or pro-inflammatory polymorphisms of the interleukin-1 and tumor necrosis factor A genes infected by H. pylori virulent strains (cagA-, vacA s1-, vacA m1- and babA2-positive) have the highest risk of gastric cancer development. Diets rich in salted and smoked food and poor in fresh fruit and vegetables favor gastric carcinogenesis. Genetic combined with bacterial and host genotyping may allow for the identification of patients at high risk of gastric cancer who can benefit from preventive eradication therapy.