Helicobacter pylori Treatment and Gastric Cancer Risk Among Individuals With High Genetic Risk for Gastric Cancer.

Importance: Helicobacter pylori treatment and nutrition supplementation may protect against gastric cancer (GC), but whether the beneficial effects only apply to potential genetic subgroups and whether high genetic risk may be counteracted by these chemoprevention strategies remains unknown. Objective: To examine genetic variants associated with the progression of gastric lesions and GC risk and to assess the benefits of H pylori treatment and nutrition supplementation by levels of genetic risk. Design, Setting, and Participants: This cohort study used follow-up data of the Shandong Intervention Trial (SIT, 1989-2022) and China Kadoorie Biobank (CKB, 2004-2018) in China. Based on the SIT, a longitudinal genome-wide association study was conducted to identify genetic variants for gastric lesion progression. Significant variants were examined for incident GC in a randomly sampled set of CKB participants (set 1). Polygenic risk scores (PRSs) combining independent variants were assessed for GC risk in the remaining CKB participants (set 2) and in an independent case-control study in Linqu. Exposures: H pylori treatment and nutrition supplementation. Main Outcomes and Measures: Primary outcomes were the progression of gastric lesions (in SIT only) and the risk of GC. The associations of H pylori treatment and nutrition supplementation with GC were evaluated among SIT participants with different levels of genetic risk. Results: Our analyses included 2816 participants (mean [SD] age, 46.95 [9.12] years; 1429 [50.75%] women) in SIT and 100 228 participants (mean [SD] age, 53.69 [11.00] years; 57 357 [57.23%] women) in CKB, with 147 GC cases in SIT and 825 GC cases in CKB identified during follow-up. A PRS integrating 12 genomic loci associated with gastric lesion progression and incident GC risk was derived, which was associated with GC risk in CKB (highest vs lowest decile of PRS: hazard ratio [HR], 2.54; 95% CI, 1.80-3.57) and further validated in the analysis of 702 case participants and 692 control participants (mean [SD] age, 54.54 [7.66] years; 527 [37.80%] women; odds ratio, 1.83; 95% CI, 1.11-3.05). H pylori treatment was associated with reduced GC risk only for individuals with high genetic risk (top 25% of PRS: HR, 0.45; 95% CI, 0.25-0.82) but not for those with low genetic risk (HR, 0.81; 95% CI, 0.50-1.34; P for interaction = .03). Such effect modification was not found for vitamin (P for interaction = .93) or garlic (P for interaction = .41) supplementation. Conclusions and Relevance: The findings of this cohort study indicate that a high genetic risk of GC may be counteracted by H pylori treatment, suggesting primary prevention could be tailored to genetic risk for more effective prevention.

Metabolite Alterations and Interactions with Microbiota in Helicobacter pylori-Associated Gastric Lesions.

Metabolites and their interactions with microbiota may be involved in Helicobacter pylori-associated gastric lesion development. This study aimed to explore metabolite alterations upon H. pylori eradication and possible roles of microbiota-metabolite interactions in progression of precancerous lesions. Targeted metabolomics assays and 16S rRNA gene sequencing were conducted to investigate metabolic and microbial alterations of paired gastric biopsy specimens in 58 subjects with successful and 57 subjects with failed anti-H. pylori treatment. Integrative analyses were performed by combining the metabolomics and microbiome profiles from the same intervention participants. A total of 81 metabolites were significantly altered after successful eradication compared to failed treatment, including acylcarnitines, ceramides, triacylglycerol, cholesterol esters, fatty acid, sphingolipids, glycerophospholipids, and glycosylceramides, with P values of <0.05 for all. The differential metabolites showed significant correlations with microbiota in baseline biopsy specimens, such as negative correlations between Helicobacter and glycerophospholipids, glycosylceramide, and triacylglycerol (P < 0.05 for all), which were altered by eradication. The characteristic negative correlations between glycosylceramides and Fusobacterium, Streptococcus, and Gemella in H. pylori-positive baseline biopsy specimens were further noticed in active gastritis and intestinal metaplasia (P < 0.05 for all). A panel including differential metabolites, genera, and their interactions may help to discriminate high-risk subjects who progressed from mild to advanced precancerous lesions in short-term and long-term follow-up periods with areas under the curve (AUC) of 0.914 and 0.801, respectively. Therefore, our findings provide new insights into the metabolites and microbiota interactions in H. pylori-associated gastric lesion progression. IMPORTANCE In this study, a panel was established including differential metabolites, genera, and their interactions, which may help to discriminate high-risk subjects for progression from mild lesions to advanced precancerous lesions in short-term and long-term follow-up.

