Prospective study of Helicobacter pylori biomarkers for gastric cancer risk among Chinese men

Helicobacter pylori with trx1 high expression promotes gastric diseases via upregulating the IL23A/NF-κB/IL8 pathway

BACKGROUND

Helicobacter pylori infection is one of the main causes of gastric cancer. thioredoxin-1 (Trx1) and arginase (RocF) expressed by H. pylori were found to be closely related to its pathogenicity. However, whether Trx1 and RocF can be used in clinical screening of highly pathogenic H. pylori and the pathogenesis of trx1 high expressing H. pylori remain still unknown.

MATERIALS AND METHODS

We investigated the expression level of H. pylori trx1 and H. pylori rocF in human gastric antrum tissues using reverse transcription and quantitative real-time PCR (RT-qPCR) and clarified the clinical application value of trx1 and rocF for screening highly pathogenic H. pylori. The pathogenic mechanism of Trx1 were further explored by RNA-seq of GES-1 cells co-cultured with trx1 high or low expressing H. pylori. Differentially expressed genes and signaling pathways were validated by RT-qPCR, Enzyme-linked immunosorbent assay (ELISA), western blot, immunohistochemistry and immunofluorescence. We also assessed the adherence of trx1 high and low expressing H. pylori to GES-1 cells.

RESULTS

We found that H. pylori trx1 and H. pylori rocF were more significantly expressed in the gastric cancer and peptic ulcer group than that in the gastritis group and the parallel diagnosis of H. pylori trx1 and H. pylori rocF had high sensitivity. The trx1 high expressing H. pylori had stronger adhesion ability to GES-1 cells and upregulated the interleukin (IL) 23A/nuclear factor κappaB (NF-κB)/IL17A, IL6, IL8 pathway.

CONCLUSIONS

H. pylori trx1 and H. pylori rocF can be used in clinical screening of highly pathogenic H. pylori and predicting the outcome of H. pylori infection. The trx1 high expressing H. pylori has stronger adhesion capacity and promotes the development of gastric diseases by upregulating the activation of NF-κB signaling pathway.

Helicobacter pylori multiplex serology and risk of non-cardia and cardia gastric cancer: a case-cohort study and meta-analysis

BACKGROUND

Helicobacter pylori infection is a major cause of non-cardia gastric cancer (NCGC), but uncertainty remains about the associations between sero-positivity to different H. pylori antigens and risk of NCGC and cardia gastric cancer (CGC) in different populations.

METHODS

A case-cohort study in China included ∼500 each of incident NCGC and CGC cases and ∼2000 subcohort participants. Sero-positivity to 12 H. pylori antigens was measured in baseline plasma samples using a multiplex assay. Hazard ratios (HRs) of NCGC and CGC for each marker were estimated using Cox regression. These were further meta-analysed with studies using same assay.

RESULTS

In the subcohort, sero-positivity for 12 H. pylori antigens varied from 11.4% (HpaA) to 70.8% (CagA). Overall, 10 antigens showed significant associations with risk of NCGC (adjusted HRs: 1.33 to 4.15), and four antigens with CGC (HRs: 1.50 to 2.34). After simultaneous adjustment for other antigens, positive associations remained significant for NCGC (CagA, HP1564, HP0305) and CGC (CagA, HP1564, HyuA). Compared with CagA sero-positive only individuals, those who were positive for all three antigens had an adjusted HR of 5.59 (95% CI 4.68-6.66) for NCGC and 2.17 (95% CI 1.54-3.05) for CGC. In the meta-analysis of NCGC, the pooled relative risk for CagA was 2.96 (95% CI 2.58-3.41) [Europeans: 5.32 (95% CI 4.05-6.99); Asians: 2.41 (95% CI 2.05-2.83); Pheterogeneity<0.0001]. Similar pronounced population differences were also evident for GroEL, HP1564, HcpC and HP0305. In meta-analyses of CGC, two antigens (CagA, HP1564) were significantly associated with a higher risk in Asians but not Europeans.

CONCLUSIONS

Sero-positivity to several H. pylori antigens was significantly associated with an increased risk of NCGC and CGC, with varying effects between Asian and European populations.

Prediction of gastric cancer risk by a polygenic risk score of Helicobacter pylori

BACKGROUND

Genetic variants of Helicobacter pylori (H. pylori) are involved in gastric cancer occurrence. Single nucleotide polymorphisms (SNPs) of H. pylori that are associated with gastric cancer have been reported. The combined effect of H. pylori SNPs on the risk of gastric cancer remains unclear.

AIM

To assess the performance of a polygenic risk score (PRS) based on H. pylori SNPs in predicting the risk of gastric cancer.

METHODS

A total of 15 gastric cancer-associated H. pylori SNPs were selected. The associations between these SNPs and gastric cancer were further validated in 1022 global strains with publicly available genome sequences. The PRS model was established based on the validated SNPs. The performance of the PRS for predicting the risk of gastric cancer was assessed in global strains using quintiles and random forest (RF) methods. The variation in the performance of the PRS among different populations of H. pylori was further examined.

RESULTS

Analyses of the association between selected SNPs and gastric cancer in the global dataset revealed that the risk allele frequencies of six SNPs were significantly higher in gastric cancer cases than non-gastric cancer cases. The PRS model constructed subsequently with these validated SNPs produced significantly higher scores in gastric cancer. The odds ratio (OR) value for gastric cancer gradually increased from the first to the fifth quintile of PRS, with the fifth quintile having an OR value as high as 9.76 (95% confidence interval: 5.84-16.29). The results of RF analyses indicated that the area under the curve (AUC) value for classifying gastric cancer and non-gastric cancer was 0.75, suggesting that the PRS based on H. pylori SNPs was capable of predicting the risk of gastric cancer. Assessing the performance of the PRS among different H. pylori populations demonstrated that it had good predictive power for cancer risk for hpEurope strains, with an AUC value of 0.78.

CONCLUSION

The PRS model based on H. pylori SNPs had a good performance for assessment of gastric cancer risk. It would be useful in the prediction of final consequences of the H. pylori infection and beneficial for the management of the infection in clinical settings.

Associations of lung cancer risk with biomarkers of Helicobacter pylori infection

Helicobacter pylori infection has been suggested to be associated with lung cancer risk. However, information is lacking on whether the association differs by H. pylori antigen. We conducted a nested case-control study within the Southern Community Cohort Study, including 295 incident lung cancer cases and 295 controls. Helicobacter pylori multiplex serology assay was performed to detect antibodies to 15 H. pylori proteins. Conditional logistic regression was used to estimate odds ratios (ORs) and confidence intervals (95% CIs) after adjustment for covariates. Overall H. pylori+ was associated with a non-statistically significant increased risk of lung cancer (OR: 1.29; 95% CI: 0.85-1.95). Significant associations, however, were observed for H. pylori+ VacA+ (OR: 1.64; 95% CI: 1.02-2.62) and H. pylori+ Catalase+ (OR: 1.75; 95% CI: 1.11-2.77). The positive association of H. pylori+ Catalase+ with lung cancer risk was predominantly seen among African Americans (OR: 2.09; 95% CI: 1.11-3.95) but not European Americans (OR: 1.20; 95% CI: 0.56-2.54). Among participants who smoked ≥ 30 pack-years, overall H. pylori+ (OR: 1.85; 95% CI: 1.02-3.35), H. pylori+ CagA+ (OR: 2.77; 95% CI: 1.35-5.70), H. pylori+ VacA+ (OR: 2.53; 95% CI: 1.25-5.13) and H. pylori+ HP1564+ (OR: 2.01; 95% CI: 1.07-3.77) were associated with increased risk of lung cancer. Our study provides novel evidence that associations of H. pylori infection with lung cancer risk differ by H. pylori biomarker, may be more evident among African Americans and may be modified by smoking habits. Furthermore, studies are warranted to confirm our findings.

Association between Helicobacter pylori antibodies determined by multiplex serology and gastric cancer risk: A meta-analysis

BACKGROUND AND AIMS

Previous studies have reported the association between limited number of Helicobacter pylori (H. pylori) antigens and gastric cancer (GC) risk. The present study evaluated the association between serum antibodies against 15 different H. pylori proteins measured by using multiplex serology assay and GC risk.

METHODS

We searched PubMed databases, Embase, Web of Science, and Cochrane Library for relevant articles. A meta-analysis was used to pool studies and to estimate odds ratios (ORs) with 95% confidence intervals (95%CIs) of different H. pylori antigens associated with GC risk. Heterogeneity was investigated using Cochran's Q test and I-squared statistic.

RESULTS

Nine studies were identified, with a total of 3209 GC cases and 6964 controls. Five H. pylori virulence factors were significantly associated with non-cardia GC risk at p-value <0.0033 including: CagA (OR = 3.22, 95%CI: 2.10-4.94), HP0305 (OR = 1.72, 95%CI: 1.32-2.25), HyuA (OR = 1.42, 95%CI: 1.13-1.79), Omp (OR = 1.83, 95%CI: 1.30-2.58), and VacA (OR = 2.05, 95%CI: 1.67-2.52). However, none of the 15 antigens was associated with cardia GC risk. In subgroup analysis by ethnicity, we identified 7 antigens associated with the risk of non-cardia GC among East Asian while only two antigens were identified in European population. Nevertheless, CagA and GroEL showed a stronger association in Caucasian (CagA OR = 5.83, 95%CI: 3.31-10.26; GroEL OR = 3.66, 95%CI: 1.58-8.50) compared with East Asian (CagA OR = 2.20, 95% CI: 1.85-2.61; GroEL OR = 1.47, 95%CI: 1.29-1.68).

