The interleukin-8-251*T/*A polymorphism is not associated with risk for gastric carcinoma development in a Portuguese population. Eur J Cancer Prev. 2008;17:28-32. [PMID: 18090907 DOI: 10.1097/cej.0b013e32809b4d0f]

The Association Between IL-8 Gene Polymorphisms and the Risk of Several Types of Cancer, Especially in Gastric Cancer

BACKGROUND

Changes in functional genetic polymorphisms may increase or decrease the risk of cancer in patients. Nowadays, the association between polymorphisms in the interleukin-8 (IL-8) gene and the susceptibility of cancer risk have been investigated in many studies, however, above relationships remain unclear.

AIM

The current study aims to comprehensively evaluate the association between IL-8 gene six polymorphisms and the whole cancer risk, especially -251 polymorphism and gastric cancer.

METHODS AND RESULTS

Six polymorphisms (-251, -353, +678, +1633, +2767, +781) were collected. The expression of serum IL-8 was calculated by ELISA assay. First, 104 case-control studies were conducted. Second, this research has made significant discoveries regarding the -251, -353 and +781 polymorphisms and the potential associations with cancer risk. Finally, the serum IL-8 levels in gastric cancer patients with AA/TT genotypes were significantly higher than those with the same genotypes of healthy controls and TT genotypes in gastric cancer patients.

CONCLUSION

Overall, the investigation has revealed that IL-8 gene polymorphisms significantly influence vulnerability to cancer development, especially for gastric cancer.

Influence of Cytokine Genetic Polymorphisms in Helicobacter pylori-Associated Gastric Inflammation According to Sex in South Korea

Background/Aims

: The relationship between genetic polymorphisms and gastric inflammation remains unclear. This study aimed to evaluate the impact of genetic polymorphisms on Helicobacter pylori (HP)-associated gastritis according to sex.

Methods

: Two hundred thirty-two male and 404 female subjects with current HP infection were prospectively enrolled. The genotyping of IL-1B-511 C/T, IL-1RN variable number of tandem repeats, IL-6-572 G/C, IL-8-251 A/T, IL-8-781 C/T, IL-10-1082 G/A, IL-10-592 C/A, TNF-A-308 G/A, and transforming growth factor (TGF)-B-509 C/T, was determined by polymerase chain reaction-restriction fragment length polymorphism. The degree of monocyte or neutrophil infiltration, atrophic gastritis, and intestinal metaplasia was evaluated using the updated Sydney system.

Results

: Among the male subjects, moderate/severe atrophic gastritis of the corpus was higher in IL-1B-511 CC carriers than in CT and TT carriers independent of age, alcohol consumption, and HP virulence factors (26.9% vs 10.4%; adjusted hazard ratio [HR], 4.377; 95% confidence interval, 1.387 to 13.814). In females, IL-8-251 AA carriers were independently and significantly associated with moderate/severe atrophic gastritis of the corpus compared with that in AT and TT carriers (21.4% vs 6.0%, adjusted HR=3.799). In males, the IL-8-251 TT genotype was associated with moderate/severe intestinal metaplasia of the corpus compared with the AT and AA genotypes (13.4% vs 5.6%, adjusted HR=3.128), while the IL-10-592 CA and CC genotypes were associated with moderate/severe monocyte infiltration of the antrum compared with AA genotype (83.6% vs 71.8%, adjusted HR=2.227).

Conclusions

: Genetic polymorphisms in cytokines play different roles in HP-associated gastritis according to sex.

Interleukin-8 genetic diversity, haplotype structure and production differ in two ethnically distinct South African populations

A single nucleotide polymorphism (SNP), 251 bases upstream from the IL-8 transcription start (-251A>T, rs4073), has been extensively investigated in cancers and inflammatory and infectious diseases in predominantly European and Asian populations. We sequenced the IL-8 gene of 109 black and 32 white South African (SA) individuals and conducted detailed characterization of gene variation and haplotype structure. IL-8 production in phytohaemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMCs) of a subset (black: N = 22; white: N = 32) of these individuals was measured using ELISA. Select variants were genotyped for additional black individuals (N = 141), and data from the 1000 Genomes Project were used for haplotype analysis and comparative purposes. In white individuals, the -251A>T SNP formed part of a prevalent six-variant haplotype [haplotype frequency (HF): 61%], Hap-1C, involving the following variants: -251A>T; +394T>G (rs2227307); +780C>T (rs2227306); +1240->A (rs2227541); +1635C>T (rs2227543) and +2770A>T (rs2227543). Hap-1C (-251T+394T+780C+1240+A+1635C+2770A) was composed of two three-variant sub-haplotypes [Hap-1Ca: -251T+394T+1240+A; Hap-1Cb: +780C+1635C+2770A) sharing similarities with haplotypes identified in the black population. Hap-1C was found to be present in European, East and South Asian populations. Four haplotypes were identified in the black population with the two prevalent haplotypes each comprised of two variants: Hap-1B [-251A>T and +1240->A; -251T+1240+A; HF: 14%] and Hap-2B [-743T>C (rs2227532) and +2452A>C (rs2227545); -743C+2452C; HF: 13%]. Populations did not differ in unstimulated PBMC IL-8 production. Upon PHA stimulation, PBMCs from white individuals produced more IL-8 (P = 0.04), suggesting the -251T allele is responsible for higher production, however further analysis revealed that Hap-1C (and constituent sub-haplotypes), did not associate with IL-8 production. Populations did however differ in monocyte number with the white population having significantly more monocytes compared to the black population (P = 0.025), and furthermore monocyte number strongly correlated with IL-8 production in both population groups (black: p = 0.0002, r = 0.71; white: P = 0.0005, r = 0.59). Hap-1B, Hap-2B, and a SNP located one base pair upstream of the IL-8 ATG start codon, +100C>T SNP (rs2227538), all associated with higher IL-8 production in the black population - individuals harbouring at least one of these haplotypes/variant associated with higher IL-8 production (P = 0.003) compared to individuals without. The black population was enriched for individuals harbouring Hap-1B and/or Hap-2B compared to the 1000 Genomes project sub-Saharan African population (P = 0.006), suggesting that SA black individuals may be high IL-8 producers. Given the paucity of IL-8-related studies that have been conducted in populations from sub-Saharan Africa, this study has significantly increased our understanding of this important chemokine in the South African population.

