Synergistic effect of HLA class II loci and cytokine gene polymorphisms on the risk of gastric cancer in Japanese patients with Helicobacter pylori infection

Association of HLA gene polymorphisms with Helicobacter pylori related gastric cancer-a systematic review

The appropriate host cell immune responses for the progression of several diseases, including gastric or stomach cancer (GC), are significantly influenced by HLA polymorphisms. Our objective was to systematically review the evidence linking HLA polymorphisms with the risk of Helicobacter. pylori related GC. We conducted a comprehensive literature search to identify studies published between 2000 and April 2023 on the association of HLA polymorphisms with H. pylori related GC using databases such as Medline through PubMed, Embase, Web of Science (core collection), The Cochrane Library, and Scopus. Two authors independently screened articles, extracted data, and assessed the risk of bias using the Risk of Bias Assessment tool for Non-randomized Studies. From 7872 retrieved studies, 19 met inclusion criteria, encompassing 1656 cases and 16,787 controls across four World Health Organization regions, with Japan contributing the most studies. We explored HLA-A/B/C, HLA-DRB1/DQA1/DQB1, HLA-G, and MICA alleles. Of 29 significant HLA polymorphisms identified, 18 showed a positive association with GC, whereas 11 were negatively associated. HLA-DQB1*06 allele was most frequently associated to susceptibility, as reported in four studies, followed by HLA-DRB1*04 and HLA-DQA1*01, each reported in two studies. Conversely, HLA-G*01, HLA-DQA1*01, HLA-DQA1*05, and HLA-DQB1*03 were identified as protective in two studies each. Additionally, five genotypes and six haplotypes were reported as positive, whereas three genotypes and two haplotypes were negative factors for the disease incidence or mortality. Despite heterogeneity in the study population and types of HLA polymorphisms examined, our analysis indicates certain polymorphisms are associated with H. pylori related GC progression and mortality in specific populations.

HLA class II peptide-binding-region analysis reveals funneling of polymorphism in action

BACKGROUND

HLA-class II proteins hold important roles in key physiological processes. The purpose of this study was to compile all class II alleles reported in human population and investigate patterns in pocket variants and their combinations, focusing on the peptide-binding region (PBR).

METHODS

For this purpose, all protein sequences of DPA1, DQA1, DPB1, DQB1 and DRB1 were selected and filtered, in order to have full PBR sequences. Proportional representation was used for pocket variants while population data were also used.

RESULTS

All pocket variants and PBR sequences were retrieved and analyzed based on the preference of amino acids and their properties in all pocket positions. The observed number of pocket variants combinations was much lower than the possible inferred, suggesting that PBR formation is under strict funneling. Also, although class II proteins are very polymorphic, in the majority of the reported alleles in all populations, a significantly less polymorphic pocket core was found.

CONCLUSIONS

Pocket variability of five HLA class II proteins was studied revealing favorable properties of each protein. The actual PBR sequences of HLA class II proteins appear to be governed by restrictions that lead to the establishment of only a fraction of the possible combinations and the polymorphism recorded is the result of intense funneling based on function.

Possible Roles of Interleukin-4 and -13 and Their Receptors in Gastric and Colon Cancer

Interleukin (IL)-4 and -13 are structurally and functionally related cytokines sharing common receptor subunits. They regulate immune responses and, moreover, are involved in the pathogenesis of a variety of human neoplasms. Three different receptors have been described for IL-4, but only IL-4 receptor type II (IL-4Rα/IL-13Rα1) is expressed in solid tumors. While IL-13 can also bind to three different receptors, IL-13 receptor type I (IL-4Rα/IL-13Rα1/IL-13Rα2) and type II (IL-4Rα/IL-13Rα1) are expressed in solid tumors. After receptor binding, IL-4 and IL-13 can mediate tumor cell proliferation, survival, and metastasis in gastric or colon cancer. This review summarizes the results about the role of IL-4/IL-13 and their receptors in gastric and colon cancer.

Association between human leukocyte antigen gene polymorphisms and multiple EPIYA-C repeats in gastrointestinal disorders

BACKGROUND

Polymorphisms of human leukocyte antigen (HLA) genes are suggested to increase the risk of gastric cancer (GC).

AIM

To investigate the HLA allele frequencies of patients with GC relative to a control group in terms of CagA+ multiple (≥ 2) EPIYA-C repeats.