CONCLUSIONS

This study determined that H. pylori infection increases the risk of non-cardia GC with differential effects by its virulence factors and with different patterns among East Asian and European populations. These results advance the understanding of the effect of H. pylori on GC.

The relative and attributable risks of cardia and non-cardia gastric cancer associated with Helicobacter pylori infection in China: a case-cohort study

BACKGROUND

Helicobacter pylori infection is a major cause of non-cardia gastric cancer (NCGC), but its causal role in cardia gastric cancer (CGC) is unclear. Moreover, the reported magnitude of association with NCGC varies considerably, leading to uncertainty about population-based H pylori screening and eradication strategies in high-risk settings, particularly in China, where approximately half of all global gastric cancer cases occur. Our aim was to assess the associations of H pylori infection, both overall and for individual infection biomarkers, with the risks of NCGC and CGC in Chinese adults.

METHODS

A case-cohort study was done in adults from the prospective China Kadoorie Biobank study, aged 30-79 years from ten areas in China (Qingdao, Haikou, Harbin, Suzhou, Liuzhou, Henan, Sichuan, Hunan, Gansu, and Zhejiang), and included 500 incident NCGC cases, 437 incident CGC cases, and 500 subcohort participants who were cancer-free and alive within the first two years since enrolment in 2004-08. H pylori biomarkers were measured in stored baseline plasma samples using a sensitive immunoblot assay (HelicoBlot 2.1), with adapted criteria to define H pylori seropositivity. Cox regression was used to estimate adjusted hazard ratios (HRs) for NCGC and CGC associated with H pylori infection. These values were used to estimate the number of gastric cancer cases attributable to H pylori infection in China.

FINDINGS

Of the 512 715 adults enrolled in the China Kadoorie Biobank between June, 2004, and July, 2008, 500 incident NCGC cases, 437 incident CGC cases, and 500 subcohort participants were selected for analysis. The seroprevalence of H pylori was 94·4% (95% CI 92·4-96·4) in NGCG, 92·2% (89·7-94·7) in CGC, and 75·6% (71·8-79·4) in subcohort participants. H pylori infection was associated with adjusted HRs of 5·94 (95% CI 3·25-10·86) for NCGC and 3·06 (1·54-6·10) for CGC. Among the seven individual infection biomarkers, cytotoxin-associated antigen had the highest HRs for both NCGC (HR 4·41, 95% CI 2·60-7·50) and CGC (2·94, 1·53-5·68). In this population, 78·5% of NCGC and 62·1% of CGC cases could be attributable to H pylori infection. H pylori infection accounted for an estimated 339 955 cases of gastric cancer in China in 2018.

INTERPRETATION

Among Chinese adults, H pylori infection is common and is the cause of large numbers of gastric cancer cases. Population-based mass screening and the eradication of H pylori should be considered to reduce the burden of gastric cancer in high-risk settings.

FUNDING

Cancer Research UK, Wellcome Trust, UK Medical Research Council, British Heart Foundation, Kadoorie Charitable Foundation, National Key Research and Development Program of China, and National Natural Science Foundation of China.

Ornithine decarboxylase (ODC1) gene variant (rs2302615) is associated with gastric cancer independently of Helicobacter pylori CagA serostatus

The primary cause of gastric cancer is chronic infection with Helicobacter pylori (H. pylori), particularly the high-risk genotype cagA, and risk modification by human genetic variants. We studied 94 variants in 54 genes for association with gastric cancer, including rs2302615 in ornithine decarboxylase (ODC1), which may affect response to chemoprevention with the ODC inhibitor, eflornithine (difluoromethylornithine; DFMO). Our population-based, case-control study included 1366 individuals (664 gastric cancer cases and 702 controls) from Western Honduras, a high incidence region of Latin America. CagA seropositivity was strongly associated with cancer (OR = 3.6; 95% CI: 2.6, 5.1). The ODC1 variant rs2302615 was associated with gastric cancer (OR = 1.36; p = 0.018) in a model adjusted for age, sex, and CagA serostatus. Two additional single nucleotide polymorphisms (SNPs) in CASP1 (rs530537) and TLR4 (rs1927914) genes were also associated with gastric cancer in univariate models as well as models adjusted for age, sex, and CagA serostatus. The ODC1 SNP association with gastric cancer was stronger in individuals who carried the TT genotype at the associating TLR4 polymorphism, rs1927914 (OR = 1.77; p = 1.85 × 10^-3). In conclusion, the ODC1 variant, rs2302615, is associated with gastric cancer and supports chemoprevention trials with DFMO, particularly in individuals homozygous for the T allele at rs1927914.

A Prospective Investigation of Circulating Metabolome Identifies Potential Biomarkers for Gastric Cancer Risk

BACKGROUND

Metabolomics is widely used to identify potential novel biomarkers for cancer risk. No investigation, however, has been conducted to prospectively evaluate the role of perturbation of metabolome in gastric cancer development.

METHODS

250 incident cases diagnosed with primary gastric cancer were selected from the Shanghai Women's Health and the Shanghai Men's Health Study, and each was individually matched to one control by incidence density sampling. An untargeted global profiling platform was used to measure approximately 1,000 metabolites in prediagnostic plasma. Conditional logistic regression was utilized to generate ORs and P values.

RESULTS

Eighteen metabolites were associated with gastric cancer risk at P < 0.01. Among them, 11 metabolites were lysophospholipids or lipids of other classes; for example, 1-(1-enyl-palmitoyl)-GPE (P-16:0) (OR = 1.56; P = 1.89 × 10^-4). Levels of methylmalonate, a suggested biomarker of vitamin B12 deficiency, was correlated with increased gastric cancer risk (OR = 1.42; P = 0.004). Inverse associations were found for three biomarkers for coffee/tea consumption (3-hydroxypyridine sulfate, quinate and N-(2-furoyl) glycine), although the associations were only significant when comparing cases that were diagnosed within 5 years after the blood collection to matched controls. Most of the identified associations were more profound in women and never smokers than their male or ever smoking counterparts and some with notable significant interactions.

CONCLUSIONS

Our study identified multiple potential risk biomarkers for gastric cancer independent of Helicobacter pylori infection and other major risk factors.

IMPACT

New risk-assessment tools to identify high-risk population could be developed to improve prevention of gastric cancer.See related commentary by Drew et al., p. 1601.

Nanohybrid-based immunosensor prepared for Helicobacter pylori BabA antigen detection through immobilized antibody assembly with @ Pdnano/rGO/PEDOT sensing platform

The gastric colonization of human hosts by Helicobacter pylori (H. pylori) increases the risk of developing gastritis, ulcers and gastric cancer. To detect H. pylori, a nanohybrid-based BabA immunosensor is developed herein. BabA is an outer membrane protein and one of the major virulence factors of H. pylori. To design the immunosensor, an Au electrode is loaded with palladium nanoparticles (Pdnano) by electrodeposition to generate reduced graphene oxide (rGO)/poly(3,4-ethylenedioxythiophene) (PEDOT). The immobilization of these nanostructured materials imparts a large surface area and electroconductivity to bio-immune-sensing molecules (here, the BabA antigen and antibodies). After optimization, the fabricated immunosensor has the ability to detect antigens (H. pylori) in a linear range from 0.2 to 20 ng/mL with a low LOD (0.2 ng/mL). The developed immunosensor is highly specific, sensitive and reproducible. Additionally, in silico methods were employed to better understand the hybrid nanomaterials of the fabricated Pdnano/rGO/PEDOT/Au electrode. Simulations performed by molecular docking, and Metropolis Monte Carlo adsorption studies were conducted. The results revealed that the hybrid nanomaterials exhibit a stable antigen-antibody complex of BabA, yielding the lowest binding energy in relation to the electrode materials, emphasizing the functionality of the constructed electrodes in the electrochemical immunosensor.

Development of Helicobacter pylori Whole-Proteome Arrays and Identification of Serologic Biomarkers for Noncardia Gastric Cancer in the MCC-Spain Study

BACKGROUND

Helicobacter pylori (H. pylori) is a bacterial carcinogen and the leading risk factor for noncardia gastric cancer (NCGC). Detecting antibodies against specific H. pylori proteins in peripheral blood can be applied to characterize infection and determine disease associations. Most studies analyzing the association between H. pylori infection and gastric cancer have focused on previously identified antigens, predominantly the virulence factor cytotoxin-associated gene A (CagA). Selecting antigens in an unbiased approach may, however, allow the identification of novel biomarkers.

METHODS

Using a combination of multiple spotting technique and cell-free, on-chip protein expression, we displayed the H. pylori genome (strain 26695) on high-density microarrays. Immunogenic proteins were identified by serum pool incubations and henceforth analyzed in individual samples. To test its applicability, we used sera from a multicase-control (MCC)-Spain study. Serologic responses between NCGC cases and controls were assessed by conditional logistic regression estimating ORs and 95% confidence intervals.

