Interleukin-8 polymorphisms are not associated with gastric cancer risk in a Polish population

Determination of Pentraxin-3, Interleukin-8 and Vascular Endothelial Growth Factor Levels in Patients with Gastric Adenocarcinoma

INTRODUCTION AND AIM

The purpose of this study was to determine the value, in terms of diagnosis, resectability and prognosis of pentraxin-3 (PTX3), interleukin-8 (IL-8) and vascular endothelial growth factor (VEGF) in cases of gastric adenocarcinoma, an important condition both worldwide and in Turkey, and to determine their levels in order to contribute to elucidating the pathogenesis of the disease.

MATERIALS AND METHODS

Serum was separated from blood specimens collected from 45 patients diagnosed with gastric adenocarcinoma and from a 30-member healthy control group. Serum PTX3, IL-8 and VEGF levels were studied by ELISA method.

RESULTS

Serum PTX3 values differed significantly between the patient group and the control group (p <0.05). Serum IL-8 values also differed significantly between the patient group and the control group (p <0.05). A significant difference was also observed between serum VEGF values in the patient group and the control group (p <0.05). Significant correlation was determined between serum PTX3 and VEGF (p <0.01; r=0.833), between serum PTX3 and IL-8 (p <0.01; r=0.818), and between serum VEGF and IL-8 (p <0.01; r=0.803), measurements when the entire study population was evaluated irrespectively of groups.

CONCLUSION

Serum PTX3, IL-8 and VEGF levels decreased in cases of gastric adenocarcinoma compared to the control group, and their levels affected one another.<br />.

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.

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.

Interleukins 17 and 23 in patients with gastric neoplasms

Recently there has been heightened interest in the potential significance of interleukin (IL)-17 and IL-23 in the development/progression of human malignancies. Here, we analyzed the systemic levels of these cytokines in 75 patients with different types of gastric neoplasms (carcinoma, gastrointestinal stromal tumors, neuroendocrine neoplasms, and lymphomas) and 42 healthy volunteers. We found that patients with all types of gastric neoplasms have significantly lower IL-23 levels. However, in comparison to the levels in healthy individuals, IL-17 concentrations were lower only in patients with types of gastric neoplasms other than carcinoma. Interestingly, IL-17 levels significantly differed between patients with early and advanced gastric carcinoma. No significant associations were detected between the systemic levels of examined interleukins and TNM staging. However, peripheral levels of IL-23 were correlated with the absolute numbers of circulating populations of bone marrow-derived mesenchymal and very small embryonic/epiblast-like stem cells in patients with gastric carcinoma. ROC curve analyses demonstrated that systemic levels of IL-17 seem to meet basic criteria for consideration as a helpful diagnostic marker in the detection of gastric carcinoma. In conclusion, our study provides translational evidence confirming the clinical significance of IL-17 and IL-23 in the pathogenesis of different types of gastric neoplasms in humans.

Association of polymorphisms in interleukin-8 gene with cancer risk: a meta-analysis of 22 case-control studies

Interleukin-8 (IL-8) is a kind of chemokine that plays an important role in the development and progression of many human malignancies. Previous studies have uncovered that polymorphisms in IL-8 is associated with the risk of many cancer types, but the results were inconsistent and inconclusive. In the present study, we aimed to explore the roles of IL-8 polymorphisms (rs2227307, rs2227306, +678T/C, rs1126647, and +1633C/T) and cancer risk through a systematic review and meta-analysis. Potential source of heterogeneity was sought out through sensitivity analysis. Desirable data were extracted and registered into databases. Finally, a total of ten publications comprising of 22 case–control studies, including 4,259 cases and 7,006 controls were ultimately eligible for the meta-analysis. No significant association was uncovered for all the five polymorphisms and the overall cancer risk. However, in the stratification analysis by cancer type, a significantly decreased risk of hepatocellular carcinoma was identified for rs2227306 polymorphism (T vs C: odds ratio [OR] =0.721, 95% confidence interval [CI] =0.567–0.916, P_z=0.007; TT vs CC: OR =0.447, 95% CI =0.274–0.728, P_z=0.001; TT vs TC + CC: OR =0.480, 95% CI =0.304–0.760, P_z=0.002). In conclusion, our data shows that rs2227306 polymorphism plays a protective role in hepatocellular carcinoma risk. Future well-designed studies with a larger sample size are warranted to verify our findings.

