Helicobacter pylori as a prognostic indicator after curative resection of gastric carcinoma: a prospective study

Heterogeneity of T cells regulates tumor immunity mediated by Helicobacter pylori infection in gastric cancer

The impact of Helicobacter pylori (H. pylori) status on gastric cancer survival remains unclear. In this study, we conducted a prognostic analysis of 488 gastric cancer patients and performed single-cell RNA sequencing (scRNA-seq) on 18,717 T cells from six tumor samples with varying H. pylori statuses. Our findings revealed that gastric cancer patients with H. pylori infection had significantly longer survival times compared to those with negative H. pylori status. After unsupervised re-clustering of T cells based on scRNA-seq data, we identified ten CD4+ and twelve CD8+ clusters. Among them, four CD8+ T cell clusters exhibited distinct distributions based on H. pylori infection status. One cluster, marked by CXCL13, showed high levels of IFNG and GZMB in H. pylori-infected patients, while another cluster, which expressed immune suppression related genes like AREG and PTGER2, was predominantly comprised of cells from non-infected patients. High PTGER2 expression was significantly associated with worse prognosis in patients with high CD8 expression. These insights advance our understanding of H. pylori's influence on T cell responses in gastric cancer, aiding in treatment and prognostic strategies.

Effect of Helicobacter pylori infection on survival outcomes of patients undergoing radical gastrectomy after neoadjuvant chemotherapy: a multicenter study in China

BACKGROUND

Neoadjuvant chemotherapy (NAC) has been confirmed to improve the prognosis of patients with advanced gastric cancer (AGC). However, no study has investigated whether Helicobacter pylori (HP) infection affects the postoperative survival of patients who receive NAC.

METHODS

This retrospective cohort study included 307 patients with AGC who underwent laparoscopic radical gastrectomy after NAC at three hospitals in China between January 1, 2016, and April 31, 2020. Cox regression was used to assess prognostic factors for survival. Kaplan-Meier was used for survival analysis.

RESULTS

The HP + and the HP- group included 141 and 166 cases. The 3-year overall survival (OS) and disease-free survival (DFS) of the HP + group were significantly better than the HP- group (3-year OS: 75.9% vs. 60.2%, 3-year DFS: 70.2% vs. 52.3%; All P < 0.001). For the HP + group, ypTNM Stage III (HR, 4.00; 95% CI, 1.11-14.39; P = 0.034), NAC ≥ 4 cycles (HR, 0.43; 95% CI, 0.20-0.90; P = 0.026), and adjuvant chemotherapy (AC) ≥ 4 cycles (HR, 0.20; 95% CI, 0.09-0.48; P < 0.001) are independent prognostic factors for OS. In the cohort of HP + patients who received ≥ 4 cycles of NAC, the prognosis of patients who received ≥ 4 cycles of AC after surgery was better than that of patients who received < 4 cycles of AC (3-year OS: 92.5% vs 71.4%; P = 0.042).

CONCLUSIONS

Following NAC, HP + patients with AGC exhibit better prognosis than that of HP- counterparts. For potentially resectable HP + AGC patients, radical surgery following ≥ 4 cycles of NAC with ≥ 4 cycles of sequential AC might be recommended to improve survival.

The dynamic oral-gastric microbial axis connects oral and gastric health: current evidence and disputes

Emerging evidence indicates that oral microbes are closely related to gastric microbes and gastric lesions, including gastric atrophy, intestinal metaplasia and gastric cancer (GC). Helicobacter pylori is a key pathogen involved in GC. However, the increasing prevalence of H. pylori-negative GC and gastric dysbiosis in GC patients emphasize the potential role of other microbial factors. In this review, we discussed the current evidence about the relationship between the oral-gastric microbial axis and oral and gastric health. Epidemiologic evidence indicates that poor oral hygiene is related to greater GC risk. Multiple oral-associated microbes are enriched in the stomach of GC patients. Once colonizing the stomach, oral-associated microbes Streptococcus anginosus and Prevotella melaninogenica, are involved in gastric inflammation or carcinogenesis. Microbial metabolites such as lactate, nitrite, and acetaldehyde promote malignant transformation. The stomach, as a checkpoint of microbial transmission in the digestive tract, is of great importance since the link between oral microbes and intestinal diseases has been emphasized. Still, new technologies and standardized metrics are necessary to identify potential pathogenetic microbes for GC and the core microbiota, interactions, richness, colonization, location and effect (CIRCLE). In the future, oral microbes could be candidates for noninvasive indicators to predict gastric diseases.

Sex disparity, prediagnosis lifestyle factors, and long-term survival of gastric cancer: a multi-center cohort study from China

BACKGROUND

This multi-center cohort study aimed to investigate whether sex and prediagnosis lifestyle affect the prognosis of gastric cancer.

METHODS

Patients with gastric cancer were from four gastric cancer cohorts of the National Cancer Center of China, The First Hospital of Lanzhou University, Lanzhou University Second Hospital, and Gansu Provincial Cancer Hospital. Prediagnosis lifestyle factors in our study included body mass index (BMI) at diagnosis, usual BMI, weight loss, the history of Helicobacter pylori (Hp) infection, and the status of smoking and drinking.

RESULTS

Four gastric cancer cohorts with 29,779 gastric cancer patients were included. In total patients, female patients had a better prognosis than male patients (HR = 0.938, 95%CI: 0.881-0.999, P = 0.046). For prediagnosis lifestyle factors, BMI at diagnosis, usual BMI and the amount of smoking were statistically associated with the prognosis of gastric cancer patients. Female patients with smoking history had a poorer survival than non-smoking females (HR = 0.782, 95%CI: 0.616-0.993, P = 0.044). Tobacco consumption > 40 cigarettes per day (HR = 1.182, 95%CI: 1.035-1.350, P = 0.013) was independent adverse prognostic factors in male patients. Obesity paradox was observed only in male patients (BMI < 18.5, HR = 1.145, 95%CI: 1.019-1.286, P = 0.023; BMI: 23-27.4, HR = 0.875, 95%CI: 0.824-0.930, P < 0.001; BMI ≥ 27.5, HR = 0.807, 95%CI: 0.735-0.886, P < 0.001).

CONCLUSIONS

Sex and some prediagnosis lifestyle factors, including BMI at diagnosis, usual BMI and the amount of smoking, were associated with the prognosis of gastric cancer.

Anti-Helicobacter pylori Treatment in Patients With Gastric Cancer After Radical Gastrectomy

Importance

Whether anti-Helicobacter pylori treatment can provide survival benefits for patients with gastric cancer who are diagnosed with H pylori infection is an area with limited research.

Objective

To explore the potential survival benefits of anti-H pylori treatment after radical gastrectomy in patients with gastric cancer and presurgical confirmation of H pylori infection.

Design, Setting, and Participants

This retrospective cohort study was conducted using data from patients with gastric cancer treated between January 1, 2010, and December 31, 2018, and followed up for outcome ascertainment until May 19, 2021. Propensity score matching was performed in patients treated with or without anti-H pylori treatment. This study involved a single institute in a comprehensive cancer treatment and research center located in Guangzhou, Guangdong Province, China. The study included patients with gastric or esophagogastric junction adenocarcinoma who underwent curative gastrectomy with D2 lymphadenectomy and tested positive for H pylori infection. Data were analyzed from March to June 2023.

Exposure

Anti-H pylori treatment, which primarily includes triple therapy regimens consisting of amoxicillin, clarithromycin, and omeprazole for 14 days.

Main Outcomes and Measures

Clinical outcomes, including overall survival (OS) and disease-free survival (DFS), were analyzed by Kaplan-Meier method, log-rank test, and Cox proportional hazards regression model. Subgroup analysis based on crucial clinical information was also conducted.

Results

All 1293 patients (median [IQR] age, 59 [50-65] years; 860 [66.5%] male) were divided into 2 groups, with 125 patients in the anti-H pylori treatment group and 1168 patients in the non-anti-H pylori treatment group based on whether they received anti-H pylori treatment during the perioperative period and the follow-up. Survival analysis showed that the 5-year OS rates were 94.1% (95% CI, 89.3%-99.2%) in the anti-H pylori group and 73.8% (95% CI, 70.7%-77.0%) in the non-anti-H pylori group, and the hazard ratio (HR) of these 2 groups was 0.33 (95% CI, 0.18-0.60; P < .001). The survival benefit remained after propensity score matching (HR, 0.50; 95% CI, 0.26-0.99; P = .048). Multivariable analysis for OS and DFS further showed the survival benefit of anti-H pylori treatment, with HRs of 0.38 (95% CI, 0.17-0.87; P = .02) and 0.48 (95% CI, 0.28-0.83; P = .008), respectively. Among patients with TNM stage II/III disease who received adjuvant chemotherapy, anti-H pylori treatment was associated with survival benefits (OS: HR, 0.49; 95% CI, 0.24-0.99; P = .046), whereas among those who did not receive adjuvant chemotherapy, anti-H pylori treatment was not associated with survival benefits (OS: HR, 0.29; 95% CI, 0.04-2.08; P = .22).

Conclusions and Relevance

This cohort study indicates that anti-H pylori treatment may be associated with improved survival in patients with gastric cancer who have H pylori infections. The study reinforces the importance of including H pylori screening and treatment in the surgical treatment of these patients.

Remnant gastritis in gastric cancer patients causes loss of muscle mass 6 months after gastrectomy: a retrospective cohort study of Helicobacter pylori infection

PURPOSE

In this study, we assessed the relationship between remnant gastritis and muscle mass loss and then investigated the potential relationship between Helicobacter pylori (HP) infection and remnant gastritis and muscle loss.