RESULTS

We successfully expressed 93% of the 1,440 H. pylori open reading frames in situ. Of these, 231 (17%) were found to be immunogenic. By comparing 58 NCGC cases with 58 matched controls, we confirmed a higher seroprevalence of CagA among cases (66%) than controls (31%). We further identified a potential novel marker, the Helicobacter outer membrane protein A (HopA).

CONCLUSIONS

In this study, we provide evidence that our H. pylori whole-proteome microarray offers a platform for unbiased de novo identification of serologic biomarkers.

IMPACT

Given its versatile workflow, antibody responses against other H. pylori strains and possible associations with diverse H. pylori-related outcomes can be systematically analyzed.

Differences in antibody levels to H. pylori virulence factors VacA and CagA among African Americans and whites in the Southeast USA

PURPOSE

Helicobacter pylori (H. pylori) is the leading cause of gastric cancer. High antibody levels to H. pylori virulence factors Vacuolating cytotoxin A (VacA) and Cytotoxin-associated gene A (CagA) have been suggested as gastric cancer risk markers. In the USA, H. pylori sero-prevalence is twofold higher in African Americans compared to whites. We sought to assess whether African Americans also exhibit higher antibody levels to VacA and CagA.

METHODS

Antibody responses to H. pylori proteins were measured by multiplex serology in 686 African Americans and whites of the Southern Community Cohort Study. Among VacA- and CagA-seropositives, we analyzed the association of race with antibody level using logistic regression models to produce odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Sero-positive African Americans had significantly higher mean antibody levels to both VacA and CagA, which resulted in increased odds for the highest quartile of antibody levels compared to sero-positive whites (VacA, OR: 6.08; 95% CI 3.41, 10.86; CagA, OR: 3.77; 95% CI 1.61, 8.84).

CONCLUSION

Our findings support future studies to assess the association of differential antibody responses by race with risk of gastric cancer in the USA, which could then aid in developing targeted H. pylori eradication strategies.

Th17 Cells in Helicobacter pylori Infection: a Dichotomy of Help and Harm

Helicobacter pylori is a Gram-negative bacterium that infects the gastric epithelia of its human host. Everyone who is colonized with these pathogenic bacteria can develop gastric inflammation, termed gastritis. Additionally, a small proportion of colonized people develop more adverse outcomes, including gastric ulcer disease, gastric adenocarcinoma, or gastric mucosa-associated lymphoid tissue lymphoma. The development of these adverse outcomes is dependent on the establishment of a chronic inflammatory response. The development and control of this chronic inflammatory response are significantly impacted by CD4⁺ T helper cell activity. Noteworthy, T helper 17 (Th17) cells, a proinflammatory subset of CD4⁺ T cells, produce several proinflammatory cytokines that activate innate immune cell antimicrobial activity, drive a pathogenic immune response, regulate B cell responses, and participate in wound healing. Therefore, this review was written to take an intricate look at the involvement of Th17 cells and their affiliated cytokines (interleukin-17A [IL-17A], IL-17F, IL-21, IL-22, and IL-26) in regulating the immune response to H. pylori colonization and carcinogenesis.

Smoking, Helicobacter Pylori Serology, and Gastric Cancer Risk in Prospective Studies from China, Japan, and Korea

Smoking is an established risk factor for gastric cancer development. In this study, we aimed to assess prospectively the association of smoking with gastric cancer risk in 1,446 non-cardia gastric cancer cases and 1,796 controls from China, Japan, and Korea with consideration of Helicobacter pylori infection as a potential effect modifier. Applying logistic regression models stratified by study and adjusted for age and sex we found that current, but not former, smoking was significantly associated with gastric cancer risk [OR = 1.33; 95% confidence interval (CI), 1.07-1.65]. However, the association was significant only in H. pylori sero-positive individuals determined by 3 different sero-markers: overall sero-positivity, sero-positivity to the onco-protein CagA, and sero-positivity to the gastric cancer associated sero-marker HP0305 and HP1564. Specifically, a significant interaction was found when stratifying by HP0305/HP1564 (P _interaction = 0.01) with a 46% increased risk of gastric cancer among HP0305/HP1564 sero-positive current smokers (95% CI, 1.10-1.93) as opposed to no increased gastric cancer risk among HP0305/HP1564 sero-negative current smokers (OR = 0.93; 95% CI, 0.65-1.33). We confirmed that current smoking is associated with an increased gastric cancer risk, however, only among individuals that are simultaneously sero-positive for the leading causal factor for gastric cancer, H. pylori.

Geospatial analyses identify regional hot spots of diffuse gastric cancer in rural Central America

BACKGROUND

Geospatial technology has facilitated the discovery of disease distributions and etiology and helped target prevention programs. Globally, gastric cancer is the leading infection-associated cancer, and third leading cause of cancer mortality worldwide, with marked geographic variation. Central and South America have a significant burden, particularly in the mountainous regions. In the context of an ongoing population-based case-control study in Central America, our aim was to examine the spatial epidemiology of gastric cancer subtypes and H. pylori virulence factors.

METHODS

Patients diagnosed with gastric cancer from 2002 to 2013 in western Honduras were identified in the prospective gastric cancer registry at the principal district hospital. Diagnosis was based on endoscopy and confirmatory histopathology. Geospatial methods were applied using the ArcGIS v10.3.1 and SaTScan v9.4.2 platforms to examine regional distributions of the gastric cancer histologic subtypes (Lauren classification), and the H. pylori CagA virulence factor. Getis-Ord-Gi hot spot and Discrete Poisson SaTScan statistics, respectively, were used to explore spatial clustering at the village level (30-50 rural households), with standardization by each village's population. H. pylori and CagA serologic status was determined using the novel H. pylori multiplex assay (DKFZ, Germany).

RESULTS

Three hundred seventy-eight incident cases met the inclusion criteria (mean age 63.7, male 66.3%). Areas of higher gastric cancer incidence were identified. Significant spatial clustering of diffuse histology adenocarcinoma was revealed both by the Getis-Ord-GI* hot spot analysis (P-value < 0.0015; range 0.00003-0.0014; 99%CI), and by the SaTScan statistic (P-value < 0.006; range 0.0026-0.0054). The intestinal subtype was randomly distributed. H. pylori CagA had significant spatial clustering only in association with the diffuse histology cancer hot spot (Getis-Ord-Gi* P value ≤0.001; range 0.0001-0.0010; SaTScan statistic P value 0.0085). In the diffuse gastric cancer hot spot, the lowest age quartile range was 21-46 years, significantly lower than the intestinal cancers (P = 0.024).

CONCLUSIONS

Geospatial methods have identified a significant cluster of incident diffuse type adenocarcinoma cases in rural Central America, suggest of a germline genetic association. Further genomic and geospatial analyses to identify potential spatial patterns of genetic, bacterial, and environmental risk factors may be informative.

Identify gene expression pattern change at transcriptional and post-transcriptional levels

Gene transcription is regulated with distinct sets of regulatory factors at multiple levels. Transcriptional and post-transcriptional regulation constitute two major regulation modes of gene expression to either activate or repress the initiation of transcription and thereby control the number of proteins synthesized during translation. Disruptions of the proper regulation patterns at transcriptional and post-transcriptional levels are increasingly recognized as causes of human diseases. Consequently, identifying the differential gene expression at transcriptional and post-transcriptional levels respectively is vital to identify potential disease-associated and/or causal genes and understand their roles in the disease development. Here, we proposed a novel method with a linear mixed model that can identify a set of differentially expressed genes at transcriptional and post-transcriptional levels. The simulation and real data analysis showed our method could provide an accurate way to identify genes subject to aberrant transcriptional and post-transcriptional regulation and reveal the potential causal genes that contributed to the diseases.

Increased H. pylori stool shedding and EPIYA-D cagA alleles are associated with gastric cancer in an East Asian hospital

BACKGROUND

Helicobacter pylori infection increases risk for gastric cancer. Geographic variation in gastric cancer risk has been attributed to variation in carriage and type of the H. pylori oncogene cagA. Colonization density may also influence disease and cagA has been associated with higher shedding in stool. However, the relationship between H. pylori load in the stool and in the stomach is not clear.

METHODS

To investigate possible differences in H. pylori load in the stomach and shedding in stool, H. pylori load and cagA genotype were assessed using droplet digital PCR assays on gastric mucosa and stool samples from 49 urea breath test-positive individuals, including 25 gastric cancer and 24 non-cancer subjects at Henan Cancer Hospital, Henan, China.

RESULTS

Quantitation of H. pylori DNA indicated similar gastric loads among cancer and non-cancer cases, but the gastric cancer group had a median H. pylori load in the stool that was six times higher than that of the non-cancer subjects. While the cagA gene was uniformly present among study subjects, only 70% had the East Asian cagA allele, which was significantly associated with gastric cancer (Fisher's Exact Test, p = 0.03).

CONCLUSION

H. pylori persists in a subset of gastric cancer cases and thus may contribute to cancer progression. In this East Asian population with a high prevalence of the cagA gene, the East Asian allele could still provide a marker for gastric cancer risk.

IMPACT

This study contributes to our understanding of H. pylori dynamics in the context of pathological changes.