Evaluation of selected interleukins in patients with different gastric neoplasms: a preliminary report

Abnormal interactions between cytokines may be an overlooked mechanism linking the development of different types of gastric neoplasms. In this study a comprehensive analysis of the systemic levels of interleukins (IL-1,IL-6, IL-8,IL-10 and IL-12) was performed in 75 patients with different gastric neoplasms (cancer, gastrointestinal stromal tumors, neuroendocrine neoplasms, lymphomas) and 40 healthy volunteers. Patients with gastric cancer (GC) have significantly higher IL-6 levels, and lower IL-8 and IL-10 concentrations, in comparison to controls and patients with other gastric neoplasms. Analogous results were observed in terms of IL-6/IL-8 and IL-6/IL-10 ratios, whose values were also higher in GC patients. In GC patients no associations were detected between the systemic levels/values of interleukins (ratios) and TNM staging. IL-6, IL-10, IL-6/IL-8 and IL-6/IL-10 ratios appeared to hold diagnostic potential in confirming/excluding the presence of GC. Their sensitivity/specificity in GC detection/exclusion was approximately 54–72%. In conclusion, disturbed systemic biochemical balance in multiple interleukins exists at the earliest stages of and appears to be specific to GC. The interleukin ratios proposed here seem to be more promising indicators of GC in humans than direct systemic levels of interleukins, and probably possess the potential to be applied as a supporting factor for techniques routinely used.

Polymorphisms of the IL-6, IL-8 and IL-10 genes and the risk of gastric pathology in patients infected with Helicobacter pylori

BACKGROUND/PURPOSE

Helicobacter pylori-induced gastric mucosal inflammation is mediated by proinflammatory and anti-inflammatory cytokines. Polymorphisms in genes that code cytokines influence cytokine secretion levels and appear to contribute to the risk of gastric diseases. In this sense, we performed this study to identify the polymorphisms in the IL-6, IL-8, and IL-10 genes and their associations with H. pylori infection and gastric pathologies.

METHODS

Gastric biopsy samples of 151 patients infected with H. pylori and 76 uninfected individuals were used. Helicobacter pylori infection was diagnosed by histological examination and the detection of the ureA and glmM genes. The polymorphisms in the IL-6 (at position -174), IL-8 (at position -251), and IL-10 (at position -819) were detected by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

Among the genetic polymorphisms studied, we observed that only the presence of the A allele at position -251 of the IL-8 gene was significantly associated with H. pylori infection. In addition, patient carriers of the A/A genotype at position -251 of the IL-8 gene and carriers of the T allele at position -819 of the IL-10 gene had an increased risk of peptic ulcer disease in the presence of H. pylori infection. We did not find a correlation between polymorphisms in the IL-6, IL-8, and IL-10 genes and a higher risk of gastric carcinoma.

CONCLUSION

We demonstrated that polymorphisms in the IL-8 gene was significantly associated with H. pylori infection. Furthermore, polymorphisms in the IL-8 and IL-10 genes were associated with an enhanced risk of peptic ulcer disease in H. pylori-positive patients.

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.

Association of interleukin-8 gene polymorphisms with the risk of hepatocellular carcinoma

Interleukin-8 (IL8) polymorphisms have been implicated in several cancers, but their roles in the pathogenesis of hepatocellular carcinoma (HCC) are largely unknown. The present study was designed to explore the association between IL8 polymorphism and the risk of HCC in a Chinese population. Four single nucleotide polymorphisms (SNPs) of the IL8 gene -251A/T, +781C/T, -353A/T and +678T/C were analyzed in 205 HCC patients and 208 healthy controls in a Chinese population. Serum levels of IL8 were detected in HCC patients and healthy controls. The association between IL8 polymorphisms and HCC risk was measured using the adjusted odds ratios (OR) and their 95% confidence intervals (CI) from multiple logistic regression analysis. Haplotype analysis and gene-environment interaction analysis was also performed. The serum level of IL8 was significantly higher in HCC patients compared with healthy controls (P < 0.001). After adjusting for confounding factors, no significant associations were found between -251A/T, +781C/T, -353A/T and +678T/C and HCC risk (all P > 0.05). Haplotype analysis showed that A(251)-C(781)-A(353)-C(678) conferred decreased risk of HCC onset (adjusted OR 0.31, 95% CI 0.13-0.77). No significant interaction effects were found between the four SNPs and HBV infection, cirrhosis, gender smoking and alcohol consumption (all P > 0.05). No association between -251A/T, +781C/T, -353A/T and +678T/C of the IL8 gene and the risk of HCC was found in this Chinese population, and the SNPs did not display any interaction with several environmental factors with regard to HCC risk. However, it appears that A(251)-C(781)-A(353)-C(678) is perhaps a protective haplotype for HCC.