METHODS

We reviewed the medical records of 463 patients who underwent distal gastrectomy between January 2017 and March 2020. Of these patients, 100 with pStage I after laparoscopic surgery were included in this analysis.

RESULTS

A multivariate analysis showed that the total Residue, Gastritis, Bile (RGB) classification score, which indicates the degree of gastritis, was significantly associated with the rate of change (rate of decrease) in the psoas muscle area (PMA) during the first 6 months after surgery (p = 0.014). Propensity score matching was performed according to HP infection, and the rate of change in the PMA and the degree of remnant gastritis in 56 patients were compared. Neither was significantly associated with HP infection.

CONCLUSIONS

Remnant gastritis did contribute to psoas muscle mass loss during the initial 6 months after gastrectomy, and HP infection was not significantly associated with either remnant gastritis or psoas muscle mass loss. Nevertheless, the potential for HP eradication to prevent muscle loss and improve the survival prognosis for gastrectomy patients merits further research.

Cross-talk between Helicobacter pylori and gastric cancer: a scientometric analysis

Background

Helicobacter pylori (HP) is considered a leading risk factor for gastric cancer (GC). The aim of this article is to conduct bibliometric and visual analysis to assess scientific output, identify highly cited papers, summarize current knowledge, and explore recent hotspots and trends in HP/GC research.

Methods

A bibliographic search was conducted on October 24, 2023, to retrieve relevant studies on HP/GC research between 2003 and 2022. The search terms were attached to HP and GC. The main data were from the Web of Science Core Collection (WoSCC). Data visualization was performed using Biblioshiny, VOSviewer, and Microsoft Excel.

Results

In HP/GC research, 1970 papers were retrieved. The total number of papers (Np) in HP/GC was growing from 2003 to 2022. China and Japan were in the leading position and made the most contributions to HP/GC. Vanderbilt University and the US Department of Veterans Affairs had the highest Np. The most productive authors were Peek Jr Richard M. and Piazuelo M Blanca. Helicobacter received the most Np, while Gastroenterology had the most total citations (TC). High-cited publications and keyword clustering were used to identify the current status and trends in HP/GC research, while historical citation analysis provided insight into the evolution of HP/GC research. The hot topics included the effect of HP on gastric tumorigenesis and progression, the pathogenesis of HP-induced GC (HP factors), and the mechanisms by which HP affects GC (host factors). Research in the coming years could focus on topics such as autophagy, gut microbiota, immunotherapy, exosomes, epithelial-mesenchymal transition (EMT), and gamma-glutamyl transpeptidase (GGT).

Conclusion

This study evaluated the global scientific output in HP/GC research and its quantitative characteristics, identified the essential works, and collected information on the current status, main focuses and emerging trends in HP/GC research to provide academics with guidance for future paths.

Potential Gastric Cancer Immunotherapy: Stimulating the Immune System with Helicobacter pylori pIRES2-DsRed-Express-ureF DNA Vaccines

Most gastric cancers (GC) are thought to be caused by Helicobacter pylori (H. pylori) infections. However, there is mounting evidence that GC patients with positive H. pylori status have improved prognoses. The H. pylori-induced cellular immune reaction may inhibit cancer. In this study, BALB/c mice were immunized using recombinant plasmids that encode the ureF gene of H. pylori. Purified functional splenic CD3+ T lymphocytes are used to study the anticancer effects in vitro and in vivo. The immunological state of GC patients with ongoing H. pylori infection is mimicked by the H. pylori DNA vaccines, which cause a change in the reaction from Th1 to Th2. Human GC cells grow more slowly when stimulated CD3+ T lymphocytes are used as adoptive infusions because they reduce GC xenograft development in vivo. The more excellent ratios of infiltrating CD8+/CD4+ T cells, the decreased invasion of regulatory FOXP3+ Treg lymphocytes, and the increased apoptosis brought on by Caspase9/Caspase-3 overexpression and Survivin downregulation may all contribute to the consequences. Our findings suggest that in people with advanced GC, H. pylori pIRES2-DsRed-Express-ureF DNA vaccines may have immunotherapeutic utility.

Prognostic effects of the gastric mucosal microbiota in gastric cancer

Gastric cancer (GC) is one of the most common malignant tumors with a high incidence and mortality. Microbiota play a significant role in human health and disease. We aimed to investigate the prognostic value of the gastric microbiota in different stomach microhabitats. We used our previously published 16S rRNA gene sequence data. We retrospectively enrolled a cohort of 132 patients with GC with complete prognostic information and selected 78 normal tissues, 49 peritumoral tissues, and 112 tumoral tissues for microbiota analysis. Patients with different prognoses showed different gastric microbiota compositions and diversity. The association network of the abundant gastric microbiota was more complicated in patients with poor prognoses. In the peritumoral microhabitat of patients with good prognoses, Helicobacter was significantly increased, whereas Halomonas and Shewanella were significantly decreased relative to that in the peritumoral microhabitat of patients with poor prognoses. PiCRUSt analysis revealed that the peritumoral microbiota had more different Kyoto Encyclopedia of Genes and Genomes pathways than did the tumoral and normal microbiota. This study evaluated the long-term prognostic value of the gastric mucosal microbiota in patients with GC. These findings suggested that the characteristic alterations of the gastric mucosal microbiota may be markers for clinical outcomes in these patients.

Factors affecting survival in operated gastric cancer

In this study, our aim was to determine the possible effects of Helicobacter pylori(HP), chronic atrophic gastritis (CAG), and gastrointestinal metaplasia (GIM) on survival in operated bowel type gastric cancer patients (INT-GC). Among 548 patients, 347(63.3%) were male. The median age was 57 years. Disease-free survival (DFS) and overall survival (OS) were significantly shorter in patients with GIM than those in patients without GIM (log rank, P = 0.003 and log rank P = 0.003, respectively). Multivariate analysis showed that presence of GIM (HR, 2.1) was found to be an independent factor of worse DFS. In our study, stage pIII patients with GIM had significantly shorter DFS and OS than those without GIM (log rank p = 0.008 and log rank p = 0.001, respectively). However, in subgroup analysis of patients with GIM, there was no significant DFS and OS difference between patients with stage pI and pII disease (log rank p = 0.999, log rank p = 0.184 vs. log rank p = 0.409, log rank p = 0.281, respectively).

Anti-Helicobacter pylori antibody status is associated with cancer mortality: A longitudinal analysis from the Japanese DAIKO prospective cohort study

Paradoxically, patients with advanced stomach cancer who are Helicobacter pylori-positive (HP+) have a higher survival rate than those who are HP-. This finding suggests that HP infection has beneficial effects for cancer treatment. The present study examines whether HP+ individuals have a lower likelihood of death from cancer than those who are HP-. Prospective cohort data (n = 4,982 subjects enrolled in the DAIKO study between 2008-2010) were used to assess whether anti-HP antibody status was associated with cancer incidence. The median age in the primary registry was 53 years-old (range 35-69 years-old). Over the 8-year observation period there were 234 (4.7%) cancer cases in the cohort and 88 (1.8%) all-cause deaths. Urine anti-HP antibody data was available for all but one participant (n = 4,981; 99.98%). The number of HP+ and HP- individuals was 1,825 (37%) and 3,156 (63%), respectively. Anti-HP antibody distribution per birth year revealed that earlier birth year was associated with higher HP+ rates. With a birth year-matched cohort (n = 3,376), all-cancer incidence was significantly higher in HP+ individuals than those who were HP- (p = 0.00328), whereas there was no significant difference in the cancer death rate between HP+ and HP- individuals (p = 0.888). Cox regression analysis for prognostic factors revealed that the hazards ratio of HP+ was 1.59-fold (95%CI 1.17-2.26) higher than HP- in all-cancer incidence. Potential systemic effects of HP+ status may contribute to reduced likelihood of death for patients after an initial diagnosis of cancer.

Signaling pathways and therapeutic interventions in gastric cancer

Gastric cancer (GC) ranks fifth in global cancer diagnosis and fourth in cancer-related death. Despite tremendous progress in diagnosis and therapeutic strategies and significant improvements in patient survival, the low malignancy stage is relatively asymptomatic and many GC cases are diagnosed at advanced stages, which leads to unsatisfactory prognosis and high recurrence rates. With the recent advances in genome analysis, biomarkers have been identified that have clinical importance for GC diagnosis, treatment, and prognosis. Modern molecular classifications have uncovered the vital roles that signaling pathways, including EGFR/HER2, p53, PI3K, immune checkpoint pathways, and cell adhesion signaling molecules, play in GC tumorigenesis, progression, metastasis, and therapeutic responsiveness. These biomarkers and molecular classifications open the way for more precise diagnoses and treatments for GC patients. Nevertheless, the relative significance, temporal activation, interaction with GC risk factors, and crosstalk between these signaling pathways in GC are not well understood. Here, we review the regulatory roles of signaling pathways in GC potential biomarkers, and therapeutic targets with an emphasis on recent discoveries. Current therapies, including signaling-based and immunotherapies exploited in the past decade, and the development of treatment for GC, particularly the challenges in developing precision medications, are discussed. These advances provide a direction for the integration of clinical, molecular, and genomic profiles to improve GC diagnosis and treatments.