The TNF-A-857*T Polymorphism is Associated with Gastric Adenocarcinoma Risk in a Costa Rican Population

BACKGROUND

Costa Rica is ranked as one of the countries with highest incidence of gastric cancer worldwide. Previous studies in Costa Rican populations have revealed associations between gastric cancer risk and several cytokine polymorphisms that seem to play a role in the regulation of the expression of these proteins. In this study, we assessed associations of the polymorphisms IL-6-174 G/C, IFNGR1-56 C/T, IL-8-251 T/A and TNF-A (-857 C/T, -308 A/G) with gastric pathologies in a high-risk population of Latin America.

METHODS

DNA samples of 47 patients with gastric adenocarcinoma, 53 with chronic gastritis, 56 with duodenal ulcer and 94 healthy controls, were genotyped for the five mentioned SNPs. All participants were ≥50-years-old. Genotyping was performed by PCR-RFLP and 5'-nuclease PCR assay. H. pylori infection, CagA status, pepsinogen (PG) I and II blood levels were determined by ELISA. Logistic regression analysis was used to determine possible associations of the polymorphisms with cancer, gastritis and duodenal ulcer, and linear regression analysis to determine associations with blood PG levels.

RESULTS

A total of 86.6% of the population was positive for H. pylori; of them, 51.6% was CagA+. Patients with the TNF-A-857*T allele had an increased risk for gastritis (OR: 3.67, p = 0.015) and gastric adenocarcinoma (OR:6.15, p = 0.001). Associations between other polymorphisms and gastric diseases, or PG levels, were not found.

CONCLUSIONS

Our results indicate that the TNF-A-857*T SNP is among the risk factors associated with the risk of gastric cancer in Costa Rica.

ASSOCIATION OF IL-8 -251T>A (RS4073) POLYMORPHISM WITH SUSCEPTIBILITY TO GASTRIC CANCER: A SYSTEMATIC REVIEW AND META-ANALYSIS BASED ON 33 CASE-CONTROL STUDIES

BACKGROUND

The role of -251A>T polymorphism in the anti-inflammatory cytokine interleukin-8 (IL-8) gene in gastric cancer was intensively evaluated, but the results of these studies were inconsistent.

OBJECTIVE

Therefore, we performed a meta-analysis to provide a comprehensive data on the association of IL-8 -251T>A polymorphism with gastric cancer.

METHODS

All eligible studies were identified in PubMed, Web of Science, EMBASE, Wanfang and CNKI databases before September 01, 2019. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were derived from a fixed effect or random effect model.

RESULTS

A total of 33 case-control studies with 6,192 cases and 9,567 controls were selected. Overall, pooled data showed that IL-8 -251T>A polymorphism was significantly associated with an increased risk of gastric cancer under all five genetic models, i.e., allele (A vs T: OR=1.189, 95% CI 1.027-1.378, P=0.021), homozygote (AA vs TT: OR=1.307, 95% CI 1.111-1.536, P=0.001), heterozygote (AT vs TT: OR=1.188, 95% CI 1.061-1.330, P=0.003), dominant (AA+AT vs TT: OR=1.337, 95% CI 1.115-1.602, P=0.002) and recessive (AA vs AT+TT: OR=1.241, 95% CI 1.045-1.474, P=0.014). The stratified analysis by ethnicity revealed an increased risk of gastric cancer in Asians and mixed populations, but not in Caucasians. Moreover, stratified by country found a significant association in Chinese, Korean and Brazilian, but not among Japanese.

CONCLUSION

This meta-analysis suggests that the IL-8 -251T>A polymorphism is associated with an increased risk of gastric cancer, especially by ethnicity (Asian and mixed populations) and country (Chinese, Korean and Brazilian).

Genetic Polymorphisms in Inflammatory and Other Regulators in Gastric Cancer: Risks and Clinical Consequences

Helicobacter pylori infection is associated with the development of a chronic inflammatory response, which may induce peptic ulcers, gastric cancer (GC), and mucosa-associated lymphoid tissue (MALT) lymphoma. Chronic H. pylori infection promotes the genetic instability of gastric epithelial cells and interferes with the DNA repair systems in host cells. Colonization of the stomach with H. pylori is an important cause of non-cardia GC and gastric MALT lymphoma. The reduction of GC development in patients who underwent anti-H. pylori eradication schemes has also been well described. Individual susceptibility to GC development depends on the host's genetic predisposition, H. pylori virulence factors, environmental conditions, and geographical determinants. Biological determinants are urgently sought to predict the clinical course of infection in individuals with confirmed H. pylori infection. Possible candidates for such biomarkers include genetic aberrations such as single-nucleotide polymorphisms (SNPs) found in various cytokines/growth factors (e.g., IL-1β, IL-2, IL-6, IL-8, IL-10, IL-13, IL-17A/B, IFN-γ, TNF, TGF-β) and their receptors (IL-RN, TGFR), innate immunity receptors (TLR2, TLR4, CD14, NOD1, NOD2), enzymes involved in signal transduction cascades (PLCE1, PKLR, PRKAA1) as well as glycoproteins (MUC1, PSCA), and DNA repair enzymes (ERCC2, XRCC1, XRCC3). Bacterial determinants related to GC development include infection with CagA-positive (particularly with a high number of EPIYA-C phosphorylation motifs) and VacA-positive isolates (in particular s1/m1 allele strains). The combined genotyping of bacterial and host determinants suggests that the accumulation of polymorphisms favoring host and bacterial features increases the risk for precancerous and cancerous lesions in patients.

Association of IL-8 gene promoter -251 A/T and IL-18 gene promoter -137 G/C polymorphisms with head and neck cancer risk: a comprehensive meta-analysis

Purpose

No consensus exists on the impact of polymorphisms in cytokines (such as interleukin IL-8 and IL-18) on cancer risk; moreover, there is very little evidence regarding head and neck cancer (HNC).

Methods

Thus, a meta-analysis including 22 studies with 4731 cases and 8736 controls was conducted to evaluate this association. The summary odds ratio (OR) and corresponding 95% confidence intervals (CIs) for C-X-C motif chemokine ligand 8 (CXCL8, which encodes IL-8) and IL-18 polymorphisms and HNC risk were estimated.

Results

The results showed a significantly increased risk of HNC susceptibility for IL18 −137 G/C in five genetic models, but, interestingly, no significant association was found for the CXCL8 −251 A/T polymorphism. When stratified by cancer type, an increased risk of nasopharyngeal cancer was found for both −137 G/C and −251A/T. When the studies were stratified by ethnicity and genotyping method, there were significant associations between Asian populations and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) studies for −137 G/C, and African populations for −251 A/T in some genetic models. A positive association was also found between the population-based groups in some models for −137 G/C; conversely, significantly decreased risk was found among the −251 A/T hospital-based group. Meta-regression was also conducted. The publication year, control source, and cancer type contributed to CXCL8 −251 A/T heterogeneity; however, no factors were found that contributed to IL-18 −137 G/C heterogeneity. Marginal significance was found in the recessive model for IL-18 −137 G/C by Egger’s test, whereas no publication bias was detected for CXCL8 −251 A/T.