METHODS

The patient group comprised 94 patients [44 GC and 50 duodenal ulcer (DU) patients], and the control group comprised 86 individuals [(50 non-ulcer dyspepsia patients and 36 people with asymptomatic Helicobacter pylori (H. pylori)]. Polymerase chain reaction was performed for the amplification of the H. pylori cagA gene and typing of EPIYA motifs. HLA sequence-specific oligonucleotide (SSO) typing was performed using Lifecodes SSO typing kits (HLA-A, HLA-B HLA-C, HLA-DRB1, and HLA-DQA1-B1 kits).

RESULTS

The comparison of GC cases in terms of CagA+ multiple (≥ 2) EPIYA-C repeats showed that only the HLA-DQB1*06 allele [odds ratio (OR): 0.37, P = 0.036] was significantly lower, but significance was lost after correction (Pc = 0.1845). The HLA-DQA1*01 allele had a high ratio in GC cases with multiple EPIYA-C repeats, but this was not significant in the univariate analysis. We compared allele frequencies in the DU cases alone and in GC and DU cases together using the same criterion, and none of the HLA alleles were significantly associated with GC or DU. Also, none of the alleles were detected as independent risk factors after the multivariate analysis. On the other hand, in a multivariate logistic regression with no discriminative criterion, HLA-DQA1*01 (OR = 1.848), HLA-DQB1*06 (OR = 1.821) and HLA-A*02 (OR = 1.579) alleles were detected as independent risk factors for GC and DU.

CONCLUSION

None of the HLA alleles were detected as independent risk factors in terms of CagA+ multiple EPIYA-C repeats. However, HLA-DQA1*01, HLA-DQB1*0601, and HLA-A*2 were independent risk factors with no criterion in the multivariate analysis. We suggest that the association of these alleles with gastric malignancies is not specifically related to cagA and multiple EPIYA C repeats.

Association between polymorphisms in HLA-A, HLA-B, HLA-DR, and DQ genes from gastric cancer and duodenal ulcer patients and cagL among cagA-positive Helicobacter pylori strains: The first study in a Turkish population

Colonization of the human gastric mucosa by H. pylori may cause peptic and duodenal ulcers (DUs), gastric lymphomas, and gastric cancers. The cagL gene is a component of cag T4SS and is involved in cagA translocation into host. An association between the risk of gastric cancer and the type of HLA class II (DR and/or DQ) was suggested in different populations. The aim of this study was to investigate, the clinical association of the cagL gene with host HLA alleles in H. pylori strains that were isolated from patients with gastric cancer, DU, and non-ulcer dyspepsia (NUD) and to determine the HLA allele that confers susceptibility or resistance for the risk of gastric cancer and DU development in Turkish patients. A total of 94 patients (44 gastric cancer and 50 DU patients; 58 male, 36 female; mean age, 49.6 years), and 86 individuals (50 NUD patients and 36 persons with normal gastrointestinal system [NGIS]; 30 male, 56 female; mean age, 47.3 years) were included as the patient and the control groups, respectively. CagA and cagL were determined by PCR method. DNA from peripheral blood samples was obtained by EZ-DNA extraction kit. For HLA SSO typing, LIFECODES SSO Typing kits (HLA-A, HLA-B HLA-C, HLA-DRB1 and HLA-DQA1/B1 kits) were used. The CagL/CagA positivity distribution in the groups were as follows: 42 (95.4%) gastric cancer, 46 (92%) DU and, 34 (68%) NUD and no NGIS cases. The HLA-DQA1*01 (OR: 3.82) allele was significantly different, suggesting that these individuals with H. pylori strains harbouring the CagL/CagA positivity are susceptible to the risk of gastric cancer and DU, and the HLA-DQA1*05 (OR, 0.318) allele was suggested as a protective allele for the risk of gastric cancer and DU using univariate analyses. HLA-DQA1*01 (OR, 2.21), HLA-DQB1*06 (OR, 2.67), sex (male, OR, 2.27), and CagL/CagA/(<2) EPIYA C repeats (OR, 5.72) were detected independent risk factors that increased the risk of gastric cancer and DU using multivariate analyses. However, the HLA-DRB1*04 (OR, 0.28) allele was shown to be a protective allele, which decreased the risk of gastric cancer and DU. Gastric pathologies result from an interaction between bacterial virulence factors, host epigenetic and environmental factors, and H. pylori strain heterogeneity, such as genotypic variation among strains and variations in H. pylori populations within an individual host.