Role of Chk1 gene in molecular classification and prognosis of gastric cancer using immunohistochemistry and LORD-Q assay

Purpose: The aim of the current study was to assess the prognostic value of the Chk1 gene in the DNA damage response pathway in gastric cancer (GC). Methods: Expression levels of the Chk1 were measured in 220 GC tumor tissues and adjacent healthy/noncancerous tissues using real-time PCR and immunohistochemical staining. Genomic instability in GC patients was measured using the long-run real-time PCR technique for DNA-damage quantification assay and comet assay. Results: Significantly downregulated expression of Chk1 was observed at the mRNA level (p < 0.0001) and protein level (p < 0.0001). Significantly increased frequency of lesions/10 kb and comets was observed in tumor tissues compared with control tissues. Conclusion: The data suggest that downregulated expression of Chk1 and positive Heliobacter pylori infection status may have prognostic significance in GC.

Helicobacter pylori modulated host immunity in gastric cancer patients with S-1 adjuvant chemotherapy

BACKGROUND

Paradoxically, Helicobacter pylori-positive (HP+) advanced gastric cancer patients have a better prognosis than those who are HP-negative (HP-). Immunologic and statistical analyses can be used to verify whether systemic mechanisms modulated by HP are involved in this more favorable outcome.

METHODS

A total of 658 advanced gastric cancer patients who underwent gastrectomy were enrolled. HP infection, mismatch repair, programmed death-ligand 1 (PD-L1), and CD4/CD8 proteins, and microsatellite instability were analyzed. Overall survival (OS) and relapse free survival (RFS) rates were analyzed after stratifying clinicopathological factors. Cox proportional hazards regression analysis was performed to identify independent prognostic factors.

RESULTS

Among 491 cases that were analyzed, 175 (36%) and 316 (64%) cases were HP+ and HP⁻, respectively. Analysis of RFS indicated an interaction of HP status among the subgroups for S-1 dose (Pinteraction=0.0487) and PD-L1 (P = .016). HP+ patients in the PD-L1⁻ group had significantly higher five-year OS and RFS than HP- patients (81% vs. 68%; P = .0011; HR 0.477; 95% CI, 0.303-0.751 and 76% vs. 63% P = .0011; HR 0.508; 95% CI, 0.335-0.771, respectively). The five-year OS and RFS was also significantly higher for HP+ compared to HP- patients in the PD-L1-/S-1-reduced group (86% vs. 46%; P = .0014; HR 0.205; 95% CI, 0.07-0.602 and 83% vs. 34%; P = .001; HR 0.190; 95% CI, 0.072-0.498, respectively). Thus, HP status was identified as one of the most potentially important independent factors to predict prolonged survival.

CONCLUSION

This retrospective study suggests that an HP-modulated host immune system may contribute to prolonged survival in the absence of immune escape mechanisms of gastric cancer.

Positive H. pylori status predicts better prognosis of non-cardiac gastric cancer patients: results from cohort study and meta-analysis

BACKGROUND

Previous researches have associated Helicobacter pylori (H. pylori) with a prognosis of gastric cancer (GC), however, without a concert conclusion. This study aimed to study this issue further by a prospective cohort study and a meta-analysis.

METHODS

Histologically diagnosed gastric cancer (GC) patients were recruited into the primary prospective cohort study between January 2009 to December 2013. All the patients were followed-up periodically to record information on post-surgery therapy and overall survival status. The pre-surgery status of H. pylori was measured by enzyme-linked immunosorbent assay. A meta-analysis was conducted after retrieving related researches in the databases of PubMed and Embase up to April 2020. Pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were summarized to validate the relationship between H. pylori infection and the survival time of GC patients. I² statistics and Q test were used to assess the heterogeneity. Sensitivity analyses were performed using Galbraith's plot, leave-one-out analysis, subgroup analyses and meta-regression to explore the sources of heterogeneity and the stability of the summary results.

RESULTS

A total of 743 GC patients with radical tumorectomy were included prospectively and 516 (69.4%) were positive on H. pylori. H. pylori-positive patients tended to survive longer than -negative ones (HR 0.92, 95%CI: 0.74-1.15), though the tendency was not statistically significant. Cohort studies on the prognosis of GC were retrieved comprehensively by assessing the full-text and 59 published studies, together with the result of our study, were included in the further meta-analysis. The summarized results related the positive status of H. pylori to better overall survival (HR 0.81, 95%CI: 0.72-0.90) and disease-free survival (HR 0.83, 95%CI: 0.67-0.99). Results from subgroup analyses indicated that the pooled magnitude of this association was relatively lower in studies not referring to H. pylori in title and abstract.

CONCLUSIONS

In conclusion, gastric cancer patients with H. pylori have a better prognosis than patients of H. pylori negative. More stringent surveillance strategies may be necessary for patients with H. pylori negative at cancer diagnosis.

Microbiome changes in the gastric mucosa and gastric juice in different histological stages of Helicobacter pylori-negative gastric cancers

BACKGROUND

The gastric microbiota in patients with gastric cancer (GC) has received increasing attention, but the profiling of the gastric microbiome through the histological stages of gastric tumorigenesis remains poorly understood, especially for patients with Helicobacter pylori-negative GC (HPNGC).

AIM

To characterize microbial profiles of gastric mucosa and juice for HPNGC carcinogenesis and identify distinct taxa in precancerous lesions.

METHODS

The 16S rRNA gene analysis was performed on gastric mucosa from 134 Helicobacter pylori-negative cases, including 56 superficial gastritis (SG), 9 atrophic gastritis (AG), 27 intestinal metaplasia (IM), 29 dysplasia (Dys), and 13 GC cases, to investigate differences in gastric microbial diversity and composition across the disease stages. In addition, paired gastric mucosa and juice samples from 18 SG, 18 IM, and 18 Dys samples were analyzed. α-Diversity was measured by Shannon and Chao1 indexes, and β-diversity was calculated using partial least squares discrimination analysis (PLS-DA). Differences in the microbial composition across disease stages in different sample types were assessed using the linear discriminant analysis effect size.

RESULTS

The diversity and composition of the bacterial microbiota in the gastric mucosa changed progressively across stages of gastric carcinogenesis. The diversity of the gastric mucosa microbiota was found to be significantly lower in the IM and Dys groups than in the SG group, and the patients with GC had the lowest bacterial community richness (P < 0.05). Patients with IM and those with Dys had similar gastric mucosa microbiota profiles with Ralstonia and Rhodococcus as the predominant genera. Microbial network analysis showed that there was increasing correlation strength between IM and Dys (|correlation threshold|≥ 0.5, P < 0.05). GC and its precancerous lesions have distinguishable bacterial taxa; our results identified HPNGC-associated bacteria Streptococcaceae and Lactobacillaceae (P < 0.05). Additionally, across precancerous lesion stages from AG to Dys in Helicobacter pylori-negative patients, Burkholderiaceae abundance continuously increased, while Streptococcaceae and Prevotellaceae abundance presented a continuous downward trend. Furthermore, the microbial diversity was higher in gastric juice (P < 0.001) than in the mucosa, while PLS-DA revealed a statistically significant difference between the two groups (ANOSIM, P = 0.001). A significant difference in the microbial structure was identified, with Proteobacteria being more prevalent in the gastric mucosa and Firmicutes being more abundant in gastric juice.

CONCLUSION

Our results provide insights into potential taxonomic biomarkers for HPNGC and its precancerous stages and assist in predicting the prognosis of IM and Dys based on the mucosal microbiota profile.

Relationship of prognostic factors in stomach cancer with Helicobacter pylori: A retrospective study

Background and study aims

The prognostic value of H. pylori, which infects more than half of the human population living in the world and plays a role in gastric cancer pathogenesis, is controversial. Our aim is to investigate the relationship between H. pylori and prognostic factors in gastric cancer.

Patients and methods

The data of 110 patients (38 females and 72 males) that underwent surgeries due to gastric cancer between 2014 and 2017 were retrospectively analyzed. The relationships between survival (disease-free and overall) and factors such as p53, HER2/neu, Ki-67, neutrophil and platelet lymphocyte ratio (NLR / PLR), histopathological and demographic characteristics were examined. In addition, the results of H. pylori positive and negative groups were compared.

Results

Sixty-one (55%) patients were H. pylori negative and 49 (45%) were positive. In multivariate analysis, TNM stage, lymph node capsule invasion and NLR were determined as independent prognostic factors in both disease-free and overall survival. Age>62 and PLR>14.3 were determined as independent predictive factors of poor prognosis in overall survival. In univariate analysis, tumor diameter of >4.3 cm, lymphovascular and perineural invasion, and diffuse p53 expression were determined as predictive factors of poor prognosis in disease-free and overall survival. The effectiveness of these markers in prognosis was not different between H. pylori negative and positive groups.

Conclusion

While age, tumor diameter, TNM stage, lymph node capsule invasion, perineural and lymphovascular invasion, diffuse p53, PLR, and NLR were determined as prognostic factors in gastric cancer, these factors were not affected by the presence of H. pylori.

The Distinct Impact of TAM Infiltration on the Prognosis of Patients With Cardia and Non-Cardia Gastric Cancer and Its Association With H. pylori Infection

BACKGROUND

In stage III gastric cancer (GC), the role of tumor-associated macrophages (TAMs) and Helicobacter pylori (H. pylori) infection impact tumor progression; however, the specific mechanisms remain controversial. We speculated whether this controversy is caused by differences in the location of TAM infiltration (in the core (CT) and invasive margin (MI) of primary tumors) and the topographical subsites of GC (cardia and non-cardia). Therefore, in this study, we investigated TAMs in different locations and H. pylori infection status as prognostic biomarkers for GC.

METHODS

Immunohistochemical staining for CD68 (pan-macrophage), CD163 (M2-like macrophage), and H. pylori in 200 samples (100 cases of cardia-GC [CGC] and 100 cases of non-cardia GC [NCGC]) was performed. We compared the number of CD68+ and CD163+ macrophages that infiltrated the CT and MI in patients with the prognosis of CGC and NCGC, respectively. In addition, we analyzed the relationship between H. pylori status and the prognosis of patients with GC in different locations, as well as the correlation with TAM infiltration.

