Progression of atrophic gastritis and intestinal metaplasia drives Helicobacter pylori out of the gastric mucosa

Characterization of cytotoxic Citrobacter braakii isolated from human stomach

Citrobacter braakii (C. braakii) is an anaerobic, gram-negative bacterium that has been isolated from the environment, food, and humans. Infection by C. braakii has been associated with acute mucosal inflammation in the intestine, respiratory tract, and urinary tract. However, the pathogenesis of C. braakii in the gastric mucosa has not yet been clarified. In this study, the bacterium was detected in 35.5% (61/172) of patients with chronic gastritis (CG) and was closely associated with the severity of mucosal inflammation. Citrobacter braakii P1 isolated from a patient with CG exhibited urease activity and acid resistance. It contained multiple secretion systems, including a complete type I secretion system (T1SS), T5aSS and T6SS. We then predicted the potential pilus-related adhesins. Citrobacter braakii P1 diffusely adhered to AGS cells and significantly increased lactate dehydrogenase (LDH) release; the adhesion rate and LDH release were much lower in HEp-2 cells. Strain P1 also induced markedly increased mRNA and protein expression of IL-8 and TNF-α in AGS cells, and the fold increase was much higher than that in HEp-2 cells. Our results demonstrate proinflammatory and cytotoxic role of C. braakii in gastric epithelial cells, indicating the bacterium is potentially involved in inducing gastric mucosa inflammation.

Fusobacterium & Co. at the Stem of Cancer: Microbe-Cancer Stem Cell Interactions in Colorectal Carcinogenesis

Adult stem cells lie at the crossroads of tissue repair, inflammation, and malignancy. Intestinal microbiota and microbe-host interactions are pivotal to maintaining gut homeostasis and response to injury, and participate in colorectal carcinogenesis. Yet, limited knowledge is available on whether and how bacteria directly crosstalk with intestinal stem cells (ISC), particularly cancerous stem-like cells (CR-CSC), as engines for colorectal cancer initiation, maintenance, and metastatic dissemination. Among several bacterial species alleged to initiate or promote colorectal cancer (CRC), the pathobiont Fusobacterium Nucleatum has recently drawn significant attention for its epidemiologic association and mechanistic linkage with the disease. We will therefore focus on current evidence for an F. nucleatum-CRCSC axis in tumor development, highlighting the commonalities and differences between F. nucleatum-associated colorectal carcinogenesis and gastric cancer driven by Helicobacter Pylori. We will explore the diverse facets of the bacteria-CSC interaction, analyzing the signals and pathways whereby bacteria either confer "stemness" properties to tumor cells or primarily target stem-like elements within the heterogeneous tumor cell populations. We will also discuss the extent to which CR-CSC cells are competent for innate immune responses and participate in establishing a tumor-promoting microenvironment. Finally, by capitalizing on the expanding knowledge of how the microbiota and ISC crosstalk in intestinal homeostasis and response to injury, we will speculate on the possibility that CRC arises as an aberrant repair response promoted by pathogenic bacteria upon direct stimulation of intestinal stem cells.

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.

Role of Helicobacter pylori in the triggering and evolution of hemorrhagic gastro-duodenal lesions

The majority of studies concerning Helicobacter pylori (H. pylori) are oriented towards the implication of infection with H. pylori in processes that end in the formation of neoplasia, without assessing the impact of the bacterium in triggering acute gastroduodenal hemorrhagic episodes. The present study includes 166 patients with upper digestive hemorrhage, admitted to the ATI Clinic, the Gastroenterology Clinic or to the Surgery II Clinic of the County Emergency Clinical Hospital in Craiova, Romania between 2017 and 2019. All patients were monitored for evolution and received treatment according to current guidelines, and hemorrhagic lesions were biopsied. In the study group, 56.8% of the patients with upper gastrointestinal bleeding (UGIB) were positive for H. pylori and 43.2% were negative. In patients less than 50 years of age, non-steroidal anti-inflammatory drug (NSAID) use and H. pylori infection had a cumulative effect in causing bleeding lesions, but in patients older than 50 years of age, the use of NSAIDs was replaced by therapies with oral antiplatelet or anticoagulant agents. The need for hemostasis surgery was more common in patients who exhibited H. pylori-positive UGIB compared to H. pylori-negative (16 vs. 9.7%). In patients with H. pylori-positive hemorrhagic lesions, gastric resection was frequently required to obtain hemostasis. Persistence of H. pylori infection in patients with a history of gastric resection (4.1%) still predisposes to a hemorrhagic or neoplastic complication.

Gastric Cancer and the Daily Intake of the Major Dish Groups Contributing to Sodium Intake: A Case-Control Study in Korea

Studies on the association between gastric cancer (GC) and the intake of soup-based dish groups (noodles and dumplings, soups, and stews), which are sodium-contributing foods, in Korea are insufficient, and the results of studies on the intake of pickled vegetables such as kimchi are inconsistent. This study aimed to determine the association between the incidence of GC and the daily intake of high-sodium dish groups (noodles and dumplings, soups, stews, and pickled vegetables) and whether these associations differ depending on behavioral risk factors for GC. In this case-control study, subjects aged 20–79 years were recruited from two hospitals between December 2002 and September 2006. A total of 440 cases and 485 controls were recruited, of which 307 pairs were matched and included for the analysis. In our results, a higher intake of noodles and dumplings was associated with a significantly increased incidence of GC. In the participants who consumed past or current alcohol, a higher intake of noodles and dumplings was associated with a significantly increased incidence of GC. Our results suggest that efforts to reduce the daily sodium intake from noodles and dumplings are needed to prevent and reduce the incidence of GC.

Changes in Gastric Corpus Microbiota With Age and After Helicobacter pylori Eradication: A Long-Term Follow-Up Study

Helicobacter pylori infection changes gastric microbiota profiles. However, it is not clear whether H. pylori eradication can restore the healthy gastric microbiota. Moreover, there has been no study regarding the changes in gastric microbiota with aging. The objective of this study was to investigate the changes in gastric corpus microbiota with age and following H. pylori eradication. Changes in corpus mucosa-associated microbiota were evaluated in 43 individuals with endoscopic follow-up > 1 year, including 8 H. pylori-uninfected and 15 H. pylori-infected subjects with no atrophy/metaplasia by histology and pepsinogen I/II ratio > 4.0; 17 H. pylori-infected subjects with atrophy/metaplasia and pepsinogen I/II ratio < 2.5; and 3 subjects with atrophy/metaplasia, no evidence of active H. pylori infection, negative for anti-H. pylori immunoglobulin G (IgG) antibody testing, and no previous history of H. pylori eradication. Successful H. pylori eradication was achieved in 21 patients. The gastric microbiota was characterized using an Illumina MiSeq platform targeting 16S ribosomal DNA (rDNA). The mean follow-up duration was 57.4 months (range, 12-145 months), and median follow-up visit was 1 (range, 1-3). Relative abundance of Lactobacillales and Streptococcus was increased with atrophy/metaplasia. In H. pylori-uninfected subjects (n = 8), an increase in Proteobacteria (Enhydrobacter, Comamonadaceae, Sphingobium); a decrease in Firmicutes (Streptococcus, Veillonella), Fusobacteria (Fusobacterium), Nocardioidaceae, Rothia, and Prevotella; and a decrease in microbial diversity were observed during the follow-up (p trend < 0.05). In 10 of 21 subjects (47.6%), H. pylori eradication induced restoration of microbial diversity; however, a predominance of Acinetobacter with a decrease in microbial diversity occurred in 11 subjects (52.3%). The presence of atrophy/metaplasia at baseline and higher neutrophil infiltration in the corpus were associated with the restoration of gastric microbiota after successful eradication, whereas a higher relative abundance of Acinetobacter at baseline was associated with the predominance of Acinetobacter after H. pylori eradication (p < 0.05). To conclude, in H. pylori-uninfected stomach, relative abundance of Proteobacteria increases, relative abundance of Firmicutes and Fusobacteria decreases, and microbial diversity decreases with aging. H. pylori eradication does not always restore gastric microbiota; in some individuals, gastric colonization by Acinetobacter species occurs after anti-Helicobacter treatment.