Gastric cancer: genome damaged by bugs

Gastric cancer (GC) is one of the leading causes of cancer-related death worldwide. The role of the microorganisms in gastric tumorigenesis attracts much attention in recent years. These microorganisms include bacteria, virus, and fungi. Among them, Helicobacter pylori (H. pylori) infection is by far the most important risk factor for GC development, with special reference to the early-onset cases. H. pylori targets multiple cellular components by utilizing various virulence factors to modulate the host proliferation, apoptosis, migration, and inflammatory response. Epstein–Barr virus (EBV) serves as another major risk factor in gastric carcinogenesis. The virus protein, EBER noncoding RNA, and EBV miRNAs contribute to the tumorigenesis by modulating host genome methylation and gene expression. In this review, we summarized the related reports about the colonized microorganism in the stomach and discussed their specific roles in gastric tumorigenesis. Meanwhile, we highlighted the therapeutic significance of eradicating the microorganisms in GC treatment.

Effects of IL-4-590C/T (rs2243250) Polymorphism on the Susceptibility of Smoking-Related Cancer: A Meta-Analysis Involving 11,407 Subjects

Background

Several previous studies have assessed the relationship between IL-4-590C/T gene polymorphism and smoking-related cancer in recent years; however, the results remain controversial. Based on it, the study intends to clarify whether IL-4-590C/T variant increases the risk of smoking-related cancer through meta-analysis.

Methods

We searched PubMed, EMBASE, Web of Science, Cochrane Library database, China National Knowledge Infrastructure, and Wanfang data information service platform to collect qualified case-control studies in strict accordance with the inclusion and exclusion standards. The 95% confidence interval (95% CI) and its odds ratio (OR) were adopted to access the relation between IL-4-590C/T gene polymorphism and smoking-related cancer; sensitivity analysis and publication bias assessment were carried out after the studies' quality evaluation.

Results

17 studies were included in total, with 5,061 patients and 6,346 control cases. A significant association between IL-4-590C/T variant and smoking-related cancer in total population was revealed in our meta-analysis results, and IL-4-590C/T variant might have a relatively protective effect on smoking-related cancer (CT vs. TT: P=0.026, OR = 0.900, 95% CI: 0.820–0.987). Subgroup analysis by ethnicity showed that the IL-4-590C/T polymorphism was associated with a decreased risk of smoking-related cancer in the Asian population (CT vs. TT: P=0.008, OR = 0.878, 95% CI: 0.798–0.967; CC + CT vs. TT: P=0.030, OR = 0.903, 95% CI: 0.824–0.990). Subgroup analysis based on types of cancer demonstrated the IL-4-590C/T variant achieved a lower risk in renal cell cancer (CC vs. TT: P=0.046, OR = 0.640, 95% CI: 0.412–0.993).

Conclusion

There is a conspicuous association between IL-4-590C/T polymorphism and decreased risk of smoking-related cancer, particularly in Asians. And IL-4-590C/T polymorphism may have a protective effect on renal cell cancer.

Genetic Association between Interleukin-4 Receptor Polymorphisms and Cancer Susceptibility: A Meta-Analysis Based on 53 Case-Control Studies

Polymorphisms in interleukin-4 receptor (IL-4R) gene have been reported susceptible to a variety of cancer types, nevertheless, data from these publications remained inconsistent and controversial. We further performed a comprehensive meta-analysis to present a precise estimation of its relationship. Extensive retrieve was performed in PubMed, Google Scholar and Web of Science up to May 25, 2018. Odds ratios (ORs) and 95% confidence intervals (CIs) were conducted to evaluate the overall strength of the associations in five genetic models, as well as in subgroup analyses, stratified by ethnicity, cancer type or source of control. Q-test, Egger's test and Begg's funnel plot were applied to evaluate the heterogeneity and publication bias. In-silico analysis was managed to demonstrate the relationship of IL-4R expression correlated with cancer tissues. Finally, 31 publications including 53 case-control studies were enrolled, with 24,452 cases and 24,971 controls. After a comprehensive analysis, no significant evidence was revealed for the association between four IL-4R polymorphisms (rs1801275, rs1805010, rs1805015, rs2057768) and cancer susceptibility in the overall population, as well as the subgroup analysis stratified by ethnicity, cancer type, the genotyping method or the source of control. To sum up, no evidence was identified between IL-4R polymorphisms and overall cancer susceptibility. Further well-designed studies with large sample sizes will be continued on this issue of interest.

Polymorphisms in HLA-DQ genes, together with age, sex, and Helicobacter pylori infection, as potential biomarkers for the early diagnosis of gastric cancer

BACKGROUND

Polymorphisms in inflammation-related genes are factors associated with the development of gastroduodenal diseases in Helicobacter pylori-infected individuals.