RESULTS

The distribution of TAMs had distinct characteristics in CGC and NCGC, especially differences between CT and MI subtype. A Kaplan-Meier analysis showed that a high number of CD68+ macrophages that infiltrated the CT in CGC was associated with a better prognosis, whereas infiltration at the MI in NCGC indicated a poor prognosis. Furthermore, a high number of CD163+ macrophages infiltrating the MI resulted in a poor prognosis in CGC and NCGC cohorts. Considering the larger differences in the relationship between the infiltration of CD68+ macrophages at different locations and prognosis, we divided the GC cases into marginal and central GC, based on this difference. This resulted in an accurate estimation of the prognosis. Moreover, positive H. pylori status in central GC was significantly associated with a better prognosis and TAM infiltration.

CONCLUSION

TAMs in different locations and H. pylori status were identified as independent prognostic markers, with an obvious correlation between them. Therefore, it is important to clarify the impact of TAM location on the prognosis of patients with GC, which contributes to the development of potential therapeutic strategies.

Relationship of prognostic factors in stomach cancer with helicobacter pylori: a retrospective study

BACKGROUND AND STUDY AIMS

The prognostic value of H. pylori, which infects more than half of the human population living in the world and plays a role in gastric cancer pathogenesis, is controversial. Our aim is to investigate the relationship between H. pylori and prognostic factors in gastric cancer.

PATIENTS AND METHODS

The data of 110 patients (38 females and 72 males) that underwent surgeries due to gastric cancer between 2014 and 2017 were retrospectively analyzed. The relationships between survival (disease-free and overall) and factors such as p53, HER2/neu, Ki-67, neutrophil and platelet lymphocyte ratio (NLR / PLR), histopathological and demographic characteristics were examined. In addition, the results of H. pylori positive and negative groups were compared.

RESULTS

Sixty-one (55%) patients were H. pylori negative and 49 (45%) were positive. In multivariate analysis, TNM stage, lymph node capsule invasion and NLR were determined as independent prognostic factors in both disease-free and overall survival. Age>62 and PLR>14.3 were determined as independent predictive factors of poor prognosis in overall survival. In univariate analysis, tumor diameter of >4.3 cm, lymphovascular and perineural invasion, and diffuse p53 expression were determined as predictive factors of poor prognosis in disease-free and overall survival. The effectiveness of these markers in prognosis was not different between H. pylori negative and positive groups.

CONCLUSION

While age, tumor diameter, TNM stage, lymph node capsule invasion, perineural and lymphovascular invasion, diffuse p53, PLR, and NLR were determined as prognostic factors in gastric cancer, these factors were not affected by the presence of H. pylori.

Surgery alone, adjuvant tegafur/gimeracil/octeracil (S-1), or platinum-based chemotherapies for resectable gastric cancer: real-world experience and a propensity score matching analysis

Background

Adjuvant chemotherapy has changed the paradigm in resectable gastric cancer. S-1 is an oral chemotherapeutic with promising efficacy in Asia. However, comparisons with close observation or platinum-based doublets post D2 gastrectomy have been less reported, notably on real-world experiences.

Methods

We retrospectively evaluated patients with D2-dissected stage IB-III gastric cancer who received S-1 (S-1, n = 67), platinum-based doublets (P, n = 145) and surgery with close observation (OBS, n = 221) from Jan 2008 to Oct 2018. A propensity score matching was used to compare for recurrence-free (RFS) and overall survivals (OS) in patients who had a locally-advanced disease (T3–4 or lymph node-positive). Adverse reactions, dosage, and associated factors for S-1 are also discussed.

Results

In a median follow-up time of 51.9 months, adjuvant S-1 monotherapy was associated with an intermediate survival as compared with P and OBS (median RFS/OS: S-1 vs. P, 20.9/35.8 vs. 31.2/50.5 months, HR = 1.76/2.14, p = 0.021/0.008; S-1 vs. OBS, 24.4/40.2 vs. 20.7/27.0 months, HR = 0.62/0.55, p = 0.041/0.024). The survival differences were more prominent in patients with N2–3 diseases. S-1 was well-tolerated with a relative dose intensity of 73.6%, a median duration of 8.3 months and associated with less adverse reactions as compared with P. S-1 monotherapy was selected by physicians based on age, lymph node stage, serum carcinoembryonic antigen and disease stage.

Conclusions

Adjuvant S-1 correlated with intermediate survival outcomes between OBS and P but conferred fewer adverse reactions as compared with P. Patients with a moderate risk of recurrence had comparable survivals when treated with S-1 while platinum-based doublets were favored in advanced cases. The study provides additional information about adjuvant S-1 in patients with selected risk of recurrence.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08487-z.

Effect of Helicobacter pylori eradication after subtotal gastrectomy on the survival rate of patients with gastric cancer: follow-up for up to 15 years

OBJECTIVE

Helicobacter pylori (HP) is known to play an important role in the development of gastric cancer (GC). The aim of this study was to analyze the effect of HP eradication on the survival rate and cancer recurrence in patients who underwent subtotal gastrectomy for GC.

DESIGN

Totally 1,031 patients diagnosed with gastric adenocarcinoma who received surgical treatment at the Seoul National University Bundang Hospital from 2003 to 2017 and positive for HP infection were analyzed. The overall and GC-related survival according to HP eradication were compared; risk factors for GC-specific death and cancer recurrence were analyzed, and propensity score matching (PSM) was performed.

RESULTS

Statistically significant benefits of overall and GC-specific survival were observed in the eradicated group compared to the non-eradicated group (P < 0.001), and these benefits were maintained after PSM (P < 0.001) in both of early and advance stage. In Cox proportional hazards multivariate analyses, cancer stage (stage II, adjusted hazard ratio [aHR] = 9.33, P < 0.001; stage III or IV, aHR = 26.17, P < 0.001), and HP positivity (aHR = 3.41, P = 0.001) were independent risk factors for GC-specific death; cancer stage (cancer stage II, aHR = 7.08, P < 0.001; cancer stage III or IV, aHR = 19.64, P < 0.001) and HP positivity (aHR = 2.70; P = 0.005) were independent risk factors for cancer recurrence.

CONCLUSION

Our results suggest that HP needed to be conducted more intensively in patients who are surgically treated for GC, regardless of cancer stage.

Prevalence of Helicobacter pylori Positive Non-cardia Gastric Adenocarcinoma Is Low and Decreasing in a US Population

BACKGROUND

Helicobacter pylori infection is an established causal factor for non-cardia gastric cancer. H. pylori negative gastric cancer prevalence among US patients is unclear.

METHODS

This retrospective cohort study examined H. pylori prevalence among consecutive patients with incident non-cardia gastric adenocarcinoma at the Houston VA Hospital (11/2007-10/2018). H. pylori positivity was defined by H. pylori on histopathology, positive antibody serology, stool antigen, or urea breath testing. We examined for trends in H. pylori negative gastric cancer based on year of diagnosis. Associations between histopathologic and cancer-related outcomes with H. pylori positivity were determined using regression models.

RESULTS

Of 91 patients with gastric adenocarcinoma, most were men (N = 87, 95.6%), black (N = 47, 51.6%), with mean age at diagnosis of 68.0 years (SD 10.8). In addition to gastric cancer biopsy histopathology, 74 patients (81.3%) had ≥ 1 testing for H. pylori, including antibody serology (n = 34), non-cancer gastric biopsy histopathology (n = 63), or stool antigen (n = 1). The overall prevalence of H. pylori infection was 38.5% and 45.9% among patients with ≥ 2 H. pylori tests. The proportions of H. pylori positive gastric cancer decreased from 50.0% (2007-2010) to 43.4% (2011-2014) and 29.3% (2015-2018) (p = 0.096). Active/acute gastritis (adjOR 3.74), atrophic gastritis (adjOR 15.30), and gastric intestinal metaplasia (adjOR 3.65) were associated with H. pylori positive gastric cancer.

DISCUSSION

The prevalence of H. pylori infection among patients with non-cardia gastric adenocarcinoma is relatively low (38.5-45.9%) and decreasing over time. This finding suggests there may be other important causal factors apart from H. pylori for gastric adenocarcinoma.

The Clinicopathological Features and Genetic Alterations in Epstein-Barr Virus-Associated Gastric Cancer Patients after Curative Surgery

Background: Epstein–Barr virus (EBV)-associated gastric cancer (GC) is one of four major gastric cancer types and is traditionally considered to be related to lymphoepithelioma-like GC. Few studies have investigated the clinical significance of EBV infection in intestinal/solid type, diffuse (poorly cohesive) type, and lymphoepithelioma-like GC. Methods: A total of 460 GC patients receiving curative surgery were enrolled. The clinicopathological features, genetic alterations and prognoses were compared between patients with and without EBV infection. Results: EBV-positive GC patients (n = 43) had more tumors located in the upper and middle stomach, more common in lymphoepithelioma-like carcinoma, more lymphoid stroma, fewer Helicobacter pylori infections, and higher programmed death-ligand 1 (PD-L1) expression than EBV-negative GC patients. For intestinal/solid type GC, EBV-positive tumors were more likely to be located in the upper and middle stomach, have more lymphoid stroma, fewer Helicobacter pylori infections, higher PD-L1 expression, and more liver metastases than EBV-negative tumors. For diffuse (poorly cohesive) type GC, EBV-positive tumors were more likely to be located in the upper stomach, and have more lymphoid stroma than EBV-negative tumors. For lymphoepithelioma-like GC, EBV-positive tumors had more PI3K/AKT pathway mutations than EBV-negative tumors. Conclusions: Intestinal/solid type GC patients with EBV-positive tumors were associated with higher PD-L1 expression and more liver metastases, while lymphoepithelioma-like GC patients with EBV-positive tumors had more PI3K/AKT pathway mutations. Immunotherapy and targeted therapy may be beneficial for these groups of patients. Routine EBV survey is recommended in GC.