Validation of a Blood Biomarker for Identification of Individuals at High Risk for Gastric Cancer

BACKGROUND

Helicobacter pylori is the leading cause of gastric cancer, yet the majority of infected individuals will not develop neoplasia. Previously, we developed and replicated serologic H. pylori biomarkers for gastric cancer risk among prospective cohorts in East Asia and now seek to validate the performance of these biomarkers in identifying individuals with premalignant lesions.

METHODS

This cross-sectional study included 1,402 individuals from Linqu County screened by upper endoscopy. H. pylori protein-specific antibody levels were assessed using multiplex serology. Multivariable-adjusted logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for prevalent intestinal metaplasia, indefinite dysplasia, or dysplasia, compared with superficial or mild atrophic gastritis.

RESULTS

Compared with individuals seronegative to Omp and HP0305, individuals seropositive to both were seven times more likely to have precancerous lesions (OR, 7.43; 95% CI, 5.59-9.88). A classification model for precancerous lesions that includes age, smoking, and seropositivity to H. pylori, Omp, and HP0305 resulted in an area under the curve (AUC) of 0.751 (95% CI, 0.725-0.777), which is significantly better than the same model, including the established gastric cancer risk factor CagA (AUC, 0.718; 95% CI, 0.691-0.746, P _difference = 0.0002).

CONCLUSIONS

The present study of prevalent precancerous gastric lesions provides support for two new serum biomarkers of gastric cancer risk, Omp and HP 0305.

IMPACT

Our results support further research into the serological biomarkers Omp and HP0305 as possible improvements over the established virulence marker CagA for identifying individuals with precancerous lesions in East Asia.

Serum Helicobacter pylori FliD antibody and the risk of gastric cancer

FliD and CagA are important virulence factors of H. pylori. We aimed to evaluate the screening values of FliD and CagA for gastric cancer (GC). Serum samples were obtained from 232 cases and 266 controls in a case-control study. Unconditional multivariate logistic regression with odds ratios (ORs) and 95% confidence intervals (CIs) was used to analyze the relationships between FliD, CagA and GC. The sensitivities, specificities and receiver operating characteristic (ROC) curves were calculated. Finally, the combined screening values of FliD, FlaA, NapA and CagA were assessed based on discriminant analysis. In all subjects, the associations of FliD and CagA with GC were evident with ORs (95% CIs) of 7.6 (4.7-12.3) and 2.5 (1.6-3.8), respectively (*p<0.001). The areas under ROC curves (AUCs) for FliD and CagA were 0.800 and 0.653, respectively. The AUC for the combination of FliD, FlaA and NapA was 0.915, which represented an increase of 0.115 over that of FliD alone (*p<0.001). These findings indicate that the FliD antibody is associated with GC and could exhibit high validity as a biomarker in screening for GC patients. The combination of FliD, FlaA and NapA improved the screening validity.

Antibody reactivity against Helicobacter pylori proteins in a sample of the Spanish adult population in 2008-2013

BACKGROUND

Differences in Helicobacter pylori protein expression have been related to the risk of severe gastric diseases. In Spain, a marked geographic pattern in gastric cancer mortality has long been reported.

OBJECTIVE

To characterize antibody reactivity patterns against 16 H. pylori proteins, by age, sex, and region of birth, in a large sample of the Spanish adult population.

MATERIALS AND METHODS

Antibody reactivity was quantified by H. pylori multiplex serology in a sample from the control group of the multicase-control study MCC-Spain. For this analysis, 2555 population-based controls were included. Each participant was classified as seropositive or seronegative for each protein according to specific cutoffs. Overall H. pylori seroprevalence was defined as positivity against ≥4 proteins. Descriptive analyses by age, sex, and region of birth were performed for both seroprevalence and seroreactivity (continuous measure). Differences among groups were tested by logistic and linear regression models.

RESULTS

Overall H. pylori seroprevalence increased with age in both sexes. For ages 55-74, seroprevalence was lower in women than in men (84% vs 92%, P<.001). Region of birth explained 7% of the variability in seroprevalence. Among H. pylori seropositive subjects, proteins with the highest seroprevalence were GroEL, NapA, HP231, and Omp. Seropositivity for most of the proteins increased or remained stable with age, rising mainly for CagA, GroEL, and HyuA in women. A clear cohort effect was not observed.

CONCLUSIONS

This is the first study to describe the antibody patterns against 16 H. pylori proteins in the Spanish population. We found variability in the H. pylori antibody profiles according to both individual factors such as age and sex, and environmental factors such as the region of birth. The slightness of the reduction in seropositivity with decreasing age highlights the ongoing importance of this infection.

Helicobacter pylori serological biomarkers of gastric cancer risk in the MCC-Spain case-control Study

BACKGROUND

Helicobacter pylori infection is one of the main risk factors for non-cardia gastric cancer. However, only a minority of infected persons develop the disease. This study aims at identifying H. pylori related serological biomarkers of risk for gastric cancer.

METHODS

Incident gastric cancer cases and population controls (age, sex and region frequency-matched) from the MCC-Spain multicase-control Study were included. Seroreactivities against 16H. pylori proteins were determined using multiplex serology. Infection was defined as seropositivity against≥4 proteins. Relation of serological results to non-cardia and cardia gastric cancer was assessed using multivariable mixed logistic regression and principal components analysis.

RESULTS

Seroprevalence was 88% among 2071 controls, 95% among 202 non-cardia gastric cancer cases (OR=1.9 (95% CI: 1.0-3.6)) and 85% among 62 cardia cancer cases (OR=0.5 (95% CI: 0.3-1.1)). In infected subjects, seropositivity for UreA, HP231, NapA and Cagδ was associated with lower non-cardia gastric cancer risk, while seropositivity for CagA and VacA was associated with higher risk. Seropositivity for CagA and seronegativity for Cagδ maintained the association after additional adjustment by serostatus of significant proteins. We identified two antibody reactivity patterns: the "virulent-pattern", related to a threefold higher risk of non-cardia gastric cancer and the "non-virulent pattern", related to a 60% decreased risk (4th vs. first quartile).

CONCLUSIONS

In our population, people seropositive for H. pylori were characterized by two patterns of antibody reactivity against H. pylori proteins: 1) Combined high seroreactivity against several proteins, associated with a lower non-cardia gastric cancer risk, and 2) High seroreactivity against CagA and VacA, associated with an increased risk.

Helicobacter pylori antibody responses in association with eradication outcome and recurrence: a population-based intervention trial with 7.3-year follow-up in China

OBJECTIVE

To identify serum biomarkers that may predict the short or long term outcomes of anti-Helicobacter pylori (H. pylori) treatment, a follow-up study was performed based on an intervention trial in Linqu County, China.

METHODS

A total of 529 subjects were selected randomly from 1,803 participants to evaluate total anti-H. pylori immunoglobulin G (IgG) and 10 specific antibody levels before and after treatment at 1-, 2- and 7.3-year. The outcomes of anti-H. pylori treatment were also parallelly assessed by¹³C-urea breath test at 45-d after treatment and 7.3-year at the end of follow-up.

RESULTS

We found the medians of anti-H. pylori IgG titers were consistently below cut-off value through 7.3 years in eradicated group, however, the medians declined in recurrence group to 1.2 at 1-year after treatment and slightly increased to 2.0 at 7.3-year. While the medians were significantly higher (>3.0 at 2- and 7.3-year) among subjects who failed the eradication or received placebo. For specific antibody responses, baseline seropositivities of FliD and HpaA were reversely associated with eradication failure [for FliD, odds ratio (OR)=0.44, 95% confidence interval (95% CI): 0.27-0.73; for HpaA, OR=0.32, 95% CI: 0.17-0.60]. The subjects with multiple positive specific antibodies at baseline were more likely to be successfully eradicated in a linear fashion (P_trend=0.006).

CONCLUSIONS

Our study suggested that total anti-H. pylori IgG level may serve as a potential monitor of long-term impact on anti-H. pylori treatment, and priority forH. pylori treatment may be endowed to the subjects with multiple seropositive antibodies at baseline, especially for FliD and HapA.

Population attributable burden of Helicobacter pylori-related gastric cancer, coronary heart disease, and ischemic stroke in China

Helicobacter pylori, a risk factor of cancer and chronic diseases, remains highly prevalent in China. This review aims to systematically evaluate the H. pylori-attributable burden for gastric cancer (GC), coronary heart disease (CHD), and ischemic stroke (IS) in the Chinese population. Helicobacter pylori prevalence was updated by pooling the results reported in studies across China. The population attributable fraction (PAF) was calculated based on the H. pylori prevalence 10 years ago and relative risks of specific disease by reviewing the prospective studies published from 2000 through 2015. In China, the nationwide average prevalence of H. pylori was estimated to be 42.06 % in the general population during 2009-2013. The fixed effects pooled relative risk (RR) of 1.89 [95 % confidence interval (CI): 1.57-2.26] was obtained for gastric cancer and H. pylori infection. Helicobacter pylori infection was responsible for around 37.38 % of noncardia GC, corresponding to about 105,536 cases in 2012. As for extra-gastric disorders, H. pylori infections had higher risk of CHD (RR = 1.55, 95 % CI: 1.37-1.76) and IS (RR = 1.54, 95 % CI: 1.42-1.66). About 23.15 % of CHD and 22.29 % of IS were attributable to H. pylori infection. The estimates of H. pylori-attributable burden reveal a great potential of reducing H. pylori-related chronic disease burden by H. pylori eradication. Large prospective studies are warranted to identify which H. pylori strains, which subtypes of the disease, and which subgroups of the population have the greatest risk of relevant diseases and the effect of H. pylori eradication on the prevention of H. pylori-related diseases.