Effect of the +781C/T polymorphism in the interleukin-8 gene on atherosclerotic cerebral infarction, and its interaction with smoking and drinking

OBJECTIVE

The aims of this study were to investigate the association between the +781C/T polymorphism of interleukin-8 (IL-8) and atherosclerotic cerebral infarction and the interaction between the +781C/T polymorphism and smoking or drinking in cerebral infarction in the Han Chinese population.

METHODS

We investigated the +781C/T polymorphism of IL-8 in 308 consecutive Han Chinese patients who were diagnosed with atherosclerotic cerebral infarction and in 294 age- and gender-matched healthy control subjects. The patients were classified using the Oxfordshire Community Stroke Project (OCSP) classification. The patients and subjects' histories of smoking and drinking were recorded, and atherosclerosis (AS) of the internal carotid artery (ICA) was evaluated in the patients. The +781C/T polymorphism was determined by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) analysis.

RESULTS

The +781C/T polymorphism and allele frequencies were not significantly different between the patients and controls and were not significantly associated with the OCSP classifications. We found that the 781C allele was significantly associated with AS of the ICA in the patients (p = 0.017), and the CT genotype was more prevalent in patients without AS of the ICA (p = 0.035). No interactions were observed between the +781C/T polymorphism and smoking or drinking.

CONCLUSION

Our results demonstrated that the +781C/T polymorphism of IL-8 did not play a role and had no interaction with smoking or drinking in the occurrence of cerebral infarction in the Han Chinese population. However, the C allele and the CT genotype might be associated with AS of the ICA in patients with ischemic stroke.

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.

Interleukin-4 receptor -3223T&#8594;C polymorphism is associated with increased gastric adenocarcinoma risk

BACKGROUND

Gastric cancer remains one of the most common types of cancer worldwide, with a large geographical variation in incidence and mortality rates. Cytokine polymorphisms are the most studied host polymorphisms and are associated with an increased risk of stomach cancer in many regions, but have not been studied extensively in Eastern European populations.

OBJECTIVE

To investigate the potential association between five cytokine promoter polymorphisms (interleukin [IL] 1b -511C→T [rs16944], IL-4 receptor [IL-4R] -3223C→T [rs2057768], IL-8 -251T→A [rs4073], IL-10 -1082A→G [rs1800896] and tumour necrosis factor-alpha -308G→A [rs1800629]) and susceptibility to gastric adenocarcinoma in a Romanian population.

METHODS

A total of 347 subjects, consisting of 105 patients with gastric adenocarcinoma and 242 controls, were included. All cytokine polymorphisms were genotyped using allele-specific, commercially available probes. Hardy-Weinberg equilibrium in both groups was analyzed using the chi squared&nbsp;test, and the relationship between targeted polymorphisms and the risk of gastric cancer was estimated using OR and 95% CI.

RESULTS

A significant association between the IL-4R -3223C→T polymorphism and risk of gastric cancer was found. Carriers of the IL-4R -3223TT genotype were at a 2.5-fold increased risk for gastric cancer (OR 2.51 [95% CI 1.08 to 5.84]; P=0.041). Moreover, the presence of the IL-4R -3223TT genotype was associated with an increased risk of noncardia gastric adenocarcinoma (OR 3.08 [95% CI 1.25 to 7.58]; P=0.023). No associations were found among the other polymorphisms.

CONCLUSION

The results suggest that the IL-4R -3223C→T polymorphism may increase the risk of gastric adenocarcinoma, mainly for the noncardia type, in the Romanian population.