Cell primitive-based biomimetic functional materials for enhanced cancer therapy

Cell primitive-based functional materials that combine the advantages of natural substances and nanotechnology have emerged as attractive therapeutic agents for cancer therapy. Cell primitives are characterized by distinctive biological functions, such as long-term circulation, tumor specific targeting, immune modulation etc. Moreover, synthetic nanomaterials featuring unique physical/chemical properties have been widely used as effective drug delivery vehicles or anticancer agents to treat cancer. The combination of these two kinds of materials will catalyze the generation of innovative biomaterials with multiple functions, high biocompatibility and negligible immunogenicity for precise cancer therapy. In this review, we summarize the most recent advances in the development of cell primitive-based functional materials for cancer therapy. Different cell primitives, including bacteria, phages, cells, cell membranes, and other bioactive substances are introduced with their unique bioactive functions, and strategies in combining with synthetic materials, especially nanoparticulate systems, for the construction of function-enhanced biomaterials are also summarized. Furthermore, foreseeable challenges and future perspectives are also included for the future research direction in this field.

Expression of p27 and p16 and their clinical significance in gastric cancer

BACKGROUND

Deregulated expression of cell cycle regulators p27 and p16 is associated with cancer progression. p27^kip1 and p16^INKa are a cyclin dependent kinase inhibitor whose major target is the cyclinE/CDK2 and cyclinD/CDK4/6 complex, respectively, that governs cell cycle transition from late G1 to S phase.

METHODS

We recruited biopsies of a total of 84 subjects including 72 primary tumor biopsies from histopathologically proven gastric carcinoma, 8 adjacent controls and 12 independent controls. We used gastric cancer cell line, AGS, for validation of our data. Expression profiling at transcript level was done by semi-quantitative RT-PCR and at proteome level by immunohistochemistry and immunofluorescence. Receiver operator characteristics analysis was done for determining the diagnostic utility of p27 and p16 with respect to the sensitivity and specificity.

RESULTS

We demonstrate that p27 and p16 are frequently over expressed in early stages of gastric carcinoma. Our semi-quantitative data show a significant upregulation of p27 (Mean ± SEM, 0.4771 ± 0.0895; p = 0.0001) and p16 (Mean ± SEM, 0.4676 ± 0.04305; p = 0.0001) at mRNA level. Concordant to semi-quantitative data, immunohistochemistry data also showed a significant upregulation of p27 (Mean ± SEM, 196.4 ± 10.84; p < 0.0001) and p16 (Mean ± SEM, 100.4 ± 23.71; p < 0.0001) at protein level.

CONCLUSIONS

The present study showed that the significant upregulation of p27 and p16 were associated with early events in gastric carcinogenesis. Our data suggests that clinical correlation of these differentially expressed genes may be useful as diagnostic biomarkers for early detection of gastric carcinoma and promising therapeutics target for GC patients.

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.

Droplet Digital PCR Detects Low-Density Infection in a Significant Proportion of Helicobacter Pylori-Negative Gastric Biopsies of Dyspeptic Patients

INTRODUCTION

Helicobacter pylori-infected individuals may present low-density infection, undetectable by conventional tests such as histology, rapid urease test, or urea breath test. Droplet digital polymerase chain reaction (ddPCR) is more sensitive than other polymerase chain reaction methods. We aimed to evaluate the ability of ddPCR to detect H. pylori infection in patients diagnosed as negative by conventional tests.

METHODS

Dyspeptic patients (n = 236) were tested for H. pylori by histology, urea breath test, and rapid urease test. Patients were classified as having 3 positive (n = 25, control group), 2 positive (n = 12), one positive (n = 41), or zero positive (n = 158) diagnostic tests. DNA was extracted from gastric biopsies. Triplicate ddPCR testing for each of the 16S rDNA, ureA, and vacA(s) genes was performed using a QX200 ddPCR system (Bio-Rad). A gene was considered positive when detected by at least 2 of 3 repeated ddPCRs. H. pylori positivity was defined as having 2 or more positive genes.

RESULTS

All the biopsies of the control patients were positive for all 3 16S rDNA, ureA, and vacA(s) genes. H. pylori infection was detected in 57 (36%), 22 (54%), and 9 (75%) patients with zero, 1, and 2 positive diagnostic tests, respectively. The density of infection was 5, 121, 599, and 3,133 copies of H. pylori genome equivalents for patients with zero, 1, and 2 of 3 positive test results and for the control group, respectively.

DISCUSSION

ddPCR detected low-density "occult" H. pylori infection in a significant proportion (36%) of patients diagnosed as negative by conventional methods. The number of conventional positive tests was related to the density of infection.

Changes of the Gastric Mucosal Microbiome Associated With Histological Stages of Gastric Carcinogenesis

The changes of gastric microbiome across stages of neoplastic progression remain poorly understood, especially for intraepithelial neoplasia (IN) which has been recognized as a phenotypic bridge between atrophic/intestinal metaplastic lesions and invasive cancer. The gastric microbiota was investigated in 30 healthy controls (HC), 21 non-atrophic chronic gastritis (CG), 27 gastric intestinal metaplasia (IM), 25 IN, and 29 gastric cancer (GC) patients by 16S rRNA gene profiling. The bacterial diversity, and abundances of phyla Armatimonadetes, Chloroflexi, Elusimicrobia, Nitrospirae, Planctomycetes, Verrucomicrobia, and WS3 reduced progressively from CG, through IM, IN to GC. Actinobacteria, Bacteriodes, Firmicutes, Fusobacteria, SR1, and TM7 were enriched in the IN and GC. At the community level, the proportions of Gram-positive and anaerobic bacteria increased in the IN and GC compared to other histological types, whereas the aerobic and facultatively anaerobic bacteria taxa were significantly reduced in GC. Remarkable changes in the gastric microbiota functions were detected after the formation of IN. The reduced nitrite-oxidizing phylum Nitrospirae together with a decreased nitrate/nitrite reductase functions indicated nitrate accumulation during neoplastic progression. We constructed a random forest model, which had a very high accuracy (AUC > 0.95) in predicating the histological types with as low as five gastric bacterial taxa. In summary, the changing patterns of the gastric microbiota composition and function are highly indicative of stages of neoplastic progression.

A Comparison of Accuracy between IMMULITE2000® and GENEDIA® for Helicobacter pylori Infection

Background/Aims: In serological tests for <i>Helicobacter pylori</i> (<i>H. pylori</i>), an enzyme-linked immunosorbent assay (GENEDIA^®) and a solid-phase, two-step chemiluminescent enzyme immunoassay (IMMULITE^®), which are easy to perform, inexpensive, and widely available, are commonly used. However, local validation of the test performance of IMMULITE^® is required. This study aimed to examine the performance of IMMULITE^® in comparison with that of GENEDIA^® in a Korean health checkup population.Materials and Methods: The sera of 300 subjects among those who underwent health checkup were analyzed using IMMULITE^®, and results were compared with those of GENEDIA^®. The two serological tests were compared for their ability to predict atrophic gastritis (AG) or intestinal metaplasia (IM) on endoscopy.Results: We found significant correlation (Pearson correlation coefficient=0.903, <i>P</i><0.0001) and an almost perfect agreement (Cohen’s Kappa coefficient=0.987, <i>P</i><0.0001) between the results of GENEDIA^® and IMMULITE^®. The area under the receiver operating characteristics curve (AUC) for AG using GENEDIA^® and IMMULITE^® were 0.590 and 0.604, respectively, and showed no statistically significant difference in predictive ability for AG (<i>Z</i>-statistics=-0.517, <i>P</i>=0.605). The AUC for IM by GENEDIA^® and IMMULITE^® were 0.578 and 0.593, respectively, with no statistically significant difference in predictive ability for IM between the two values (<i>Z</i>-statistics=-0.398, <i>P</i>=0.691).Conclusions: No statistically significant difference in diagnostic value for <i>H. pylori</i> infection was found between GENEDIA^® and IMMULITE^®.