Conclusions

The results indicate that the IL-18 −137 G/C polymorphism is associated with HNC risk, especially nasopharyngeal cancer, in Asian populations and, when using PCR-RFLP, CXCL8 −251 A/T polymorphisms play a complex role in HNC development.

Human and Helicobacter pylori Interactions Determine the Outcome of Gastric Diseases

The innate immune response is a critical hallmark of Helicobacter pylori infection. Epithelial and myeloid cells produce effectors, including the chemokine CXCL8, reactive oxygen species (ROS), and nitric oxide (NO), in response to bacterial components. Mechanistic and epidemiologic studies have emphasized that dysregulated and persistent release of these products leads to the development of chronic inflammation and to the molecular and cellular events related to carcinogenesis. Moreover, investigations in H. pylori-infected patients about polymorphisms of the genes encoding CXCL8 and inducible NO synthase, and epigenetic control of the ROS-producing enzyme spermine oxidase, have further proven that overproduction of these molecules impacts the severity of gastric diseases. Lastly, the critical effect of the crosstalk between the human host and the infecting bacterium in determining the severity of H. pylori-related diseases has been supported by phylogenetic analysis of the human population and their H. pylori isolates in geographic areas with varying clinical and pathologic outcomes of the infection.

Combination of Helicobacter pylori infection and the interleukin 8 -251 T > A polymorphism, but not the mannose-binding lectin 2 codon 54 G > A polymorphism, might be a risk factor of gastric cancer

Background

Mannose-binding lectin (MBL) acts in the innate immune response to Helicobacter pylori. Interleukin 8 (IL-8) is a potent cytokine produced by gastric epithelial cells in response to H. pylori. We aimed to investigate whether polymorphisms in MBL2 and IL-8 influence susceptibility to H. pylori infection, and the associations of these polymorphisms with the risk of gastroduodenal diseases in a Korean population.

Methods

We consecutively enrolled 176 H. pylori-negative control subjects, 221 subjects with H. pylori-positive non-atrophic gastritis, 52 mild atrophic gastritis (AG), 61 severe AG, 175 duodenal ulcer, and 283 gastric cancer (GC). Allele-specific PCR-RFLP was conducted for polymorphisms in MBL2 exon 1 (codon 52, 54, and 57) and IL-8 -251 T > A. IL-8 levels in gastric mucosal tissues and serum MBL levels were measured by enzyme-linked immunosorbent assay.

Results

MBL2 exon 1 polymorphic variants were found only in codon 54, and the allele frequencies did not differ significantly between the control and disease groups. Although serum MBL levels in codon 54 A/A mutants were markedly low, it did not influence susceptibility to H. pylori infection or the risk of gastroduodenal diseases. IL-8 levels were significantly different between T/T wild type, T/A heterozygote, and A/A mutant genotypes. IL-8 -251 A allele carriers (A/A + T/A) showed increased IL-8 levels, and were significantly associated with the risk of severe AG and GC.

Conclusions

We suggest that a combination of H. pylori infection and the IL-8 -251 T > A polymorphism might increase the risk of severe AG and GC in a Korean population.

IL-8 interacts with metadherin promoting proliferation and migration in gastric cancer

It has been reported that IL-8 was involved in the promotion of invasion of Gastric Cancer (GC), however the underlying mechanism by which IL-8 was observed to be able to promote invasion remains unknown. Here, in our study, IL-8 was shown to be significantly up-regulated in GC compared with paired normal control tissues whose expression was markedly associated with inferior overall prognosis; and IL-8 was displayed to be capable of directly interacting with metadherin (MTDH), which in turn can up-regulate IL-8 expression. Blockage of IL-8/MTDH using specific mono-antibody can abolish the invasion IL-8 mediated. Taken together, our results may provide a novel explanation of working mechanism of IL-8 in the invasion of GC.

Interleukin-8 -251A/T gene polymorphism and lung cancer susceptibility: a meta-analysis

Many studies have examined the association between the interleukin-8 -251T/A (rs4073) gene polymorphism and lung cancer risk in various populations, but the results have been inconsistent. In this meta-analysis, PubMed was searched for case-control studies published through 01 December 2013. The data were extracted, and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated. We assessed six published studies on the association between the interleukin-8 -251T/A polymorphism and lung cancer risk. The included studies yielded a total of 3265 lung cancer cases and 3607 controls. For the homozygous A/A and A allele carriers (T/A + A/A), the pooled ORs for all studies combining 3265 cases and 3607 controls were 1.03 (95% CI = 0.92-1.14; P = 0.235 for heterogeneity) and 1.07 (95% CI = 0.96-1.19; P = 0.245 for heterogeneity) when compared with the homozygous wild-type genotype (T/T). When the analysis was stratified by ethnicity, significant risks were found among Asians for both the A allele carriers and the homozygous A/A individuals. However, no significant associations were found in non-Asian populations using any of the genetic models. This meta-analysis suggests that the interleukin-8 -251A allele confer an increased risk for the development of lung cancer among Asians.

Ethnic differences in gastric cancer genetic susceptibility: allele flips of interleukin gene

Polymorphisms in promoter regions of inflammatory cytokines have been widely studied, and potentially functional polymorphisms have been discovered. Conflicting results from meta-analyses of interleukin (IL)-1B and IL-10 polymorphisms show differences in gastric cancer susceptibilities between Caucasian and Asian populations. In particular, we note the suggestion of an allele flip in IL-1B and IL-10 gene polymorphisms. In Asian populations, the IL-1B-1464G/-511C/-31T haplotype indicates risk for gastric cancer, while the opposite haplotype, IL-1B-1464C/-511T/-31C is the risk-related allele in Caucasians. Furthermore, while IL-10-1082G/-819C/-592C is associated with gastric cancer in Asians, IL-10-1082A/-819T/-592T is linked to gastric cancer risk in Caucasians. These seemingly contradictory results may be attributed to distinct carcinogenic mechanisms underlying the different gastric cancer subtypes. The allele flip observed in IL-10 and gastric cancer appears to reflect allelic heterogeneity, similar to that observed in IL-1B. In this review, we focus on the allele flip phenomenon observed between different ethnic groups in an effort to resolve certain controversial results from recent studies on interleukin polymorphism. In addition, we re-emphasize the importance of stratifying gastric cancer subtypes based on anatomical site and Lauren classification to prevent false associations arising through dilution of true ones.