MATERIALS AND METHODS

We aimed to analyze polymorphisms in HLA-DQ, together with other host and H. pylori variables as risk factors for precancerous and cancerous gastric lesions. 1052 individuals were studied, including nonatrophic gastritis (NAG), intestinal metaplasia (IM), gastric cancer (GC) or duodenal ulcer (DU) patients, and healthy volunteers.

RESULTS

Patients with alleles DQA*01:01 (OR 0.78), *01:02 (OR 0.29), *01:03 (OR 0.31), and DQB*02:01/02 (OR 0.40) showed a reduced risk for GC. A multivariate logistic regression analyses showed that patients with homozygote genotypes DQA1*03:01 (OR 7.27) and DQA1*04:01 (OR 8.99) and DQB1*05:01:01 (OR 12.04) were at significantly increased risk for GC. Multivariate analyses also demonstrated that age (OR>10.0) and gender (OR>2.0) were variables that influenced significantly the risk for GC, while H. pylori infection (OR>2.5) increased the risk for IM.

CONCLUSIONS

We identified HLA-DQ alleles associated with IM and GC, and confirm that age, sex, and H. pylori infection are variables that also influence the risk for disease. The use of multiple markers, HLA-DQ alleles, age, sex, and H. pylori infection may be useful biomarkers for the early diagnosis of patients with IM and GC.

Association of IL4, IL13, and IL4R polymorphisms with gastrointestinal cancer risk: A meta-analysis

Background

Previous studies have suggested that IL4, IL13, and IL4R are associated with serum IgE levels and allergies, and common variants of these genes may alter cancer risk. To clarify these associations, we conducted a meta-analysis to investigate the associations of IL4, IL13, and IL4R polymorphisms with gastrointestinal cancer risk.

Methods

We used 27 eligible case–control studies describing the associations of six polymorphisms of IL4, IL13, and IL4R with gastrointestinal cancer risk to calculate summary odds ratios (ORs) and 95% confidence intervals (CIs) using five different genetic models. The Q-statistic and I² statistic were calculated to examine heterogeneity.

Results

The IL4 rs2070874 T allele seems to be associated with an increased risk of gastrointestinal cancer (OR 1.11; 95% CI, 1.00–1.24 for T allele vs. C allele). This association was significant in studies conducted outside of Asia (OR 1.28; 95% CI, 1.03–1.58 for T allele vs. C allele) and in studies investigating the association with gastric cancer (OR 1.17; 95% CI, 1.03–1.34 for T allele vs. C allele). However, the IL4R rs1801275 heterozygote seems to be associated with a reduced risk of gastrointestinal cancer (OR 0.79; 95% CI, 0.65–0.96 for AG vs. AA). Other polymorphisms did not show any significant associations with gastrointestinal cancer risk in any of the genetic models and subgroup analyses.

Conclusions

Our results suggest that certain polymorphisms of IL4 and IL4R may affect susceptibility to gastrointestinal cancer. However, further studies are required to confirm these findings.

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This meta-analysis included 27 eligible case–control studies.

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IL4 rs2070874 T allele may increase the risk of gastrointestinal cancer.

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IL4R rs1801275 variant may reduce the risk of gastrointestinal cancer.

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Polymorphisms in IL4 and IL4R may affect susceptibility to gastrointestinal cancer.

Interleukin (IL)-4 -590C>T polymorphism is not associated with the susceptibility of gastric cancer: An updated meta-analysis

Gastric cancer (GC) is a common cancer affecting patients around the world. The pathogenesis of gastric cancer has not been understood completely. Genetic mutations and the inflammation induced by Helicobacter pylori (HP) seem to play important roles. The cytokine Interleukin-4 (IL-4) has effects in inflammation, allergies and cancer including GC. The association of IL-4 -590 C>T polymorphism and gastric cancer has been studied in different populations with inconsistent results. Here, we report this meta-analysis showing that the polymorphism of IL-4 -590C>T might not be associated with the GC susceptibility in both Asian and Caucasian populations.

Genetic association between interluekin-4 rs2243250 polymorphism and gastric cancer susceptibility: evidence based on a meta-analysis

Purpose

Numerous studies have suggested that the interleukin-4 (IL-4) rs2243250 polymorphism is associated with gastric cancer susceptibility. However, the results were inconsistent. Hence, we carried out a meta-analysis to confirm the conclusion.