Influence of duodenogastric reflux in the gastric mucosa histological changes of rats infected with Helicobacter pylori

ABSTRACT Objective: to evaluate the influence of Duodenal reflux in histological changes of the gastric mucosa of rats infected with Helicobacter pylori submitted to pyloroplasty. Methods: after two weeks of acclimation, we infected 30 male Wistar rats with Helicobacter pylori. We randomly divided them into three groups: one submitted to pyloroplasty, another to partial gastrectomy and the third, only infected, was not operated. After six months of surgery, euthanasia was carried out. Gastric fragments were studied by light microscopy to count the number of H. pylori, and to observe the histological changes (gastritis, metaplasia, dysplasia and neoplasia). We confirmed these changes by immunohistochemistry using the molecular markers PCNA and TGF-beta. Results: the animals submitted to pyloroplasty had higher percentage of colonization by H. pylori (median=58.5; gastrectomy=16.5; control=14.5). There was a positive correlation between the amount of H. pylori and the occurrence of chronic gastritis present in the antral fragments. Neoplasia occurred in 40% of rats from the group submitted to pyloroplasty. The staining with PCNA and TGF-ß confirmed the histopathological changes visualized by optical microscopy. Conclusions: the antral region was the one with the highest concentration of H. pylori, regardless of the group. There was a positive correlation between the appearance of benign disorders (chronic gastritis, metaplasia, dysplasia) and cancer in mice infected with H. pylori submitted to pyloroplasty.

Helicobacter pylori blood biomarker for gastric cancer risk in East Asia

BACKGROUND

Incidence and mortality rates for gastric cancer, the fifth most commonly diagnosed and third most deadly cancer worldwide, are highest in East Asia. We sought to identify gastric cancer risk biomarkers among eight prospective studies from China, Japan and Korea.

METHODS

This pooled nested case-control study included 1608 incident non-cardia gastric cancer cases and 1958 matched controls. Pre-diagnostic antibody levels to 15 Helicobacter pylori proteins were assessed using multiplex serology. Conditional logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Sero-positivity to 10 H. pylori antigens (Omp, CagA, VacA, HcpC, HP 0305, GroEL, NapA, HyuA, Cad, HpaA) was associated with a 1.29- to 3.26-fold increase in odds of gastric cancer. Omp and HP 0305 consistently remained associated with gastric cancer risk after mutually adjusting for all other markers. Sero-positivity to both Omp and HP 0305 was associated with an over 4-fold increase in gastric cancer incidence (OR, 4.09; 95% CI 3.26-5.13). When limited to only those who are CagA+ H. pylori+, Omp/HP 0305 sero-positivity remained strongly associated with an over 3-fold increase in the odds of gastric cancer (OR, 3.34; 95% CI 2.27-4.91). The results were highly consistent among the cohorts.

CONCLUSIONS

We have confirmed new H. pylori biomarkers that are strongly associated with gastric cancer risk, even among those infected with the known H. pylori virulence factor CagA. These results may help to design cost-efficient prevention strategies to reduce gastric cancer incidence in East Asia.

Anti-Helicobacter pylori Antibody Profiles in Epstein-Barr virus (EBV)-Positive and EBV-Negative Gastric Cancer

BACKGROUND

Helicobacter pylori is the primary cause of gastric cancer, but about 9% of cases harbor Epstein-Barr virus (EBV) in the tumor cells. There is limited evidence on the possible interaction or antagonism between these infectious agents in gastric carcinogenesis.

METHODS

We compared H. pylori serologic profiles of EBV-positive (n = 58) and EBV-negative (n = 111) noncardia gastric cancer patients from the United States National Cancer Institute's International EBV-Gastric Cancer Consortium. EBV positivity of tumors was assessed by in situ hybridization. Serum levels of 15 antibodies to immunogenic proteins of H. pylori (Cad, CagA, Cagδ, CagM, Catalase, GroEL, HcpC, HP0231, HP0305, HpaA, HyuA, NapA, Omp, UreA, VacA) were assessed using bead-based multiplex serology. Logistic regression models were used to adjust odds ratios (OR) for country, age, sex, and year of diagnosis.

RESULTS

Seropositivity to individual proteins ranged up to 90% overall. Antibodies to Catalase were borderline associated with tumor EBV positivity (adjusted OR = 3.15, p = .0024, Bonferroni corrected p = .036). Distributions of other antibodies did not vary by tumor EBV status.

CONCLUSION

Similarity of host-response indicates the essential etiological role of H. pylori in EBV-positive gastric cancer.

Association of helicobacter pylori infection and chronic atrophic gastritis with risk of colonic, pancreatic and gastric cancer: A ten-year follow-up of the ESTHER cohort study

OBJECTIVES

To assess the association of H. pylori and chronic atrophic gastritis (AG) with colonic, pancreatic and gastric cancer in a population-based prospective cohort.

METHODS

Serum antibodies against H. pylori in general and specific to cytotoxin-associated gene A (CagA), as well as serum pepsinogen I and II were analyzed in 9,506 men and women, aged 50-75 years in a cohort study from Saarland, Germany. Incident cases of colonic, pancreatic and gastric cancer were ascertained by record linkage with data from the Saarland Cancer Registry.

RESULTS

During an average follow-up of 10.6 years, 108 colonic, 46 pancreatic and 27 gastric incident cancers were recorded. There was no association between H. pylori infection and colonic cancer (HR = 1.07; 95% CI 0.73-1.56) or pancreatic cancer (HR = 1.32; 0.73-2.39), regardless of either CagA seropositivity or AG status. In contrast, CagA+ infection was associated with a strongly increased risk of gastric cancer, especially non-cardia gastric cancer, and this association was particularly pronounced in the presence of AG. Compared to people without AG and without CagA+ infection, people with both risk factors had a significantly increased risk of non-cardia gastric cancer (HR = 32.4; 7.6-137.6).

CONCLUSIONS

This large cohort study did not observe an association of H. pylori infection or AG with colonic or pancreatic cancer, but underlines that the vast majority of non-cardia gastric cancers arise from AG and infection with CagA+ H. pylori strains.

Serological response to Helicobacter pylori infection among Latin American populations with contrasting risks of gastric cancer

Gastric cancer is a rare outcome of chronic Helicobacter pylori infection. Serologic profiles may reveal bacterial, environmental and/or host factors associated with cancer risk. We therefore compared specific anti-H. pylori antibodies among populations with at least twofold differences in gastric cancer mortality from Mexico, Colombia and Chile. Our study included 1,776 adults (mean age 42 years) from three nationally representative surveys, equally divided between residents of high- and low-risk areas. Antibodies to 15 immunogenic H. pylori antigens were measured by fluorescent bead-based multiplex assays; results were summarized to identify overall H. pylori seropositivity. We used logistic regression to model associations between antibody seroreactivity and regional cancer risk (high vs. low), adjusting for country, age and sex. Both risk areas had similar H. pylori seroprevalence. Residents in high- and low-risk areas were seroreactive to a similar number of antigens (means 8.2 vs. 7.9, respectively; adjusted odds ratio, OR: 1.02, p = 0.05). Seroreactivities to Catalase and the known virulence proteins CagA and VacA were each significantly (p < 0.05) associated with residence in high-risk areas, but ORs were moderate (1.26, 1.42 and 1.41, respectively) and their discriminatory power was low (area under the curve < 0.6). The association of Catalase was independent from effects of either CagA or VacA. Sensitivity analyses for antibody associations restricted to H. pylori-seropositive individuals generally replicated significant associations. Our findings suggest that humoral responses to H. pylori are insufficient to distinguish high and low gastric cancer risk in Latin America. Factors determining population variation of gastric cancer burden remain to be identified.

Association of Streptococcus gallolyticus subspecies gallolyticus with colorectal cancer: Serological evidence

The colonic opportunist Streptococcus gallolyticus subspecies gallolyticus (SGG) is potentially associated with colorectal cancer (CRC). Large-scale seroepidemiological data for SGG antibodies and their possible association with CRC is currently missing. Associations between CRC and antibody responses to SGG were examined in 576 CRC cases and 576 controls matched by sex, age and province from a population-based multicase-control project (MCC-Spain). MCC-Spain was conducted between 2008 and 2013 in 12 Spanish provinces. Antibody responses to recombinant affinity-purified SGG pilus proteins Gallo1569, 2039, 2178 and 2179 were analysed by multiplex serology. Polyomavirus (PyV) JC VP1 and PyV 6 VP1 proteins served as disease-specificity controls. In the control population, antibody responses to pilus proteins were mostly weak. Antibody responses to individual pilus proteins Gallo2039 (OR: 1.58, 95% CI: 1.09-2.28), Gallo2178 (OR: 1.58, 95% CI: 1.09-2.30) and Gallo2179 (OR: 1.45, 95% CI: 1.00-2.11) were significantly associated with CRC risk. The association was stronger for positivity to two or more pilus proteins of Gallo1569, Gallo2178 and Gallo2179 (OR:1.93, 95% CI: 1.04-3.56) and for double-positivity to Gallo2178 and Gallo2179 (OR: 3.54, 95% CI: 1.49-8.44). The association between SGG infection and CRC risk was stronger among individuals younger than 65 years. For the first time we demonstrated a statistically significant association of exposure to SGG antigens and CRC in a large seroepidemiological study. These results should stimulate further studies on the role of SGG in CRC pathogenesis.