The polymorphism interleukin-8 -251A/T is associated with a significantly increased risk of cancers from a meta-analysis

Emerging evidences show that interleukin-8 (IL-8) has important regulatory functions in tumorigenesis. IL-8 -251A/T is a single nucleotide polymorphism in the promoter region of the IL-8 gene and affects IL-8 production. Analysis of previous studies on the association of -251A/T polymorphism with different cancer types remained to be illustrated. To further assess the effect of -251A/T polymorphism on cancer risks, we performed this meta-analysis, up to November 2013, of 12,917 cases with different cancer types and 17,689 controls from 47 published case-control designed studies. Statistical analyses were performed using STATA 11.0 software. Crude odds ratios (ORs) with 95 % confidence intervals (CIs) were used to assess the strength of associations. ORs with 95 % CIs for IL-8 -251A/T polymorphism and cancer were estimated using fixed- and random-effects models when appropriate. Significantly increased risks were found in overall under the models of A allele vs. T allele, AA vs. TT, and AA vs. AT/TT. Significantly elevated risks were observed in breast cancer under the models of A allele vs. T allele, AT vs. TT, AA/AT vs. TT, and AA vs. AT/TT, and in nasopharyngeal carcinoma under the models of AT vs. TT, AA/AT vs. TT, and AA vs. AT/TT. We found that significantly elevated risks were observed in the Asian population and hospital-based studies in all comparison models. Thus, this meta-analysis indicates that IL-8 -251A/T polymorphism is associated with a significantly increased risk of cancers and may provide evidence-based medical certificate to study the cancer susceptibility.

Interleukin-4 and -8 gene polymorphisms and risk of gastric cancer in a population in Southwestern China

BACKGROUND

Gastric carcinogenesis is a complicated process that involves environmental and genetic factors like interleukin-4 (IL-4) and IL-8. Single nucleotide polymorphisms in their genes are associated with changed levels of gene expression. Here, we investigated the association between IL4-590 C>T and IL8-251T>A and gastric cancer (GC) risk in Sichuan of Southwestern China.

MATERIALS AND METHODS

We surveyed the research subjects using a self-designed questionnaire with questions on demographic factors and putative risk factors. Approximately 2-5ml of whole blood was collected after field survey to analyze IL4-590 C>T and IL8-251T>A genotypes using MALDI-TOF MS.

RESULTS

Our study recruited 308 pairs of GC patients and controls, including 224 (72.7%) men and 84 (27.3%) women in each group. There were 99 cardia and 176 noncardia GC patients in the case group. The case and control groups had an average age of 57.7±10.6 (mean±SD) and 57.6±11.1 years. GC patients reported a significantly greater proportion of family history of cancer (29.9% vs 10.7%, p<0.01) and drinking (54.6% vs 43.2%, p<0.01) than did controls. Variant genotypes of IL-4-590 C>T and IL-8-251 T>A were not associated with overall GC risk (adjusted OR, 0.89; 95%CI, 0.61-1.28 for CT or CC vs TT; adjusted OR, 1.14; 95%CI, 0.86-1.79 for TA or AA vs TT). Stratification analysis of two SNPs for risk by subsites only found that variant IL-8-251 TA or AA genotype was associated with increased noncardia GC risk (adjusted OR, 2.58; 95%CI, 1.19-5.57). We did not observe interactions between the IL-8-251 T>A genotype and smoking (adjusted OR, 0.38; 95%CI, 0.08-1.79) or drinking (adjusted OR, 0.36; 95%CI, 0.08-1.65) for risk of noncardia GC.

CONCLUSIONS

Our data indicate no association between the two SNPs of IL-4-590 and IL-8-251 with overall GC risk, while the IL-8-251 TA or AA genotype conferred risk of cardia GC. Our findings contribute to the evidence body for risk of SNPs associated with the development of gastric cancer in this region.

Positive association between Interleukin-8 -251A > T polymorphism and susceptibility to gastric carcinogenesis: a meta-analysis

Backgrounds

The associations between the polymorphisms of interleukin-8 (IL-8) gene and gastric carcinogenesis have been extensively investigated in recent years. However, the results remain conflicting rather than conclusive.

Methods

A meta-analysis of 18 eligible studies was performed to evaluate the association of IL-8 -251A > T polymorphism with risk of gastric carcinogenesis. A systematic literature search of MEDLINE, Embase, and Web of Science, CNKI databases was conducted. Statistical analysis was performed by using the Revman 5.1 software and the Stata 12.0 software.

Results

Of the 293 unique studies identified using our search criteria, 18 studies fulfilled our inclusion criteria and were included in the meta-analysis. These studies cumulatively reported 5,321 cases and 6,465 controls. The combined results based on all studies showed that the IL-8 -251A > T polymorphism was associated with the risk of gastric carciongenesis (A vs. T: OR: 1.14 [1.02, 1.26], P = 0.02), especially gastric cancer (A vs. T: OR: 1.15 [1.03, 1.29], P = 0.02), but not associated with the risk of precancerous lesion (A vs. T: OR: 1.09 [0.99, 1.20], P = 0.08). Analysis stratified by ethnicity may seem that IL-8 -251A > T polymorphism was susceptible to gastric cancer in Asian population, but not in Caucasian population.

Conclusions

Our meta-analysis results provide evidence that IL-8 -251A > T polymorphism is significantly associated with increased risk of gastric carcinogenesis in Asian population, particularly in gastric cancer. Further large and well-designed studies are required to confirm this conclusion.

Genotyping of IL-8-251 T > A yields prognostic information in patients with gastric carcinoma

This study was designed to investigate the association of the IL-8-251 T > A gene polymorphism with clinicopathological features and the prognostic role of the gene polymorphism in patients with gastric adenocarcinoma. The gene polymorphism was detected by the polymerase chain reaction-restriction fragment length polymorphism method, followed by univariate and multivariate analyses to elicit its prognostic role. The frequency of IL-8-251 A/A, A/T and T/T genotypes were 11.0% (23/210), 43.8% (92/210) and 45.2% (95/210), respectively. The IL-8-251 gene polymorphism was closely correlated with depth of invasion (p = 0.007), grade of differentiation (p = 0.002) and TNM stage (p = 0.009). A/A genotype carriers showed more frequency of serosa involvement, low grade of differentiation and advanced stage of gastric carcinoma. IL-8-251 T > A gene polymorphism have no significant correlation with other clinicopathological features. The 5-year overall survival of IL-8-251 A/A genotype and T allele carriers were 30.8% and 59.2%, respectively. There is a significant discrepancy among the different genotype carriers. Multivariate analysis with the Cox regression model revealed that the IL-8-251 A/A genotype is an independent prognostic indicator (HR = 2.285, 95% Confidence Interval = 1.06-4.93, p = 0.035). We conclude that the IL-8-251 A/A genotype may indicate a poor prognosis for gastric adenocarcinoma patients.