Allium vegetable intake associated with the risk of incident gastric cancer: a continuous follow-up study of a randomized intervention trial.

BACKGROUND: Allium vegetable components have antibacterial, antioxidative, and immune modulation properties, thus potentially exhibiting antitumor effects. Despite evidence from case-control studies, prospective studies linking allium vegetables with gastric cancer (GC) have been sparse. OBJECTIVE: In a prospective study, we examined whether allium vegetable intake would change the risk of GC occurrence and whether the associations would be modified by vitamin supplementation, garlic supplementation, and Helicobacter pylori (H. pylori) treatment. METHODS: The study was conducted on the basis of the Shandong Intervention Trial, a randomized, placebo-controlled, factorial-designed trial (1995-2003) in a well-recognized high-risk area for GC in China. Participants were continuously followed up to December 2017 for 22.3 y (1995-2017). A total of 3229 subjects were included, with information on the intake of allium vegetables (garlic vegetables and scallions), collected by structured questionnaires in 1994. The associations of total and individual allium vegetable intake with the risk of GC were examined, respectively. RESULTS: During the follow-up, 144 incident cases of GC were identified. Garlic vegetable intake was associated with a decreased risk of incident GC (P-trend = 0.02; OR: 0.83; 95% CI: 0.70, 0.98, per 1 kg/y increment), whereas scallion intake showed no association (P-trend = 0.80). An inverse association of the risk of GC with total allium vegetable and garlic vegetable intake was particularly stronger among those receiving the placebo for vitamin supplementation or garlic supplementation, indicating potential effect modifications by nutritional supplementation on allium vegetable intake and the risk of developing GC. Similar findings were found for analyses of the combined prevalence of dysplasia or GC. CONCLUSIONS: We found a significant reduction in the risk of developing GC with increasing dietary intake of allium vegetables, particularly garlic vegetables. The findings add to the literature on the potential inverse association of garlic vegetable intake with the risk of GC, therefore holding public health implications for dietary recommendations. This trial was registered at clinicaltrials.gov as NCT00339768.

Beneficial effects of endoscopic screening on gastric cancer and optimal screening interval: a population-based study.

BACKGROUND : The effectiveness of endoscopic screening on gastric cancer has not been widely investigated in China and the screening interval of repeated screening has not been determined. METHODS : In a population-based prospective study, we included 375,800 individuals, 14,670 of whom underwent endoscopic screening (2012-2018). We assessed the associations between endoscopic screening and risk of incident gastric cancer and gastric cancer-specific mortality, and examined changes in overall survival and disease-specific survival following screening. The optimal screening interval for repeated endoscopy for early detection of gastric cancer was explored. RESULTS : Ever receiving endoscopic screening significantly decreased the risk of invasive gastric cancer (age- and sex-adjusted relative risk [RR] 0.69, 95 % confidence interval [CI] 0.52-0.92) and gastric cancer-specific mortality (RR 0.33, 95 %CI 0.20-0.56), particularly for noncardia gastric cancer. Repeated screening strengthened the beneficial effect on invasive gastric cancer-specific mortality of one-time screening. Among invasive gastric cancers, screening-detected individuals had significantly better overall survival (RR 0.18, 95 %CI 0.13-0.25) and disease-specific survival (RR 0.18, 95 %CI 0.13-0.25) than unscreened individuals, particularly for those receiving repeated endoscopy. For individuals with intestinal metaplasia or low grade intraepithelial neoplasia, repeated endoscopy at an interval of < 2 years, particularly within 1 year, significantly enhanced the detection of early gastric cancer, compared with repeated screening after 2 years (P-trend = 0.02). CONCLUSION : Endoscopic screening prevented gastric cancer occurrence and death, and improved its prognosis in a population-based study. Repeated endoscopy enhanced the effectiveness. Screening interval should be based on gastric lesion severity.

Microbiota alteration at different stages in gastric lesion progression: a population-based study in Linqu, China.

