Polymorphisms in Th1-type cell-mediated response genes and risk of gastric cancer

Crosstalk between Helicobacter pylori and gastrointestinal microbiota in various gastroduodenal diseases-A systematic review

Gastroduodenal diseases have prevailed for a long time and more so due to dominance of gut bacteria Helicobacter pylori in most of the cases. But habitation by other gut microbiota in gastroduodenal diseases and the relationship between Helicobacter pylori and gastrointestinal microbiota in different gastroduodenal diseases is somewhat being unravelled in the current times. For this systematic review, we did a literature search of various gastroduodenal diseases and the effect on gut microbiota pertaining to it. A search of the online bibliographic databases PUBMED and PUBMED CENTRAL was carried out to identify articles published between 1977 and May 2022. The analysis of these selected studies highlighted the inhabitation of other gut microbiota such as Fusobacteria, Bacteroidetes, Streptococcaceae, Prevotellaceae, Fusobacteriaceae, and many others. Interplay between these microbiota and H. pylori have also been noted which suggested that gastroduodenal diseases and gut microbiota are intertwined by a symbiotic association regardless of the H. pylori status. The relationship between the gut microbiota and many gastroduodenal diseases, such as gastritis, gastric cancer, lymphomas, and ulcers, demonstrates the dysbiosis of the gut microbiota in both the presence and absence of H. pylori. The evolving ways for eliminating H. pylori are provided along with inhibiting qualities of other species on H. pylori. Most significant member of our gut system is Helicobacter pylori which has been associated with numerous diseases like gastric cancer, gastritis, duodenal ulcer.

A multi-omics-based investigation of the prognostic and immunological impact of necroptosis-related mRNA in patients with cervical squamous carcinoma and adenocarcinoma

Necroptosis is a kind of programmed necrosis mode that plays a double-edged role in tumor progression. However, the role of necroptosis-related Messenger RNA (mRNA) in predicting the prognosis and immune response of cervical squamous carcinoma and adenocarcinoma (CESC) has not been fully studied. Firstly, the incidence of somatic mutation rate and copy number variation for 74 necroptosis-related mRNAs (NRmRNAs) were analyzed. Secondly, CESC patients were divided into four stable clusters based on the consensus clustering results and analyzed for correlations with a series of clinical factors. Subsequently, a total of 291 The Cancer Genome Atlas samples were randomly divided into either training or validation cohorts. A Cox proportional hazard model consisting of three NRmRNAs (CXCL8, CLEC9A, and TAB2) was constructed by univariate, least absolute shrinkage and selection operator and multivariate COX regression analysis to identify the prognosis and immune response. Its performance and stability were further validated in another testing dataset (GSE44001) from Gene Expression Omnibus database. The results of the receiver operating characteristic curve, principal component analysis, t-SNE, and nomogram indicated that the prognostic model we constructed can serve as an independent prognostic factor. The combination of the prognostic model and the classic TNM staging system could improve the performance in predicting the survival of CESC patients. In addition, differentially expressed genes from high and low-risk patients are screened by R software for functional analysis and pathway enrichment analysis. Besides, single-sample gene set enrichment analysis revealed that tumor-killing immune cells were reduced in the high-risk group. Moreover, patients in the low-risk group are more likely to benefit from immune checkpoint inhibitors. The analysis of tumor immune dysfunction and exclusion scores, M6A-related genes, stem cell correlation and Tumor mutational burden data with clinical information has quantified the expression levels of NRmRNAs between the two risk subgroups. According to tumor immune microenvironment scores, Spearman’s correlation analysis, and drug sensitivity, immunotherapy may have a higher response rate and better efficacy in patients of the low-risk subgroup. In conclusion, we have reported the clinical significance of NRmRNAs for the prognosis and immune response in CESC patients for the first time. Screening of accurate and effective prognostic markers is important for designing a multi-combined targeted therapeutic strategy and the development of individualized precision medicine.

Role of interferon-gamma (IFN-γ) and IFN-γ receptor 1/2 (IFNγR1/2) in regulation of immunity, infection, and cancer development: IFN-γ-dependent or independent pathway

IFN-γ, a soluble cytokine being produced by T lymphocytes, macrophages, mucosal epithelial cells, or natural killer cells, is able to bind to the IFN-γ receptor (IFNγR) and in turn activate the Janus kinase (JAK)-signal transducer and transcription protein (STAT) pathway and induce expression of IFN-γ-stimulated genes. IFN-γ is critical for innate and adaptive immunity and aberrant IFN-γ expression and functions have been associated with different human diseases. However, the IFN-γ/IFNγR signaling could be a double-edged sword in cancer development because the tissue microenvironments could determine its anti- or pro-tumorigenic activities. The IFNγR protein consists of two IFNγR1 and IFNγR2 chains, subunits of which play different roles under certain conditions. This review assessed IFNγR polymorphisms, expression and functions in development and progression of various human diseases in an IFN-γ-dependent or independent manner. This review also discussed tumor microenvironment, microbial infection, and vital molecules in the IFN-γ upstream signaling that might regulate IFNγR expression, drug resistance, and druggable strategy, to provide evidence for further application of IFNγR.

Induction and Regulation of the Innate Immune Response in Helicobacter pylori Infection

Gastric cancer (GC) is the fifth most common cancer and the fourth most common cause of cancer-related death worldwide. The intestinal type of GC progresses from acute to chronic gastritis, multifocal atrophic gastritis, intestinal metaplasia, dysplasia, and carcinoma. Infection of the stomach by Helicobacter pylori, a Gram-negative bacterium that infects approximately 50% of the world's population, is the causal determinant that initiates the gastric inflammation and then disease progression. In this context, the induction of the innate immune response of gastric epithelial cells and myeloid cells by H. pylori effectors plays a critical role in the outcome of the infection. However, only 1% to 3% of infected patients develop gastric adenocarcinoma, emphasizing that other mechanisms regulate the localized non-specific response, including the gastric microbiota and genetic factors. This review summarizes studies describing the factors that induce and regulate the mucosal innate immune response during H. pylori infection.

The Role of Tumor Necrosis Factor-α (TNF-α) Polymorphisms in Gastric Cancer: a Meta-Analysis

PURPOSE

Tumor necrosis factor alpha (TNF-α) is an inflammatory cytokine which may play a role in the development of gastric cancer (GC). This study aimed to investigate the association of five TNF-α polymorphisms including TNF-α-857, TNF-α-1031, TNF-α-863, TNF-α-308, and TNF-α-238 polymorphisms with GC risk.

METHODS

All eligible case-control studies were collected by searching PubMed, Scopus, and Web of Science. The association of the risk of GC with TNF-α polymorphisms was estimated using odds ratio (OR) and 95% confidence interval (CI). Heterogeneity was assessed via Cochrane's Q and I² analyses.

RESULTS

A total of 46 publications involving 16, 715 cases with GC and 27, 998 controls were recruited. The study revealed a significant association for TNF-α 308 (recessive model: OR = 0.646, P = 0.035), TNF-α-1031 (homozygote model: OR = 1.584, P = 0.027), and TNF-α-857 (homozygote model: OR = 1.760, P = 0.001) polymorphisms with the GC risk. The results of subgroup analysis based ethnicity found a significant association between GC risk and TNF-α-857 polymorphism in Caucasian subgroup (P = 0.005) and TNF-α-1031 polymorphism and GC risk in Asians (P = 0.018).