A meta-analysis of interleukin-8 -251 promoter polymorphism associated with gastric cancer risk

Background

Potential functional allele A/T single nucleotide polymorphism (SNP) of Interleukin 8 (IL-8) promoter -251has been implicated in gastric cancer risk.

Methods

We aimed to explore the role of A/T SNP of IL-8 -251 in the susceptibility to gastric cancer through a systematic review and meta-analysis. Each initially included article was scored for quality appraisal. Desirable data were extracted and registered into databases. Eighteen studies were ultimately eligible for the meta-analysis of IL-8 - 251 A/T SNP. We adopted the most probably appropriate genetic model (codominant model). Potential sources of heterogeneity were sought out via stratification and sensitivity analyses, and publication biases were estimated.

Results

Between IL-8 -251 AA genotype with gastric cancer risk, statistically significant association could be noted with overall gastric cancer, evidently noted in Asians, witnessed in high quality subgroup, and apparently noted in intestinal-type gastric cancer.

Conclusions

Our meta-analysis indicates that IL-8 -251 AA genotype is associated with the overall risk of developing gastric cancer and may seem to be more susceptible to overall gastric cancer in Asian populations. IL-8 -251 AA genotype is more associated with the intestinal-type gastric cancer. IL-8 -251 AA genotype is not associated with Helicobacter Pylori infection status in our meta-analysis.

Impact

The analyses suggest that IL-8 -251 AA genotype may be an important biomarker of gastric cancer susceptibility for Asians, especially for Chinese Han population, the assumption that needs to be further confirmed in future well-designed studies in China.

-251 T/A polymorphism of the interleukin-8 gene and cancer risk: a HuGE review and meta-analysis based on 42 case-control studies

The -251T/A (rs4073), a single nucleotide polymorphism, has been identified in the promoter region of the interleukin-8 (IL-8) gene. It's presence could influence the production of IL-8 protein by regulating the transcriptional activity of the gene. A large number of studies have been performed to evaluate the role of -251T/A polymorphism on various cancers, with inconsistent results being reported. In this paper, we summarized 13,189 cases and 16,828 controls from 42 case-control studies and attempted to assess the susceptibility of -251T/A polymorphism to cancers by a comprehensive meta-analysis. Pooled odds ratios and 95% confidence intervals were calculated by using the random-effects model. Publication bias, subgroup, and sensitivity analysis were also performed. Results showed that the carriers of the -251A allele had about a 12-21% increased risk for the reviewed cancer, in total. The carriers of -251A had an elevated risk to breast cancer, gastric cancer and nasopharyngeal cancer and a reduced risk to prostate cancer, but no evidence was found to indicate that the -251A allele predisposed its carriers to colorectal and lung cancers. When stratified separately by 'racial descent' and 'study design', it was found that the carriers of the -251A allele among the African group, Asian group and hospital-based case-control study group were at a higher risk for cancer, but not in European group and population-based case-control study. These results show that -251A allele is susceptible in the development of low-penetrance cancers.

[Single nucleotide polymorphisms and helicobacter pylori-related gastric cancer]

Helicobacter pylori-related gastric cancer is a special-type gastric cancer determined by genetic, environmental, and life style factors. A series of single nucleotide polymorphisms (SNPs) of susceptibility genes, including inflammation-related genes, gastric acid inhibition-related genes, and immune response-related genes, could be specifically involved in the development of Helicobacter pylori-related gastric cancer that consists of three major stages: Helicobacter pylori infection, gastric atrophy development, and carcinogenesis. The aim of the present paper was to review and evaluate the most recently published evidence on the contribution of SNPs to the carcinogenesis of Helicobacter pylori-related gastric cancer in humans.

Correlation of polymorphism of IL-8 and MMP-7 with occurrence and lymph node metastasis of early stage cervical cancer

The IL-8 and MMP-7 genes participate in the carcinogenesis of many malignancies, but the role of both genes in cervical cancer is not fully elucidated. The aim of this study was to determine the frequency of IL-8 and MMP-7 gene mutations and to assess their effects on the risk of early stage cervical cancer and lymph node metastasis. The clinical stage and histological grade of cervical cancer were also studied. The peripheral blood from the patients with early stage cervical cancers and normal controls was collected and the DNA was extracted. The incidence of IL-8 and MMP-7 gene mutations was assessed by using tetra-primer amplification refractory mutation system polymerase chain reaction (ARMS PCR) and restriction fragment length polymorphism (RFLP). The data were statistically analyzed by x2 test. The results showed that: (1) The genotype frequency of IL-8 -251AT and TT was significantly higher in the cervical cancer group than in the normal control group (OR=2.290 and 2.619 respectively, P=0.001), and it was also higher in the lymphatic metastasis group than that without metastasis (OR=2.917, P=0.035); (2) The frequency of MMP-7 -181G/G genotype was significantly higher in the cervical cancer group and in the lymphatic metastasis group (P<0.05); (3) The incidence of IL-8 mutation was two times higher in IIa cervical cancer group than in Ib1 and Ib2 cervical cancer group (P=0.006). For the MMP-7 gene, there was statistically significant difference in the incidence of mutation between the Ib1, Ib2 and the IIa (P=0.000); (4) Different histological types and different grades of cervical cancer had different incidence of mutations, statistically. It was suggested that there was significant difference in the genotype of IL-8 -251TT and MMP-7 -181GG polymorphism between the cervical cancer group and the lymph node metastasis group. Moreover, individuals with IL-8 T allele or MMP-7 G allele carriers were at significantly higher risk of cervical cancer, particularly the early (IIa) and medium, poorly differentiated cervical cancer (G2+G3).