In addition to Helicobacter pylori (H.pylori), gastric microbiota may be involved in carcinogenesis process. However, the longitudinal study to assess changes in the gastric microbiota associated with the development of gastric carcinogenesis is still limited. The aim of this study is to explore dynamic microbial alterations in gastric cancer (GC) development based on a 4-year endoscopic follow-up cohort in Linqu County, China. Microbial alterations were investigated by deep sequencing of the microbial 16S ribosomal RNA gene in 179 subjects with various gastric lesions, and validated in paired gastric biopsies prospectively collected before and after lesion progression and in non-progression controls. Significant differences were found in microbial diversity and community structure across various gastric lesions, with 62 candidate differential taxa between at least two lesion groups. Further validations identified Helicobacter, Bacillus, Capnocytophaga and Prevotella to be associated with lesion progression-to-dysplasia (DYS)/GC (all P < 0.05), especially for subjects progressing from intestinal metaplasia (IM) to DYS/GC. The combination of the four genera in a microbial dysbiosis index showed a significant difference after lesion progression-to-DYS/GC compared to controls (P = 0.027). The panel including the four genera identified subjects after progression-to-DYS/GC with an area under the receiver-operating curve (AUC) of 0.941. Predictive significance was found before lesion progression-to-DYS/GC with an AUC = 0.776 and an even better AUC (0.927) for subjects progressing from IM to DYS/GC. Microbiota may play different roles at different stages in gastric carcinogenesis. A panel of bacterial genera associated with gastric lesions may help to assess gastric microbial dysbiosis and show potential predictive values for lesion progression. Our findings provide new clues for the microbial mechanism of H.pylori-associated carcinogenesis.

Suppression of Helicobacter pylori infection by daily cranberry intake: A double-blind, randomized, placebo-controlled trial.

BACKGROUND AND AIM: Dietary strategies that contribute to reducing incidence of Helicobacter pylori infection without negative side effects are highly desirable owing to worldwide bacterial prevalence and carcinogenesis potential. The aim of this study was to determine dosage effect of daily cranberry consumption on H. pylori suppression over time in infected adults to assess the potential of this complementary management strategy in a region with high gastric cancer risk and high prevalence of H. pylori infection. METHODS: This double-blind, randomized, placebo-controlled trial on 522 H. pylori-positive adults evaluated dose-response effects of proanthocyanidin-standardized cranberry juice, cranberry powder, or their placebos on suppression of H. pylori at 2 and 8 weeks by 13 C-urea breath testing and eradication at 45 days post-intervention. RESULTS: H. pylori-negative rates in placebo, low-proanthocyanidin, medium-proanthocyanidin, and high-proanthocyanidin cranberry juice groups at week 2 were 13.24%, 7.58%, 1.49%, and 13.85% and at week 8 were 7.35%, 7.58%, 4.48%, and 20.00%, respectively. Consumption of high-proanthocyanidin juice twice daily (44 mg proanthocyanidin/240-mL serving) for 8 weeks resulted in decreased H. pylori infection rate by 20% as compared with other dosages and placebo (P < 0.05). Percentage of H. pylori-negative participants increased from 2 to 8 weeks in subjects who consumed 44 mg proanthocyanidin/day juice once or twice daily, showing a statistically significant positive trend over time. Encapsulated cranberry powder doses were not significantly effective at either time point. Overall trial compliance was 94.25%. Cranberry juice and powder were well-tolerated. CONCLUSIONS: Twice-daily consumption of proanthocyanidin-standardized cranberry juice may help potentiate suppression of H. pylori infection. TRIAL REGISTRATION: ChiCTR1800017522, per WHO ICTRP.

Helicobacter pylori associated aberrant methylation genes in blood leukocyte and gastric mucosa.

Background and Aim: Methylation alterations may be involved in Helicobacter pylori-associated gastric carcinogenesis. This study aims to explore the potential H.pylori-associated methylation biomarkers in blood leukocyte and gastric mucosa. Methods: Five candidate H.pylori-associated aberrant methylation genes were selected from the previous genome-wide profiling panels and validated in blood leukocyte and gastric mucosa in multi-stages (case-control validation between H.pylori positive and negative subjects and self-control validation before and after anti-H.pylori treatment). Results: GNAS methylation level was decreased in blood leukocyte (62.07% v.s. 46.33%, p<0.001) and gastric mucosa (56.30% v.s. 32.42%, p<0.001) of H.pylori positive subjects compared to negative controls. While, MTERF1 methylation level was increased significantly in blood leukocyte (29.57% v.s. 56.02%, p<0.001) and gastric mucosa (31.10% v.s. 47.50%, p<0.001) of positive subjects compared to controls. After successful H.pylori eradication, the methylation levels were increased from 44.87% to 60.88% (p<0.001) for GNAS and decreased from 46.19% to 34.56% (p<0.001) for MTERF1 in blood leukocyte. Similar increasing and decreasing methylation alterations were also found for the two genes after successful eradication in paired gastric mucosa. In TCGA database, an inverse relationship was found between GNAS methylation and mRNA expression (r=-0.12, p=0.027). The GC cases with higher GNAS expression levels showed significantly worse survival (HR, 2.09, 95%CI, 1.22-3.57, p=0.007) compared to lower expression subjects. Conclusions: GNAS and MTERF1 methylation levels may be affected by H.pylori infection in gastric mucosa and blood leukocyte. GNAS may be involved in advanced stage of GC development, although the possible mechanism still needs further study in precancerous lesions.