Effect of Helicobacter pylori eradication according to the IL-8-251 polymorphism in Koreans

Previous studies suggested that polymorphisms of proinflammatory cytokine genes are important host genetic factors in Helicobacter pylori infection. The present study evaluated whether IL-8-251 polymorphism affected H. pylori eradication rate and to investigate the effect of H. pylori eradication on angiogenesis and the inflammatory process according to the IL-8-251 polymorphism. A total of 250 H. pylori-positive patients treated by endoscopic resection of the gastric neoplasm were classified into 3 groups (134 H. pylori-eradicated group, 19 H. pylori-eradication failure group, and 97 H. pylori-infected group). H. pylori status, histology, and angiogenic factor levels were evaluated at baseline, 6 months, and 18 months. H. pylori eradication rate was 92.9% in AA genotype, 85.7% in AT genotype and 88.4% in TT genotype (P value = 0.731). Elevated IL-8 and matrix metalloproteinase-9 concentrations in H. pylori-infected gastric mucosa were reversible by successful eradication of H. pylori, independent of the IL-8-251 polymorphism. It is suggested that elevated IL-8 and MMP-9 concentrations in H. pylori-infected gastric mucosa are altered significantly after successful eradication and these conditions continue for 18 months. However, IL-8-251 polymorphism does not affect H. pylori eradication rate and the sequential changes of related angiogenic factors after H. pylori eradication in Koreans.

The lL-8 and IL-13 gene polymorphisms in inflammatory bowel disease and colorectal cancer

Inflammatory bowel diseases (IBD) and colorectal cancer (CRC) are disorders that originate from immune disturbances. In our study, we evaluated the association between the -251 T/A interleukin (IL)-8 and the -1112 C/T IL-13 polymorphisms, the risk of IBD, and CRC development. Genotypes were determined by PCR-restriction fragment length polymorphism in 191 patients with CRC, 150 subjects with IBD, and 205 healthy controls. We found an association between CRC and the presence of the -251 TA genotype and A allele of the IL-8 gene (odds ratios [ORs] 2.28 and 1.65). A similar relationship was observed between these polymorphic variants and ulcerative colitis (OR 2.05 for the -251 TA genotype and OR 1.47 for the -251 A allele) as well as Crohn's disease (ORs 3.11 and 1.56, respectively). Our research also revealed that the CT and TT genotypes of the IL-13 -1112 C/T polymorphism may be connected with a higher risk of CRC (ORs 2.28 and 1.65). The same genotypes affected the susceptibility of IBD (ORs 2.26 and 3.72). Our data showed that the IL-8 -251 T/A and IL-13 -1112 C/T polymorphisms might be associated with the IBD and CRC occurrence and might be used as predictive factors of these diseases in a Polish population.

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.

Impact of interleukin-8 gene polymorphisms and environmental factors on oral cancer susceptibility in Taiwan

OBJECTIVES

Interleukin-8 (IL-8), which is an angiogenic chemokine with a high expression level in tumor tissues, plays important roles in developing many human malignancies including oral squamous cell carcinoma (OSCC). This study was designed to examine the association of IL-8 gene polymorphisms with the susceptibility and clinicopathological characteristics of OSCC.

METHODS

A total of 270 patients with OSCC and 350 healthy control subjects were recruited. Four single nucleotide polymorphisms (SNPs) of IL-8 genes were analyzed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) genotyping analysis.

RESULTS

Results showed that four IL-8 SNPs (-251 T/A, +781 C/T, +1633 C/T, and +2767 A/T) were not associated with oral cancer susceptibility as well as clinicopathological parameters. But among 345 smokers, IL-8 polymorphisms carriers with betel quid chewing were found to have a 17.41- to 23.14-fold risk to have oral cancer compared to IL-8 wild-type carriers without betel quid chewing. Among 262 betel quid chewers, IL-8 polymorphisms carriers with smoking have a 10.54- to 20.44-fold risk to have oral cancer compared to those who carried wild type without smoking.

CONCLUSIONS

Our results suggest that the combination of IL-8 gene polymorphisms and environmental carcinogens might be highly related to the risk of oral cancer.