CONCLUSIONS

This study suggested that TNF-α-857 and TNF-α-1031 polymorphisms may be associated with the increased gastric cancer risk.

Estrogen Aggravates Tumor Growth in a Diffuse Gastric Cancer Xenograft Model

Gastric cancer has the fifth-highest incidence rate and is the third leading cause of cancer-related deaths worldwide. The incidence of gastric cancer is higher in men than in women, but for the diffuse types of gastric cancer, the trend is opposite. Estrogen is considered the prime culprit behind these differences. Nevertheless, the action of estrogen in gastric cancers remains unclear. In this study, we investigated the effect of estrogen on diffuse-type gastric cancer. Human female diffuse gastric cancer SNU-16 cells were transplanted into male and female mice to analyze the effect of endogenous estrogen on tumor growth. Furthermore, the effect of exogenous estrogen was evaluated in ovariectomized mice. Expressed genes were compared between female and male xenograft models using RNA sequencing analysis. Furthermore, human gene expression omnibus databases were utilized to examine the effect of our target genes on overall survival. SNU-16-derived tumor growth was faster in female mice than in male mice. In total RNA sequencing, interferon gamma receptor 2 (IFNGR2), IQ motif containing E (IQCE), transient receptor potential cation channel subfamily M member 4 (TRPM4), and structure-specific endonuclease subunit SLX4 (SLX4) were found. These genes could be associated with the tumor growth in female diffuse-type gastric cancer which was affected by endogenous estrogen. In an ovariectomized gastric cancer xenograft model, exogenous estrogen promoted tumor growth. Especially, our results indicated that estrogen induced G protein-coupled estrogen receptor expression in these mice. These results suggest that estrogen aggravates tumor progression in female diffuse gastric cancer.

The role of the gastric bacterial microbiome in gastric cancer: Helicobacter pylori and beyond

A link between chronic inflammation and carcinogenesis has been depicted in many organ systems. Helicobacter pylori is the most prevalent bacterial pathogen, induces chronic gastritis and is associated with more than 90% of cases of gastric cancer (GC). However, the introduction of nucleotide sequencing techniques and the development of biocomputional tools have surpassed traditional culturing techniques and opened a wide field for studying the mucosal and luminal composition of the bacterial gastric microbiota beyond H. pylori. In studies applying animal models, a potential role in gastric carcinogenesis for additional bacteria besides H. pylori has been demonstrated. At different steps of gastric carcinogenesis, changes in bacterial communities occur. Whether these microbial changes are a driver of malignant disease or a consequence of the histologic progression along the precancerous cascade, is not clear at present. It is hypothesized that atrophy, as a consequence of chronic gastric inflammation, alters the gastric niche for commensals that might further urge the development of H. pylori-induced GC. Here, we review the current state of knowledge on gastric bacteria other than H. pylori and on their synergism with H. pylori in gastric carcinogenesis.

What is the Relevance of Gastric Microbiota Beyond H. pylori?

PURPOSE

The role of Helicobacter pylori as key factor in gastric inflammation and the development of (pre-)cancerous lesions is undisputable. As an open system, the human upper gastrointestinal tract harbors a complex bacterial community which is highly impacted by the absence or presence of H. pylori. The interaction between other bacteria and H. pylori might impact on gastric carcinogenesis.

RECENT FINDINGS

Several studies demonstrated differences in the composition of the gastric bacterial community in different stages of gastritis and between samples from tumor and adjacent tissue. In addition, animal studies demonstrated an increased and accelerated development of precancerous lesions in mice colonized with intestinal flora and H. pylori compared with mice mono-infected with H. pylori.

CONCLUSION

Other bacteria beyond H. pylori enter the focus in research on gastric carcinogenesis. However, we are still far from a thorough understanding of the pathophysiology of host-microbiota interaction and its impact on the development of malignant and precancerous changes.

An updated association between TNF-α -238G/A polymorphism and gastric cancer susceptibility in East Asians

Polymorphisms in the tumor necrosis factor α (TNF-α) gene are emerging as key determinants of gastric diseases. The TNF-α-238G/A single-nucleotide polymorphism (SNP) is the most extensively studied. However, this association is inconsistent amongst different populations. We therefore conducted an updated meta-analysis to obtain a more precise estimate of the association of TNF-α-238G/A polymorphism with gastric cancer (GC) risk. A comprehensive search of PubMed, Embase, Chinese (CNKI and WanFang) databases was performed to identify relevant studies through 5 May 2018. Odds ratio (OR) and 95% confidence interval (CI) were used to assess the strength of the association. Fourteen studies were included in our meta-analysis involving 2999 cases and 4685 controls. There was no significant association between TNF-α-238G/A polymorphism and GC risk in the overall populations. In the subgroup analysis, we found that TNF-α-238G/A polymorphism was associated with the increased risk of GC amongst Asians, especially in Chinese, but not in Caucasians. Subgroup analysis by genotyping methods revealed increased risk for other methods. In conclusion, our present meta-analysis shows that TNF-α-238G/A polymorphism is associated with the risk of GC in East Asian individuals.

Relationship Between Tumor Necrosis Factor-α rs361525 Polymorphism and Gastric Cancer Risk: A Meta-Analysis

Tumor necrosis factor (TNF)-α, a major part in inflammatory, infectious and tumor processes, and is pivotal at the early stages of gastric cancer. Relationship between its risk and TNF-α rs361525 polymorphism has been demonstrated, but remains conflicting and controversial. Therefore, a meta-analysis was conducted to more precisely estimate this relationship. PubMed, Web of Science, EMBASE and CNKI were comprehensively searched to find out relevant articles through October 5, 2017. The strength of the relationship was assessed using pooled odds ratios and 95% confidence intervals. Totally 20 articles were included involving 4,084 cases and 7,010 controls. No significant relationship between TNF-α rs361525 polymorphism and increased GC risk was found in the whole populations. Subgroup analyses uncovered TNF-α rs361525 polymorphism intensified the risk of GC among Asians under five models, but decreased the risk of GC among Caucasiansin the allelic and dominant models. Subgroup analysis by genotyping methods revealed increased risk for other methods. In conclusion, this meta-analysis suggests TNF-α rs361525 polymorphism is related to the risk of GC, especially for Asians.

Role of interleukin-12 gene polymorphisms in the onset risk of cancer: a meta-analysis

Many molecular epidemiologic studies have explored the possible links between interleukin-12 (IL-12) polymorphisms and various cancers. However, results from these studies remain inconsistent. This meta-analysis is aimed to shed light on the associations between three common loci (rs568408, rs2243115, rs3212227) of IL-12 gene and overall cancer risk. Our meta-analysis finally included 33 studies comprising 10,587 cancer cases and 12,040 cancer-free controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the cancer risk. We observed a significant association between IL-12B rs3212227 and overall cancer risk, especially in hepatocellular carcinoma, nasopharyngeal cancer, and among Asians. IL-12A polymorphisms (rs2243115 and rs568408) were found no influence on overall cancer risk. Nevertheless, stratification analyses demonstrated that rs568408 polymorphism contributed to increasing cancer risk of Caucasians and cervical cancer. And, rs2243115 may enhance the risk of brain tumor. These findings provided evidence that IL-12 polymorphisms may play a potential role in cancer risk.