Effect of Citric Acid on Accuracy of 13C-Urea Breath Test after Helicobacter pylori Eradication Therapy in a Region with a High Prevalence of Atrophic Gastritis

Background/Aims

The validity of ¹³C-urea breath test (¹³C-UBT) for Helicobacter pylori detection is influenced by atrophic gastritis. The aim of this study was to evaluate the effect of citric acid on the accuracy of ¹³C-Urea breath test after H. pylori eradication therapy in a region where atrophic gastritis is common.

Methods

In this prospective study, H. pylori-positive patients received ¹³C-UBT after H. pylori eradication regimen. They were classified into citric acid group and control group. To determine diagnostic accuracy of ¹³C-UBT, patients were offered invasive methods.

Results

A total of 1,207 who successfully took H. pylori-eradication regimen received UBT. They were assigned into the citric acid group (n=562) and the control group (n=645). The mean ¹³C-UBT value of the citric acid group was 10.3±26.4‰, which was significantly (p<0.001) higher than that of that control group (5.1‰±12.6‰). Of these patients 122 patients were evaluated by endoscopic biopsy methods. Based on invasive tests, the accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of ¹³C-UBT for the citric acid group were 83.3%, 91.7%, 81.3%, 55.0%, and 97.5%, respectively. Those of the control group were 87.7%, 90.9%, 88.2%, 62.5%, and 97.8%, respectively. They were not significantly different between the two groups. Although the presence of gastric atrophy and intestinal metaplasia (IM) decreased the accuracy, the decrease was not significant.

Conclusions

In a country with high prevalence of atrophic gastritis or IM, false positivity remained common despite the use of citric acid in ¹³C-UBT.

Gastric Xanthomas and Fundic Gland Polyps as Endoscopic Risk Indicators of Gastric Cancer

Background/Aims

Fundic gland polyps (FGPs), hyperplastic polyps (HPs), and xanthomas (XTs) are common benign gastric lesions that can be diagnosed by endoscopic appearance alone in most cases. The aim of this study was to evaluate associations between gastric cancer and these benign lesions.

Methods

Two expert endoscopists reviewed a series of gastroscopy images. FGPs, HPs, and XTs were diagnosed by endoscopic appearance, whereas all gastric cancers were confirmed pathologically.

Results

Of the 1,227 patients reviewed, 114 (9.3%) had a concurrent or past history of gastric cancer. The overall prevalences of FGPs, HPs and XTs were 9.4%, 6.3% and 14.2%, respectively. HPs and XTs coexisted in 1.6% of patients, whereas other combinations were rarer. XTs were observed in 39.3% and 11.5% of patients with and without gastric cancer, respectively (p<0.001). In contrast, no gastric cancer patients had FGPs, whereas 10.4% of patients without cancer had FGPs (p<0.001). The prevalence of HPs was similar between the two groups (8.8% and 6.0% of patients with and without cancer, respectively, p=0.29). Multivariate and Mantel-Haenszel analyses demonstrated that XTs were positively associated and FGPs were negatively associated with gastric cancer.

Conclusions

XTs and FGPs might be useful as endoscopic risk indicators for monitoring gastric cancer.

Types of Gastric Carcinomas

Gastric cancer has reduced prevalence, but poor prognoses. To improve treatment, better knowledge of carcinogenesis and cells of origin should be sought. Stomach cancers are typically localized to one of the three mucosae; cardial, oxyntic and antral. Moreover, not only the stem cell, but the ECL cell may proliferate and give rise to tumours. According to Laurén, the classification of gastric carcinomas seems to reflect biological important differences and possible different cell of origin since the two subtypes, intestinal and diffuse, do not transform into the other and show different epidemiology. The stem cell probably gives rise to the intestinal type, whereas the ECL cell may be important in the diffuse type. Elevation of gastrin may be the carcinogenic factor for Helicobacter pylori as well as the recently described increased risk of gastric cancer due to proton pump inhibitor treatment. Therefore, it is essential to determine the role of the gastrin target cell, the ECL cell, in gastric carcinogenesis. Clinical trials with gastrin antagonists could improve prognoses in those with gastrin receptor positive tumours. However, further studies on gastric carcinomas applying relative available methods and with the highest sensitivity are warranted to improve our knowledge of gastric carcinogenesis.

Long-term outcome of group D patients with negative serum anti-Helicobacter pylori antibody and positive serum pepsinogen test in healthy Koreans

OBJECTIVE

The aim of this study was to assess the clinical characteristics and long-term outcomes of group D patients (negative H. pylori antibodies and positive pepsinogen level).

METHODS

Group D patients were divided into two groups, that is, the limited endoscopic atrophic gastritis (EAG) group with EAG confined to the antrum and angle (C1 and C2) and the advanced EAG group with gastric body-involved EAG (C3 to O3). We compared the progression of precursor lesions and the occurrence of gastric neoplasms between the two groups.

RESULTS

Among 107 group D patients, the advanced EAG group (n = 60) was elder and had a lower pepsinogen I level and a lower pepsinogen I to II ratio (PGI/II) than the limited EAG group (n = 47). Among the 52 patients who underwent a follow-up endoscopy, three gastric neoplasms were detected (one in the limited and two in the advanced EAG groups). During a median follow-up of 44 months, 10 (43.5%) patients in the limited and 13 (52.0%) in the advanced EAG groups showed EAG progression or newly occurred intestinal metaplasia. A family history of GC (odds ratio [OR] 44.974, 95% confidence interval [CI] 1.360-1487.087), a lower PGI/II (OR 0.247, 95% CI 0.085-0.717) and a longer follow-up duration (OR 1.832, 95% CI 1.200-2.796) increased the risk of progression.

CONCLUSION

A family history of GC and low baseline PGI/II were independently associated with an increased risk of progression of precursor lesions of GC.

Effects of Helicobacter pylori eradication for metachronous gastric cancer prevention: a randomized controlled trial

BACKGROUND AND AIMS

Whether eradication of Helicobacter pylori reduces the incidence of metachronous gastric cancer (MGC) is still debatable. We aimed to evaluate the long-term effect of H pylori eradication on the development of MGC after endoscopic gastric tumor resection.

METHODS

We undertook an open-label, prospective, randomized controlled trial at a tertiary hospital in Seoul, Korea. Participants were recruited during April 2005 to February 2011 and followed until December 2016. We assigned 898 patients with H pylori infection treated with endoscopic resection (ER) for gastric dysplasia or early gastric cancer to receive (n =442) or not receive (n =456) eradication therapy using a random-number chart. Eradication group patients received oral omeprazole 20 mg, amoxicillin 1 g, and clarithromycin 500 mg twice daily for a week, whereas control group patients received no H pylori treatment. The primary outcome was the incidence of MGC (intention-to-treat analysis).

RESULTS

The 877 patients who attended ≥1 follow-up examination (eradication group, 437; control group, 440) were analyzed. Median follow-up was 71.6 months (interquartile range, 42.1-90.0). MGC developed in 18 (4.1%) eradication and 36 (8.2%) control group patients (log-rank test, P = .01). In our yearly analysis, the effect of eradication showed a significant difference in 5 years after allocation (log-rank test, P = .02). The adjusted hazard ratio for the control group was 2.02 (95% CI, 1.14-3.56; P = .02), compared with the eradication group.

CONCLUSIONS

H pylori eradication significantly reduces the incidence of MGC after ER of gastric tumors and should be considered for H pylori-positive gastric tumor patients treated with ER. (Clinical trial registration number: NCT01510730.).

The Characteristics and Prognosis of Diffuse-Type Early Gastric Cancer Diagnosed during Health Check-Ups

Background/Aims

Because of the poor prognosis of diffuse-type gastric cancer, early detection is important. We investigated the clinical characteristics and prognosis of diffuse-type early gastric cancer (EGC) diagnosed in subjects during health check-ups.

Methods

Among 121,111 subjects who underwent gastroscopy during a routine health check-up, we identified 282 patients with 286 EGC lesions and reviewed their clinical and tumor-specific parameters.