Genetics of inflammation in the gastrointestinal tract and how it can cause cancer

Genetic epidemiology is an important discipline that is helping to unravel the aetiology and pathogenesis of complex human diseases. In the context of gastrointestinal malignancy, the paradigm model of host genetic influence on disease outcome is H. pylori-associated gastric adenocarcinoma. This cancer represents a classic example of an inflammation-induced malignancy and highlights the importance of host genetics in disease development. This chapter gives an insight into how genetic epidemiology can play an important role in the development of gastric cancer. Increasing our understanding of host genetics in cancer development may allow particularly susceptible individuals to be targeted for screening or treatment to reduce risk of future malignant transformation.

The role of CXC chemokines in the transition of chronic inflammation to esophageal and gastric cancer

Chronic inflammation may increase the risk to develop cancer, for instance esophagitis or gastritis may lead to development of esophageal or gastric cancer, respectively. The key molecules attracting leukocytes to local inflammatory sites are chemokines. We here provide a systematic review on the impact of CXC chemokines (binding the receptors CXCR1, CXCR2, CXCR3 and CXCR4) on the transition of chronic inflammation in the upper gastrointestinal tract to neoplasia. CXCR2 ligands, including GRO-α,β,γ/CXCL1,2,3, ENA-78/CXCL5 and IL-8/CXCL8 chemoattract pro-tumoral neutrophils. In addition, angiogenic CXCR2 ligands stimulate the formation of new blood vessels, facilitating tumor progression. The CXCR4 ligand SDF-1/CXCL12 also promotes tumor development by stimulating angiogenesis and by favoring metastasis of CXCR4-positive tumor cells to distant organs producing SDF-1/CXCL12. Furthermore, these angiogenic chemokines also directly enhance tumor cell survival and proliferation. In contrast, the CXCR3 ligands Mig/CXCL9, IP-10/CXCL10 and I-TAC/CXCL11 are angiostatic and attract anti-tumoral T lymphocytes and may therefore mediate tumor growth retardation and regression. Thus, chemokines exert diverging, sometimes dual roles in tumor biology as described for esophageal and gastric cancer. Therefore extensive research is needed to completely unravel the complex chemokine code in specific cancers. Possibly, chemokine-targeted cancer therapy will have to be adapted to the individual's chemokine profile.

Relationship of interleukin-8 gene polymorphisms with hepatocellular carcinoma susceptibility and pathological development

BACKGROUND AND OBJECTIVES

Hepatocellular carcinoma (HCC) is one of the most frequent malignant neoplasms worldwide, and the second leading cause of death from cancer in Taiwan. Interleukin-8 (IL-8) is an angiogenic chemokine with important roles in the development and progression of many human malignancies including HCC. This study investigates the effects of single-nucleotide polymorphisms (SNPs) in the IL-8 gene on the susceptibility and clinicopathological characteristics of HCC.

METHODS

One hundred thirty-one HCC patients and 340 control subjects were analyzed for four IL-8 SNPs (-251 T/A, +781 C/T, +1633 C/T, and +2767 A/T) using PCR-RFLP genotyping analysis.

RESULTS

After adjusting for other confounders, results show that individuals with the IL-8 +781 T/T polymorphic genotype had a significantly lower risk of developing HCC than those with the wild-type (C/C) genotype (AOR = 0.346; 95% CI: 0.132-0.909). Multiple regression analysis showed that the presence of T/A or A/A at IL-8 -251 may indicate higher potential risk of hepatitis B infection (AOR = 2.847; 95% CI: 1.083-8.656). Additionally, these four IL-8 SNPs did not associate with liver-related clinicopathological markers in serum.

CONCLUSIONS

Genetic polymorphism at IL-8 +781 is an important factor in determining susceptibility to HCC in the Taiwanese population.

-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.

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.

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.

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.

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.

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.

Genetic polymorphisms of interleukin 8 and risk of ulcerative colitis in the Chinese population

BACKGROUND

Interleukin-8 (IL-8), a CXC chemokine that recruits and activates inflammatory cells, plays a critical role in the pathogenesis of ulcerative colitis (UC). There are no studies on the association of single nucleotide polymorphisms (SNPs) of the IL-8 gene with the risk of UC.