Methods

We searched PubMed, Embase, CBM, CNKI, and Wanfang Data to identify relevant studies up to August 20, 2015. Odds ratio (OR) and 95% confidence interval (CI) were used to estimate the association between IL-4 rs2243250 polymorphism and gastric cancer susceptibility. All the statistical analyses were performed with Stata 12.0 software.

Results

A total of eleven published case–control studies were identified, including 2,247 gastric cancer patients and 3,370 controls. Overall, no significant association between IL-4 rs2243250 polymorphism and gastric cancer susceptibility was observed in this meta-analysis (T vs C: OR =1.05, 95% CI =0.95–1.17; TT vs CC: OR =1.20, 95% CI =0.89–1.63; CT vs CC: OR =1.14, 95% CI =0.87–1.48; TT + CT vs CC: OR =1.13, 95% CI =0.89–1.44; TT vs CT + CC: OR =1.02, 95% CI =0.88–1.20). Similar results were found in subgroup analyses according to ethnicity and Hardy–Weinberg equilibrium in controls.

Conclusion

This meta-analysis suggests that IL-4 rs2243250 polymorphism may not be associated with gastric cancer susceptibility. Further studies are needed to validate this conclusion.

A Causal Role of Genetically Elevated Circulating Interleukin-10 in the Development of Digestive Cancers: Evidence from Mendelian Randomization Analysis Based on 29,307 Subjects

Recent studies have observed a high level of circulating interleukin-10 (IL-10) in patients with digestive cancers, yet whether elevated IL-10 is causally associated with digestive cancers so far remained unresolved. We therefore meta-analyzed available observational studies with Mendelian randomization method to explore this causal association by employing IL-10 gene 3 variants (-592C>A, -819C>T, and -1082A>G) as instruments. Data were available from 52 articles encompassing 29,307 subjects. Subgroup analysis by cancer type indicated that -1082A>G was associated with increased risk of gastric cancer (odds ratio [OR] = 1.19; 95% confidence interval [CI]: 1.05-1.35; P = 0.006), and the association was reinforced for intestinal type gastric cancer (OR = 1.26; 95%CI: 1.09-1.44; P = 0.001). By ethnicity, risk estimate for -1082G allele carriers was increased by 21% for digestive cancers in East Asians (95%CI: 1.05-1.40; P = 0.009). As for the genotype-phenotype association, carriers of -1082G allele had an overall 20.21 pg/mL higher IL-10 level than those with -1082AA genotype (P = 0.023). In further Mendelian randomization analysis, the predicted OR for 10 pg/mL increment in IL-10 was 1.14 (95%CI: 1.01-16.99) in gastric cancer. Our findings provided evidence for a causal role of genetically elevated IL-10 in the development of gastric cancer, especially in East Asians and for intestinal type gastric cancer.

Genetic association of osteopontin (OPN) and its receptor CD44 genes with susceptibility to Chinese gastric cancer patients

PURPOSE

(1) To investigate associations between single nucleotide polymorphisms (SNPs) in osteopontin (OPN) and its receptor-cluster of differentiation 44 (CD44) genes and gastric cancer susceptibility. (2) To explore the correlation of OPN and CD44 expression of gastric cancer.

METHODS

We detected 26 SNPs of the genes in gastric cancer patients from the Chinese Han population by Sequenom technique and performed expression of OPN in combination with CD44 in 243 tissues samples of the cases by tissue microarray and immunohistochemistry (IHC).

RESULTS

We found that the minor alleles of OPN rs4754C>T and OPN rs9138C>A remained strongly associated with decreased gastric cancer risk (P = 1.53 × 10(-4), odds ratio (OR) 0.642, 95 % confidence interval (CI) 0.511-0.808 and P = 1.59 × 10(-4), OR 0.642, 95 %CI 0.510-0.809). OPN variant rs1126772A>G and CD44 variant rs353639A>C significantly contributed to elevated risk of gastric cancer (P = 0.042, OR 1.279, 95 % CI 1.008-1.622 and P = 0.047, OR 1.334, 95 % CI 1.003-1.772). Haplotypes of OPN and CD44 variants significantly influenced risk of gastric cancer. Clinical data indicated that rs4754 and rs9138 of OPN were significantly associated with smoking (P = 0.029, OR 0.343, 95 % CI 0.127-0.926 and P = 0.029, OR 0.343, 95 %CI 0.127-0.926) and OPN rs1126772 revealed associations with tumor-node-metastasis (TNM) stage (P = 0.025, OR 1.765, 95 % CI 1.073-2.905) and tumor differentiation (P = 0.031, OR 1.722, 95 % CI 1.049-2.825). OPN expression was observed in 133 of the 243 cases (54.7 %) by IHC and was correlated with serosa invasion (P = 0.013), TNM stage (P = 0.003) and lymph node metastasis (P = 0.002). CD44 expression was found in 92 of the 243 cases (37.9 %) and was associated with tumor size (P = 0.005) and lymph node metastasis (P = 0.023), respectively. The OPN expression displayed a positive association with CD44 (P = 0.01, r s = 0.164).