Results

Patients with diffuse-type EGC were younger, and 48.1% of them were female. Serum anti-Helicobacter pylori IgG (Hp-IgG) was positive in 90.7% of diffuse-type EGC patients (vs 75.9% of intestinal-type EGC, p=0.002), and the proportion of diffuse-type EGC cases increased significantly with increasing Hp-IgG serum titers (p<0.001). Diffuse-type EGC had pale discolorations on the tumor surface (26.4% vs 4.0% in intestinal-type EGC, p<0.001) and were often located in the middle third of the stomach. Submucosal invasion or regional nodal metastasis was observed more commonly in patients with diffuse-type EGC. However, during the median follow-up period of 50 months, 5-year disease-free survival rates did not differ between the groups.

Conclusions

Diffuse-type EGC shows different clinical and endoscopic characteristics. Diffuse-type EGC is more closely associated with Hp-IgG seropositivity and a higher serum titer. Early detection results in excellent prognosis.

The histologic detection of Helicobacter pylori in seropositive subjects is affected by pathology and secretory ability of the stomach

BACKGROUND

Helicobacter pylori is unevenly distributed in hypochlorhydric environments. The study aim was to elucidate the risk factors for a negative Giemsa staining finding in seropositive subjects by measuring the secretory ability of the stomach.

METHODS

Subjects aged over 18 years were included consecutively after endoscopic biopsy at gastric lesions with color or structural changes. Blood was sampled for the serum pepsinogen (PG) assay and H. pylori serology test. After excluding the subjects with past H. pylori eradication, the risk factors for a negative Giemsa staining finding in seropositive subjects were analyzed.

RESULTS

Among 872 included subjects, a discrepancy between the serum anti-H. pylori IgG and Giemsa staining findings was found in 158 (18.1%) subjects, including 145 Giemsa-negative, seropositive subjects. Gastric adenocarcinoma/adenoma (OR = 11.090, 95% CI = 3.490-35.236) and low serum PG II level (OR = 0.931, 95% CI = 0.899-0.963) were the independent risk factors for a negative Giemsa staining finding in seropositive subjects. The cutoff value of serum PG II level was 7.45 ng/mL (area under curve [AUC] = 0.904, 95% CI = 0.881-0.927). Follow-up studies of Giemsa staining at different sites of the stomach revealed that 75% of the Giemsa-negative seropositive subjects with adenocarcinoma are positive, whereas none of those with low serum PG II level of <7.45 ng/mL revealed positive findings.

CONCLUSIONS

The risk of a negative Giemsa staining finding in seropositive subjects is increased in gastric adenocarcinoma/adenoma specimens and in subjects with a diminished gastric secretory ability with low serum PG II level of <7.45 ng/mL. A false-negative Giemsa staining finding is common in subjects with adenocarcinoma, and therefore, additional biopsies at different sites should be performed in these subjects.

Dynamic Changes in Helicobacter pylori Status Following Gastric Cancer Surgery

Background/Aims

Helicobacter pylori eradication is recommended in patients with early gastric cancer. However, the possibility of spontaneous regression raises a question for clinicians about the need for "retesting" postoperative H. pylori status.

Methods

Patients who underwent curative gastrectomy at Seoul National University Bundang Hospital and had a positive H. pylori status without eradication therapy at the time of gastric cancer diagnosis were prospectively enrolled in this study. H. pylori status and atrophic gastritis (AG) and intestinal metaplasia (IM) histologic status were assessed pre- and postoperatively.

Results

One hundred forty patients (mean age, 59.0 years; 60.7% male) underwent subtotal gastrectomy with B-I (65.0%), B-II (27.1%), Roux-en-Y (4.3%), jejunal interposition (0.7%), or proximal gastrectomy (4.3%). Preoperative presence of AG (62.9%) and IM (72.9%) was confirmed. The mean period between surgery and the last endoscopic follow-up was 38.0±25.6 months. Of the 140 patients, 80 (57.1%) were found to be persistently positive for H. pylori, and 60 (42.9%) showed spontaneous negative conversion at least once during follow-up. Of these 60 patients, eight (13.3%) showed more complex postoperative dynamic changes between negative and positive results. The spontaneous negative conversion group showed a trend of having more postoperative IM compared to the persistent H. pylori group.

Conclusions

A high percentage of spontaneous regression and complex dynamic changes in H. pylori status were observed after partial gastrectomy, especially in individuals with postoperative histological IM. It is better to consider postoperative eradication therapy after retesting for H. pylori.

Analysis of Gastric Body Microbiota by Pyrosequencing: Possible Role of Bacteria Other Than Helicobacter pylori in the Gastric Carcinogenesis

Background

Gastric microbiota along with Helicobacter pylori (HP) plays a key role in gastric disease. The aim of our study is to investigate the difference of human gastric microbiota between antrum and body according to disease (control vs. gastric cancer) and HP status.

Methods

Each antrum and body biopsy was collected from 12 subjects at Seoul National University Bundang Hospital. Gastric microbiota was analyzed by bar-coded 454 pyrosequencing of the 16S rRNA gene. Twelve subjects consisted of HP-negative control (n = 2), HP-negative cancer (n = 2), HP-positive control (n = 3), and HP-positive cancer (n = 5). The analysis was focused on non-HP urease-producing bacteria (UB) and non-HP nitrosating or nitroreducing bacteria (NB) between antrum and body.

Results

Gastric body samples showed higher diversity compared to gastric antrum mucosa samples but there was no significant difference. The mean of operational taxonomic units was higher in HP(−) cancer than HP(+) cancer (antrum, 273.5 vs. 228.2, P = 0.439; body, 585.5 vs. 183.2, P = 0.053). The number of non-HP UB and non-HP NB was higher in HP(−) cancer groups than the others. These differences were more pronounced in the body (P = 0.051 and P = 0.081, respectively). Analysis of overlap of non-HP UB and non-HP NB revealed the higher composition of Streptococcus pseudopneumoniae, S. parasanguinis, and S. oralis in HP(−) cancer groups than the others, only in the body (P = 0.030) but not in the antrum (P = 0.123).

Conclusions

Higher diversity and higher composition of S. pseudopneumoniae, S. parasanguinis, and S. oralis in HP(−) cancer group than the other groups in the body suggest that analysis of microbiota from body mucosa could be beneficial to identify a role of non-HP bacteria in the gastric carcinogenesis.

Colorectal neoplasm in cases of Clostridium septicum and Streptococcus gallolyticus subsp. gallolyticus bacteraemia

BACKGROUND

Bacteremia with Clostridium septicum (CS) and Streptococcus gallolyticus subsp. gallolyticus (SGG) have both been associated with colorectal neoplasms (CRN) and colonoscopic examination is advised, however the differences and similarities in colorectal findings are not well known.

METHODS

This is a multicenter, comparative study of patients with CS bacteremia [44 of 664 cases (6.6%) of Clostridium spp.] and SGG bacteremia [257 of 596 cases (44.2%) of S. bovis group], carried out in three hospitals from Spain. Clinical findings related to bacteremia and associated CRN were collected.

RESULTS

The main sources of infection were abdominal (77.7%) for CS bacteremia and endovascular (75%) for SGG bacteremia. CS bacteremia was more often associated with malignancies, (72.6% vs. 19.4%) and neutropenia (29.5% vs. 3.1%), and was more acute, with shock at presentation (63.6% vs. 3.9%) and higher 30-day mortality (47.7% vs. 9.7%) compared to SGG (P<0.05 for all). Both, patients with CS and SGG bacteremia often had concomitant CRN (43.1% vs. 49.8%) and most of them presented as occult CRN (73.7% vs. 91.4%; P=0.02). CS cases more often had invasive carcinomas (94.7% vs. 19.5%), location of CRN in the right colon (73.7% vs. 23.4%), larger tumor size (median 7 vs. 1.5cm), and a higher overall CRN related mortality rate (68.4% vs. 7.8%) compared to SGG cases (P<0.05 for all).

CONCLUSIONS

Both, CS and SGG bacteremia are associated with occult CRN. CS cases more often had advanced carcinomas than SGG cases, suggesting a distinct temporal association with CRN.