The relationship between tumor necrosis factor-α polymorphisms and gastric cancer risk: An updated meta-analysis

The aim of the present study was to evaluate the relationship between tumor necrosis factor-α (TNF-α) and the development of gastric cancer, and to investigate whether it can be used as a biological marker for gastric cancer. In the current study, a new meta-analysis was performed to assess the association between TNF-α gene polymorphisms and gastric cancer susceptibility. Subgroup analyses based on ethnicity, control population source and non-cardia cancers were also conducted. Summary odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using a random-effects model. TNF-α 308 polymorphisms indicated a significant relationship with gastric cancer risk among a normal population [GA/AA vs. GG; 1.17 (1.10–1.23)]. In analysis stratified by ethnicity, TNF-α 238 displayed an association with gastric cancer risk in eastern populations [GA/AA vs. GG: 1.24 (1.02–1.50)], but not in western populations [GA/AA vs. GG: 0.96 (0.79–1.18)]. The overall ORs (95% CIs) for TNF-α 857, TNF-α 1031 and TNF-α 863 were 1.13 (1.04–1.24), 0.94 (0.85–1.05) and 0.89 (0.78–1.02), respectively, under dominant genetic model comparison. Among the above three SNPs, only TNF-α 857 was robustly associated with gastric cancer inclination, and this association remained consistently robust when limited to non-cardia gastric cancers [GA/AA vs. GG: 1.16 (1.03–1.31)]. TNF-α 308 and TNF-α 857 genotypes were potential risk factors of statistical significance in gastric cancer, and TNF-α 238 indicated to be significantly associated with gastric cancer risk only in eastern populations. TNF-α 1031 and TNF-α 863 were not significantly associated with gastric cancer risk.

Tumor Necrosis Factor-α T-857C (rs1799724) Polymorphism and Risk of Cancers: A Meta-Analysis

Objectives. To investigate the potential association of tumor necrosis factor-α T-857C polymorphism with susceptibility to the five common malignant tumors. Materials and Methods. A comprehensive search of PubMed/Medline, Embase, and Web of Science databases was performed up to November 2015. Pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated to assess the strength of the association. Subgroup analysis, heterogeneity analyses, and publication bias were also texted in the meta-analysis. Results. A total of twenty-two publications involving 5215 cases and 6755 controls were recruited. Overall, the meta-analysis revealed an increased risk between the TNF-α T-857C polymorphism and gastric cancer susceptibility in T versus C model, heterozygote genetic model, and dominant genetic model. An increased risk between the TNF-α T-857C polymorphism and hepatocellular cancer susceptibility in homozygote genetic model and recessive genetic model was also found. No significant association was found between the TNF-α T-857C polymorphism and colorectal cancer, cervical cancer, and prostate cancer. Conclusions. Our meta-analyses suggest that TNF-α T-857C polymorphism may be associated with increased risk of gastric cancer and hepatocellular cancer development. Therefore, the TNF-α T-857C polymorphism could be considered as one possible risk factor of gastric cancer and hepatocellular cancer according to our study.

Loss of gastrokine-2 drives premalignant gastric inflammation and tumor progression

Chronic mucosal inflammation is associated with a greater risk of gastric cancer (GC) and, therefore, requires tight control by suppressive counter mechanisms. Gastrokine-2 (GKN2) belongs to a family of secreted proteins expressed within normal gastric mucosal cells. GKN2 expression is frequently lost during GC progression, suggesting an inhibitory role; however, a causal link remains unsubstantiated. Here, we developed Gkn2 knockout and transgenic overexpressing mice to investigate the functional impact of GKN2 loss in GC pathogenesis. In mouse models of GC, decreased GKN2 expression correlated with gastric pathology that paralleled human GC progression. At baseline, Gkn2 knockout mice exhibited defective gastric epithelial differentiation but not malignant progression. Conversely, Gkn2 knockout in the IL-11/STAT3-dependent gp130F/F GC model caused tumorigenesis of the proximal stomach. Additionally, gastric immunopathology was accelerated in Helicobacter pylori-infected Gkn2 knockout mice and was associated with augmented T helper cell type 1 (Th1) but not Th17 immunity. Heightened Th1 responses in Gkn2 knockout mice were linked to deregulated mucosal innate immunity and impaired myeloid-derived suppressor cell activation. Finally, transgenic overexpression of human gastrokines (GKNs) attenuated gastric tumor growth in gp130F/F mice. Together, these results reveal an antiinflammatory role for GKN2, provide in vivo evidence that links GKN2 loss to GC pathogenesis, and suggest GKN restoration as a strategy to restrain GC progression.

Helicobacter pylori vs immune system or antibiotics

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

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

BACKGROUND

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Correlation analysis of gene polymorphisms and β-lactam allergy

A total of 64 patients with β-lactam allergy and 30 control subjects were enrolled in a case-control study. This study is aimed to analyze the relationship between β-lactam allergy and 10 single nucleotide polymorphisms (SNPs) in interleukin-10 (IL-10), IL-13, IL-4Rα, high-affinity immunoglobulin E-receptor β chain (FcεRIβ), interferon γ receptor 2 (IFNGR2), and CYP3A4, and within the Han Chinese population of Northwest China. Genotyping for the SNPs was conducted using the Sequenom MassARRAY(®) platform. SPSS 17.0 was employed to analyze the statistical data and SHEsis was used to perform the haplotype reconstruction and analyze linkage disequilibrium of SNPs of IL-10 and IL-13. The results showed that the genotype distribution of CYP3A4 rs2242480/CT differed significantly between case and control groups of males (P=0.022; odds ratio (OR)=0.167, 95% confidence interval (CI): 0.032-0.867). Further analysis showed that CCA, CCG, and TAA haplotypes of IL-10 had no significant correlation in patients with β-lactam allergy. The correlation between CCT and CAC haplotypes of IL-13 and β-lactam allergy needs to be further studied. The analysis did not reveal any differences in the distribution of others gene polymorphisms between cases and controls.

GATA-3 augmentation down-regulates Connexin43 in Helicobacter pylori associated gastric carcinogenesis

Helicobacter pylori (H. pylori) is a risk factor of gastric carcinoma, and inflammation with H.pylori infection has widely been suggested to trigger gastric carcinogenesis through "inflammation-carcinoma chain" (non-atrophic gastritis (NAG) → chronic atrophic gastritis (CAG) → intestinal metaplasia (IM) → dysplasia (DYS) and gastric carcinoma (GC)). Connexin43 (Cx43) is a major constituent of gap junction in normal gastric mucosa (NGM) and it is continuously down-regulated from normal gastric mucosa to precancerous lesions or ultimate gastric carcinoma, which shows novel target against gastric carcinoma by preventing the Cx43 decline. Our previous studies demonstrated that H. pylori infection in gastric mucosa down-regulates Cx43 expression, but its mechanism remains unknown. The transcriptional factor, GATA binding protein 3 (GATA-3) is the key to regulate adaptive immune response, which possibly relates to inflammation toward malignant transformation. Here the substantial rising of GATA-3 was screened by transcriptional factor microarray along the developmental stages of H. pylori associated gastric carcinoma. Moreover, the increased GATA-3 and inhibited Cx43 were confirmed in clinical specimens, Mongolian gerbils and normal gastric epithelial cell line GES-1 with H. pylori infection. GATA-3 silencing generated the Cx43 restoration both in intermediate differentiation gastric cancer cells BGC-803 and in H. pylori infected GES-1 cells. Dual-luciferase reporter assay further revealed the GATA-3 as one of Cx43 down-regulators by directly binding to its promoters. Together, the incremental GATA-3 is found in H. pylori associated gastric carcinogenesis, which is responsible for Cx43 inhibition as well.