Possible association between a genetic polymorphism at 8q24 and risk of upper gastrointestinal cancer

Over recent years, genome-wide association studies have contributed to our understanding of genetic susceptibility to sporadic cancer. In this study, we assessed the association between upper gastrointestinal cancer risk and four genome-wide association studies-identified single nucleotide polymorphisms (SNPs), implicated earlier in prostate and colorectal cancer susceptibility. Genotyping for each SNP was performed in two independent Caucasian population-based case-control studies. The first study comprised 290 gastric cancer cases and 374 controls. The second study included 185 noncardia gastric cancers, 123 cardia cancers, 158 oesophageal cancers and 209 controls. Odds ratios (ORs) were computed from logistic models and adjusted for potential confounding variables. An inverse association was observed between the SNP rs1447295, located at 8q24, and gastric cancer risk in the first study population (OR=0.63; 95% confidence interval: 0.41-0.97). A positive association was observed for the same SNP and oesophageal squamous cell carcinoma in the second study population (OR=7.43; 95% confidence interval: 1.37-49.98). No significant associations were detected in either study for the three remaining SNPs (rs6983297, rs10505477 and rs719725). Our data represent novel findings on heritable susceptibility to gastric and oesophageal cancer and warrant validation in additional populations.

Polymorphism of IL-8 in 251 allele and gastric cancer susceptibility: a meta-analysis

BACKGROUND

The relationship of gastric cancer to the presence of interleukin-8 (IL-8) 251 T/A has been reported with conflicting results.

AIM

To further explore the association of IL-8 251 allele polymorphism with gastric cancer susceptibility.

METHODS

We performed an extensive search of relevant studies and carried out a meta-analysis, including ten studies with 2,195 gastric cancer cases and 3,505 controls, to obtain a more precise estimate.

RESULTS

The combined results based on all studies showed that the IL-8 251 allele AA genotype was a risk factor for gastric cancer [AA versus TT: odds ratio (OR) = 1.363, 95% confidence interval (CI): 1.199-1.527]. In subgroup analysis, a clear effect of AA in IL-8 251 allele was shown in Asians (AA versus TT: OR = 1.593, 95% CI: 1.013-2.173) but not in Caucasians or Mexicans. When stratified by Lauren classification, we found that the IL-8 251 allele TA and AA polymorphism was significantly associated with the diffuse type of gastric cancer (TA versus TT: OR = 1.448, 95% CI: 1.177-1.720; AA versus TT: OR = 1.586, 95% CI: 1.128-2.044). The IL-8 251 AA genotype was found to be a risk factor for cardiac gastric cancer (AA versus TT: OR = 1.840, 95% CI: 1.112-2.568) but not for noncardiac gastric cancer.

CONCLUSIONS

This meta-analysis suggested that IL-8 251 allele A>T polymorphism might be a risk factor for gastric cancer.

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.

IL-8 -251A/T polymorphism is associated with decreased cancer risk among population-based studies: evidence from a meta-analysis

Growing evidence suggests that interleukin-8 (IL-8) play pivotal roles in the pathogenesis of cancer through the modulation of tumour immune response or enhanced angiogenesis. A single nucleotide polymorphism, -251A/T, has been identified in the promoter region of the IL-8 gene and has been shown to influence its production. Results from previous studies on the association of -251A/T polymorphism with different cancer types remained contradictory. To assess the effect of -251A/T of IL-8 on cancer susceptibility, we conducted a meta-analysis, up to May 2009, of 14,876 cases with different cancer types and 18,465 controls from 45 published case-control studies. Summary odds ratios and corresponding 95% confidence intervals (CIs) for IL-8 polymorphism and cancer were estimated using fixed- and random-effects models when appropriate. The AA/AT genotypes were associated with a significantly increased risk of nasopharyngeal carcinoma when compared with TT genotype (OR=1.48; 95% CI, 1.16-1.89). Moreover, significantly elevated risks were observed in 'other cancers', and also in African population when population is concerned. Interestingly, when stratified separately by population-based studies and hospital-based studies, significantly elevated risk was found among hospital-based studies (OR=1.21, 95% CI, 1.07-1.37), whereas significantly decreased risk was found among population-based studies (OR=0.90, 95% CI, 0.83-0.97). This meta-analysis shows that IL-8 -251A/T polymorphism may play a complex role in cancer development.

Influence of interleukin polymorphisms on development of gastric cancer and peptic ulcer

Pro-inflammatory cytokines are produced in the gastric mucosa by inflammatory cells activated by chronic Helicobacter pylori (H. pylori) infection. Polymorphisms of these cytokine genes are associated with individual differences in gastric mucosal cytokine mRNA level, which result in differences in gastric mucosal inflammation, acid inhibition and gastroduodenal disease risk in response to H. pylori infection. Although polymorphisms of interleukin (IL)-1B, IL-1RN and TNF-A have been reported to relate well with gastric cancer and peptic ulcer risk, those of IL-2, IL-4, IL-6 and IL-8 genes are unclear. In combined analyses using data from previous studies, we found that the risk of gastric non-cardia cancer development was significantly associated with IL-4-168 C allele (OR: 0.81, 95% CI: 0.69-1.00) and IL-4-590 T allele carrier status (0.61, 0.53-0.73), and IL-6-174 G/G genotype (2.02, 1.31-3.10). In peptic ulcer development, IL-2-330 G and IL-4-590 T allele carriers had a significantly decreased risk (0.37, 0.27-0.50 and 0.58, 0.34-0.99, respectively). Moreover, IL-2, IL-4, IL-6 and IL-8 gene genotypes prevalence differs among populations. The inflammatory cytokine gene polymorphisms (e.g. IL-4-590 and IL-6-572 for gastric cancer, and IL-4-590, IL-6-572 and IL-8-251 for peptic ulcer) have a more potent influence on development of gastroduodenal diseases in Western than East Asian populations. These cytokine gene polymorphisms, as well as those of IL-1B, IL-1RN and TNF-A, may be used to identify groups at higher risk of gastric cancer and peptic ulcer, and those suitable for their prevention by H. pylori eradication therapy in Western populations.

Helicobacter pylori infection generates genetic instability in gastric cells

The discovery that Helicobacter pylori is associated with gastric cancer has led to numerous studies that investigate the mechanisms by which H. pylori induces carcinogenesis. Gastric cancer shows genetic instability both in nuclear and mitochondrial DNA, besides impairment of important DNA repair pathways. As such, this review highlights the consequences of H. pylori infection on the integrity of DNA in the host cells. By down-regulating major DNA repair pathways, H. pylori infection has the potential to generate mutations. In addition, H. pylori infection can induce direct changes on the DNA of the host, such as oxidative damage, methylation, chromosomal instability, microsatellite instability, and mutations. Interestingly, H. pylori infection generates genetic instability in nuclear and mitochondrial DNA. Based on the reviewed literature we conclude that H. pylori infection promotes gastric carcinogenesis by at least three different mechanisms: (1) a combination of increased endogenous DNA damage and decreased repair activities, (2) induction of mutations in the mitochondrial DNA, and (3) generation of a transient mutator phenotype that induces mutations in the nuclear genome.