Clinical implications of pre-existing adenoma in endoscopically resected early gastric cancers

Background

Although gastric adenoma is widely accepted as a precursor of gastric cancer, pre-existing adenoma is not always detected in gastric cancer patients.

Objective

To investigate the clinical characteristics of early gastric cancer (EGC) arising from adenoma, compared with those of EGC without pre-existing adenoma.

Methods

Patients who underwent endoscopic resection for EGC at a single tertiary hospital were divided into two groups based on the presence (ex-adenoma group) or absence (de novo group) of pre-existing adenoma on pathologic specimens. Clinicopathologic characteristics, endoscopic features and long-term outcomes were analyzed.

Results

Of 1,509 patients, 236 (15.6%) were included in the ex-adenoma group. Mean age (P = 0.003) and Helicobacter pylori infection rate (P = 0.040) were significantly higher in the ex-adenoma than in the de novo group. Mean endoscopic size was significantly larger, elevated lesions were more prevalent (both P < 0.001), and carcinomas were more differentiated in the ex-adenoma group than in the de novo group (P = 0.037). The degree of atrophy (P = 0.025) or intestinal metaplasia (P < 0.001) was more advanced in the ex-adenoma group. Synchronous gastric neoplasia was significantly more prevalent in the ex-adenoma group (P < 0.001), whereas metachronous cancer recurrence rate was not significantly different between the two groups.

Conclusions

EGCs with pre-existing adenoma show a greater association with H. pylori–related chronic inflammation than those without, which could explain the differences in the characteristics between groups. Potential differences in carcinogenic mechanisms between the groups were explored.

Link between Serum Pepsinogen Concentrations and Upper Gastrointestinal Endoscopic Findings

The serum pepsinogen (PG) assay findings are correlated with the status of Helicobacter pylori infection, but there are controversies on the link with upper gastrointestinal (UGI) endoscopic findings. The aim of this study was to determine the significance of a serum PG assay for correlating with endoscopic findings in H. pylori-seroprevalent adult population. Korean adults who visited for a health check-up were included consecutively. Subjects after gastrectomy or H. pylori eradication were excluded. After completing the serum PG assay and anti-H. pylori immunoglobulin G (IgG) titer on the same day of UGI endoscopy, subjects with equivocal serology test finding or gastric neoplasm were excluded. Of the 4,830 included subjects, 3,116 (64.5%) were seropositive for H. pylori. Seropositive finding was related to high serum PG I (P < 0.001) and PG II (P < 0.001) concentrations, low PG I/II ratio (P < 0.001), old age (P < 0.001), and male gender (P = 0.006). After adjusting age and gender, the serum PG I and II concentrations were positively correlated with the presence of nodular gastritis (NG) (all P = 0.003). The serum PG I was positively correlated with gastric ulcer (P = 0.003), and it was correlated with duodenal ulcer in seropositive subjects (P = 0.008). The PG I/II ratio was positively correlated with erosive esophagitis, while it was inversely related to chronic atrophic gastritis and metaplastic gastritis (all P < 0.001). Our findings suggest that the serum PG assay finding correlates well with the UGI endoscopic finding. A higher serum PG concentration in subjects with NG and peptic ulcer disease suggests that endoscopic findings reflect gastric secreting ability.

Investigation of mucosal pattern of gastric antrum using magnifying narrow-band imaging in patients with chronic atrophic fundic gastritis

BACKGROUND

Magnifying narrow-band imaging (M-NBI) can reportedly help predict the presence and distribution of atrophy and intestinal metaplasia in the gastric corpus. However, the micro-mucosal pattern of the antrum shown by M-NBI differs from that of the corpus. We studied the distribution and histology of the micro-mucosal pattern in the antrum based on magnifying endoscopy.

METHODS

Endoscopic images of the greater curvature of the antrum were evaluated in 50 patients with chronic atrophic fundic gastritis (CAFG). The extent of CAFG was evaluated by autofluorescence imaging. The micro-mucosal pattern was evaluated by M-NBI and classified into groove and white villiform types. The localization of white villiform type mucosa was classified into three types in relation to the areae gastricae: null, central, and segmental types. Biopsies were taken from regions showing different micro-mucosal patterns. Associations among the extent of CAFG, micro-mucosal pattern, and histology were examined.

RESULTS

As the extent of CAFG increased, the proportion of white villiform type mucosa increased, whereas that of groove type mucosa decreased (P=0.022). In patients with extensive CAFG, most of the areae gastricae was composed of the segmental or central type of white villiform type mucosa (P=0.044). The white villiform type mucosa had significantly higher grades of atrophy (P=0.002) and intestinal metaplasia (P<0.001) than did the groove type mucosa.

CONCLUSION

White villiform type mucosa is indicative of atrophy and intestinal metaplasia in the gastric antrum. It extends to the whole or central part of the areae gastricae as CAFG becomes more extensive.

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.

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.

Endoscopic gastritis, serum pepsinogen assay, and Helicobacter pylori infection

Endoscopic findings of the background gastric mucosa are important in the Helicobacter pylori-seroprevalent population. It is strongly correlated not only with the risk of gastric cancer, but also with the excretion ability of gastric mucosa cells. In noninfected subjects, common endoscopic findings are regular arrangement of collecting venules, chronic superficial gastritis, and erosive gastritis. In cases of active H. pylori infection, nodularity on the antrum, hemorrhagic spots on the fundus, and thickened gastric folds are common endoscopic findings. The secreting ability of the gastric mucosa cells is usually intact in both noninfected and actively infected stomachs, and the intragastric condition becomes hyperacidic upon inflammation. Increased serum pepsinogen II concentration correlates well with active H. pylori infection, and also indicates an increased risk of diffuse-type gastric cancer. In chronic inactive H. pylori infection, metaplastic gastritis and atrophic gastritis extending from the antrum (closed-type chronic atrophic gastritis) toward the corpus (open-type chronic atrophic gastritis) are common endoscopic findings. The intragastric environment is hypoacidic and the risk of intestinal-type gastric cancer is increased in such conditions. Furthermore, there is a decrease in serum pepsinogen I concentration when the secreting ability of the gastric mucosa cells is damaged. Serologic and endoscopic changes that occur upon H. pylori infection are important findings for estimating the secreting ability of the gastric mucosa cells, and could be applied for the secondary prevention of gastric cancer.

Follow-Up Study on CDX1 and CDX2 mRNA Expression in Noncancerous Gastric Mucosae After Helicobacter pylori Eradication

BACKGROUND

Changes in CDX1/CDX2 in gastric mucosae following Helicobacter pylori eradication have not been clarified yet.

AIMS

To evaluate the changes in CDX1/CDX2 expression after H. pylori eradication, in relation to the reversibility of intestinal metaplasia (IM).

METHODS

Time course of CDX1/CDX2 expressions was investigated in 176 subjects with various gastroduodenal disorders. Among them, 132 patients were H. pylori positives; H. pylori were eradicated in 107 of them; 13 failed to eradicate; and 12 did not receive H. pylori eradication therapy. Forty-four subjects were H. pylori negatives. Expression levels in CDX1 and CDX2 from noncancerous gastric mucosae of the corpus, as well as the histologic findings of gastric mucosae, were evaluated during the follow-up.

RESULTS

Average follow-up duration was 33.7 months (range 2-97 months). Expression levels in both CDX1 and CDX2 mRNAs were correlated with IM grade in the corpus (ρ = 0.633 and 0.554, respectively, all P < 0.001). Changes in CDX1/CDX2 mRNA expressions following H. pylori eradication showed only insignificant results; IM grade at the antrum and corpus showed a tendency to decrease after H. pylori eradication without statistical significance (P > 0.05). However, histologic improvement of IM at the corpus was associated with a decrease in CDX2 mRNA expression during the follow-up (linear mixed model, P for slope = 0.015).

CONCLUSIONS

In this study, eradication of H. pylori did not show any beneficial effects on aberrant CDX1/CDX2 expressions or IM. Reversibility of IM may be associated with a decrease in CDX2 mRNA expression.