IL-1α -889 C/T polymorphism and cancer susceptibility: a meta-analysis

The -889 C/T polymorphism in the interleukin-1α (IL-1α) gene has been implicated in the risk of cancer, but the results are inconclusive. The present meta-analysis aimed to investigate the association between the -889 C/T polymorphism and cancer risk. A literature search in PubMed, Embase™, Web of Science™, Science Direct^®, SpringerLink, EBSCO, Wanfang, and Chinese National Knowledge Infrastructure (CNKI) databases was carried out to identify studies investigating the association between IL-1α -889 C/T polymorphism and cancer risk. The odds ratio (OR) with 95% confidence interval (CI) were used to assess the strength of association. A total of 20 publications, involving 6,782 cases and 7,767 controls, were included in this meta-analysis. Combined analysis revealed a significant association between -889 C/T polymorphism and cancer risk under an allele model (OR =1.12, 95% CI =1.02–1.24, P=0.02), recessive model (OR =1.34, 95% CI =1.06–1.68, P=0.01), and homozygous comparison (OR =1.38, 95% CI =1.10–1.74, P<0.01). Subgroup analysis by ethnicity showed there was significant association between cancer risk and IL-1α -889C/T polymorphism in Asian populations under a recessive model (OR =2.57, 95% CI =1.11–5.98, P=0.03) and homozygous comparison (OR =2.60, 95% CI =1.12–6.04, P=0.03). Moreover, a subgroup analysis was conducted by source of control, and a statistically increased cancer risk was found in the hospital-based group, under a recessive model (OR =1.62, 95% CI =1.03–2.56, P=0.04) and homozygous comparison (OR =1.67, 95% CI =1.04–2.68, P=0.03). This meta-analysis suggests that IL-1α -889 C/T polymorphism contributes to cancer susceptibility. Further large and well-designed studies are needed to confirm this association.

Investigation of -308G>A and -1031T>C polymorphisms in the TNFA promoter region in Polish peptic ulcer patients

BACKGROUND/AIMS

Tumor necrosis factor α (TNF-α) encoded by TNFA is a key mediator in inflammation, a precursor condition for peptic ulceration. Promoter polymorphisms of TNFA that influence its transcriptional activity and TNF-α production are known. TNFA-308G>A (rs1800629) and TNFA-1031T>C (rs1799964), which are responsible for increased TNFA transcription, could influence the risk of peptic ulceration. This study aimed to investigate these polymorphisms and to evaluate their association with peptic ulcer disease and Helicobacter pylori infection in the Polish population.

METHODS

Gastric mucosa specimens obtained from 177 Polish peptic ulcer patients were used to conduct rapid urease tests and to assess the investigated polymorphisms by polymerase chain reaction-restriction fragment length polymorphism. Genotyping data were compared with the results obtained from healthy individuals of Polish origin.

RESULTS

There were no significant differences in genotype and allele frequency of the investigated polymorphisms between peptic ulcer patients and healthy individuals. No associations between the frequencies of particular genotypes and alleles for both single-nucleotide polymorphisms (SNPs) and the presence of H. pylori infection in peptic ulcer patients and in subgroups of men and women with peptic ulcer disease were found.

CONCLUSIONS

The investigated SNPs are not risk factors for either peptic ulcer or H. pylori infection development in the Polish population. The results require verification in a larger cohort.

Helicobacter pylori: perspectives and time trends

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

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

At the bedside: Helicobacter pylori, dysregulated host responses, DNA damage, and gastric cancer

Clinical trials performed in populations at high GC risk have demonstrated that eradication of Helicobacter pylori from the stomach with a course of combination antimicrobials helps prevent gastric carcinogenesis when they are administered before precancerous lesions have yet developed. In this review, we consider the insights into H. pylori-associated gastric carcinogenesis that have been gained from these and many other clinical studies in the field to highlight priority areas for basic research and clinical investigation. Among these are defining the magnitude of the risk reduction that may be achieved in clinical practice and at a population level by H. pylori eradication and investigating when, during the slow multistep progression to GC, intervention will be of the most benefit. Additional strategies to prevent GC induced by H. pylori, including chemoprevention, dietary modification, and close endoscopic surveillance, may also have value in augmenting the risk reduction. Why only a small subpopulation of those infected by H. pylori go on to develop GC may be partially explained by genetic susceptibility related to SNPs in several genes regulating the intensity of the gastric inflammatory response to H. pylori. Investigation of the basic mechanisms underlying the promotion of GC by H. pylori and the associated inflammatory response will likely continue to improve clinical strategies for the prevention of one of the most common causes of cancer death globally. See related review, At the Bench: H. pylori, dysregulated host responses, DNA damage, and gastric cancer.

Cytokines, cytokine gene polymorphisms and Helicobacter pylori infection: Friend or foe?

Helicobacter pylori (H. pylori) is a flagellated, spiral-shaped, microaerophilic Gram-negative bacillus that colonises the gastric mucosa of more than 50% of the human population. Infection is a risk factor for gastritis, ulcer disease and stomach cancer. Immunity against H. pylori is mainly related to Th1/Th17 skewing, and the activation of regulatory T cells is the main strategy used to limit inflammatory responses, which can result in the pathogen persistence and can lead to chronic gastrointestinal diseases, including cancer. Furthermore, host genetic factors that affect cytokines may determine differences in the susceptibility to many diseases. In this review, we present the cytokine profiles and the main cytokine gene polymorphisms associated with resistance/susceptibility to H. pylori and discuss how such polymorphisms may influence infection/disease outcomes.

Helicobacter pylori and gastric cancer

Infection with Helicobacter pylori is established as the major risk factor for gastric cancer development. Damage of the mucosal barrier due to H. pylori-induced inflammation enhances the carcinogenic effect of other risk factors such as salt intake or tobacco smoking. The genetic disposition of both the bacterial strain and the host can increase the potential towards gastric cancer formation. Genetic variance of the bacterial proteins CagA and VacA is associated with a higher gastric cancer risk, as are polymorphisms and epigenetic changes in host gene coding for interleukins (IL1β, IL8), transcription factors (CDX2, RUNX3) and DNA repair enzymes. Application of high-throughput assays for genome-wide assessment of either genetic structural variance or gene expression patterns may lead to a better understanding of the pathobiological background of these processes, including the underlying signaling pathways. Understanding of the stepwise alterations that take place in the transition from chronic atrophic gastritis, via metaplastic changes, to invasive neoplasia is vital to define the 'point of no return' before which eradication of H. pylori has the potential to prevent gastric cancer. Currently, eradication as preventive strategy is only recommended for high-incidence regions in Asia; large population studies with an adequate follow-up are required to demonstrate the effectiveness of such an approach in Western populations.

TNF-α-308 polymorphism and risk of digestive system cancers: A meta-analysis

AIM: To evaluate the association between the tumour necrosis factor alpha-308 (TNF-α-308) gene polymorphism and the risk of digestive system cancers.