Multiplex H. pylori Serology and Risk of Gastric Cardia and Noncardia Adenocarcinomas

The reported associations with gastric adenocarcinoma and seropositivity to different Helicobacter pylori antigens using multiplex serology have not been consistent across studies. We aimed to investigate the association between 15 different multiplex serology antigens and the risk of gastric cardia (GCA) and gastric noncardia (GNCA) adenocarcinomas in northeastern Iran, a population with high rates of gastric adenocarcinoma. We included 272 cases of gastric adenocarcinoma (142 GCA, 103 GNCA, and 27 unspecified) and 524 controls who were individually matched to cases for age, sex, and place of residence in a population-based case-control study. Seropositivity to H. pylori was assessed using both multiplex serology and H. pylori IgG ELISA. Ninety-five percent of controls were seropositive to H. pylori. Of the 15 antibodies in the multiplex assay, 11 showed no significant association with gastric adenocarcinomas. CagA and VacA were associated with a significantly increased risk of all gastric adenocarcinoma and GNCA in multivariate models. Surprisingly, GroEL and NapA were significantly associated with a reduced risk of these tumors. Only CagA antigen was associated with significantly elevated risk of GCA. We found no associations between H. pylori seropositivity overall either by whole-cell ELISA test or multiplex serology, likely due to the high prevalence of seropositivity. Individual antigen testing showed that CagA positivity was associated with increased risk of both noncardia and cardia adenocarcinoma, which is similar to some other Asian populations, whereas two antigens were associated with lower risk of gastric cancer. This latter result was unexpected and should be retested in other populations.

Biomarkers for Helicobacter pylori infection and gastroduodenal diseases

Helicobacter pylori infection is a major cause of gastric cancer. Although identifying H. pylori infected subjects is the first approach for delineating the high-risk population for gastric cancer, the presence of H. pylori antibodies is not sufficient for gastric cancer screening. Among H. pylori infected subjects, only a minority of infected individuals develop gastric cancer. Serologic markers of H. pylori infection can serve as potential predictors for the development of gastric cancer. Serum or urinary H. pylori antibodies, cytotoxin-associated gene A antibodies, pepsinogen and microRNAs were reported to be associated with precancerous lesions or gastric cancer. In this review, we summarized the utilities and limitations of each strategy.

Association of risk of gastric cancer and consumption of tobacco, alcohol and tea in the Chinese population

This study aimed at summarizing epidemiological research findings on associations between tobacco, alcohol and tea consumption and risk of gastric cancer (GC) in the Chinese population. The review searched PubMed, Embase, China National Knowledge Infrastructure (CNKI) and China Biology Medicine (CBM) databases and reference lists of review papers for all studies published in English or Chinese languages. Information extracted, via two independent researchers, from retrieved articles included first author, year of publication, study design, sample size, source of controls and adjusted odds ratio (OR) or relative risk (RR) with the corresponding 95% confidence intervals (CIs) for each category. Statistical analyses used software STATA version 12.0. The systematic search found 89 articles containing 25,821 GC cases and 135,298 non-cases. The overall random effects in terms of pooled OR and 95%CI for tobacco, alcohol and tea consumption were 1.62 (95%CI: 1.50-1.74), 1.57 (95%CI: 1.41-1.76) and 0.67 (95%CI: 0.59-0.76) respectively; while the heterogeneity among included studies ranged from 80.1% to 87.5%. The majority of subgroup analyses revealed consistent results with the overall analyses. All three behavioral factors showed statistically significant dose-dependent effects on GC (P<0.05). The study revealed that tobacco smoking and alcohol drinking were associated with over 1/2 added risk of GC, while tea drinking conferred about 1/3 lower risk of GC in the Chinese population. However, these results should be interpreted with caution given the fact that most of the included studies were based on a retrospective design and heterogeneity among studies was relatively high.

Risk of gastric cancer by water source: evidence from the Golestan case-control study

Background

Gastric cancer (GC) is the world’s fifth most common cancer, and the third leading cause of cancer-related death. Over 70% of incident cases and deaths occur in developing countries. We explored whether disparities in access to improved drinking water sources were associated with GC risk in the Golestan Gastric Cancer Case Control Study.

Methods and Findings

306 cases and 605 controls were matched on age, gender, and place of residence. We conducted unconditional logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CI), adjusted for age, gender, ethnicity, marital status, education, head of household education, place of birth and residence, homeownership, home size, wealth score, vegetable consumption, and H. pylori seropositivity. Fully-adjusted ORs were 0.23 (95% CI: 0.05–1.04) for chlorinated well water, 4.58 (95% CI: 2.07–10.16) for unchlorinated well water, 4.26 (95% CI: 1.81–10.04) for surface water, 1.11 (95% CI: 0.61–2.03) for water from cisterns, and 1.79 (95% CI: 1.20–2.69) for all unpiped sources, compared to in-home piped water. Comparing unchlorinated water to chlorinated water, we found over a two-fold increased GC risk (OR 2.37, 95% CI: 1.56–3.61).

Conclusions

Unpiped and unchlorinated drinking water sources, particularly wells and surface water, were significantly associated with the risk of GC.

Prospective study of Helicobacter pylori antigens and gastric noncardia cancer risk in the nutrition intervention trial cohort

Helicobacter pylori (H. pylori) infection is the strongest known risk factor for gastric noncardia adenocarcinoma (GNCA). We used multiplex serology to determine whether seropositivity to 15 H. pylori proteins is associated with the subsequent development of noncardia gastric cancer in Linxian, China. We included 448 GNCA cases and 1242 controls from two time points within the Linxian General Population Nutrition Intervention Trial, Linxian. H. pylori multiplex seropositivity was defined as positivity to ≥4 of the 15 included antigens. Odds ratios (ORs) and 95% confidence intervals (CIs) were adjusted for major GNCA risk factors. In addition, we undertook a meta-analysis combining H. pylori multiplex serology data from both time points. H. pylori multiplex seropositivity was associated with a significant increase in risk of GNCA at one time point (1985; OR: 3.44, 95% CI: 1.91, 6.19) and this association remained significant following adjustment for H. pylori or CagA ELISA seropositivity (OR: 2.92, 95% CI: 1.56, 5.47). Combining data from both time points in a meta-analysis H. pylori multiplex seropositivity was associated with an increased risk of GNCA, as were six individual antigens: GroEL, HP0305, CagA, VacA, HcpC and Omp. CagM was inversely associated with risk of GNCA. We identified six individual antigens that confer an increase in risk of GNCA within this population of high H. pylori seroprevalence, as well as a single antigen that may be inversely associated with GNCA risk. We further determined that the H. pylori multiplex assay provides additional information to the conventional ELISA methods on risk of GNCA.

Helicobacter pylori protein JHP0290 exhibits proliferative and anti-apoptotic effects in gastric epithelial cells

The influence of Helicobacter pylori infection on gastric epithelial cell proliferation, apoptosis and signaling pathways contributes to the development of infection-associated diseases. Here we report that JHP0290, which is a poorly functionally characterized protein from H. pylori, regulates multiple responses in human gastric epithelial cells. The differential expression and release of JHP0290 homologues was observed among H. pylori strains. JHP0290 existed in monomeric and dimeric forms in H. pylori cell extracts and culture broth. Recombinant purified JHP0290 (rJHP0290) also showed monomeric and dimeric forms, whereas the rJHP0290 C162A mutant exhibited only a monomeric form. The dimeric form of the protein was found to bind more efficiently to gastric epithelial cells than the monomeric form. The exposure of gastric epithelial cells to rJHP0290 induced proliferation in a dose-dependent manner. Faster progression into the cell cycle was observed in rJHP0290-challenged gastric epithelial cells. Furthermore, we detected an anti-apoptotic effect of rJHP0290 in gastric epithelial cells when the cells were treated with rJHP0290 in combination with Camptothecin (CPT), which is an inducer of apoptosis. CPT-induced caspase 3 activation was significantly reduced in the presence of rJHP0290. In addition, the activation of ERK MAPK and the transcription factor NFκB was observed in rJHP0290-challenged gastric epithelial cells lines. Our results suggest that JHP0290 may affect H. pylori-induced gastric diseases via the regulation of gastric epithelial cell proliferation and anti-apoptotic pathways.