Prognostic significance of helicobacter pylori-infection in gastric diffuse large B-cell lymphoma

Background

Helicobacter pylori (H. pylori) is thought to have an oncogenic effect on the development of gastric malignancies. However, the effect of H. pylori status on the prognosis of gastric diffuse large B-cell lymphoma (DLBCL) remains unconfirmed. This study aimed to identify the prognostic importance of H. pylori infection in de novo gastric DLBCL.

Methods

One hundred and twenty-nine patients diagnosed with primary de novo gastric DLBCL at the West China Hospital of Sichuan University from 1st January 2009 to 31st May 2016 were included. The clinical features of the patients were documented. H. pylori status was assessed via urease breath tests and histologic examinations. The prognostic value of H. pylori was verified via univariate and multivariate analyses.

Results

Over a median follow-up of 52.2 months (range 4–116), the 5-year overall survival (OS) for all patients was 78.7%. Patients with H. pylori infections had significantly better 5-year PFS and OS than did the H. pylori-negative subgroup (5-year PFS, 89.3% vs. 74.1%, P = 0.040; 5-year OS, 89.7% vs. 71.8%, P = 0.033). Negative H. pylori status and poor ECOG performance were independent negative prognostic indicators for both PFS and OS (PFS, P = 0.045 and P = 0.001, respectively; OS, P = 0.021 and P < 0.001, respectively).

Conclusions

H. pylori status in de novo gastric DLBCL can be a promising predictor of disease outcome, and patients with negative H. pylori status require careful follow-up since they tend to have a worse outlook.

The prognostic role of Helicobacter pylori in gastric cancer patients: A meta-analysis

BACKGROUND

The prognostic value of Helicobacter pylori (H. pylori) infection in gastric cancer patients has been investigated over many years; however, the results remain inconclusive. Thus, we performed a comprehensive review of currently available evidence via a systemic meta-analysis to evaluate the effects of H. pylori infection on the prognosis of gastric cancer patients.

METHODS

Studies that evaluated the prognostic value of H. pylori infection in gastric cancer were extracted in March 2016 by searching PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials. We obtained or calculated hazard ratios (HRs) and the associated 95% confidence intervals (CIs) from the identified studies, and conducted random-effects model analyses of overall survival and progression-free survival. Twenty-four studies with a cumulative sample size of 7191 patients were included in our analysis.

RESULTS

Our meta-analysis revealed that H. pylori infection is an indicator of improved overall survival in gastric cancer patients (HR, 0.79; 95% CI, 0.64-0.99); however, this was only true for European patients. The benefits of H. pylori infection were not detected in Asian gastric cancer patients (HR, 1.01; 95% CI, 0.91-1.12) or those in the United States (HR, 0.88; 95% CI, 0.73-1.05). Subgroup analyses revealed that the prognostic significance of H. pylori infection differed with respect to the year of study publication, number of patients, H. pylori detection method, tumor stage, H. pylori-positive rate, and risk of bias. The prognostic value of H. pylori infection on progression-free survival was unclear (HR, 0.84; 95% CI, 0.70-1.01).

CONCLUSIONS

These data provide limited, moderate-quality evidence that H. pylori infection is an indicator of good prognosis in European gastric cancer patients. However, this is not necessarily true for other populations.

Activation of CD3+ T cells by Helicobacter pylori DNA vaccines in potential immunotherapy of gastric carcinoma

Most of gastric carcinoma (GC) is attributed to infection by Helicobacter pylori (H. pylori) but there is increasing evidence that the positive H. pylori status correlates with better prognosis in GC. The H. pylori-induced cellular immune response may suppress cancer and in this work, recombinant pcDNA3 plasmids encoding various fragments of H. pylori virulence genes of cagA, vacA and babA are constructed and combined into groups to immunize BALB/c mice. The activated splenic CD3⁺ T cells are purified and the anticancer effects are investigated in vitro and in vivo. The H. pylori DNA vaccines induce a shift in the response from Th1 to Th2 that mimicks the immune status in patients of GC with chronic H. pylori infection. The stimulated CD3⁺ T cells inhibit the growth of human GC cells in vitro and adoptive transfusions of the CD3⁺ T cells suppress the growth of GC xenograft in vivo. The effects may be caused by the larger ratios of infiltrated CD8⁺/CD4⁺ T cells, reduced infiltration of regulatory FOXP3⁺ T cells, and enhanced apoptosis induced by upregulation of Caspase-9/Caspase-3 and downregulation of Survivin. Our results reveal the potential immunotherapeutic value of H. pylori vaccine-activated CD3⁺ T cells in those with advanced GC.

Comparison of the Clinicopathological Characteristics and Genetic Alterations Between Patients with Gastric Cancer with or Without Helicobacter pylori Infection

BACKGROUND

Helicobacter pylori (HP) can induce epithelial cells and intestinal metaplasia with genetic damage that makes them highly susceptible to the development of gastric cancer (GC).

MATERIALS AND METHODS

Between 2005 and 2010, 356 patients with gastric cancer who received curative surgery were enrolled. Analysis of HP, Epstein-Barr virus (EBV) infection, PIK3CA amplification, and mutation analysis of 68 mutations in eight genes using a mass spectrometric single-nucleotide polymorphism genotyping technology was conducted. The clinicopathological characteristics of patients with or without HP infection were compared.

RESULTS

Among the 356 patients, 185 (52.0%) had HP infection. For intestinal-type GC, patients with HP infection were more likely to be younger and had fewer PI3K/AKT pathway genetic mutations than those without HP infection. For diffuse-type GC, patients with HP infection were characterized by less male predominance, less lymphoid stroma, fewer microsatellite instability-high tumors, and fewer PI3K/AKT pathway genetic mutations than those without HP infection. Patients with HP infection had less tumor recurrence and a better 5-year overall survival (87.7% vs. 73.9%, p = .012) and disease-free survival (64.1% vs. 51.3%, p = .013) than those without HP infection, especially for intestinal-type GC. For EBV-negative GC, patients with HP infection had fewer PI3K/AKT pathway mutations and a better 5-year overall survival and disease-free survival than those without HP infection. Multivariate analysis demonstrated that HP infection was an independent prognostic factor regarding overall survival and disease-free survival.

CONCLUSION

Patients with GC with HP infection were associated with fewer PI3K/AKT pathway genetic mutations and better survival than those without HP infection, especially for EBV-negative and intestinal-type GC.

IMPLICATIONS FOR PRACTICE

Patients with gastric cancer with Helicobacter pylori (HP) infection had fewer PI3K/AKT pathway genetic mutations, less tumor recurrence, and better survival than those without HP infection, especially for Epstein-Barr virus (EBV)-negative and intestinal-type gastric cancer. HP infection is an independent prognostic factor regarding overall survival and disease-free survival. Future in vivo and in vitro studies of the correlation among HP infection, PI3K/AKT pathway, and EBV infection in gastric cancer are required.

Postoperative Helicobacter pylori Infection as a Prognostic Factor for Gastric Cancer Patients after Curative Resection

Background/Aims

Few studies have evaluated the effect of Helicobacter pylori infection on the prognosis of patients diagnosed with gastric cancer (GC) after curative surgery. We investigated the association between the H. pylori infection status and clinical outcome after surgery.

Methods

We assessed the H. pylori status of 314 patients who underwent curative resection for GC. The H. pylori status was examined using a rapid urease test 2 months after resection. Patients were followed for 10 years after surgery.

Results

An H. pylori infection was observed in 128 of 314 patients. The median follow-up period was 93.5 months. A Kaplan-Meier analysis indicated that patients with H. pylori had a higher cumulative survival rate than those who were negative for H. pylori. Patients with stage II cancer who tested negative for H. pylori were associated with a poor outcome. In a multivariate analysis, H. pylori-negative status was a significant independent prognostic factor for poor overall survival.

Conclusions

Having a negative H. pylori infection status seems to indicate poor prognosis for patients with GC who have undergone curative resection. Further prospective controlled studies are needed to evaluate the mechanism by which H. pylori affects GC patients after curative surgery in Korea.

MicroRNA-143-3p, up-regulated in H. pylori-positive gastric cancer, suppresses tumor growth, migration and invasion by directly targeting AKT2

Our previous studies have suggested a protective role for H. pylori infection in the prognosis of gastric cancer. Based on those findings, we hypothesized that H. pylori-positive and -negative gastric cancers may exhibit different growth patterns and pathobiological behaviors, indicating different mechanisms of cancer progression. By microarray analysis, we studied miRNAs expression profiles in 42 gastric cancer patients, comparing 21 H. pylori-positive and 21 H. pylori-negative groups. Luciferase reporter assay and western blot were used to examine the potential target genes of the interested miRNA. In the present study, 53 miRNAs were significantly differentially expressed in H. pylori-positive and -negative gastric cancer tissues. We investigated the expression and function of one candidate, miR-143-3p, which was the most significantly increased miRNA in H. pylori-positive gastric cancer tissues. We observed that miR-143-3p expression was significantly decreased in gastric cancer tissues and cells, which correlated with late stage and lymph node metastasis. Using gain- and loss-of-function experiments in vitro, we demonstrate that miR-143-3p negatively regulated cell growth, apoptosis, migration and invasion. We further characterized AKT2 as a novel direct target of miR-143-3p. Knockdown of AKT2 expression mimicked the effects of miR-143-3p restoration. In conclusion, our data suggest that miR-143-3p acts as a novel tumor suppressive miRNA by regulating tumor growth, migration and invasion through directly targeting AKT2 gene. Further investigation is warranted to characterize the mechanisms underlying gastric cancer progression and may eventually contribute to its therapy.