METHODS: All eligible case-control studies published up to December 2012 were identified by searching PubMed, Web of Science, Embase and China National Knowledge Internet without language restrictions. The risk of digestive system cancers associated with the TNF-α-308 polymorphism was estimated for each study using odds ratio (OR) together with its 95%CI, respectively. Cochrane Collaboration RevMan 5.1 was used to perform the analysis. A χ²-test-based Q statistic test and an I² test were performed to assess the between-study heterogeneity. When the Q test was significant (P < 0.05) or I² > 50%, the random effects model was used, otherwise the fixed effects model was used.

RESULTS: Fifty-eight studies from fifty-five publications with a total of 9986 cancer patients and 15511 healthy controls were included. Overall, a significant association was found between the TNF-α-308 polymorphism and the risk of digestive system cancers [dominant model: OR = 1.23, 95%CI: 1.09-1.39, (G/A) vs (G/G): OR = 1.15, 95%CI: 1.02-1.28, (A/A) vs (G/G): OR = 1.44, 95%CI: 1.19-1.73, recessive model: OR = 1.38, 95%CI: 1.15-1.66]. Furthermore, when the analysis was stratified by ethnicity, similar results were observed in both the Asian and Caucasian populations, except for the dominant model and heterozygote comparisons in the Asian population [dominant model: OR = 1.24, 95%CI: 0.99-1.56, (G/A) vs (G/G): OR = 1.09, 95%CI: 0.96-1.24]. When the cancer type subgroups were examined, similar results were detected in gastric and hepatocellular carcinomas; however, no significant association was observed among other digestive system cancers.

CONCLUSION: The TNF-α-308 gene polymorphism may be significantly associated with the risk of gastric and hepatocellular carcinomas, but not colorectal, pancreatic, or oesophageal cancer, in the Asian population.

Association between tumor necrosis factor-α rs1800629 polymorphism and risk of gastric cancer: a meta-analysis

Gastric cancer is mainly initiated by inflammation and chronic superficial gastritis, and tumor necrosis factor-α (TNF-α) is an inflammatory cytokine which plays an important role in the inflammation. TNF-α rs1800629 G/A polymorphism was proposed to be associated with gastric cancer risk, but previous studies on Caucasians reported conflicting results. We performed a meta-analysis to comprehensively assess the association between TNF-α rs1800629 polymorphism and gastric cancer risk in Caucasians. The pooled odds ratio (OR) with 95% confidence interval (95% CI) was calculated to assess the association. Eleven case-control studies with 7,427 subjects were finally included into the meta-analysis. Overall, TNF-α rs1800629 polymorphism was significantly associated with the increased risk of gastric cancer under four genetic comparison models (A versus G: OR = 1.32, 95% CI 1.12-1.56, P = 0.001; AA versus GG: OR = 1.76, 95% CI 1.37-2.26, P < 0.001; AA versus GG/GA: OR = 1.62, 95% CI 1.27-2.07, P < 0.001; AA/GA versus GG: OR = 1.35, 95% CI 1.14-1.60, P = 0.001). Meta-analysis of those studies with high quality showed that TNF-α rs1800629 polymorphism was still significantly associated with the increased risk of gastric cancer under four genetic comparison models. There was no risk of publication bias in the meta-analysis. The meta-analysis suggests that TNF-α rs1800629 polymorphism is associated with the increased risk of gastric cancer in Caucasians.

Quantitative assessment of the influence of tumor necrosis factor alpha polymorphism with gastritis and gastric cancer risk

Tumor necrosis factor alpha (TNFA) is an important molecule in inflammatory, infectious, and tumoral processes. Inflammation is one of the early phases in the development of gastric cancer (GC). Therefore, several studies have examined the association of polymorphism in TNFA with gastritis and GC risk. A functional polymorphism, -308G>A (rs1800629), which is located in the promoter of TNFA gene, has been suggested to alter the production of TNF-α and influence cancer risk. To date, a number of studies have been carried out to investigate the relationship between the polymorphism and gastritis or GC susceptibility, but the results were conflicting. To investigate this inconsistency, we performed a meta-analysis of 36 studies for TNFA -308G>A polymorphism to evaluate the effect of TNFA on genetic susceptibility for gastritis and GC. An overall random-effects per-allele odds ratio of 1.16 (95 % confidence interval 1.04-1.29, P = 0.008) was found for the polymorphism. Significant results were also observed using dominant or recessive genetic models. In the subgroup analyses by ethnicity, significant results were found in Caucasians, whereas no significant associations were found among East Asians and other ethnic populations. No associations between the polymorphism and gastritis were observed. In addition, our data indicate that TNFA is involved in GC susceptibility and confers its effect primarily in diffuse type of tumors. Besides, -308G>A polymorphism was found to be significantly associated with both cardiac and noncardiac tumors. This meta-analysis demonstrated that the TNFA -308G>A polymorphism is a risk factor for developing GC, but the associations vary in different ethnic populations.

Tumor necrosis factor-α 238 G/A polymorphism and gastric cancer risk: a meta-analysis

Though many studies were performed to assess the association between tumor necrosis factor-α (TNF-α) 238 G/A polymorphism and gastric cancer risk, there were no conclusive findings. A meta-analysis of previous published studies was performed to get a comprehensive assessment of the association between TNF-α 238 G/A polymorphisms and gastric cancer. The pooled odds ratios (ORs) and 95% confidence intervals (95 % CIs) were calculated to assess the association. Fifteen studies with a total of 7,795 participants were finally included into this meta-analysis. Overall, there was an obvious association between TNF-α 238 G/A polymorphism and increased risk of gastric cancer (A vs. G: OR = 1.32, 95% CI 1.02-1.72, P = 0.036; GA vs. GG: OR = 1.32, 95% CI 1.01-1.72, P = 0.042; and AA/GA vs. GG: OR = 1.34, 95% CI 1.02-1.76, P = 0.036). Subgroup analysis by ethnicity showed the statistically significant association between TNF-α 238 G/A polymorphism and gastric cancer was limited to Asian populations (A vs. G: OR = 1.59, 95% CI 1.29-1.97, P < 0.001; GA vs. GG: OR = 1.63, 95% CI 1.29-2.04, P < 0.001; and AA/GA vs. GG: OR = 1.64, 95%CI 1.31-2.05, P < 0.001), and there was no obvious association in Caucasians. In conclusion, TNF-α 238 G/A polymorphism is significantly associated with increased risk of gastric cancer, especially in Asians.