CONCLUSIONS

We found that the polymorphisms rs4754, rs9138 and rs1126772 of OPN gene and rs353639 of CD44 gene were significantly associated with gastric cancer. Our IHC data indicated that interaction of OPN and CD44 protein would promote progression and metastasis of gastric cancer.

Host genetic factors respond to pathogenic step-specific virulence factors of Helicobacter pylori in gastric carcinogenesis

The interindividual differences in risk of Helicobacter pylori (H. pylori)-associated gastric cancer involve significant heterogeneities of both host genetics and H. pylori strains. Several recent studies proposed a distinct sequence for H. pylori exerting its virulence in the host stomach: (i) adhering to and colonizing the surface of gastric epithelial cells, (ii) evading and attenuating the host defense, and (iii) invading and damaging the gastric mucosa. This review focuses on several key issues that still need to be clarified, such as which virulence factors of H. pylori are involved in the three pathogenic steps, which host genes respond to the step-specific virulence factors, and whether and/or how the corresponding host genetic variations influence the risk of gastric carcinogenesis. Urease, BabA and SabA in the adhesion-step, PGN and LPS in the immune evasion-step, and CagA, VacA and Tipα in the mucosal damage-step were documented to play an important role in step-specific pathogenicity of H. pylori infection. There is evidence further supporting a role of potentially functional polymorphisms of host genes directly responding to these pathogenic step-specific virulence factors in the susceptibility of gastric carcinogenesis, especially for urease-interacting HLA class II genes, BabA-interacting MUC1, PGN-interacting NOD1, LPS-interacting TLR4, and CagA-interacting PTPN11 and CDH1. With the continuous improvement of understanding the genetic profile of H. pylori-associated gastric carcinogenesis, a person at increased risk for gastric cancer may benefit from several aspects of efforts: (i) prevent H. pylori infection with a vaccine targeting certain step-specific virulence factor; (ii) eradicate H. pylori infection by blocking step-specific psychopathological characteristics of virulence factors; and (iii) adjust host physiological function to resist the carcinogenic role of step-specific virulence factors or interrupt the cellular signal transduction of the interplay between H. pylori and host in each pathogenic step, especially for the subjects with precancerous lesions in the stomach.

The interleukin 10 -819C/T polymorphism and cancer risk: a HuGE review and meta-analysis of 73 studies including 15,942 cases and 22,336 controls

The aim of the present work was to perform a meta-analysis to evaluate the association between the interleukin 10 (IL-10) -819C/T (rs1800871) polymorphism and cancer risk. A total of 73 studies, including 15,942 cancer cases and 22,336 controls, were identified in this meta-analysis. The odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using the random-effects model. Overall, no significant association was identified between the IL-10 -819C/T polymorphism and cancer risk. In the subgroup analyses, the T allele and TT genotype were associated with a moderately reduced cancer risk in the Asian population (T allele vs. C allele: OR=0.93, 95%CI: 0.87, 0.99; TT vs. CC: OR=0.86, 95%CI: 0.76, 0.98; TT vs. CT/CC: OR=0.90, 95%CI: 0.82, 0.98). Individuals who were homozygous for the T allele (TT) were found to be associated with significantly reduced gastric cancer risk in the Asian population. The heterozygous variant (CT) and the dominant model (TT/CT vs. CC) were associated with an increased risk for cervical and ovarian cancer. However, the IL-10 -819C/T polymorphism was not significantly associated with breast cancer, colorectal cancer, lung cancer, hepatocellular carcinoma, prostate cancer, lymphoma, or melanoma. The depressed cancer risk of the TT genotype occurred in the studies of hospital-based case-control studies and the studies recruited less than 500 subjects, but no statistically significant results were found in the stratified analyses using genotyping method. The results suggest that the IL-10 -819TT genotype may be a protective factor for cancer in Asians, especially gastric cancer. In contrast, the CT genotype and the dominant model could be risk factors for cervical and ovarian cancer. The importance of stratifying by ethnicity, cancer type, study design, and sample size needs to be standardized in future studies, together with considering the association between the IL-10 -819C/T polymorphism and cancer risk. Furthermore, the linkage of -819C/T with other polymorphisms of the IL-10 gene may help explain the variability in findings.