Effect of Helicobacter pylori eradication on incidence of gastric cancer in human and animal models: underlying biochemical and molecular events

BACKGROUND

Gastric cancer remains one of the most common cancers worldwide. A strong association exists between Helicobacter pylori infection and the risk of developing noncardia gastric cancer. H. pylori eradication by antibiotic treatment is regarded as a primary chemoprevention strategy to reduce gastric cancer incidence.

AIM

To analyze the efficacy of H. pylori eradication in preventing gastric cancer in human and animal models, and to discuss whether biochemical, genetic, and epigenetic changes associated with H. pylori infection are reversible after curing the infection.

RESULTS

Several intervention trials have indicated that in some patients, H. pylori eradication leads to regression and prevents the progression of precancerous lesions. The eradication therapy reduces gastric cancer incidence in patients without any precancerous lesions at the baseline and is most effective before the development of atrophic gastritis. A few recent intervention studies in Japan have demonstrated significant prophylactic effects of eradication therapy on the development of gastric cancer, suggesting the use of eradication therapy in high-risk populations as a gastric cancer reduction strategy. However, gastric cancer may still develop despite successful eradication therapy. Studies in animal models have confirmed the use of eradication therapy at an early point of infection to prevent gastric cancer development.

CONCLUSION

H. pylori eradication may not completely abolish the risk of gastric cancer. However, eradication therapy may be used in high-risk populations to reduce gastric cancer incidence. It can reverse many biochemical, genetic, and epigenetic changes that H. pylori infection induces in the stomach.

Cytokine genetic polymorphisms and prostate cancer aggressiveness

Prostate cancer (PCa) is one of the most common cancers in the world. Inflammation has been described as a risk factor for PCa and depends on the production of cytokines in response to tissue damage or the presence of stimuli that induces cellular stress. Interindividual variation in cytokine production is partially controlled by single-nucleotide polymorphisms (SNPs) that have been associated with differential production of cytokines. We have recently showed that SNP-SNP interactions of cytokine genes are associated with PCa risk. However, little is known about the association of cytokine SNPs and PCa aggressiveness. In this study, we evaluated the association of 15 SNPs in five cytokine genes and aggressiveness of PCa in African- and Caucasian-American individuals. Caucasian Americans with the genotypes IL10-1082GG or IL1B+3954TT had 2.31-fold [95% confidence interval (CI) = 1.13-4.72] and 3.11 (95% CI = 1.20-8.06)-fold risk, respectively, of developing aggressive PCa, as compared with individuals without those genotypes. We did not find any associations in the African-American group. Using Multivariate Adaptive Regression Splines modeling for exploratory SNP-SNP interactions, our results showed that more aggressive PCa in Caucasians Americans is associated with the CT genotype at IL8-47 [odds ratios (OR) = 3.50; 95% CI = 1.13-10.88] or combined genotypes of IL1B-511CC and IL10-1082GG (OR = 3.38; 95% CI = 1.70-6.71). Unfortunately, the same analysis could not be performed in the African-Americans due to limited number of individuals. With limited sample size, the results from this study suggest that SNPs in cytokine genes may be associated with PCa aggressiveness. More extensive studies are warranted to validate our findings.

Soybean product intake modifies the association between interleukin-10 genetic polymorphisms and gastric cancer risk

In this study, our aim was to investigate the association of inflammation-related genetic polymorphisms and gastric cancer risk and to examine whether the combined effect of soybean product intake modified cancer risk. Eighty-four incident gastric cancer cases and 336 matched controls were selected from the Korean Multi-Center Cancer Cohort. We selected 14 single nucleotide polymorphisms (SNP) from 5 genes [interleukin (IL)-1beta, IL-2, IL-4, IL-8, and IL-10] and used unconditional logistic regression model to calculate the odds ratios (OR) and 95% CI adjusting for H. pylori seropositivity, smoking, age, sex, enrollment year, and residential area. The risk for gastric cancer in relation to genetic polymorphisms and haplotypes were assessed according to soybean product intake levels. Although no single SNP effect was found, the combined effect between IL-10 gene variants of -592 GG/GA, -819 TC/CC, or -1082 AG/GG and low intake of soybean products had an increased risk for gastric cancer compared with the group with no risk gene variants and a high intake of soybean products (OR [95% CI] = 2.82 [1.04-7.62], 2.75 [1.02-7.44], and 4.34 [1.51-12.5], respectively). Among the low-soybean product intake group, IL-10 CCG haplotype had an increased risk of gastric cancer (OR = 3.38 [1.40-8.13]) relative to the ATA haplotype. Our results suggest that the association between IL-10 genetic polymorphisms and gastric cancer risk was modified by soybean product intake.

CD14-159C/T and TLR9-1237T/C polymorphisms are not associated with gastric cancer risk in Caucasian populations

Host genetic factors play an important role in modifying the risk of human disease, including cancers of the upper gastrointestinal tract, with increasing interest in Toll-like receptor (TLR) signaling and the impact of genetic polymorphisms in these systems. The CD14-159C/T and the TLR9-1237T/C promoter polymorphisms have previously been shown to be associated with various inflammatory conditions including Helicobacter pylori-induced gastritis in Caucasian populations. In this study, we assessed the association of these two functional single nucleotide polymorphisms with gastric cancer in two independent Caucasian population-based case-control studies of upper gastrointestinal tract cancer, initially in 312 noncardia gastric carcinoma cases and 419 controls and then in 184 noncardia gastric carcinomas, 123 cardia carcinomas, 159 esophageal cancers, and 211 frequency-matched controls. Odds ratios were computed from logistic models and adjusted for potential confounding factors. No significant association was found between the CD14-159C/T and the TLR9-1237T/C promoter polymorphisms and increased risk of gastric cancer. Neither single nucleotide polymorphism has been assessed in a Caucasian gastric cancer case-control study before; although the CD14-159C/T polymorphism has been reported to show no apparent association with H. pylori-related gastric malignancy in a Taiwanese Chinese population. In conclusion, although our earlier preliminary studies suggested that the CD14-159C/T and the TLR9-1237T/C promoter polymorphisms increase the risk of precancerous outcomes, they do not seem to increase the risk of gastric cancer itself. This discrepancy merits further examination.