Association between tumor necrosis factor-alpha 857C/T polymorphism and gastric cancer: a meta-analysis

Tumor necrosis factor-alpha (TNF-α) is an inflammatory cytokine which may play an important role on the immune response may control the progression of gastric cancer. Previous studies on the association between TNF-α 857C/T polymorphism and gastric cancer risk reported conflicting results. We performed a meta-analysis to comprehensively assess the association between TNF-α 857C/T polymorphism and gastric cancer risk. Literature search was performed for all publications on the association between TNF-α 857C/T polymorphism and gastric cancer risk through March 6, 2013. The pooled odds ratios (ORs) with their 95% confidence interval (95%CIs) were calculated to assess the association between TNF-α 857C/T polymorphism and gastric cancer risk. Nine individual case-control studies with a total of 5,054 subjects (1,835 cases and 3,219 controls) were finally included into the meta-analysis. Meta-analysis of total nine studies showed that TNF-α 857C/T polymorphism was significantly associated with increased risk of gastric cancer under four genetic models (for T vs. C: OR = 1.19, 95%CI 1.07-1.33, P = 0.002; for TT vs. CC: OR = 1.44, 95%CI 1.03-2.02, P = 0.032; for CT vs. CC: OR = 1.19, 95%CI 1.05-1.36, P = 0.008; and for TT/CT vs. CC: OR = 1.21, 95%CI 1.07-1.38, P = 0.003). Subgroup analysis by ethnicity further showed that there was a significant association between TNF-α 857C/T polymorphism and increased risk of gastric cancer in Asians but not in Caucasians. The meta-analysis suggests that TNF-α 857C/T polymorphism is significantly associated with increased risk of gastric cancer, especially in Asians.

Osteopontin promoter polymorphisms are associated with susceptibility to gastric cancer

GOALS

To evaluate the significance of osteopontin (OPN) genotypes in the susceptibility to gastric cancer.

BACKGROUND

The expression of OPN has been correlated with development, invasiveness, metastasis, and survival of gastric cancer, but the role of polymorphisms in the OPN promoter has not been investigated.

STUDY

We enrolled 146 gastric cancer patients and 128 controls. DNA was extracted from peripheral blood leucocytes. Single-nucleotide polymorphisms (SNPs) in the OPN promoter (-66, -156, -443, -616, -1748, and -1776) were analyzed by pyrosequencing and direct sequencing methods. Logistic regression analyses were used to evaluate the associations between SNPs and development of gastric cancer.

RESULTS

SNP -443 C/C and -616 T/T of the OPN promoter were significantly associated with gastric cancer [odds ratio (OR)=2.88; 95% confidence interval (CI), 1.16-7.12 and OR=1.95; 95% CI, 1.35-2.82, respectively]. Analysis of the combined effect of OPN promoter SNPs revealed that the combination of SNP -443 (T/C or C/C) and SNP -616 (T/T or T/G) had the most significant association with gastric cancer (OR=3.95; 95% CI, 1.58-9.90).

CONCLUSIONS

Our results suggest that polymorphisms in the OPN promoter are associated with the development of gastric cancer, and the combination of SNP -443 (T/C or C/C) and -616 (T/T or T/G) most significantly increases susceptibility to gastric cancer.

3rd Brazilian Consensus on Helicobacter pylori

Signicant progress has been obtained since the Second Brazilian Consensus Conference on Helicobacter pylori Infection held in 2004, in São Paulo, SP, Brazil, and justify a third meeting to establish updated guidelines on the current management of H. pylori infection. The Third Brazilian Consensus Conference on H pylori Infection was organized by the Brazilian Nucleus for the Study of Helicobacter, a Department of the Brazilian Federation of Gastroenterology and took place on April 12-15, 2011, in Bento Gonçalves, RS, Brazil. Thirty-one delegates coming from the five Brazilian regions and one international guest, including gastroenterologists, pathologists, epidemiologists, and pediatricians undertook the meeting. The participants were allocated in one of the five main topics of the meeting: H pylori, functional dyspepsia and diagnosis; H pylori and gastric cancer; H pylori and other associated disorders; H pylori treatment and retreatment; and, epidemiology of H pylori infection in Brazil. The results of each subgroup were submitted to a final consensus voting to all participants. Relevant data were presented, and the quality of evidence, strength of recommendation, and level of consensus were graded. Seventy per cent and more votes were considered as acceptance for the final statement. This article presents the main recommendations and conclusions to guide Brazilian doctors involved in the management of H pylori infection.

Downregulation of Hlx closely related to the decreased expressions of T-bet and Runx3 in patients with gastric cancer may be associated with a pathological event leading to the imbalance of Th1/Th2

T-bet plays an important role in immunoregulation; it induces the differentiation of Th1 together with the homeobox transcription factor gene Hlx. Recent studies show that T-bet and Th1-associated factors are critical in regulating tumor development. However, the contributions of Hlx in the occurrence and development of cancer remain unknown. In this study, the Hlx, T-bet, Runx3, and IFN-γ were measured in PBMC from patients with gastric cancer and the correlation between Hlx and T-bet or IFN-γ was assessed. The expression levels of Hlx, T-bet, and IFN-γwere significantly decreased, and there was a positive correlation between Hlx and T-bet or IFN-γ. In addition, the Runx3 expression was also downregulated with the lower T-bet mRNA level. These results suggested that the decreased Hlx expression was closely associated with T-bet and Runx3 downregulations and may contribute to the development of gastric cancer.

Single nucleotide polymorphism in the interleukin 12B gene is associated with risk for breast cancer development

We analysed the association of a single nucleotide polymorphism (SNP) in the gene encoding the IL-12 subunit p40 (IL12B, rs3212227, A>C) with breast cancer. The SNPs allelic and genotypic frequencies were compared between patients (n = 191) and healthy (n = 194) women in a case-control study from Croatia. The major allele (A) was associated with susceptibility to breast cancer (P = 0.003; OR = 1.67; 95% CI: 1.17-2.38). Likewise, the minor allele (C) was significantly correlated with protection (P = 0.003; OR = 0.60; 95% CI: 0.42-0.86). At the genotype level, AA homozygosity was significantly associated with predisposition to disease (P = 0.013; OR = 1.68, 95% CI: 1.09-2.59), whereas the minor allele homozygosity (CC) was correlated with protection to disease (P = 0.020, OR = 0.28, 95% CI: 0.09-0.91). The heterozygous genotype showed no significant correlation with disease. The product of the IL12B gene (IL-12 p40) can either form a homodimeric cytokine or be part of two pro-inflammatory (IL-12 and IL-23) cytokines. It is presently unclear whether the major allele is associated with higher or lower protein levels of IL-12 p40 and IL-12 p70, which are critical in inflammation and adaptive immune responses. However, as the A allele is high producer of IL12B (p40) mRNA, these results might imply that higher levels of IL-12 p40 (either as homodimers or joined with one or both of the other two subunits) predispose to breast cancer.

Functional polymorphisms in the interleukin-12 gene contribute to cancer risk: evidence from a meta-analysis of 18 case-control studies

BACKGROUND

Emerging evidence from preclinical and clinical studies has shown that interleukin-12 (IL-12) has some effectiveness against endogenously arising carcinogenesis. Several potentially functional polymorphisms of IL-12 gene have been implicated in cancer risk, but individually published studies showed inconclusive results. The aim of this study was to investigate the association between IL-12 polymorphisms and cancer risk.

METHODS

The MEDLINE, EMBASE, Web of science and CBM databases were searched for all articles published up to June 10, 2012 that addressed IL-12 polymorphisms and cancer risk. Statistical analyses were performed using RevMan 5.1.6 and STATA 12.0 softwares.