Association between IL-4 -590C>T polymorphism and gastric cancer risk

Published studies on the association between interleukin-4 (IL-4) -590C>T polymorphism and gastric cancer risk have yielded conflicting results. Thus, a meta-analysis of published studies was performed to assess the possible association. All eligible studies of -590C>T polymorphism and gastric cancer risk were collected from the PubMed, the Cochrane Library, and the Embase electronic databases. Statistical analyses were performed by Review Manager 5.0 and Stata 11.0. When all groups were pooled, we did not detect a significant association of -590C>T polymorphism with gastric cancer risk. When stratifying for race, there was a significant association between -590C>T polymorphism and decreased gastric cancer risk under dominant model and allelic model in the subgroup of Caucasians. However, significant association was absent in Asians. Based on our meta-analysis, -590C>T polymorphism was associated with a lower gastric cancer risk under dominant model and allelic model in Caucasians. Nevertheless, we suggest that further studies should be made to confirm these findings.

The -590C/T polymorphism in the IL-4 gene and the risk of cancer: a meta-analysis

Interleukin-4 (IL-4) plays an important role in the pathogenesis of cancer. The -590C/T polymorphism in the IL-4 gene has been implicated in susceptibility to cancer, but the results have been inconclusive. The aim of this study was to analyze the association between this polymorphism with the risk of cancer by meta-analysis. PubMed, Embase, CNKI, and Wanfang databases were searched for all publications concerning the association between this polymorphism and cancer risk. Statistical analyses were analyzed by using RevMan 4.2 and STATA10.0 softwares. A total of 8,715 cases and 9,532 controls in 23 case-control studies were included. The results suggested that there was no significant association between IL-4 -590C/T polymorphism and cancer risks (TT + TC vs. CC: OR = 0.97, 95 % CI = 0.90-1.04, P = 0.36). In the subgroup analysis by ethnicity, no significant association was detected in Asians and Caucasians. In the subgroup analysis by cancer types, no significant association was found in gastric cancer and colorectal cancer. The current meta-analysis suggested that the -590C/T polymorphism in the IL-4 gene might not be associated with increased/decreased risk of cancer. The -590C/T polymorphism might be not a risk factor for cancers.

The interleukin-10 promoter polymorphism rs1800872 (-592C>A), contributes to cancer susceptibility: meta-analysis of 16,785 cases and 19,713 controls

Interleukin-10 (IL-10) is a multifunctional cytokine which participates in the development and progression of various malignant tumors. To date, a number of case–control studies were conducted to detect the association between IL-10-592C>A polymorphism and cancer risk in humans. However, the results of these studies on the association remain conflicting. In an effort to solve this controversy, we performed a meta-analysis based on 70 case–control studies from 65 articles, including 16 785 cancer cases and 19 713 controls. We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the association. The overall results suggested that the variant homozygote genotype AA of the IL-10-592C>A polymorphism was associated with a moderately decreased risk of all cancer types (OR = 0.90, 95% CI = 0.83–0.98 for homozygote comparison, OR = 0.92, 95% CI = 0.86–0.98 for recessive model). In the stratified analyses, the risk remained for studies of smoking-related cancer, Asian populations and hospital-based studies. These results suggested that the IL-10-592C>A polymorphism might contribute to the cancer susceptibility, especially in smoking-related cancer, Asians and hospital-based studies. Further studies are needed to confirm the relationship.

The roles of beta-adrenergic receptors in tumorigenesis and the possible use of beta-adrenergic blockers for cancer treatment: possible genetic and cell-signaling mechanisms

Cancer is the leading cause of death in the USA, and the incidence of cancer increases dramatically with age. Beta-adrenergic blockers appear to have a beneficial clinical effect in cancer patients. In this paper, we review the evidence of an association between β-adrenergic blockade and cancer. Genetic studies have provided the opportunity to determine which proteins link β-adrenergic blockade to cancer pathology. In particular, this link involves the major histocompatibility complex class II molecules, the renin-angiotensin system, transcription factor nuclear factor-kappa-light-chain-enhancer of activated B cells, poly(ADP-ribose) polymerase-1, vascular endothelial growth factor, and the reduced form of nicotinamide adenine dinucleotide phosphate oxidase. Beta-adrenergic blockers also exert anticancer effects through non-genomic factors, including matrix metalloproteinase, mitogen-activated protein kinase pathways, prostaglandins, cyclooxygenase-2, oxidative stress, and nitric oxide synthase. In conclusion, β-adrenergic blockade may play a beneficial role in cancer treatment. Additional investigations that examine β-adrenergic blockers as cancer therapeutics are required to further elucidate this role.