METHODS

All 162 unrelated UC patients and 203 control subjects were analyzed for 5 IL-8 SNPs ((-845 (T/C), -738 (T/A), -353 (A/T), -251 (T/A) and +678 (T/C)) using polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) assay and PCR-sequence-specific primers (SSP) method. Serum IL-8 concentrations were measured in all subjects.

RESULTS

Individual SNPs were not associated with risk for UC. However, the frequency of -353A/-251A/+678T haplotype was significantly higher in UC patients than in healthy controls (OR=1.454, p=0.036). By subgroup analyses, this haplotype tended to be more common in severe UC patients than in those with mild-to-moderate disease (OR=2.281, p=0.027). Furthermore, patients with AAT diplotype showed significantly increased serum IL-8 concentrations than those with other diplotypes (p<0.001).

CONCLUSION

These results suggest that IL-8 is a novel susceptibility gene to UC in Chinese UC patients, and furthermore, that IL-8 polymorphisms may be related to severe clinical subtype of UC.

Cancer genetic association studies in the genome-wide age

Genome-wide association studies of hundreds of thousands of SNPs have led to a deluge of studies of genetic variation in cancer and other common diseases. Large case-control and cohort studies have identified novel SNPs as markers of cancer risk. Genome-wide association study SNP data have also advanced understanding of population-specific genetic variation. While studies of risk profiles, combinations of SNPs that may increase cancer risk, are not yet clinically applicable, future, large-scale studies will make individualized cancer screening and prevention possible.

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.

Variants in inflammation genes and the risk of biliary tract cancers and stones: a population-based study in China

To evaluate the role of chronic inflammation in the development of gallstones and biliary tract cancer, we examined the risk associated with 62 single nucleotide polymorphisms (SNPs), in 22 inflammation-related genes, in a population-based case-control study conducted in Shanghai, China, where the incidence of biliary tract cancer has been increasing in recent decades. The study included 411 cases with biliary tract cancer (237 gallbladder, 127 extrahepatic bile duct, and 47 ampulla of Vater), 895 with biliary stones, and 786 controls randomly selected from the population. Unconditional logistic regression was used to calculate odds ratios and 95% confidence intervals for the association of individual SNPs and haplotypes with biliary stones and biliary tract cancer. Of the 62 SNPs examined, 14 were related to the risk of biliary cancer and stones. Specifically, variants in the IL8, IL8RB, RNASEL, and NOS2 genes were associated with biliary stones, whereas VEGF variants were associated with gallbladder cancer. Of the 10 genes with multiple SNPs from which we inferred haplotypes, only one IL8RB haplotype, consisting of 3 SNPs (rs2230054, rs1126579, and rs1126580), was associated with the risk of bile duct cancer (P = 0.003) and biliary stones (P = 0.02), relative to the most frequent haplotype. In summary, common variants in genes that influence inflammatory responses may predispose to gallstones and biliary tract cancer, suggesting the need for future studies into the immunologic and inflammatory pathways that contribute to biliary diseases, including cancer.

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.

The interleukin-8-251*T/*A polymorphism is not associated with risk for gastric carcinoma development in a Portuguese population

It has been demonstrated that polymorphisms within inflammation-related genes are associated with risk of gastric carcinoma in Helicobacter pylori-infected individuals. Recently, several studies have reported conflicting results regarding the association between the interleukin (IL)8-251*T/*A polymorphism and risk of gastric carcinoma. In this study, we performed a case-control analysis, including 693 controls, 187 chronic gastritis cases and 333 gastric carcinoma cases, to determine the association between the IL8-251 polymorphism and risk of chronic gastritis and gastric carcinoma in the northern Portugal population. We found no significant association between the IL8-251 polymorphism and increased risk of chronic gastritis or gastric carcinoma, in agreement with that reported in other populations of white origin. The retrospective analysis of published data shows that the association between the IL8-251 polymorphism and risk of gastric carcinoma tends to be reproducible in populations of Asian origin. The estimated effect of the polymorphism under analysis was not significantly different in subgroups of gastric carcinoma cases defined by histologic type and anatomic site of the tumours, and by sex and age of the participants. In conclusion our results indicate that although the IL8-251 polymorphism might be a relevant host susceptibility factor for gastric carcinoma development, this association is likely to be ethnic-specific.