Historical review of the causes of cancer

In the early 1900s, numerous seminal publications reported that high rates of cancer occurred in certain occupations. During this period, work with infectious agents produced only meager results which seemed irrelevant to humans. Then in the 1980s ground breaking evidence began to emerge that a variety of viruses also cause cancer in humans. There is now sufficient evidence of carcinogenicity in humans for human T-cell lymphotrophic virus, human immunodeficiency virus, hepatitis B virus, hepatitis C virus, human papillomavirus, Epstein-Barr virus, and human herpes virus 8 according to the International Agency for Research on Cancer (IARC). Many other causes of cancer have also been identified by the IARC, which include: Sunlight, tobacco, pharmaceuticals, hormones, alcohol, parasites, fungi, bacteria, salted fish, wood dust, and herbs. The World Cancer Research Fund and the American Institute for Cancer Research have determined additional causes of cancer, which include beta carotene, red meat, processed meats, low fibre diets, not breast feeding, obesity, increased adult height and sedentary lifestyles. In brief, a historical review of the discoveries of the causes of human cancer is presented with extended discussions of the difficulties encountered in identifying viral causes of cancer.

Diagnosis of Helicobacter pylori by invasive test: histology

The accurate detection of Helicobacter pylori (H. pylori), a major cause of gastric cancer, is essential for managing infected patients. Among various diagnostic methods, histology plays a pivotal role in detecting H. pylori and it also provided more information about the degree of inflammation and associated pathology, such as, atrophic gastritis (AG), intestinal metaplasia (IM), and gastric cancer. The diagnosis of H. pylori could be performed in hematoxylin and eosin (H&E) staining, however the specificity can be improved by special stains such as modified Giemsa, Warthin-Starry silver, Genta, and immunohistochemical (IHC) stains. Thus, at least two kinds of stain methods are recommended for diagnosis in practice; H&E staining is routine and Giemsa stain seems to have advantage over other stains because of its simplicity and consistency. IHC stain may be useful in special situations. However, histology has several limitations, including higher cost, longer turnaround time, dependence on the skills of the operator, and interobserver variability in assessment. Furthermore, the density of H. pylori can vary at different sites, possibly leading to sampling error, and the sensitivity of histology may decrease in patients taking proton pump inhibitor (PPI). The updated Sydney system recommend to take five biopsy specimens from different sites; however if this is not possible, the gastric body greater curvature could be a better site to detect current H. pylori infections, especially in the presence of peptic ulcer bleeding, AG and IM, or gastric cancer. In the presence of peptic ulcer bleeding, histology is also the most reliable test. PPIs can affect the result of histology and should be stopped 2 weeks before testing. Postbiopsy bleeding may be increased in patients with anticoagulation therapy, so careful precautions should be taken.

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.

Different methylation profiles between intestinal and diffuse sporadic gastric carcinogenesis

OBJECTIVE

Gastric cancer (GC) is histologically classified into intestinal type and diffuse type, and diffuse type cancer can be further subdivided into poorly differentiated carcinoma (PDC) and signet ring cell carcinoma (SRCC). Recent evidence suggests that early SRCC is an initial, differentiated form of diffuse GC that may evolve into PDC. This study aimed at identifying the molecular features of epigenetic methylation changes in histologic differentiation status of GC.

METHODS

Included in this study are 149 samples of paraffin-embedded tissues and 115 fresh endoscopically biopsied tissues. Multiple paraffin tissues involving normal (n=22), dysplasias (GDs, n=39), differentiated cancers (DCs, n=35), PDCs (n=33) and SRCCs (n=20) were included as an experimental group. For the validation group, endoscopically biopsied tissues of DCs (n=50), PDCs (n=31), and SRCs (n=34) were analyzed. DNAs, isolated from each group were analyzed to determine the methylation status of 6 genes (GDNF, RORA, MINT25, KLF7, CDH1, LINE-1) using pyrosequencing.

RESULTS

LINE-1 was hypomethylated in GCs compared to normal and GD. GDNF, RORA and MINT25 were more hypermethylated in intestinal type GCs than those of diffuse type GCs, whereas CDH1 showed opposite patterns of methylation. Among diffuse type GCs, SRCCs showed lower level of methylation for GDNF, RORA, MINT25 and KLF7, and higher level for CDH1 compared to PDCs.

CONCLUSIONS

In conclusion, intestinal type of GCs shows different epigenetic methylation profiles compared to the diffuse one. Moreover, SRCCs have different methylation profiles compared with PDCs, suggesting a unique molecular pathway in the gastric carcinogenesis.

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.

Up-regulation of CLDN1 in gastric cancer is correlated with reduced survival

Background

The genetic changes in gastric adenocarcinoma are extremely complex and reliable tumor markers have not yet been identified. There are also remarkable geographical differences in the distribution of this disease. Our aim was to identify the most differentially regulated genes in 20 gastric adenocarcinomas from a Norwegian selection, compared to matched normal mucosa, and we have related our findings to prognosis, survival and chronic Helicobacter pylori infection.

Methods

Biopsies from gastric adenocarcinomas and adjacent normal gastric mucosa were obtained from 20 patients immediately following surgical resection of the tumor. Whole genome, cDNA microarray analysis was performed on the RNA isolated from the sample pairs to compare the gene expression profiles between the tumor against matched mucosa. The samples were microscopically examined to classify gastritis. The presence of H. pylori was examined using microscopy and immunohistochemistry.

Results

130 genes showed differential regulation above a predefined cut-off level. Interleukin-8 (IL-8) and Claudin-1 (CLDN1) were the most consistently up-regulated genes in the tumors. Very high CLDN1 expression in the tumor was identified as an independent and significant predictor gene of reduced post-operative survival. There were distinctly different expression profiles between the tumor group and the control mucosa group, and the histological subsets of mixed type, diffuse type and intestinal type cancer demonstrated further sub-clustering. Up-regulated genes were mapped to cell-adhesion, collagen-related processes and angiogenesis, whereas normal intestinal functions such as digestion and excretion were associated with down-regulated genes. We relate the current findings to our previous study on the gene response of gastric epithelial cells to H. pylori infection.

Conclusions

CLDN1 was highly up-regulated in gastric cancer, and CLDN1 expression was independently associated with a poor post-operative prognosis, and may have important prognostic value. IL-8 and CLDN1 may represent central links between the gene response seen in acute H. pylori infection of gastric epithelial cells, and ultimately gastric cancer.

Endoscopic tri-modal imaging improves detection of gastric intestinal metaplasia among a high-risk patient population in Singapore

BACKGROUND

Detection of pre-neoplastic gastric mucosal changes and early gastric cancer (EGC) by white-light endoscopy (WLE) is often difficult. In this study we investigated whether combined autofluorescence imaging (AFI) and narrow band imaging (NBI) can improve detection of pre-neoplastic lesions and early gastric cancer in high-risk patients.

PATIENTS AND METHODS

Chinese patients who were 50-years-old or above with dyspepsia were examined by both high-resolution WLE and combined AFI followed by NBI (AFI-NBI), consecutively in a prospective randomized cross-over setting, by two experienced endoscopists. The primary outcome was diagnostic ability of the two methods for patients with pre-neoplastic lesions such as intestinal metaplasia (IM) and mucosal atrophy.

RESULTS

Sixty-five patients were recruited. One patient with large advanced gastric cancer was found and excluded from the analysis. Among the remaining 64 patients, 38 (59%) had IM; of these, 26 (68%) were correctly identified by AFI-NBI (sensitivity 68%, specificity 23%) and only 13 (34%) by WLE (sensitivity 34%, specificity 65%). AFI-NBI detected more patients with IM than did WLE (p=0.011). Thirty-one patients (48%) had mucosal atrophy. Ten patients (32%) were identified by AFI-NBI (sensitivity 32%, specificity 79%) and four patients (13%) by WLE (sensitivity 13%, specificity 88%) (p=0.100). No dysplasia or EGC was found.