Helicobacter pylori infection is associated with favorable outcome in advanced gastric cancer patients treated with S-1 adjuvant chemotherapy

BACKGROUND AND OBJECTIVES

Limited information exists regarding beneficial effects of Helicobacter pylori. To examine the effect in advanced gastric cancer, we compared survival for patients treated with surgery-only or adjuvant chemotherapy on the basis of H. pylori infection status.

METHODS

A cohort of 491 patients who underwent R0 resection for locally advanced gastric cancer between 2000 and 2009 at 12 institutions in northern Japan was included. H. pylori infection status, was assessed from paraffin-embedded formalin-fixed samples. Overall survival (OS) and disease-free survival (DFS) in surgery-only (Surgery) and adjuvant chemotherapy (S-1) groups were analyzed. A propensity score matching was employed to correct for confounding factors by indication.

RESULTS

H. pylori infection was positive in 175 patients and negative in 316 patients. H. pylori-positive patients showed significantly better survival than H. pylori-negative patients in both OS (hazard ratio [HR] 0.593, 95% confidence interval [CI] 0.417-0.843; P = 0.003]) and DFS (HR 0.679, 95%CI 0.492-0.937; P = 0.018). Propensity score matching further confirmed that S-1 was virtually only effective when tumors were H. pylori-positive.

CONCLUSIONS

The favorable outcome of H. pylori-positive patients implies that the host immune system is modulated by H. pylori enhancing the chemotherapeutic efficacy.

Prior gastroscopy and mortality in patients with gastric cancer: a matched retrospective cohort study

BACKGROUND AND AIMS

The role of prior gastroscopy on the outcome of patients with gastric cancer remains unknown. This study determines the association between intervals of prior gastroscopy and mortality in patients with gastric cancer.

METHODS

We identified 20,066 newly diagnosed patients with gastric cancer in the National Health Insurance Database of Taiwan between 2002 and 2007. After we excluded patients who had gastroscopies performed ≤6 months before the diagnosis of cancer, patients were matched into 3 cohorts according to the intervals of prior gastroscopy: 6 months to 2 years (<2 Y cohort), 2 to 5 years (2-5 Y cohort), and none within the previous 5 years (>5 Y cohort). The 3 cohorts were matched for age, curative treatment for gastric cancer, Helicobacter pylori therapy, and propensity scores comprised of sex, comorbidities, and concomitant medication usage. The primary outcome is the hazard ratio (HR) of all-cause mortality.

RESULTS

After matching, we identified 1286, 1286, and 5144 patients for the <2 Y, 2 to 5 Y, and >5 Y cohorts. Compared with the >5 Y cohort, the HR of all-cause mortality for the <2 Y and 2 to 5 Y cohorts was 0.80 (95% confidence interval [CI], 0.72-0.89; P < .001) and 0.83 (95% CI, 0.76-0.91; P < .001), respectively. The HRs of gastric cancer-specific mortality were significantly lower in the <2 Y (0.80; 95% CI, 0.71-0.91; P < .001) and 2 to 5 Y cohorts (0.83; 95% CI, 0.75-0.93; P < .001).

CONCLUSIONS

Patients with gastric cancer who had a gastroscopy performed within 5 years before the cancer diagnosis had significantly lower mortality. Our results may support the role of repeat endoscopic examination or surveillance endoscopy in selected patients.

How to stomach an epigenetic insult: the gastric cancer epigenome

Gastric cancer is a deadly malignancy afflicting close to a million people worldwide. Patient survival is poor and largely due to late diagnosis and suboptimal therapies. Disease heterogeneity is a substantial obstacle, underscoring the need for precision treatment strategies. Studies have identified different subgroups of gastric cancer displaying not just genetic, but also distinct epigenetic hallmarks. Accumulating evidence suggests that epigenetic abnormalities in gastric cancer are not mere bystander events, but rather promote carcinogenesis through active mechanisms. Epigenetic aberrations, induced by pathogens such as Helicobacter pylori, are an early component of gastric carcinogenesis, probably preceding genetic abnormalities. This Review summarizes our current understanding of the gastric cancer epigenome, highlighting key advances in recent years in both tumours and pre-malignant lesions, made possible through targeted and genome-wide technologies. We focus on studies related to DNA methylation and histone modifications, linking these findings to potential therapeutic opportunities. Lessons learned from the gastric cancer epigenome might also prove relevant for other gastrointestinal cancers.

Positive Helicobacter pylori status is associated with better overall survival for gastric cancer patients: evidence from case-cohort studies

Helicobacter pylori (H. pylori) infection increases the gastric cancer risk; however, the influences of H. pylori infection status on the outcomes for gastric cancer patients have not yet clearly defined. Herein, we systematically assessed the epidemiological studies regarding the associations between the H.pylori infection status at diagnosis and the prognosis for gastric cancer patients with the meta-analysis methods. Thirty-three eligibility studies with 8,199 participants that had determined the H.pylori infection status and the outcomes for gastric cancer patients were identified through searching the PubMed and MEDLINE databases updated to March 1^st, 2017. The random-effects model suggested that positive H. pylori infection was associated with better overall survival with the pooled hazard ratio (HR) was 0.79 [95% confidence interval (CI) = 0.66-0.93; Q = 134.86, df = 32, P-heterogeneity < 0.001; I² = 76.3%] compared to negative patients. The association was found to be more prominent in studies with higher quality, longer following-up time and more sensitive detection methods. An inverse but not statistically significant association between the H.pylori status and the disease-free survival of the patients (pooled HR = 0.84, 95% CI = 0.61-1.05;Q = 30.48, df = 11, P-heterogeneity = 0.001; I² = 63.9%) was found, while no significant association was noticed in any subgroup analyses. These results suggested that gastric cancer patients with positive H.pylori infection status at diagnosis have better overall survival compared to negative; however, more studies are warranted to confirm the results and elucidate the underlying mechanisms.

Effect of Helicobacter pylori infection on outcomes in resected gastric and gastroesophageal junction cancer

BACKGROUND

Helicobacter pylori (H pylori) infection is a known risk factor for gastric cancer (GC) and has been linked with gastroesophageal junction (GEJ) cancer. Studies examining the relationship between H. pylori infection, GC characteristics and prognosis are limited and have yielded conflicting results. We report on the clinicopathologic characteristics and oncologic outcomes of gastric and GEJ cancer patients with and without a history of H. pylori treated at our institution.

METHODS

We retrospectively reviewed the medical records of patients over the age of 18 years who underwent curative resection for GEJ and GC at Mount Sinai Hospital between 2007 and 2012 who had histopathologic documentation of the presence or absence of H pylori infection. Demographic, clinical, pathologic, treatment characteristics and outcomes including recurrence-free survival (RFS) and overall survival (OS) were compared.

RESULTS

Ninety-five patients were identified. The majority of patients were male (61%), white (36%) or Asian (34%), with median age at diagnosis 64. Tumors were stage I (51%), stage II (23%), stage III (25%), and stage IV (1%). H pylori infection status was documented at the time of cancer diagnosis in 89 (94%) patients, and following cancer diagnosis and treatment in 6 (6%) patients. Younger age at diagnosis, Asian race and Lauren histologic classification were associated with H Pylori infection. H pylori positive patients exhibited higher 5-year OS and 5-year RFS compared to H pylori negative patients, though the difference was not statistically significant in either univariate or multivariate analyses.

CONCLUSIONS

In this retrospective series of predominantly early stage GC and GEJ cancers, H. pylori positive patients were significantly younger at cancer diagnosis and were more frequently Asian compared to H. pylori negative patients. Other demographic and histologic classifications except for Lauren histologic classification were similar between the two groups. H pylori positive patients appeared to have improved outcomes compared to H. pylori negative patients.

Polymorphisms of cancer stem cell marker gene CD133 are associated with susceptibility and prognosis of gastric cancer

AIM

This study was aimed to investigate the associations between single nucleotide polymorphisms of cancer stem cell marker genes, CD44 and CD133, and susceptibility and prognosis of gastric cancer.

PATIENTS & METHODS

Five single nucleotide polymorphisms in CD44 and CD133 genes were genotyped in 898 gastric cancer cases and 992 controls.

RESULTS

The A/C or C/C genotypes of CD133 rs2240688 were associated with decreased risk of gastric cancer comparing with the A/A genotype (odds ratio: 0.81; 95% CI: 0.67-0.97; p = 0.023). The T allele of CD133 rs3130 predicted a worse survival for gastric cancer patients receiving tumorectomy (hazard ratio: 1.28; 95% CI: 1.04-1.58; p = 0.020), independent from tumor node metastasis stage, vessel invasion and postoperational chemotherapy.

CONCLUSION

 CD133 polymorphisms are promising biomarkers for genetic susceptibility and prognosis prediction of gastric cancer.

Distinct Clinicopathological Features and Prognosis of Helicobacter pylori Negative Gastric Cancer

BACKGROUND

Whether the characteristics and prognosis of gastric cancer (GC) are different in patients with and without Helicobacter pylori (HP) remains controversial. The definitions of HP status in patients with atrophic gastritis but negative tests for HP are heterogeneous. We aimed to assess the impact of HP on the prognosis of GC using different definitions.