Why are East Asians more susceptible to several infection-associated cancers (carcinomas of the nasopharynx, stomach, liver, adenocarcinoma of the lung, nasal NK/T-cell lymphomas)?

There are at least five cancers with uniquely high incidence amongst East and Southeast Asian ethnic groups - namely nasopharyngeal carcinoma (NPC); gastric carcinoma; hepatocellular carcinoma (HCC); adeno-carcinoma of the lung in female non-smokers and nasal NK/T-cell lymphomas. They all appear to be related to an infective cause (Epstein Barr Virus, Helicobacter pylori, hepatitis B virus). We hypothesize that a genetic bottleneck 30,000years ago at the Last Glacial Maximum could have resulted in unique genetic polymorphisms in Toll-like receptor 8, making East Asians more vulnerable to these infective associated cancers. This bottleneck could have been caused by the presence of malaria in the southern Himalayan conduit between central and East Asia; and only those with an attenuated innate immune response to the malarial parasite (perhaps reflected by the TLR8 polymorphism) were spared the ravages of cerebral malaria; allowing these people to cross into east Asia, but then rendering them susceptible to later endemic infections and their associated cancers.

microRNAs as novel epigenetic biomarkers for human cancer

MicroRNAs (miRNAs) are regulatory, non-coding RNAs that are approximately 22 nucleotides in length. Nearly 1000 unique miRNAs encoded in the human genome have been identified, shedding new light on the posttranscriptional regulation of more than one-third of human genes. These miRNAs are involved in numerous biological processes, including development, differentiation, apoptosis, homeostasis and stem cell biology. Aberrant miRNA expression patterns also play a substantial role in carcinogenesis. It is believed that genetic and epigenetic regulation is responsible for changes in miRNA expression in cancer development, however the exact mechanisms remain unclear. miRNAs are involved in almost all aspects of cancer biology such as apoptosis, invasion, metastasis and angiogenesis. Thanks to this wide range of biological functions, the analysis of changes in overall miRNA expression occurring within human tumours has helped identify miRNA signatures associated with diagnosis, staging, progression, prognosis and response to treatment. This positions miRNA- targeting therapeutics as a novel and promising tool for cancer treatment.

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

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

Helicobacter pylori infection and nonmalignant diseases

Several interesting studies have been published on nonmalignant Helicobacter pylori-related conditions over the past year, which are reviewed in this article. A revival of interest in the histologic classification of gastritis has led to grading of gastritis into stages correlating with risk of neoplastic progression, new data to improve this concept have been published. Unselected prescription of proton-pump inhibitors in patients with dyspepsia has been questioned by the finding that withdrawal of proton-pump inhibitors induces acid-related symptoms in healthy volunteers, probably by the mechanism of rebound gastric acid hypersecretion. Additional data on the rationale of tapering proton-pump inhibitor therapy are therefore awaited. Moreover, new data on peptic ulcer disease and its complications provide clear recommendations for daily clinical practice. Testing and eradication of H. pylori in patients with peptic ulcer bleeding is essential. However, in H. pylori-negative peptic ulcer disease, high overall patient mortality should be acknowledged, and this should guide considering continuation of nonsteroidal anti-inflammatory drugs. The role of H. pylori in the pathogenesis of gastroesophageal reflux disease is still unclear. An association has been described by several studies; however, it cannot be translated to individual risks for development of gastroesophageal reflux disease after H. pylori eradication. Possibly, additional data on subgroups, such as gastric ulcer, duodenal ulcer patients, and associated gastric mucosal changes, will solve this issue.

Helicobacter pylori and gastric adenocarcinoma

Gastric cancer is the second most common cause of cancer death worldwide. A large body of evidence supports a causal role of Helicobacter pylori in the majority of gastric malignancies. Great strides have been made in understanding the pathogenesis of this relationship, but much remains to be learned. Moreover, because of the high prevalence of infection, the lack of definitive trials, and the challenges of H. pylori treatment, there remains no consensus on the role of routine screening and treatment of this infection to prevent cancer. This article reviews the current knowledge on H. pylori and gastric cancer and presents some of the clinical and public health challenges associated with this pathogen.