CONCLUSION

AFI-NBI identified significantly more patients with IM than did WLE. Our result warrants further studies to define the role of combined AFI-NBI endoscopy for detection of precancerous conditions.

Screening and treating intermediate lesions to prevent gastric cancer

Early gastric cancer is defined as adenocarcinoma confined to the mucosa or submucosa irrespective of lymph node involvement. In Japan, mucosal high-grade neoplasia is diagnosed as intramucosal early gastric cancer. Some early gastric cancers progress to advanced gastric cancer after several years of follow-up. Image-enhanced endoscopy (chromoendoscopy), narrow-band imaging, and magnifying endoscopy increase the diagnostic yield in characterizing early gastric cancer. Endoscopic resection of intramucosal early gastric cancer with endoscopic mucosal resection or endoscopic submucosal dissection is currently performed in East Asian countries to prevent the development of advanced gastric cancer and preserve patients' quality of life after treatment.

Additional corpus biopsy enhances the detection of Helicobacter pylori infection in a background of gastritis with atrophy

Background

The best sites for biopsy-based tests to evaluate H. pylori infection in gastritis with atrophy are not well known. This study aimed to evaluate the site and sensitivity of biopsy-based tests in terms of degree of gastritis with atrophy.

Methods

One hundred and sixty-four (164) uninvestigated dyspepsia patients were enrolled. Biopsy-based tests (i.e., culture, histology Giemsa stain and rapid urease test) and non-invasive tests (anti-H. pylori IgG) were performed. The gold standard of H. pylori infection was defined according to previous criteria. The sensitivity, specificity, positive predictive rate and negative predictive rate of biopsy-based tests at the gastric antrum and body were calculated in terms of degree of gastritis with atrophy.

Results

The prevalence rate of H. pylori infection in the 164 patients was 63.4%. Gastritis with atrophy was significantly higher at the antrum than at the body (76% vs. 31%; p<0.001). The sensitivity of biopsy-based test decreased when the degree of gastritis with atrophy increased regardless of biopsy site (for normal, mild, moderate, and severe gastritis with atrophy, the sensitivity of histology Giemsa stain was 100%, 100%, 88%, and 66%, respectively, and 100%, 97%, 91%, and 66%, respectively, for rapid urease test). In moderate to severe antrum or body gastritis with atrophy, additional corpus biopsy resulted in increased sensitivity to 16.67% compare to single antrum biopsy.

Conclusions

In moderate to severe gastritis with atrophy, biopsy-based test should include the corpus for avoiding false negative results.

A bacterial driver-passenger model for colorectal cancer: beyond the usual suspects

Cancer has long been considered a genetic disease. However, accumulating evidence supports the involvement of infectious agents in the development of cancer, especially in those organs that are continuously exposed to microorganisms, such as the large intestine. Recent next-generation sequencing studies of the intestinal microbiota now offer an unprecedented view of the aetiology of sporadic colorectal cancer and have revealed that the microbiota associated with colorectal cancer contains bacterial species that differ in their temporal associations with developing tumours. Here, we propose a bacterial driver-passenger model for microbial involvement in the development of colorectal cancer and suggest that this model be incorporated into the genetic paradigm of cancer progression.

Comprehensive investigation of areae gastricae pattern in gastric corpus using magnifying narrow band imaging endoscopy in patients with chronic atrophic fundic gastritis

BACKGROUND

Barium radiographic studies have suggested the importance of evaluating areae gastricae pattern for the diagnosis of gastritis. Significance of endoscopic appearance of areae gastricae in the diagnosis of chronic atrophic fundic gastritis (CAFG) was investigated by image-enhanced endoscopy.

MATERIALS AND METHODS

 Endoscopic images of the corpus lesser curvature were studied in 50 patients with CAFG. Extent of CAFG was evaluated with autofluorescence imaging endoscopy. The areae gastricae pattern was evaluated with 0.2% indigo carmine chromoendoscopy. Micro-mucosal structure was examined with magnifying chromoendoscopy and narrow band imaging.

RESULTS

 In patients with small extent of CAFG, polygonal areae gastricae separated by a narrow intervening part of areae gastricae was observed, whereas in patients with wide extent of CAFG, the size of the areae gastricae decreased and the width of the intervening part of areae gastricae increased (p < 0.001). Most areae gastricae showed a foveola-type micro-mucosal structure (82.7%), while intervening part of areae gastricae had a groove-type structure (98.0%, p < 0.001). Groove-type mucosa had a higher grade of atrophy (p < 0.001) and intestinal metaplasia (p < 0.001) compared with foveola type.

CONCLUSIONS

 As extent of CAFG widened, multifocal groove-type mucosa that had high-grade atrophy and intestinal metaplasia developed among areae gastricae and increased along the intervening part of areae gastricae. Our observations facilitate our understanding of the development and progression of CAFG.

Gut bacteria in health and disease: a survey on the interface between intestinal microbiology and colorectal cancer

A healthy human body contains at least tenfold more bacterial cells than human cells and the most abundant and diverse microbial community resides in the intestinal tract. Intestinal health is not only maintained by the human intestine itself and by dietary factors, but is also largely supported by this resident microbial community. Conversely, however, a large body of evidence supports a relationship between bacteria, bacterial activities and human colorectal cancer. Symbiosis in this multifaceted organ is thus crucial to maintain a healthy balance within the host-diet-microbiota triangle and accordingly, changes in any of these three factors may drive a healthy situation into a state of disease. In this review, the factors that sustain health or drive this complex intestinal system into dysbiosis are discussed. Emphasis is on the role of the intestinal microbiota and related mechanisms that can drive the initiation and progression of sporadic colorectal cancer (CRC). These mechanisms comprise the induction of pro-inflammatory and pro-carcinogenic pathways in epithelial cells as well as the production of (geno)toxins and the conversion of pro-carcinogenic dietary factors into carcinogens. A thorough understanding of these processes will provide leads for future research and may ultimately aid in development of new strategies for CRC diagnosis and prevention.

Helicobacter pylori-negative gastric cancer in South Korea: incidence and clinicopathologic characteristics

BACKGROUND AND AIM

It is difficult to determine the exact incidence rate of Helicobacter pylori (H. pylori) infection-negative gastric cancer (HPIN-GC) because H. pylori detection rates decrease with the progression of gastric atrophy and intestinal metaplasia. The aim of this study was to evaluate the incidence and clinicopathologic characteristics of HPIN-GC in South Korea.

METHODS

Helicobacter pylori infection status was evaluated by histology, a rapid urease test (CLO test), culturing, serology, and history of H. pylori eradication for 627 patients with gastric cancer. Current H. pylori infection was defined as positive results from histology, the CLO test, and culturing. Previous H. pylori infection was defined as negative in all three biopsy-based tests and positive serology or history of H. pylori eradication. Patients were considered to be negative for H. pylori infection if all results from five methods were negative. However, patients who were found to have severe gastric atrophy by the serum pepsinogen test or metaplastic gastric atrophy by histology were assumed to have had a previous H. pylori infection even if results from other tests for H. pylori infection were all negative.

RESULTS

The number of patients with gastric cancer with current or previous H. pylori infection was 439 (70.0%) and 154 (24.6%), respectively. The rate of HPIN-GC occurrence was 5.4% (n = 34). Sex, age, Lauren type, location of the tumor, and treatment modalities were not different according to H. pylori infection status. However, HPIN-GC had a more advanced pT classification (T3/T4; 51.9 vs 31.1%, p = .025) and a more advanced stage (more than stage I; 63 vs 41.3%, p = .027) than H. pylori-positive gastric cancer.

CONCLUSION

At least 5.4% cases of gastric cancer were H. pylori negative among South Korean patients. HPIN-GC looks like to have a poorer prognosis than H. pylori-positive cases.

Gastric cancer risk according to the distribution of intestinal metaplasia and neutrophil infiltration

BACKGROUND AND AIM

Gastritis and intestinal metaplasia (IM) have long been known to be risk factors for and precursors of gastric cancer. We aimed to elucidate the association between gastric cancer risk and the distribution of precancerous lesions in the stomach by histological analyses.