Cohort Profile: The Shanghai Men's Health Study

The Shanghai Men's Health Study (SMHS) is a population-based cohort study of 61,480 men aged 40-74 years, launched in 2002 in urban Shanghai to investigate the contribution of lifestyle/environmental factors and genetic susceptibility to cancer and other non-communicable diseases (NCDs). At baseline, trained interviewers collected detailed information on personal and dietary habits, occupational/medical history and physical activity, and took anthropometric measurements (response rate: 74%). Blood, urine and DNA were collected from 75%, 89% and 89% of participants, respectively. The cohort has been followed up through a combination of in-person surveys every 3-4 years and annual record linkage with cancer and vital statistics registries. Response rates for in-person follow-up surveys were over 91% and coverage for mortality nearly 100%. SMHS participants have a high smoking rate (58.6%) and moderate alcohol-drinking rate (29.3%), but low obesity rate (2.6%). They have a low calorie intake from fat (16.2% of total calorie intake) and protein (16.4%), high calorie intake from carbohydrates (67.4%), and high intake of soy food, cruciferous vegetables and fish (156.5, 110.6 and 51.7 g/day, respectively). With its unique exposure pattern and wealth of data and biological samples, the SMHS is well positioned for long-term research into NCD aetiology and prognosis. Information about accessing the SMHS resources can be found at: http://www.mc.vanderbilt.edu/swhs-smhs/.

Implementation of gastric cancer screening - the global experience

Gastric cancer (GC) is still an important global healthcare problem, and in absolute figures it is going to remain at the present level in foreseeable future. In general, survival of patients with GC is poor mainly due to advanced-stage diagnosis. Early-stage GC can be cured by endoscopic resection or less invasive surgical treatment. Unfortunately, there is no appropriate screening strategy available for global application. This article provides a description of established national and regional GC screening programs and the screening modalities used. This review also summarizes current approaches to develop cancer-screening biomarkers. Although candidates with initial promising results have been suggested, moving discovery into clinical practice is still a major challenge. Well-designed biomarker studies, with systematic validation steps, are needed to decrease the burden of this fatal disease.

Association of seropositivity to Helicobacter species and biliary tract cancer in the ATBC study

Helicobacter have been detected in human bile and hepatobiliary tissue. Despite evidence that Helicobacter species promote gallstone formation and hepatobiliary tumors in laboratory studies, it remains unclear whether Helicobacter species contribute to these cancers in humans. We used a multiplex panel to assess whether seropositivity to 15 Helicobacter pylori proteins was associated with subsequent incidence of hepatobiliary cancers in the Finnish Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study. We included 64 biliary cancers, 122 liver cancers, and 224 age-matched controls which occurred over the course of 22 years. Helicobacter pylori seropositivity was defined as those positive to ≥ 4 antigens. Odds ratios (OR) and 95% confidence intervals were adjusted for major hepatobiliary cancer risk factors. Among the controls, 88% were seropositive to H. pylori at baseline. Among those who subsequently developed hepatobiliary cancer, the prevalence of seropositivity was higher: 100% for gallbladder cancer, 97% of extrahepatic bile duct cancer, 91% of ampula of Vater cancer, 96% of intrahepatic bile duct cancer, and 94% of hepatocellular carcinoma. Although the OR for gallbladder cancer could not be calculated, the OR for the other sites were 7.01 (95% confidence interval [CI]: 0.79-62.33), 2.21 (0.19-25.52), 10.67 (0.76-150.08), and 1.20 (0.42-3.45), respectively, with an OR of 5.47 (95% CI: 1.17-25.65) observed for the biliary tract cancers combined. ORs above 1 were observed for many of the investigated antigens, although most of these associations were not statistically significant.

CONCLUSION

Seropositivity to H. pylori proteins was associated with an increased risk of biliary tract cancers in ATBC. Further studies are needed to confirm our findings and to determine how H. pylori might influence the risk of biliary tract cancer.

Challenges and opportunities in international molecular cancer prevention research: An ASPO Molecular Epidemiology and the Environment and International Cancer Prevention Interest Groups Report

The International Agency for Research on Cancer estimates that over half of the new cancer cases and almost two-thirds of the cancer deaths in 2012 occurred in low and middle income countries. To discuss the challenges and opportunities to reducing the burden of cancer worldwide, the Molecular Epidemiology and the Environment and the International Issues in Cancer Special Interest Groups joined forces to hold a session during the 38th Annual Meeting of the American Society of Preventive Oncology (March 2014, Arlington, Virginia). The session highlighted three topics of particular interest to molecular cancer prevention researchers working internationally, specifically: 1) biomarkers in cancer research; 2) environmental exposures and cancer; and 3) molecular pathological epidemiology. A major factor for successful collaboration illuminated during the discussion was the need for strong, committed, and reliable international partners. A key element of establishing such relationships is to thoroughly involve individual international collaborators in the development of the research question; engaged international collaborators are particularly motivated to champion and shepherd the project through all necessary steps, including issues relating to institutional review boards, political sensitivity, laboratory-based assays, and tumor subtyping. Also essential is allotting time for the building, maintaining, and investing in such relationships so that successful international collaborations may take root and bloom. While there are many challenges inherent to international molecular cancer research, the opportunities for furthering the science and prevention of cancer worldwide are great, particularly at this time of increasing cancer incidence and prevalence in low and middle income countries.

Helicobacter pylori antibody patterns in Germany: a cross-sectional population study

BACKGROUND

Helicobacter pylori infection that is usually acquired in childhood and lasts for lifetime is mostly asymptomatic but associated with severe gastrointestinal disease including cancer. During chronic infection, the gastric mucosa is histologically changing. This forces H. pylori to permanent adaptation in its gastric habitat by expression of different proteins which might be reflected in distinctive antibody patterns.

METHODS

To characterize dynamics of the immune response to H. pylori we analysed 1797 sera of a cross-sectional study representative for the German population (age range 1-82 years) with multiplex serology, a fluorescent bead-based antibody binding assay that allows simultaneous and quantitative detection of antibodies. Fifteen recombinant, affinity-purified H. pylori proteins (UreA, GroEL, Catalase, NapA, CagA, CagM, Cagδ, HP0231, VacA, HpaA, Cad, HyuA, Omp, HcpC and HP0305) were used as antigens.

RESULTS

H. pylori seroprevalence (positivity for at least three antigens) was 48% and increased with age from 12% in children <15 years to 69% in females and 90% in males >65 years. Prevalences were highest (>83%) for Omp, VacA and GroEL. For 11 proteins, seroprevalence was higher in males than females (P < 0.05) from age 55 onwards. For all antigens, the median prevalence increase per age decade was stronger in males (8.4%, range 3.8-12.9%) than females (6.1%, range 3.4-10.8%). However, among seropositives the median number of antigens recognized increased from children <15 years to individuals >65 years stronger in females (P = 0.02). Antibody reactivities to GroEL, HyuA, CagM, Catalase, NapA and UreA also increased stronger in females (average 1.7-fold/decade, SD 0.5) than in males (1.5-fold/decade, SD 0.4).

CONCLUSION

H. pylori antibody response accumulates qualitatively and quantitatively with age. This may reflect a lifelong stimulation of the immune response by chronically active infection.

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.

Diet, Helicobacter pylori strain-specific infection, and gastric cancer risk among Chinese men

Evidence for the association of diet and gastric cancer is equivocal, and the majority of previous studies have not evaluated the interaction of diet and infection with Helicobacter pylori, the leading risk factor for gastric cancer. We examined these associations among 226 cases and 451 controls nested within a prospective cohort. Dietary intakes were calculated from validated food frequency questionnaires. Blood levels of 15 antibodies to Helicobacter pylori proteins were assessed using multiplex serology. Odds ratios (ORs) were calculated using logistic regression. Among individuals infected with high-risk Helicobacter pylori (sero-positivity to 5-6 virulent H. pylori proteins), increasing intake of red meat, heme iron, and sodium increased risk (comparing highest tertile to lowest: ORs [95% confidence interval {CI}]: 1.85 [1.01-3.40]; 1.95 [1.06-3.57]; and 1.76 [0.91-3.43], respectively) while increasing intake of fruit decreased gastric cancer risk (comparing highest tertile of intake to lowest: OR [95% CI]: 0.52 [0.28-0.94]). No associations of diet with risk were found among individuals infected with low-risk H. pylori (P for interaction for red meat and sodium: 0.02 and 0.01, respectively). In this population with over 90% prevalence of CagA-positive H. pylori infection, categorizing individuals using H. pylori multiplex serology may identify individuals for whom a diet intervention may be effective.

Helicobacter pylori enhances CIP2A expression and cell proliferation via JNK2/ATF2 signaling in human gastric cancer cells

Helicobacter pylori (H. pylori) infection plays an important role in the development of gastric carcinomas. Cancerous inhibitor of protein phosphatase 2A (CIP2A) is a novel human oncoprotein that functions as an important regulator of cell growth and malignant transformation. In the present study, we aimed to investigate the potential mechanisms by which H. pylori upregulates the expression of CIP2A and the functional impact of H. pylori-induced CIP2A in gastric cancer cells. We demonstrated that infection of MKN-45 cells with H. pylori led to a marked increase in the expression of CIP2A at the mRNA and protein levels. H. pylori-induced CIP2A was associated with increased cell proliferation. In addition, H. pylori was found to activate the JNK2 pathway. Importantly, both H. pylori-induced CIP2A production and cell proliferation were partially reversed by inhibition of JNK2 signaling. Similarly, the blockade of H. pylori-induced CIP2A expression by siRNA against CIP2A also inhibited cell proliferation. Thus, H. pylori appears to stimulate the expression of CIP2A and proliferation of gastric cancer cells via JNK2 signaling. These findings suggest that H. pylori-induced upregulation of CIP2A contributes to the development and progression of gastric cancer. Further in vivo studies are warranted to explore the biological role of CIP2A and its interaction with JNK2 signaling in gastric cancer.