CDH1 C-160A promoter polymorphism and gastric cancer risk

The objective of this study was to find out whether C-160A single nucleotide polymorphism of the promoter region of the E-cadherin gene might be a potential genetic marker for identifying individuals at risk for gastric cancer (GC). To test this hypothesis, 412 GC patients and 408 controls were analyzed statistically. A PCR-restriction fragment length polymorphism assay was adopted for C-160A single nucleotide polymorphism detection. No statistical differences were found among CC, CA, and AA genotypes and the risk of GC, even stratifying according to age, sex, and area of residence. Similarly, genotype was not associated with intestinal or diffuse histotypes, or with cardia or noncardia carcinomas. In conclusion, the C-160A polymorphism is not associated with GC risk in the Italian population.

Helicobacter Pylori associated global gastric cancer burden

Helicobacter pylori infection is ubiquitous, infecting close to one-half of the world's population, but its prevalence is declining in developed countries. Chronic H. pylori infection is etiologically linked to gastric adenocarcinoma, especially non-cardia type (63% of all stomach cancer or ~5.5% of the global cancer burden: ~25% of cancers associated with infectious etiology), and to gastric mucosal associated lymphoid tissue (MALT) lymphoma, which accounts for up to 8% of all non-Hodgkin lymphoma. Epidemiological, clinical, and animal studies have established a central role for H. pylori in gastric carcinogenesis and provided insights into the mechanisms and biologic relationships between bacterial infection, host genetics, nutrition, and environmental factors. These discoveries invite strategies to prevent infection to be the logical primary goals in a multi-pronged effort to curtail suffering and death from H. pylori infection-associated cancers.

A systematic review of meta-analyses on gene polymorphisms and gastric cancer risk

BACKGROUND

Individual variations in gastric cancer risk have been associated in the last decade with specific variant alleles of different genes that are present in a significant proportion of the population. Polymorphisms may modify the effects of environmental exposures, and these gene-environment interactions could partly explain the high variation of gastric cancer incidence around the world. The aim of this report is to carry out a systematic review of the published meta-analyses of studies investigating the association between gene polymorphisms and gastric cancer risk, and describe their impact at population level. Priorities on the design of further primary studies are then provided.

METHODS

A structured bibliographic search on Medline and EMBASE databases has been performed to identify meta-analyses on genetic susceptibility to gastric cancer, without restriction criteria. We report the main results of the meta-analyses and we describe the subgroup analyses performed, focusing on the detection of statistical heterogeneity. We investigated publication bias by pooling the primary studies included in the meta-analyses, and we computed the population attributable risk (PAR) for each polymorphism.

RESULTS

Twelve meta-analyses and one pooled-analysis of community based genetic association studies were included, focusing on nine genes involved in inflammation (IL-1beta, IL-1RN, IL-8), detoxification of carcinogens (GSTs, CYP2E1), folate metabolism (MTHFR), intercellular adhesion (E-cadherin) and cell cycle regulation (p53). According to their random-Odds Ratios, individuals carrying one of the IL-1RN *2, IL-1beta -511T variant alleles or homozygotes for MTHFR 677T are significantly at higher risk of gastric cancer than those with the wild type homozygote genotypes, showing high PARs. The main sources of heterogeneity in the meta-analyses were ethnicity, quality of the primary study, and selected environmental co-exposures. Effect modification by Helicobacter pylori infection for subjects carrying the unfavourable variant of IL-1 polymorphisms and by low folate intake for individuals homozygotes for MTHFR 677T allele has been reported, while genes involved in the detoxification of carcinogens show synergistic interactions. Publication bias was observed (Egger test, p = 0.03).

DISCUSSION

The published meta-analyses included in our systematic review focused on polymorphisms having a small effect in increasing gastric cancer risk per se. Nevertheless, the risk increase by interacting with environmental exposures and in combination with additional unfavourable polymorphisms. Unfortunately meta-analyses are underpowered for many subgroup analyses, so additional primary studies performed on larger population and collecting data on environmental and genetic co-exposures are demanded.

Cytokine gene polymorphisms and the risk of adenocarcinoma of the stomach in the European prospective investigation into cancer and nutrition (EPIC-EURGAST)

BACKGROUND

The relative contribution to gastric cancer (GC) risk of variants in genes that determine the inflammatory response remains mostly unknown and results from genotyping studies are inconsistent.

PATIENTS AND METHODS

A nested case-control study within the prospective European Prospective Investigation into Cancer and Nutrition cohort was carried out, including 248 gastric adenocarcinomas and 770 matched controls. Twenty common polymorphisms at cytokine genes [interleukin (IL)1A, IL1B, IL1RN, IL4, IL4R, IL6, IL8, IL10, IL12A, IL12B, lymphotoxin alpha and tumor necrosis factor (TNF)] were analyzed. Antibodies against Helicobacter pylori (Hp) and CagA were measured.

RESULTS

IL1RN 2R/2R genotype [odds ratio (OR) 2.43; 95% confidence interval (CI) 1.19-4.96] and allele IL1RN Ex5-35C were associated with an increased risk of Hp(+) non-cardia GC. IL8 -251AA genotype was associated with a decreased risk of Hp(+) non-cardia GC (OR 0.51; 95% CI 0.32-0.81), mainly of the intestinal type. These associations were not modified by CagA status. Carriers of IL1B -580C and TNF -487A alleles did not associate with an increased risk. A moderately increased risk of Hp(+) non-cardia GC for IL4R -29429T variant was observed (OR 1.74; 95% CI 1.15-2.63).

CONCLUSION

This prospective study confirms the association of IL1RN polymorphisms with the risk of non-cardia GC and indicates that IL8 -251T>A may modify the risk for GC.

Extragastric manifestations of Helicobacter pylori infection -- other Helicobacters

Today there is evidence that Helicobacter pylori has a critical role in different extragastric diseases. The discovery of a number of other novel Helicobacter species has stimulated the research in different extragastric diseases, in which an infectious hypothesis is plausible. Enterohepatic Helicobacter species have been hypothesized to play a role in different disorders, including hepatocellular carcinoma, gallstones formation and cholangiocellular carcinoma, as well as enteric diseases and inflammatory bowel diseases. Concerning the extragastric manifestations of H. pylori infection, idiopathic thrombocytopenic purpura, and sideropenic anemia represent, based on the current data, the diseases in which the pathogenic link appears to be strongest. There is also an increasing evidence for a possible association of H. pylori with cardiovascular disease.