METHODS

We analyzed patients from whom two biopsy specimens (one from the antrum and one from the corpus) were obtained by upper gastrointestinal endoscopy. Specimens were assessed for Helicobacter pylori, IM, and neutrophil infiltration (NI). Patients were classified into three groups based on the presence of IM. Patients were also classified into four groups based on the presence of NI. The prevalence of gastric cancer was compared between groups.

RESULTS

A total of 1395 patients were analyzed. Of these, 54 had gastric cancer (34 intestinal and 20 diffuse type). A multivariate analysis showed that male sex and the distribution of IM were independent risk factors for intestinal-type cancer. Compared with patients without IM (n = 1005), the odds ratio (OR) for patients with IM in the antrum only (n = 240) was 2.34 (95% confidence interval: 1.08-4.96), and that for patients with IM in the corpus (n = 150) was 5.84 (2.92-11.8). However, NI was related to diffuse-type cancer. Compared with patients without NI (n = 899), the OR for patients with NI in the corpus only (n = 122) was 3.66 (1.02-12.2).

CONCLUSIONS

The histological pattern and distribution of gastric mucosal change assessed by two biopsy specimens were related to gastric cancer.

Genome-wide DNA methylation profiles in noncancerous gastric mucosae with regard to Helicobacter pylori infection and the presence of gastric cancer

BACKGROUND AND AIMS

To determine genome-wide DNA methylation profiles induced by Helicobacter pylori (H. pylori) infection and to identify methylation markers in H. pylori-induced gastric carcinogenesis.

METHODS

Gastric mucosae obtained from controls (n = 20) and patients with gastric cancer (n = 28) were included. A wide panel of CpG sites in cancer-related genes (1505 CpG sites in 807 genes) was analyzed using Illumina bead array technology. Validation of the results of Illumina bead array technique was performed using methylation-specific PCR method for four genes (MOS, DCC, CRK, and PTPN6).

RESULTS

 The Illumina bead array showed that a total of 359 CpG sites (269 genes) were identified as differentially methylated by H. pylori infection (p < .0001). The correlation between methylation-specific PCR and bead array analysis was significant (p < .0001, Spearman coefficient = 0.5054). Methylation profiles in noncancerous gastric mucosae of the patients with gastric cancer showed quite distinct patterns according to the presence or absence of the current H. pylori infection; however, 10 CpG sites were identified to be hypermethylated and three hypomethylated in association with the presence of gastric cancer regardless of H. pylori infection (p < .01).

CONCLUSIONS

 Genome-wide methylation profiles showed a number of genes differentially methylated by H. pylori infection. Methylation profiles in noncancerous gastric mucosae from the patients with gastric cancer can be affected by H. pylori-induced gastritis. Differentially methylated CpG sites in this study needs to be validated in a larger population using quantitative methylation-specific PCR method.

Towards the human colorectal cancer microbiome

Multiple factors drive the progression from healthy mucosa towards sporadic colorectal carcinomas and accumulating evidence associates intestinal bacteria with disease initiation and progression. Therefore, the aim of this study was to provide a first high-resolution map of colonic dysbiosis that is associated with human colorectal cancer (CRC). To this purpose, the microbiomes colonizing colon tumor tissue and adjacent non-malignant mucosa were compared by deep rRNA sequencing. The results revealed striking differences in microbial colonization patterns between these two sites. Although inter-individual colonization in CRC patients was variable, tumors consistently formed a niche for Coriobacteria and other proposed probiotic bacterial species, while potentially pathogenic Enterobacteria were underrepresented in tumor tissue. As the intestinal microbiota is generally stable during adult life, these findings suggest that CRC-associated physiological and metabolic changes recruit tumor-foraging commensal-like bacteria. These microbes thus have an apparent competitive advantage in the tumor microenvironment and thereby seem to replace pathogenic bacteria that may be implicated in CRC etiology. This first glimpse of the CRC microbiome provides an important step towards full understanding of the dynamic interplay between intestinal microbial ecology and sporadic CRC, which may provide important leads towards novel microbiome-related diagnostic tools and therapeutic interventions.

Towards the human colorectal cancer microbiome

Multiple factors drive the progression from healthy mucosa towards sporadic colorectal carcinomas and accumulating evidence associates intestinal bacteria with disease initiation and progression. Therefore, the aim of this study was to provide a first high-resolution map of colonic dysbiosis that is associated with human colorectal cancer (CRC). To this purpose, the microbiomes colonizing colon tumor tissue and adjacent non-malignant mucosa were compared by deep rRNA sequencing. The results revealed striking differences in microbial colonization patterns between these two sites. Although inter-individual colonization in CRC patients was variable, tumors consistently formed a niche for Coriobacteria and other proposed probiotic bacterial species, while potentially pathogenic Enterobacteria were underrepresented in tumor tissue. As the intestinal microbiota is generally stable during adult life, these findings suggest that CRC-associated physiological and metabolic changes recruit tumor-foraging commensal-like bacteria. These microbes thus have an apparent competitive advantage in the tumor microenvironment and thereby seem to replace pathogenic bacteria that may be implicated in CRC etiology. This first glimpse of the CRC microbiome provides an important step towards full understanding of the dynamic interplay between intestinal microbial ecology and sporadic CRC, which may provide important leads towards novel microbiome-related diagnostic tools and therapeutic interventions.

Increased exposure to bacterial antigen RpL7/L12 in early stage colorectal cancer patients

BACKGROUND

Cancer 2010. (c) 2010 American Cancer Society. : Intestinal bacteria have long been implicated in colorectal cancer pathology, and many reports point to a close linkage between Streptococcus bovis biotype I (recently renamed Streptococcus gallolyticus) infections and tumors of the human colon. This work aims to investigate the humoral immune response to this bacterium during different stages of colorectal cancer.

METHODS

The presence of serum antibodies against S. bovis antigen RpL7/L12, previously assigned as a potential diagnostic antigen, was evaluated in Dutch (n = 209) and American (n = 112) populations using a newly developed enzyme-linked immunosorbent assay.

RESULTS

The analyses consistently showed that an immune response against this bacterial antigen was increased in polyp patients and stage I/II colorectal cancer patients as compared with asymptomatic individuals. This was not paralleled by increased antibody production to endotoxin, an intrinsic cell wall component of the majority of intestinal bacteria, which implies that the humoral immune response against RpL7/L12 is not a general phenomenon induced by the loss of colonic barrier function. Notably, increased anti-RpL7/L12 levels were not or were only mildly detected in late stage colorectal cancer patients having lymph node or distant metastasis.

CONCLUSIONS

Cancer 2010. (c) 2010 American Cancer Society. : These findings are indicative of an increased exposure to antigen RpL7/L12 during early stages of colon carcinogenesis and suggest that intestinal bacteria such as S. bovis constitute a risk factor for the progression of premalignant lesions into early stage carcinomas. Clearly, the current findings emphasize the necessity for further studies on the possible etiologic relationship between intestinal bacteria and human colorectal cancer.

The role of serum pepsinogen in the detection of gastric cancer

The incidence of gastric cancer is very high in Japan, Korea, and China. Reducing the morbidity and mortality associated with gastric cancer requires early diagnosis, which can be facilitated by applying gastroscopy more frequently in high-risk groups. A strategy of population screening for gastric cancer is currently being adopted in Korea, Japan, and the Matsu region of Taiwan, but using different screening methods. In addition, the history of pepsinogen (PG) in research as a gastric cancer biomarker has varied, in that the use of serum levels of PGI and PGII and the PGI/PGII ratio as gastric cancer screening tools was introduced in Japan before 1990, but in Korea the first research results were only reported in 2008. This review first evaluates the physiology of PG, followed by the usefulness or limitations of serum PG testing with regard to the detection of gastric cancer. Finally, the factors affecting the efficacy of PG tests as a gastric cancer biomarker (i.e., Helicobacter pylori infection status, gender, histopathologic features, and cancer location and depth) are evaluated. It was found that the strategies used to increase the efficacy of PG tests should be individualized in each country according to the seroprevalence of H. pylori.