Association Between Lifestyle Factors, Vitamin and Garlic Supplementation, and Gastric Cancer Outcomes: A Secondary Analysis of a Randomized Clinical Trial.

Importance: The associations of lifestyle factors with gastric cancer (GC) are still underexplored in populations in China. Long-term nutritional supplementation may prevent GC in high-risk populations, but the possible effect modification by lifestyle factors remains unknown. Objective: To evaluate how lifestyle factors, including smoking, alcohol intake, and diet, may change the risk of GC incidence and mortality and whether the effects of vitamin and garlic supplementation on GC are associated with major lifestyle factors. Design, Setting, and Participants: This is a secondary analysis of the Shandong Intervention Trial, a masked, randomized, placebo-controlled trial that aimed to assess the effect of vitamin and garlic supplementations and Helicobacter pylori treatment on GC in a factorial design with 22.3 years of follow-up. The study took place in Linqu County, Shandong province, China, a high-risk area for GC. Data were collected from Jully 1995 to December 2017. Overall, 3365 participants aged 35 to 64 years identified in 13 randomly selected villages who agreed to undergo gastroscopy were invited to participate in the trial and were included in the analysis. Data analysis was conducted from March to May 2019. Interventions: Participants received vitamin and garlic supplementation for 7.3 years, H pylori treatment for 2 weeks (among participants with H pylori ), or placebo. Main Outcomes and Measures: The primary outcomes were GC incidence and GC mortality (1995-2017). We also examined the progression of gastric lesions (1995-2003) as a secondary outcome. Results: Of the 3365 participants (mean [SD] age, 47.1 [9.2] years; 1639 [48.7%] women), 1677 (49.8%) were randomized to receive active vitamin supplementation, with 1688 (50.2%) receiving placebo, and 1678 (49.9%) receiving active garlic supplementation, with 1687 (50.1%) receiving placebo. Overall, 151 GC cases (4.5%) and 94 GC deaths (2.8%) were identified. Smoking was associated with increased risk of GC incidence (odds ratio, 1.72; 95% CI, 1.003-2.93) and mortality (hazard ratio [HR], 2.01; 95% CI, 1.01-3.98). Smoking was not associated with changes to the effects of vitamin or garlic supplementation. The protective effect on GC mortality associated with garlic supplementation was observed only among those not drinking alcohol (never drank alcohol: HR, 0.33; 95% CI, 0.15-0.75; ever drank alcohol: HR, 0.92; 95% CI, 0.55-1.54; P for interaction = .03), and significant interactions were only seen among participants with H pylori (never drank alcohol: HR, 0.31; 95% CI, 0.12-0.78; ever drank alcohol: HR, 0.91; 95% CI, 0.52-1.60; P for interaction = .04). No significant interactions between vitamin supplementation and lifestyle factors were found. Conclusions and Relevance: In this secondary analysis of a randomized clinical trial, smoking was associated with an increased risk of GC incidence and mortality. Not drinking alcohol was associated with a stronger beneficial effect of garlic supplementation on GC prevention. Our findings provide new insights into lifestyle intervention for GC prevention, suggesting that mass GC prevention strategies may need to be tailored to specific population subgroups to maximize the potential beneficial effect. Trial Registration: ClinicalTrials.gov Identifier: NCT00339768.

Effect of Helicobacter pylori on gastrointestinal microbiota: a population-based study in Linqu, a high-risk area of gastric cancer.

OBJECTIVE: Gastrointestinal microbiota may be involved in Helicobacter pylori-associated gastric cancer development. The aim of this study was to explore the possible microbial mechanisms in gastric carcinogenesis and potential dysbiosis arising from H. pylori infection. DESIGN: Deep sequencing of the microbial 16S ribosomal RNA gene was used to investigate alterations in paired gastric biopsies and stool samples in 58 subjects with successful and 57 subjects with failed anti-H. pylori treatment, relative to 49 H. pylori negative subjects. RESULTS: In H. pylori positive subjects, richness and Shannon indexes increased significantly (both p<0.001) after successful eradication and showed no difference to those of negative subjects (p=0.493 for richness and p=0.420 for Shannon index). Differential taxa analysis identified 18 significantly altered gastric genera after eradication. The combination of these genera into a Microbial Dysbiosis Index revealed that the dysbiotic microbiota in H. pylori positive mucosa was associated with advanced gastric lesions (chronic atrophic gastritis and intestinal metaplasia/dysplasia) and could be reversed by eradication. Strong coexcluding interactions between Helicobacter and Fusobacterium, Neisseria, Prevotella, Veillonella, Rothia were found only in advanced gastric lesion patients, and were absent in normal/superficial gastritis group. Changes in faecal microbiota included increased Bifidobacterium after successful H. pylori eradication and more upregulated drug-resistant functional orthologs after failed treatment. CONCLUSION: H. pylori infection contributes significantly to gastric microbial dysbiosis that may be involved in carcinogenesis. Successful H. pylori eradication potentially restores gastric microbiota to a similar status as found in uninfected individuals, and shows beneficial effects on gut microbiota.