A CagA-independent cluster of antigens related to the risk of noncardia gastric cancer: associations between Helicobacter pylori antibodies and gastric adenocarcinoma explored by multiplex serology

Because of the differences in bacterial epitopes and host characteristics, infections with Helicobacter pylori (H. pylori) induce different immune responses. We explored the possibility that certain antibody response patterns are more closely linked to gastric adenocarcinoma (GAC) than others. In a Swedish population-based case-control study, serum samples were obtained from 268 cases and 222 controls, aged 40-79 years and frequency-matched according to age and sex. We measured antibodies against 17 H. pylori proteins using multiplex serology. Associations were estimated with multivariably adjusted logistic regression models, using odds ratio (OR) with 95% confidence interval (CI) as measures of relative risk. Associations were essentially confined to non-cardia GAC but did not differ significantly between intestinal and diffuse subtypes. Point estimates for all antibodies were above unity, 15 significant with top three being CagA (OR = 9.2), GroEL (6.6), HyuA (3.6). ORs were substantially attenuated in individuals with chronic atrophic gastritis. Principal component analysis identified two significant factors: a CagA-dominant factor (antibodies against CagA, VacA and Omp as prominent markers), and a non-CagA factor (antibodies against NapA and Catalase as prominent markers). Both factors showed dose-dependent associations with non-cardia GAC risk (CagA-dominant factor, highest vs. lowest quartiles, OR = 16.2 [95% CI 4.8-54.9]; non-CagA factor OR = 5.3 [95% CI 2.1-13.3]). Overall, our results confirm that serum antibodies against different H. pylori proteins are associated with the presence of non-cardia GAC. Although strongest association is detected by antibodies against CagA and covarying proteins, a pattern of antibodies unrelated to CagA is also significantly linked to the risk of non-cardia GAC.

Intake of specific nonfermented soy foods may be inversely associated with risk of distal gastric cancer in a Chinese population

Because the association between soy consumption and gastric cancer is inconsistent, we evaluated the putative preventive effect of soy food on gastric cancer risk in the Shanghai Women's and Men's Health Studies, comprising a total of 128,687 participants. Intake of nonfermented soy foods was estimated using 2 validated food-frequency questionnaires. HRs were calculated with 95% CIs for intake amounts of total nonfermented soy food intake, soy protein, and isoflavones as well as individual soy food groups using Cox proportional hazards regression. A total of 493 distal gastric cancer cases were identified by 2010. Although all risk estimates for summary measures of soy food intake above the lowest quartile (quartile 1) were suggestive of a protective effect, no statistically significant associations with risk of distal gastric cancer were found. Among the separate soy food groups, significant reductions in risk of distal gastric cancer by increasing intake of tofu were found in men in quartile 2 (HR: 0.59; 95% CI: 0.40, 0.86), quartile 3 (HR: 0.62; 95% CI: 0.44, 0.88), and quartile 4 (HR: 0.64; 95% CI: 0.42, 0.99), resulting in a significant trend (P-trend = 0.02). Dry bean intake was also inversely associated with decreased risk of gastric cancer, but in postmenopausal women only [quartile 2 (HR: 0.54; 95% CI: 0.30, 0.96); quartile 3 (HR: 0.90; 95% CI: 0.64, 1.27); and quartile 4 (HR: 0.63; 95% CI: 0.43, 0.91)], resulting in a significant trend (P-trend = 0.03). Overall, our study found no statistically significant association between nonfermented soy food intake and distal gastric cancer risk, though the data supported the hypothesis that tofu may protect against distal gastric cancer in men and dry bean consumption may decrease the risk of gastric cancer in postmenopausal women.

Biomarkers of Helicobacter pylori-associated gastric cancer

Helicobacter pylori-associated gastric cancer is a major cause of morbidity and mortality worldwide, and is predicted to become even more common in developing countries as the population ages. Since gastric cancer develops slowly over years to decades, and typically progresses though a series of well-defined histologic stages, cancer biomarkers have potential to identify asymptomatic individuals in whom surgery might be curative, or even those for whom antibiotics to eradicate H. pylori could prevent neoplastic transformation. Here we describe some of the challenges of biomarker discovery, summarize current approaches to biomarkers of gastric cancer, and explore some recent novel strategies.

Helicobacter pylori protein JHP0290 binds to multiple cell types and induces macrophage apoptosis via tumor necrosis factor (TNF)-dependent and independent pathways

Activated macrophages at the sub-mucosal space play a major role in generating innate immune responses during H. pylori infection. Final disease outcome largely depends on how H. pylori and bacterium-derived products modulate macrophage responses. Here, we report that JHP0290, a functionally unknown protein from H. pylori, regulates macrophage functions. Recombinant purified JHP0290 (rJHP0290) had the ability to bind to several cell types including macrophages, human gastric epithelial cell lines, human monocyte-derived dendritic cells (MoDC) and human neutrophils. Exposure to rJHP0290 induced apoptosis in macrophages concurrent with release of proinflammatory cytokine tumor necrosis factor (TNF). A mutant strain of H. pylori disrupted in the jhp0290 gene was significantly impaired in its ability to induce apoptosis and TNF in macrophages confirming the role of endogenous protein in regulating macrophage responses. Intracellular signaling involving Src family of tyrosine kinases (SFKs) and ERK MAPK were required for rJHP0290-induced TNF release and apoptosis in macrophages. Furthermore, rJHP0290-induced TNF release was partly dependent on activation of nuclear transcription factor-κB (NF-κB). Neutralizing antibodies against TNF partially blocked rJHP0290-induced macrophage apoptosis indicating TNF-independent pathways were also involved. These results provide mechanistic insight into the potential role of the protein JHP0290 during H. pylori-associated disease development. By virtue of its ability to induce TNF, an acid suppressive proinflammatory cytokine and induction of macrophage apoptosis, JHP0290 possibly helps in persistent survival of the bacterium inside the stomach.

Helicobacter pylori infection and esophageal cancer risk: an updated meta-analysis

AIM

To clarify the association between Helicobacter pylori (H. pylori) infection and the risk of esophageal carcinoma through a meta-analysis of published data.

METHODS

Studies which reported the association between H. pylori infection and esophageal cancer published up to June 2013 were included. The odds ratios (ORs) and corresponding 95%CIs of H. pylori infection on esophageal cancer with respect to health control groups were evaluated. Data were extracted independently by two investigators and discrepancies were resolved by discussion with a third investigator. The statistical software, STATA (version 12.0), was applied to investigate heterogeneity among individual studies and to summarize the studies. A meta-analysis was performed using a fixed-effect or random-effect method, depending on the absence or presence of significant heterogeneity.

RESULTS

No significant association between H. pylori infection and esophageal squamous cell carcinoma (ESCC) risk was found in the pooled overall population (OR = 0.97, 95%CI: 0.76-1.24). However, significant associations between H. pylori infection and ESCC risk were found in Eastern subjects (OR = 0.66, 95%CI: 0.43-0.89). Similarly, cytotoxin-associated gene-A (CagA) positive strains of infection may decrease the risk of ESCC in Eastern subjects (OR = 0.77, 95%CI: 0.65-0.92), however, these associations were not statistically significant in Western subjects (OR = 1.26, 95%CI: 0.97-1.63). For esophageal adenocarcinoma (EAC) the summary OR for H. pylori infection and CagA positive strains of infection were 0.59 (95%CI: 0.51-0.68) and 0.56 (95%CI: 0.45-0.70), respectively.

CONCLUSION

H. pylori infection is associated with a decreased risk of ESCC in Eastern populations and a decreased risk of EAC in the overall population.

Circulating cytokines and gastric cancer risk

PURPOSE

Chronic inflammation has been hypothesized to play a significant role in the aetiology of cancer, including gastric cancer. In the present study, we sought to examine pre-diagnostic systemic cytokine levels in plasma, which can be seen as markers of aggregate inflammation, and risk of distal gastric cancer in a case-control study nested within the prospective Shanghai Men's Health Study.

METHODS

Circulating levels of eight inflammation-related cytokines were measured in the plasma collected at baseline for 180 incident cases of distal gastric cancer and 358 matched controls. Helicobacter pylori sero-positivity was assessed using multiplex serology. Conditional logistic regression was used to calculate odds ratios (ORs) and 95 % confidence intervals (CI).

RESULTS

Individuals with IL-8 levels above the lowest quartile were at twofold increased odds of gastric cancer [OR 1.91 (95 % CI 1.05-3.46), OR 2.10 (95 % CI 1.19-3.74), and OR 2.30 (95 % CI 1.26-4.19), for the second through fourth quartiles, respectively]. While there were suggestions of an increase in risk with increased level of many of the other cytokines measured (IL-1β, IL-2, IL-4, IL-6, IL-10, TNF-α, and IFN-γ), no significant associations were found at the p < 0.05 level. Infection with CagA-positive H. pylori did not modify these associations.

CONCLUSIONS

In a population with high gastric cancer incidence and high H. pylori prevalence, increased circulating levels of IL-8 may indicate increased risk of gastric cancer. These findings add to our understanding of the disease and further efforts to uncover biomarkers of disease risk.