METHODS

From 1998 Nov to 2011 Jul, five hundred and sixty-seven consecutive patients with GC were included. HP status was determined by serology and histology. Patients with any positive test were defined as HP infection. Patients without HP infection whose serum pepsinogen (PG) I <70 ng/dl and PG I/II ratio < 3.0 were defined as atrophic gastritis and they were categorized into model 1: HP positive; model 2: HP negative; and model 3: exclusion of these patients.

RESULTS

We found four characteristics of HP negative GC in comparison to HP positive GC: (1) higher proportion of the proximal tumor location (24.0%, P = 0.004), (2) more diffuse histologic type (56.1%, p = 0.008), (3) younger disease onset (58.02 years, p = 0.008) and (4) more stage IV disease (40.6%, p = 0.03). Patients with negative HP had worse overall survival (24.0% vs. 35.8%, p = 0.035). In Cox regression models, the negative HP status is an independent poor prognostic factor (HR: 1.34, CI:1.04-1.71, p = 0.019) in model 1, especially in stage I, II and III patients (HR: 1.62; CI:1.05-2.51,p = 0.026).

CONCLUSION

We found the distinct characteristics of HP negative GC. The prognosis of HP negative GC was poor.

Comprehensive profiling of virus microRNAs of Epstein-Barr virus-associated gastric carcinoma: highlighting the interactions of ebv-Bart9 and host tumor cells

BACKGROUND AND AIM

Epstein-Barr virus (EBV) is suggested to actively utilize its ebv-microRNAs (miRNAs) to manipulate viral and cellular functions during neoplasia transformation. A systemic profiling of ebv-miRNAs expressed in EBV-associated gastric carcinoma (EBVa GC) helps understand its epigenetic regulation of carcinogenesis.

METHODS

A total of 1039 patients with gastric cancer were screened for EBVa GC using EBV-encoded RNAs in situ hybridization. A comprehensive profiling of ebv-miRNAs expressed in EBVa GC was constructed using stem-loop quantitative polymerase chain reaction. Functional assay of specific ebv-miRNA was conducted. Expression of epithelial-to-mesenchymal transition (EMT) markers among EBVa GC and non-EBVa GC was compared.

RESULTS

The prevalence of EBVa GC was 5.0% (52 out of 1039) in our series. The most abundant ebv-miRNAs of EBVa GC were Bart4, followed by Bart11, Bart2, Bart6, Bart9, and Bart18, in the decreasing order. Of them, Bart9 exhibited the same seed sequence as to hsa miR-200a and miR-141. Expression of E-cadherin of EBV-positive SNU-719 was increased after BART9 knockdown. Depleting endogenous Bart9 of SNU-719 induced a surged expression of miR-200a and miR-141, accompanied by decreased proliferative and invasive ability. Expression of mesenchymal markers in EBVa GC was increased compared with those of non-EBVa GC, albeit the two cohorts exhibited a comparable long-term survival.

CONCLUSIONS

We constructed a comprehensive profiling of ebv-miRNAs in EBVa GC. BART9 plays an important role during carcinogenesis through EMT. Inherent mesenchymal phenotype of EBVa GC represents a unique virus-induced morphology and microenvironment rather than being able to predict the prognosis.

Comparison between Resectable Helicobacter pylori-Negative and -Positive Gastric Cancers

BACKGROUND/AIMS

Controversy exists regarding the characteristics of Helicobacter pylori infection-negative gastric cancer (HPIN-GC). The aim of this study was to evaluate clinicopathologic features of HPIN-GC compared to H. pylori infection-positive gastric cancer (HPIP-GC) using a comprehensive analysis that included genetic and environmental factors.

METHODS

H. pylori infection status of 705 resectable gastric cancer patients was determined by the rapid urease test, testing for anti-H. pylori antibodies, histologic analysis and culture of gastric cancer tissue samples, and history of H. pylori eradication. HPIN-GC was defined as gastric cancer that was negative for H. pylori infection based on all five methods and that had no evidence of atrophy in histology or serology.

RESULTS

The prevalence of HPIN-GC was 4% (28/705). No significant differences with respect to age, sex, smoking, drinking, family history of gastric cancer or obesity were observed between the two groups. HPIN-GC tumors were marginally more likely to involve the cardia (14.3% for HPIN-GC vs 5.3% for HPIP-GC, p=0.068). The Lauren classification, histology, and TNM stage did not differ according to H. pylori infection status. Microsatellite instability was not different between the two groups, but p53 overexpression in HPIN-GC was marginally higher than in HPIP-GC (56.0% for HPIN-GC vs 37.0% for HPIP-GC, p=0.055).

CONCLUSIONS

The prevalence of HPIN-GC was extremely low, and its clinicopathologic characteristics were similar to HPIP-GC.

Short-Term Outcomes of Endoscopic Submucosal Dissection in Patients with Early Gastric Cancer: A Prospective Multicenter Cohort Study

BACKGROUND/AIMS

Endoscopic submucosal dissection (ESD) is an effective treatment for early gastric cancer (EGC) that has demonstrated a minimal risk of lymph node metastasis in retrospective studies. We sought to prospectively evaluate the short-term outcomes of ESD treatment in EGCs.

METHODS

A prospective multicenter cohort study of neoplasms 3 cm or less in diameter at endoscopic size evaluation was performed in 12 Korean ESD study grouprelated university hospitals and the National Cancer Center. Resected specimens were evaluated by the central pathologic review board.

RESULTS

A patient cohort (n=712) with a total of 737 EGCs was analyzed. The margin-free en bloc resection rate was 97.3%, and curative resection of 640 lesions (86.8%) was achieved. Lower curative resection rates were associated with lesions 2 to 3 cm in size prior to ESD compared with lesions 2 cm or less in size (78.6% vs 88.1%, respectively, p=0.009). Significant factors associated with noncurative resection were moderately or poorly differentiated histological type, posterior wall tumor location, tumor size larger than 3 cm, ulceration, and submucosal invasion. Delayed bleeding occurred in 49 patients (6.9%), and 12 patients (1.7%) exhibited perforations.

CONCLUSIONS

ESD is an effective treatment with a high curative resection rate for EGCs that meets relatively conservative pre-ESD indications. Long-term survival outcomes should be evaluated in followup studies.

Inflammatory microenvironment contributes to epithelial-mesenchymal transition in gastric cancer

Gastric cancer (GC) is the fifth most common malignancy in the world. The major cause of GC is chronic infection with Helicobacter pylori (H. pylori). Infection with H. pylori leads to an active inflammatory microenvironment that is maintained by immune cells such as T cells, macrophages, natural killer cells, among other cells. Immune cell dysfunction allows the initiation and accumulation of mutations in GC cells, inducing aberrant proliferation and protection from apoptosis. Meanwhile, immune cells can secrete certain signals, including cytokines, and chemokines, to alter intracellular signaling pathways in GC cells. Thus, GC cells obtain the ability to metastasize to lymph nodes by undergoing the epithelial-mesenchymal transition (EMT), whereby epithelial cells lose their epithelial attributes and acquire a mesenchymal cell phenotype. Metastasis is a leading cause of death for GC patients, and the involved mechanisms are still under investigation. In this review, we summarize the current research on how the inflammatory environment affects GC initiation and metastasis via EMT.

Gastric Carcinomas in Young (Younger than 40 Years) Chinese Patients: Clinicopathology, Family History, and Postresection Survival

Little is known about clinicopathological characteristics of gastric carcinoma (GC) in young (≤40 years) Chinese patients. We aimed in this study to analyze those features along with family history and prognostic factors after resection. We retrospectively reviewed all 4671 GC resections (surgical and endoscopic) performed at our center from 2004 to 2014 and identified 152 (3.2%) consecutive young patients. Patient demographics, clinical results, family history, and endoscopic-pathological findings were analyzed along with the older (>41 years) GC controls recruited in the same study period. Clinicopathological factors related to postresection outcomes were assessed statistically. The trend of GC resections in young patients was not changed over the study period. Compared to old GCs, the young GC cohort was predominant in women, positive family history, middle gastric location, the diffuse histology type, shorter duration of symptoms, and advanced stage (pIII+pIV, 53.3%). Radical resection was carried out in 90.1% (n = 137) with a better 5-year survival rate (70.3%) than palliative surgery (0%, n = 15). There was no significant difference in clinicopathological characteristics between familial GC (FGC, n = 38) and sporadic GC (SGC, n = 114) groups. Very young patients (≤ 30 years, n = 38) showed lower Helicobacter pylori (Hp) infection and significantly higher perineural invasion rates, compared to older (31-40 years) patients. Hp infection was more commonly seen in the Lauren's intestinal type and early pT stages (T1+T2). Independent prognostic factors for worse outcomes included higher serum CA 72-4, CA 125 levels, positive resection margin, and stage pIII-pIV tumors. The 5-year survival rate was significantly higher in patients with radical resection than those without. GCs in young Chinese patients were prevalent in women with advanced stages but showed no significant differences in clinicopathology between FGC and SGC groups. High serum CA 72-4 and CA 125 levels may help identify patients with worse outcomes. Radical resection improved postresection survival.

Effect of Helicobacter pylori Eradication on Long-Term Survival after Distal Gastrectomy for Gastric Cancer

Purpose

Negative Helicobacter pylori status has been identified as a poor prognostic factor for survival in gastric cancer (GC) patients who underwent surgery. The aim of this study was to examine the effect of H. pylori eradication on long-term outcomes after distal gastrectomy for GC.

Materials and Methods

We analyzed the survival of 169 distal GC patients enrolled in a prospective randomized trial evaluating histologic changes of gastric mucosa after H. pylori eradication in the remnant stomach. The outcomes measured were overall survival (OS) and GC recurrence rates.