Effects of Helicobacter pylori treatment and vitamin and garlic supplementation on gastric cancer incidence and mortality: follow-up of a randomized intervention trial.

OBJECTIVE: To assess the effects of Helicobacter pylori treatment, vitamin supplementation, and garlic supplementation in the prevention of gastric cancer. DESIGN: Blinded randomized placebo controlled trial. SETTING: Linqu County, Shandong province, China. PARTICIPANTS: 3365 residents of a high risk region for gastric cancer. 2258 participants seropositive for antibodies to H pylori were randomly assigned to H pylori treatment, vitamin supplementation, garlic supplementation, or their placebos in a 2×2×2 factorial design, and 1107 H pylori seronegative participants were randomly assigned to vitamin supplementation, garlic supplementation, or their placebos in a 2×2 factorial design. INTERVENTIONS: H pylori treatment with amoxicillin and omeprazole for two weeks; vitamin (C, E, and selenium) and garlic (extract and oil) supplementation for 7.3 years (1995-2003). MAIN OUTCOME MEASURES: Primary outcomes were cumulative incidence of gastric cancer identified through scheduled gastroscopies and active clinical follow-up through 2017, and deaths due to gastric cancer ascertained from death certificates and hospital records. Secondary outcomes were associations with other cause specific deaths, including cancers or cardiovascular disease. RESULTS: 151 incident cases of gastric cancer and 94 deaths from gastric cancer were identified during 1995-2017. A protective effect of H pylori treatment on gastric cancer incidence persisted 22 years post-intervention (odds ratio 0.48, 95% confidence interval 0.32 to 0.71). Incidence decreased significantly with vitamin supplementation but not with garlic supplementation (0.64, 0.46 to 0.91 and 0.81, 0.57 to 1.13, respectively). All three interventions showed significant reductions in gastric cancer mortality: fully adjusted hazard ratio for H pylori treatment was 0.62 (95% confidence interval 0.39 to 0.99), for vitamin supplementation was 0.48 (0.31 to 0.75), and for garlic supplementation was 0.66 (0.43 to 1.00). Effects of H pylori treatment on both gastric cancer incidence and mortality and of vitamin supplementation on gastric cancer mortality appeared early, but the effects of vitamin supplementation on gastric cancer incidence and of garlic supplementation only appeared later. No statistically significant associations were found between interventions and other cancers or cardiovascular disease. CONCLUSIONS: H pylori treatment for two weeks and vitamin or garlic supplementation for seven years were associated with a statistically significant reduced risk of death due to gastric cancer for more than 22 years. H pylori treatment and vitamin supplementation were also associated with a statistically significantly reduced incidence of gastric cancer. TRIAL REGISTRATION: ClinicalTrials.gov NCT00339768.

Sex-structured wild and sterile mosquito population models with different release strategies.

In this paper, we propose sex-structured mathematical models in terms of continuous-time differential equations. We investigate the interactive dynamics of the sex-structured wild and sterile mosquitoes from several aspects including the existence of equilibria and their stability. We consider different strategies of releasing the sterile mosquitoes to control mosquitoes in an effective way. In addition, numerical simulations are provided to illustrate the dynamical features of the models.

Whole Genome Messenger RNA Profiling Identifies a Novel Signature to Predict Gastric Cancer Survival.