RESULTS

Eighteen studies were included with a total of 6463 cancer cases and 7412 healthy controls. We found that the 3'UTR A>C (rs3212227) polymorphism of IL-12B gene was associated with significantly increased overall risk of cancers using random effects model (C vs A: odds ratio [OR]=1.14, 95% confidence interval [CI]: 1.02-1.27; AC+CC vs AA: OR=1.20, 95%CI: 1.01-1.43). However, the 3'UTR G>A (rs568408), IVS2 T>A (rs582054) and 5'UTR T>G (rs2243115) polymorphisms of IL-12A gene did not appear to have an influence on cancer susceptibility. Further subgroup analyses showed that the 3'UTR A>C (rs3212227) polymorphism was associated with increased cancer risks in the subgroups of Asians, cervical and nasopharyngeal cancers.

CONCLUSIONS

Results from the current meta-analysis indicates that the 3'UTR A>C (rs3212227) polymorphism of IL-12B gene might be a potential biomarker for cancer risk among Asians, especially for cervical and nasopharyngeal cancers.

Eradication Treatment of Helicobacter pylori Infection: Its Importance and Possible Relationship in Preventing the Development of Gastric Cancer

Helicobacter pylori is the most important carcinogen for gastric adenocarcinoma. Bacterial virulence factors are essential players in modulating the immune response involved in the initiation of carcinogenesis in the stomach; host genetic factors contribute to the regulation of the inflammatory response and to the aggravation of mucosal damage. In terms of environmental factors, salt intake and smoking contribute to the development of lesions. Various therapeutic schemes are proposed to eradicate H. pylori infection, which could potentially prevent gastric cancer, offering the greatest benefit if performed before premalignant changes of the gastric mucosa have occurred.

Interleukin-12: clinical usage and molecular markers of cancer susceptibility

The last decade has seen the emergence of immunomodulators as therapeutic agents in cancer treatment. Interleukins (ILs) are a category of small cell-signaling molecules that organize communication and interaction between immune cells and therefore they could be used as perfect immunomodulators. IL-12 is a promising candidate for cancer immunotherapy since it plays a major role in development of antitumor immune response. Numerous studies report that IL-12 promotes an effective destruction of cancer cells both in vivo and in vitro. In addition, IL-12 has anti-angiogenic activity and it is able to dramatically decrease tumor-supportive activities of tumor-associated macrophages. The first part of the review is devoted to immunobiology of IL-12. Signaling pathways of IL-12 as well as clinical trials of this cytokine are discussed. The second part of the review is concerned on the inherited variations in IL-12A and IL-12B genes that could modulate cancer susceptibility, and as a consequence, possess predictive, therapeutic, or prognostic significance. It is known that functional single nucleotide polymorphisms (SNPs) in IL-12A and IL-12B genes may dramatically affect on protein expression level, or alter its functions, which may lead to immune disorders, autoimmune diseases, and eventually contribute to cancer occurrence. The list of genetic polymorphisms for further investigations might include the following: IL-12B_+1188A/C (rs3212227), IL-12A_+277G/A (rs568408), IL-12A_-798T/A (rs582054), IL-12A_-504T/G (rs190533), IL-12A_-1148T/C (rs2243123), and IL-12B_+16974 A/C. Perhaps, some of these SNPs may become an attractive target for oncogenomics and possibly could be used in programs of early cancer diagnosis as well as cancer prevention in the nearest future.

T cells and adoptive immunotherapy: recent developments and future prospects in gastrointestinal oncology

Gastrointestinal oncology is one of the foremost causes of death: the gastric cancer accounts for 10.4% of cancer deaths worldwide, the pancreatic cancer for 6%, and finally, the colorectal cancer for 9% of all cancer-related deaths. For all these gastrointestinal cancers, surgical tumor resection remains the primary curative treatment, but the overall 5-year survival rate remains poor, ranging between 20-25%; the addition of combined modality strategies (pre- or postoperative chemoradiotherapy or perioperative chemotherapy) results in 5-year survival rates of only 30-35%. Therefore, many investigators believe that the potential for making significant progress lies on understanding and exploiting the molecular biology of gastrointestinal tumors to investigate new therapeutic strategies such as specific immunotherapy. In this paper we will focus on recent knowledge concerning the role of T cells and the use of T adoptive immunotherapy in the treatment of gastrointestinal cancers.

Gene-gene interactions between interleukin-12A and interleukin-12B with the risk of brain tumor

Emerging evidence from preclinical and clinical studies has shown that interleukin-12 (IL-12) has some effectiveness against endogenously arising brain tumor. The aim of this study was to investigate interactions of IL-12A and IL-12B polymorphisms on the risk of brain tumor. We analyzed IL-12A rs2243115 and IL-12B rs3212227 polymorphisms in 170 patients with brain tumor and 222 healthy controls in a Chinese population using a polymerase chain reaction-restriction fragment length polymorphism assay and DNA sequencing method. Individuals carrying a G allele of IL-12A rs2243115 had a significantly higher risk of developing brain tumor compared with those carrying a T allele (odds ratio [OR]=2.01, 95% confidence interval [CI], 1.17-3.45). After stratification analysis according to tumor types, a similarly higher risk was detected in patients with glioma (OR=2.56, 95% CI, 1.25-5.21). When gene-gene interactions were examined, carriers at both loci rs2243115 TG/GG and rs3212227 AC/CC had a 2.62-fold increased risk of glioma compared with those with rs2243115 TT and rs3212227 AC/CC genotypes (OR=2.62, 95% CI, 1.05-6.50). This study provides evidence that IL-12A rs2243115 may be associated with the risk of brain tumor. Additionally, gene-gene interactions of IL-12A rs2243115 and IL-12B rs3212227 may contribute to brain tumor susceptibility.

Systemic cytokine levels and subsequent risk of gastric cancer in Chinese Women

Although control of the host cytokine network is known to influence gastric cancer susceptibility, the specific inflammatory responses in gastric carcinogenesis remain unclear. We prospectively examined the relationships between gastric cancer risk and plasma levels of interleukin (IL)-1β, IL-6, IL-8 and tumor necrosis factor (TNF)-α in a nested case control study within The Shanghai Women's Health Study. Two controls were matched to each case on the basis of age, menopausal status, and sample collection parameters. The associations between gastric cancer risk and tertiles of cytokine levels were estimated by odds ratios (OR) and 95% confidence intervals (CI) from conditional logistic regression, adjusting for education. During a median follow-up period of 4 years (range 0.1-8 years), 141 women developed gastric cancer and were matched to 282 cancer-free study participants. Elevated levels of plasma IL-6 were associated with an increased risk of gastric cancer (P(trend) = 0.04). Risk increased 70% (OR = 1.7; 95% CI 1.0, 3.0) for women in the highest tertile (>4 pg/mL) of IL-6 compared with those in the lowest tertile (<1.8 pg/mL). The association between gastric cancer risk and IL-6 was stronger after 4 years of follow-up (OR = 2.6 [95% CI 1.0, 6.7] for highest versus lowest tertile) compared with an OR of 1.4 (95% CI 0.7, 2.9) for those diagnosed within 1-4 years of follow-up. No associations were observed with the other pro-inflammatory cytokines examined, namely IL-1β, IL-8, and TNF-α. Systemic plasma IL-6 levels may inform long-term gastric cancer risk. This novel finding awaits confirmation in future studies with sequential plasma collection.