Results

The median follow-up duration was 9.4 years. In the modified intention-to-treat analysis including patients who underwent H. pylori treatment (n=87) or placebo (n=82), 5-year OS rates were 98.9% in the treatment group and 91.5% in the placebo group, and Kaplan-Meier analysis showed no significant difference in OS (p=0.957) between groups. In multivariate analysis, no difference in overall mortality was observed between groups (adjusted hazard ratio [aHR] for H. pylori treatment, 0.75; p=0.495) or H. pylori-eradicated status (aHR for positive H. pylori status, 1.16; p=0.715), while old age, male sex, and advanced stage ≥ IIIa were independent risk factors. Six patients in the treatment group (6.9%) and seven patients in the placebo group (8.5%) had GC recurrences, and GC recurrence rates were not different according to H. pylori treatment (5-year GC recurrence rates, 4.6% in the treatment group vs. 8.5% in the placebo group; p=0.652).

Conclusion

H. pylori eradication for GC patients who underwent distal gastrectomy did not compromise long-term survival after surgery.

Preoperative Helicobacter pylori Infection is Associated with Increased Survival After Resection of Gastric Adenocarcinoma

BACKGROUND

Limited data exist on the prognosis of preoperative Helicobacter pylori (H. pylori) infection in gastric adenocarcinoma (GAC).

METHODS

Patients who underwent curative-intent resection for GAC from 2000 to 2012 at seven academic institutions comprising the United States Gastric Cancer Collaborative were included in the study. The primary end points of the study were overall survival (OS), recurrence-free survival (RFS), and disease-specific survival (DSS).

RESULTS

Of 559 patients, 104 (18.6 %) who tested positive for H. pylori were younger (62.1 vs 65.1 years; p = 0.041), had a higher frequency of distal tumors (82.7 vs 71.9 %; p = 0.033), and had higher rates of adjuvant radiation therapy (47.0 vs 34.9 %; p = 0.032). There were no differences in American Society of Anesthesiology (ASA) class, margin status, grade, perineural invasion, lymphovascular invasion, nodal metastases, or tumor-node-metastasis (TNM) stage. H. pylori positivity was associated with longer OS (84.3 vs 44.2 months; p = 0.008) for all patients. This relationship with OS persisted in the multivariable analysis (HR 0.54; 95 % CI 0.30-0.99; p = 0.046). H. pylori was not associated with RFS or DSS in all patients. In the stage 3 patients, H. pylori was associated with longer OS (44.5 vs 24.7 months; p = 0.018), a trend of longer RFS (31.4 vs 21.6 months; p = 0.232), and longer DSS (44.8 vs 27.2 months; p = 0.034).

CONCLUSIONS

Patients with and without preoperative H. pylori infection had few differences in adverse pathologic features at the time of gastric adenocarcinoma resection. Despite similar disease presentations, preoperative H. pylori infection was independently associated with improved OS. Further studies examining the interaction between H. pylori and tumor immunology and genetics are merited.

The Effect of Helicobacter pylori on Gastric Cancer Treated with Adjuvant Chemotherapy After Curative Resection

Helicobacter pylori has been associated with diverse pathologies of varying severity. We investigated the H. pylori infection status and its association with the pathologic features and clinical outcomes in stage III gastric cancer patients treated with adjuvant therapy after curative resection. Between 2004 and 2009, the records of 76 consecutive patients were retrospectively reviewed. H. pylori infection was confirmed by examination of pathological specimen. The relationship between H. pylori and the clinicopathological features was analyzed by Fisher exact test, Student's t test, and Kaplan-Meier method. Of the 76 patients, 16 patients (21.1 %) were confirmed for H. pylori infection. The median age was 59 years. Twenty-three patients received chemotherapy and remainder received chemoradiotherapy. H. pylori status did not correlate with the clinicopathologic features. It was greater in non-neoplastic tissue than the tumor tissue (21.1 vs 7.9 %). Median follow-up was 21 months. During this period, 88.2 % patients had experienced tumor recurrence, and 85.5 % patients had died. Recurrence was observed in 87.5 % patients and in 88.3 % patients in H. pylori-positive and H. pylori-negative patients, respectively (P = 0.92). Disease-free survival was 28.4 ± 7.9 months and overall survival was 31.5 ± 7.4 months in H. pylori-positive patients compared with 28.3 ± 3.7 and 33.2 ± 3.4 months, respectively, in H. pylori-negative patients. H. pylori infection status did not have effect on the overall or disease-free survival (p = 0.85 and P = 0.86), respectively. H. pylori status might not be useful as a prognostic and predictive factor for clinical outcomes.

[Characterization, influence and manipulation of the gastrointestinal microbiota in health and disease]

The gastrointestinal tract harbors trillions of microorganisms that are indispensable for health. The gastrointestinal microbiota can be studied using culture and molecular methods. The applications of massive sequencing are constantly increasing, due to their high yield, increasingly accessible costs, and the availability of free software for data analysis. The present article provides a detailed review of a large number of studies on the gastrointestinal microbiota and its influence on human health; particular emphasis is placed on the evidence suggesting a relationship between the gastrointestinal microbial ecosystem and diverse physiological and immune/inflammatory processes. Discussion of the articles analyzed combines a medical approach and current concepts of microbial molecular ecology. The present revision aims to be useful to those interested in the gastrointestinal microbiota and its possible alteration to maintain, re-establish and enhance health in the human host.

Helicobacter pylori and Molecular Markers as Prognostic Indicators for Gastric Cancer in Korea

Background:

The prognosis of H. pylori infection-negative gastric cancer (HPIN-GC) has been rarely investigated. Applying a strict definition of H. pylori status, the prognosis and molecular prognostic markers in HPIN-GC were evaluated.

Methods:

A combination of multiple methods was carried out to strictly evaluate H. pylori infection in gastric cancer (GC) patients between June 2003 and October 2012 at Seoul National University Bundang Hospital. H. pylori infection was defined as negative if histology, a rapid urease test, culturing, serology and history of H. pylori eradication were all negative. Patients with severe gastric atrophy by the serum pepsinogen test or histology were assumed to have had a previous H. pylori infection. Epstein-Barr virus (EBV) in situ hybridization, PCR-based microsatellite instability (MSI) testing, and p53 immunohistochemistry were performed.

Results:

Compared to 509 H. pylori infection-positive gastric cancer (HPIN-PC) patients, 24 HPIN-GC patients showed a significantly higher frequency of cardia location (P=0.013), and the depth of invasion in HPIN-GC was more advanced, although there was no statistical significance (pT3-pT4, 37.5% for HPIN-GC vs. 28.5% for HPIP-GC, P=0.341). In multivariate analysis, depth of invasion and lymph node metastasis were identified as the most important prognostic factors for relapse-free survival and overall survival (P<0.001). However, the status of H. pylori infection was not an independent prognostic factor for relapse-free survival and overall survival. The positivity of EBV in both groups was low, and the survivals according to MSI and p53 status in HPIN-GC patients were not significantly different.

Conclusions:

The status of H. pylori infection was not a prognostic factor for survival in GC patients when applying the strict definition of H. pylori infection. The prognostic implication of MSI and p53 on survival in HPIN-GC patients was not clear.

Helicobacter pylori infection, gastrin and cyclooxygenase-2 in gastric carcinogenesis

Gastric cancer is one of the most frequent neoplasms and a main cause of death worldwide, especially in China and Japan. Numerous epidemiological, animal and experimental studies support a positive association between chronic Helicobacter pylori (H. pylori) infection and the development of gastric cancer. However, the exact mechanism whereby H. pylori causes gastric carcinogenesis remains unclear. It has been demonstrated that expression of cyclooxygenase-2 (COX-2) is elevated in gastric carcinomas and in their precursor lesions. In this review, we present the latest clinical and experimental evidence showing the role of gastrin and COX-2 in H. pylori-infected patients and their possible association with gastric cancer risk.

Characteristics of gastric cancer according to Helicobacter pylori infection status

BACKGROUND AND AIMS

The definition and incidence of gastric cancer (GC) without Helicobacter pylori (Hp) infection varies between studies. The aim of our study was to compare the characteristics of GC according to Hp infection status.

METHODS

We evaluated the presence of Hp infection in 1833 GC patients with rapid urease tests, serology examinations, and histological evaluations. GC was classified as GC with current Hp infection (HpC-GC), GC with past Hp infection (HpP-GC), and GC not associated with Hp infection (HpN-GC). HpP-GC was defined as GC without current infection but with a positive serology test, glandular atrophy, and/or intestinal metaplasia. HpN-GC was defined as GC with negative Hp test results and no histological changes.

RESULTS

The numbers of HpC-GC, HpP-GC, and HpN-GC were 1378 (75.2%), 412 (22.5%), and 43 (2.3%), respectively. Among GCs without current infection, 90.5% (412/455) were associated with HpP-GC. HpP-GCs were more common in older and male patients, had an increased incidence of synchronous cancer, and less frequently had a diffuse-type histology than HpC-GCs. HpN-GCs were more common in younger, female patients; had a higher proportion of diffuse-type cancers; and more frequently showed distant metastasis than HpP-GCs. In the 40s, the proportion of HpP-GCs with diffuse-type histology (41.9%) was lower than that of HpC-GCs (60.3%) (P = 0.016). The difference was also significant in the 50s (29.1% vs 40.1%, respectively, P = 0.004).

CONCLUSIONS

Most GCs in Korea without current Hp infection showed evidence of past Hp infection. The proportion of GCs with diffuse-type histology decreased in patients with past infection.