OBJECTIVES: Molecular prognostic biomarkers for gastric cancer (GC) are still limited. We aimed to identify potential messenger RNAs (mRNAs) associated with GC prognosis and further establish an mRNA signature to predict the survival of GC based on the publicly accessible databases. METHODS: Discovery of potential mRNAs associated with GC survival was undertaken for 441 patients with GC based on the Cancer Genome Atlas (TCGA), with information on clinical characteristics and vital status. Gene ontology functional enrichment analysis and pathway enrichment analysis were conducted to interrogate the possible biological functions. We narrowed down the list of mRNAs for validation study based on a significance level of 1.00 × 10, also integrating the information from the methylation analysis and constructing the protein-protein interaction network for elucidating biological processes. A total of 54 mRNAs were further studied in the validation stage, using the Gene Expression Omnibus (GEO) database (GSE84437, n = 433). The validated mRNAs were used to construct a risk score model predicting the prognosis of GC. RESULTS: A total of 13 mRNAs were significantly associated with survival of GC, after the validation stage, including DCLK1, FLRT2, MCC, PRICKLE1, RIMS1, SLC25A15, SLCO2A1, CDO1, GHR, CD109, SELP, UPK1B, and CD36. Except CD36, DCLK1, and SLCO2A1, other mRNAs are newly reported to be associated with GC survival. The 13 mRNA-based risk score had good performance on distinguishing GC prognosis, with a higher score indicating worse survival in both TCGA and GEO datasets. CONCLUSIONS: We established a 13-mRNA signature to potentially predict the prognosis of patients with GC, which might be useful in clinical practice for informing patient stratification.

The spread of influenza-like-illness within the household in Shanghai, China.

High-density urban habitats provide a hotbed for the rapid spread of infectious diseases. School children densely aggregate in classrooms. So schools are high incidence area of infectious diseases. This paper aims at investigating the transmission of influenza-like-illness within households with a school child using a survey study of fourth grade elementary school students in Shanghai, China. We found that the pairwise transmission probability within a household is only 0.172, which implies that the average number of infections caused by a single infectious individual in a household in Shanghai is only 0.304. Thus, the majority of transmission must occur outside of a household for a disease to cause an outbreak.

Telomere Length of Circulating Cell-Free DNA and Gastric Cancer in a Chinese Population at High-Risk.

Background: Telomeres have long been found to be involved in cancer development, while little was known about the dynamic changes of telomere length in carcinogenesis process. Methods: The present study longitudinally investigated telomere alterations of cell-free DNA (cfDNA) in 86 gastric cancer (GC) subjects recruited through a 16-year prospective cohort with 2-4 serums collected before each GC-diagnosis from baseline and three follow-up time-points (a total of 276 samples). As the control, 86 individual-matched cancer-free subjects were enrolled with 276 serums from the matched calendar year. Results: In the 73 pairs of baseline serums from GC and control subjects, shortened telomeres showed increased subsequent GC risk [odds ratio (OR) = 9.17, 95% CI: 2.72-31.25 for 1 unit shortening]. In each baseline gastric lesion category, higher risks of GC progression were also found with shortened cfDNA telomeres; ORs per 1 unit shortening were 6.99 (95% CI: 1.63-30.30) for mild gastric lesions, 6.06 (95% CI: 1.89-19.61) for intestinal metaplasia and 15.63 (95% CI: 1.91-125.00) for dysplasia. With all measurements from baseline and follow-up time-points, shortened telomeres also showed significant association with GC risk (OR = 7.37, 95% CI: 2.06-26.32 for 1 unit shortening). In temporal trend analysis, shortened telomeres were found in GC subjects compared to corresponding controls more than 3 years ahead of GC-diagnosis (most P < 0.05), while no significant difference was found between two groups within 3 years approaching to GC-diagnosis. Conclusion: Our findings suggest that telomere shortening may be associated with gastric carcinogenesis, which supports further etiological study and potential biomarker for risk stratification.

Methylation and Expression of Nonclustered Protocadherins Encoding Genes and Risk of Precancerous Gastric Lesions in a High-Risk Population.

Nonclustered protocadherins (PCDH) family is a group of cell-cell adhesion molecules. We have found differentially methylated genes in the nonclustered PCDHs family associated with Helicobacter pylori (H. pylori) infection in prior genome-wide methylation analysis. To further investigate the methylation and expression of nonclustered PCDHs encoding genes in H. pylori--related gastric carcinogenesis process, four candidate genes including PCDH7, PCDH10, PCDH17, and PCDH20 were selected, which were reported to be tumor suppressors for digestive cancers. A total of 747 participants with a spectrum of gastric lesions were enrolled from a high-risk population of gastric cancer. Promoter methylation levels of four genes were significantly higher in H. pylori-positive subjects than the negative group (all P < 0.001). Elevated methylation levels of PCDH10 and PCDH17 were observed with the increasing severity of gastric lesions (both P trend < 0.001). In the protein expression analysis, PCDH17 expression was inversely associated with gastric lesions; the OR [95% confidence interval (CI)] was 0.49 (0.26-0.95) for chronic atrophic gastritis (CAG), 0.31 (0.15-0.63) for intestinal metaplasia, and 0.38 (0.19-0.75) for indefinite dysplasia and dysplasia, compared with superficial gastritis. In addition, PCDH10 expression was significantly lower in CAG (OR, 0.40; 95% CI, 0.24-0.68). The inverse association between methylation and protein expression of PCDH10 and PCDH17 was further supported when we explored the methylation and mRNA expression in The Cancer Genome Atlas database (all P < 0.001). Our study found elevated promoter methylation and decreased expression of PCDH10 and PCDH17 in advanced gastric lesions, suggesting that elevated PCDH10 and PCDH17 methylation may be an early event in gastric carcinogenesis. Cancer Prev Res; 11(11); 717-26. ©2018 AACR.