Potentially functional polymorphisms in IL-23 receptor and risk of esophageal cancer in a Chinese population

Interleukin-23 (IL-23)/IL-23 receptor (IL-23R) is essential for Th17 cell-mediated immune response, involved in autoimmune diseases and cancer pathogenesis. Two potentially functional genetic single nucleotide polymorphisms (SNPs; IL-23R rs6682925 T>C and rs1884444 T>G) were found to contribute to cancer susceptibility. In our study, we conducted a case-control study including 1,645 patients with esophageal cancer and 1,694 cancer-free controls in a Chinese population to assess the association between the two SNPs and the risk of esophageal cancer. We found that IL-23R rs6682925 TC/CC and rs1884444 TG/GG variant genotypes were associated with significantly increased risk of esophageal cancer [rs1884444: adjusted odds ratio (OR) = 1.16, 95% confidence intervals (CIs) =1.01-1.33; rs6682925: adjusted OR = 1.23, 95% CIs = 1.07-1.42], compared to their corresponding wild-type homozygotes. Furthermore, the increased risks associated with the two SNPs were independent from smoking and alcohol drinking status. These findings indicated that genetic variants in IL-23R may contribute to esophageal cancer risk in our Chinese population.

Gastric carcinogenesis

INTRODUCTION

In most patients, gastric cancer is diagnosed in advanced stage. Curative treatment options are limited and the mortality is high. The process of gastric carcinogenesis is triggered by Helicobacter pylori-driven gastritis and is further characterized by its complexity of interaction with other risk factors. Health care systems are challenged for the improvement of prevention, early diagnosis, and effective treatments.

METHODS

An extensive literature research has been performed to elucidate the interplay between etiological factors involved in gastric carcinogenesis.

RESULTS

H. pylori is the most important carcinogen for gastric adenocarcinoma. Evidence is provided by experiments including animal studies as well as clinical observational and interventional studies in humans. Eradication has the potential to prevent gastric cancer and offers the greatest benefit if performed before premalignant changes of the gastric mucosa have occurred. Bacterial virulence factors are essential players in modulating the immune response involved in the initiation of the carcinogenesis in the stomach. Host genetic factors contribute to the regulation of the inflammatory response and in the aggravation of mucosal damage. The harmful role of environmental factors is restricted to salt intake and smoking of tobacco. The ingestion of fruit and vegetables has some protective effect.

CONCLUSION

Infection with H. pylori is the major risk factor for gastric cancer development, and thus, eradication of the Helicobacter offers a promising best option for prevention of the disease. Bacterial virulence, host genetic factors, and environmental influences are interacting in the multifactorial process of gastric carcinogenesis.

Genetic Mechanisms and Aberrant Gene Expression during the Development of Gastric Intestinal Metaplasia and Adenocarcinoma

Gastric adenocarcinoma occurs via a sequence of molecular events known as the Correa’s Cascade which often progresses over many years. Gastritis, typically caused by infection with the bacterium H. pylori, is the first step of the cascade that results in gastric cancer; however, not all cases of gastritis progress along this carcinogenic route. Despite recent antibiotic intervention of H. pylori infections, gastric adenocarcinoma remains the second most common cause of cancer deaths worldwide. Intestinal metaplasia is the next step along the carcinogenic sequence after gastritis and is considered to be a precursor lesion for gastric cancer; however, not all patients with intestinal metaplasia develop adenocarcinoma and little is known about the molecular and genetic events that trigger the progression of intestinal metaplasia into adenocarcinoma. This review aims to highlight the progress to date in the genetic events involved in intestinal-type gastric adenocarcinoma and its precursor lesion, intestinal metaplasia. The use of technologies such as whole genome microarray analysis, immunohistochemical analysis and DNA methylation analysis has allowed an insight into some of the events which occur in intestinal metaplasia and may be involved in carcinogenesis. There is still much that is yet to be discovered surrounding the development of this lesion and how, in many cases, it develops into a state of malignancy.

The molecular pathogenesis of STAT3-driven gastric tumourigenesis in mice is independent of IL-17

Chronic activation of the gastric mucosal adaptive immune response is a characteristic trait of gastric cancer. It has recently emerged that a new class of T helper (Th) cells, defined by their ability to produce interleukin (IL)-17A (Th17), is associated with a host of inflammatory responses, including gastritis. However, the role of these Th17 cells in the pathogenesis of gastric cancer is less clear. To formally address this, we employed gp130(F/F) mice, which spontaneously develop gastric inflammation-associated tumours akin to human intestinal-type gastric cancer. At the molecular level, these tumours demonstrate hyper-activation of the latent transcription factor signal transducer and activator of transcription (STAT)3 via the IL-6 cytokine family member, IL-11. In gp130(F/F) mice, the generation of Th17 cells, as well as the gastric expression of IL-17a and other Th17-related factors (Rorγt, IL-23), were augmented compared to wild-type gp130(+/+) mice. Consistent with a role for IL-6 and STAT3 in regulating IL-17A, increased Th17 generation and gastric expression of Th17-related factors in gp130(F/F) mice were reduced to wild-type levels in gp130(F/F) :Stat3(-/+) mice displaying normalized STAT3 activity, and also in gp130(F/F) :IL-6(-/-) mice. Importantly, genetic ablation of IL-17A in gp130(F/F) :IL-17a(-/-) mice did not suppress the initiation and growth of gastric tumours. Furthermore, IL-17A and RORC gene expression was strongly increased in human gastric biopsies from patients with gastritis, but not gastric cancer. Collectively, our data suggest that increased expression of Th17-related factors does not correlate with the molecular pathogenesis of gastric tumourigenesis.

Polymorphisms in chemokine and receptor genes and gastric cancer risk and survival in a high risk Polish population

OBJECTIVE

To examine if genetic variations in chemokine receptor and ligand genes are associated with gastric cancer risk and survival.

METHODS

The study included 298 cases and 417 controls from a population-based study of gastric cancer conducted in Warsaw, Poland in 1994-1996. We investigated seven single nucleotide polymorphisms in a chemokine ligand (CXCL12) and chemokine receptor (CCR2, CCR5, CX3CR1) genes and one frameshift deletion (CCR5) in blood leukocyte DNA in relation to gastric cancer risk and survival. Genotyping was conducted at the NCI Core Genotyping Facility. Odds ratios and 95% confidence intervals were computed using univariate and multivariate logistic regression models. Survival analysis was performed using Cox proportional hazards models.

RESULTS

Gastric cancer risk was not associated with single chemokine polymorphisms. A CCR5 haplotype that contained the common alleles of IVS1+151 G>T (rs2734648), IVS2+80 C>T (rs1800024) and minor allele of IVS1+246 A>G (rs1799987) was associated with a borderline significantly increased risk (OR = 1.5, 95% CI: 1.0?2.2). For gastric cancer cases, there was a greater risk of death for carriers of the minor alleles of CCR2 Ex2+241 G>A (rs1799864) (HR = 1.5, 95% CI: 1.1-2.1) and CCR5 IVS2+80 C>T (rs1800024) (HR = 1.5, 95% CI: 1.1-2.1). Carriers of the CCR5 minor allele of IVS1+151 G>T (rs2734648) had a decreased risk of death compared to homozygote carriers of the common allele (HR = 0.8, 95% CI: 0.6-1.0).

CONCLUSIONS

Our findings do not support an association between gastric cancer risk and single chemokine genetic variation. The observed associations between cancer risk and a CCR5 haplotype and between survival and polymorphisms in CCR2 and CCR5 need replication in future studies.