After Helicobacter pylori, genetic susceptibility to gastric carcinoma revisited

Genetically, it is possible to distinguish two main forms of gastric carcinoma (GC): a hereditary form in which the initiating genetic alteration is inherited and the remaining mutations are acquired somatically; and a sporadic form in which every mutation is of somatic origin and where the environment is thought to play a major role. Although rare, the identification of germline mutations is proving invaluable in the clinical management of GC families. In the setting of sporadic-type GC it has been shown that individuals infected with Helicobacter pylori have an increased risk of developing GC. Recently, abundant evidence has been collected showing that the risk for sporadic GC development also depends on host genetic factors. Despite providing important insights into the understanding of the disease pathogenesis, the genetic markers we have at present are not sensitive/specific enough to form the basis of a screening strategy.

Single nucleotide polymorphism and haplotype association of the interleukin-8 gene with nasopharyngeal carcinoma

The cytokine interleukin-8 (IL-8) may play a role in the pathogenesis of nasopharyngeal carcinoma (NPC) through the modulation of tumor immune response or enhanced angiogenesis. Polymorphism of IL-8 gene, which may affect the production level of cytokine, has been inversely associated with a number of cancers. To test this hypothesis, we investigated the relationship of IL-8 gene polymorphisms and NPC in a Chinese population. We analyzed single nucleotide polymorphisms (SNPs) of IL-8 gene -845 T/C, -738 T/A, -353 A/T, -251 A/T and +678 T/C in 280 patients with NPC and 290 age and sex matched controls, using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and polymerase chain reaction-sequence specific primers method (PCR-SSP). There were significant differences in the genotype and allele distribution of -251 A/T polymorphism of the IL-8 gene among cases and controls. The -251 AA and AT genotypes were associated with a significantly increased risk of NPC as compared with the -251 TT genotypes (OR=1.820, 95% CI, 1.120-2.959, P=0.015 and OR=1.590, 95% CI, 1.104-2.290, P=0.013, respectively). Haplotype analysis revealed that the homozygosity of the AAT haplotype (defined by SNPs at positions -353, -251 and +678) of IL-8 gene conveys the highest risk for NPC compared with the homozygosity for the TTC haplotype (OR=1.396; 95% CI, 1.064-1.831; P=0.016). The -251 A/T polymorphism of IL-8 and its haplotype are associated with NPC in a Chinese population. Our data suggests that IL-8 gene may play a role in the development of NPC.

Association of common polymorphisms in inflammatory genes with risk of developing cancers of the upper aerodigestive tract

OBJECTIVES

The purpose of this study was to investigate the role of polymorphisms of genes involved in inflammation in the risk of cancers of the upper aerodigestive tract (UADT).

METHODS

We have evaluated the role of polymorphisms in key genes related to inflammation, namely IL1B (rs1143627), COX2/PTGS2 (rs5275), and IL8 (rs4073) in a large case-control study comprising 811 UADT cancer cases and 1,083 controls.

RESULTS

An association was observed for squamous cell carcinoma of the pharynx for a polymorphism in the promoter of the IL1B gene, with an OR of 2.39 (95% CI = 1.19-4.81) for the homozygotes for the minor allele A promoter polymorphism of IL8 was associated with decreased risk of laryngeal cancer, with an OR of 0.70 (95% CI = 0.50-0.98) for carriers of the minor allele.

CONCLUSIONS

To our knowledge, this is the first report on the role of these polymorphisms with respect to UADT carcinogenesis. Our results suggest that inflammation-related polymorphisms play a role, albeit minor, in the risk of developing cancers of the upper aerodigestive tract.

Helicobacter and digestive malignancies

Important new data were published during the past year on the relationship of Helicobacter infection and gastric neoplasias. In the pathogenesis of gastric cancer, a thrilling new hypothesis was put forward based on animal experiments. Helicobacter infection induces gastric mucosal damage and bone marrow-derived cells (mobilized into peripheral blood and attracted to the inflamed mucosa) replace the areas of damaged gastric tissue and turn into neoplastic proliferation. Several studies focused on mechanisms related to the development of gastric malignancy in infected individuals with particular attention to inflammatory cytokine gene polymorphisms. Some new evidence is also reported to suggest that Helicobacter infection increases the risk of neoplasias outside the stomach in the liver and colon.