Association Between Gut Microbiota and Helicobacter pylori-Related Gastric Lesions in a High-Risk Population of Gastric Cancer.

Eradication of Helicobacter pylori has been found to be effective for gastric cancer prevention, but uncertainties remain about the possible adverse consequences such as the potential microbial dysbiosis. In our study, we investigated the association between gut microbiota and H. pylori-related gastric lesions in 47 subjects by deep sequencing of microbial 16S ribosomal RNA (rRNA) gene in fecal samples. The dominant phyla in fecal samples were Bacteroidetes, Firmicutes, and Proteobacteria with average relative abundances of 54.77, 31.37 and 12.91%, respectively. Microbial diversity analysis showed that observed species and Shannon index were increased in subjects with past or current H. pylori infection compared with negative subjects. As for the differential bacteria, the average relative abundance of Bacteroidetes was found to significantly decrease from H. pylori negative (66.16%) to past infection group (33.01%, p = 0.007), as well as from normal (76.49%) to gastritis (56.04%) and metaplasia subjects (46.83%, p = 0.027). For Firmicutes and Proteobacteria, the average relative abundances showed elevated trends in the past H. pylori infection group (47.11, 20.53%) compared to negative group (23.44, 9.05%, p = 0.068 and 0.246, respectively), and similar increased trends were also found from normal (18.23, 5.05%) to gastritis (35.31, 7.23%, p = 0.016 and 0.294, respectively) or metaplasia subjects (32.33, 20.07%, both p < 0.05). These findings suggest that the alterations of fecal microbiota, especially the dominant phyla of Bacteroidetes, Firmicutes and Proteobacteria, may be involved in the process of H. pylori-related gastric lesion progression and provide hints for future evaluation of microbial changes after H. pylori eradication.

Cut-off optimization for 13C-urea breath test in a community-based trial by mathematic, histology and serology approach.

The performance of diagnostic tests in intervention trials of Helicobacter pylori (H.pylori) eradication is crucial, since even minor inaccuracies can have major impact. To determine the cut-off point for 13C-urea breath test (13C-UBT) and to assess if it can be further optimized by serologic testing, mathematic modeling, histopathology and serologic validation were applied. A finite mixture model (FMM) was developed in 21,857 subjects, and an independent validation by modified Giemsa staining was conducted in 300 selected subjects. H.pylori status was determined using recomLine H.pylori assay in 2,113 subjects with a borderline 13C-UBT results. The delta over baseline-value (DOB) of 3.8 was an optimal cut-off point by a FMM in modelling dataset, which was further validated as the most appropriate cut-off point by Giemsa staining (sensitivity = 94.53%, specificity = 92.93%). In the borderline population, 1,468 subjects were determined as H.pylori positive by recomLine (69.5%). A significant correlation between the number of positive H.pylori serum responses and DOB value was found (rs = 0.217, P < 0.001). A mathematical approach such as FMM might be an alternative measure in optimizing the cut-off point for 13C-UBT in community-based studies, and a second method to determine H.pylori status for subjects with borderline value of 13C-UBT was necessary and recommended.

Genome-wide DNA methylation profiles altered by Helicobacter pylori in gastric mucosa and blood leukocyte DNA.

PURPOSE: To investigate Helicobacter pylori (H.pylori) associated genome-wide aberrant methylation patterns in gastric mucosa and blood leukocyte DNA, a population-based study was conducted in Linqu County. RESULTS: A total of 3000 and 386 CpGs were differentially methylated after successful H.pylori eradication in gastric mucosa and blood leukocyte DNA respectively, and 17 were the same alteration trend in the both tissues. The differentially methylated CpGs were located more frequently in promoters or CpG islands for gastric mucosa and gene body or open sea for blood leukocyte DNA. In eradicated gastric mucosa, the hypermethylated CpGs were enriched across inflammatory pathways, while the hypomethylated CpGs in tube morphogenesis, development and so on. The final validation found lower SPI1, PRIC285 and S1PR4 methylation levels in H.pylori positive subjects by case-control comparison, and increased methylation levels in H.pylori eradicated gastric mucosa by self-comparison. The Cancer Genome Atlas (TCGA) database analysis suggested that the up-regulation of the three genes by hypomethylation might be associated with gastric carcinogenesis. EXPERIMENTAL DESIGN: Infinium HumanMethylation 450K BeadChip was used to compare methylation profiles prior to and after eradication treatment. The methylation levels of identified candidate differentially methylated genes before and after H.pylori eradication were further validated by two stages (Stage I: self-comparison of 16 subjects before and after anti-H.pylori treatment; Stage II: case-control comparison of 25 H.pylori positive and 25 negative subjects and self-comparison of 50 anti-H.pylori treated subjects). CONCLUSIONS: Novel H.pylori associated aberrant methylated genes were identified across the whole genome both in gastric mucosa and blood leukocyte DNA.

Hypomethylation of repetitive elements in blood leukocyte DNA and risk of gastric lesions in a Chinese population.

BACKGROUND: To explore the association between hypomethylation of repetitive elements (LINE-1, Sat2, and ALU) in blood leukocyte DNA and risks of gastric lesions, and development of gastric cancer (GC), a population-based study was conducted in a high-risk area of GC in China. MATERIALS: Methylation levels were determined by MethyLight in 902 subjects with various gastric lesions from two cohort studies at baseline and 276 subjects with long-term follow-up data. RESULTS: The frequency of LINE-1 or Sat2 hypomethylation was significantly increased in subjects with dysplasia (DYS) compared with superficial gastritis/chronic atrophic gastritis. The odds ratios (ORs) were 2.22 [95% confidence interval (CI): 1.45-3.40] for LINE-1 and 1.58 (95% CI: 1.14-2.21) for Sat2. A dose-response pattern was found for the risk of DYS and LINE-1 hypomethylation (P-trend<0.001). Further stratified analysis indicated that the frequency of LINE-1 or Sat2 hypomethylation was higher in subjects with Helicobacter pylori infection. The ORs were 1.83 (95% CI: 1.12-2.99) for LINE-1 and 1.44 (95% CI: 1.01-2.05) for Sat2. The follow-up data indicated that the risk of progression to GC was increased in intestinal metaplasia (IM) subjects with LINE-1 hypomethylation (OR=2.82; 95% CI: 1.17-6.77) or Sat2 hypomethylation (OR=2.78; 95% CI: 1.15-6.74). The risk of progression to GC was also increased in DYS subjects with Sat2 hypomethylation (OR=5.24; 95% CI: 2.00-13.74). CONCLUSIONS: These findings suggest that hypomethylation of repetitive elements in blood leukocytes is associated with the risks of advanced gastric lesions and development of GC.

Alterations of Cyclooxygenase-2 Methylation Levels Before and After Intervention Trial to Prevent Gastric Cancer in a Chinese Population.

To explore the epigenetic mechanisms underlying the effects of anti-Helicobacter pylori (H. pylori) alone and combined with COX-2 inhibitor (celecoxib), we dynamically evaluated the associations between COX-2 methylation alterations and gastric lesion evolution during the process of interventions. In a total of 809 trial participants COX-2 methylation levels were quantitatively detected before and after treatment. The self-comparison at the same stomach site for each subject showed significant methylation alteration differences among intervention groups (P < 0.001). With placebo group as reference, COX-2 methylation levels were decreased in anti-H. pylori [OR, 3.30; 95% confidence interval (CI), 2.16-5.02], celecoxib (OR, 2.04; 95% CI, 1.36-3.07), and anti-H. pylori followed by celecoxib (OR, 2.10; 95% CI, 1.38-3.17) groups. When stratified by baseline histology, the three active arms significantly decreased COX-2 methylation levels in indefinite dysplasia/dysplasia subjects, and ORs were 3.65 (95% CI, 1.96-6.80) for anti-H. pylori, 2.43 (95% CI 1.34-4.39) for celecoxib, and 2.80 (95% CI, 1.52-5.15) for anti-H. pylori followed by celecoxib, respectively. No additive effect on COX-2 methylation was found for anti-H. pylori followed by celecoxib than two treatments alone. Compared with subjects without methylation reduction, higher opportunity for gastric lesion regression was found in subjects with decreased COX-2 methylation levels, especially for indefinite dysplasia/dysplasia subjects (OR, 1.92; 95% CI, 1.03-3.60). These findings suggest that anti-H. pylori or celecoxib treatment alone could decrease COX-2 methylation levels in gastric mucosa. COX-2 methylation alteration was associated with the regression of indefinite dysplasia/dysplasia, which might serve as a potential biomarker for chemoprevention efficacy. Cancer Prev Res; 9(6); 484-90. ©2016 AACR.