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Simple Summary: Gastric cancer (GC) is regarded as one of the most perilous malignancies globally, with over one billion new cases and seven hundred and eighty-three thousand deaths reported in 2020. The incidence of GC is particularly high in Asian countries. Moreover, multiple oncogenic signaling pathways are activated and implicated in gastric carcinogenesis, leading to malignant phenotype acquisition. This review outlines the most updated epidemiology of GC in Asian countries, along with targeted therapies for GC treatment. Despite the decline in incidence and mortality rates, gastric cancer (GC) is the fifth leading cause of cancer deaths worldwide. The incidence and mortality of GC are exceptionally high in Asia due to high H. pylori infection, dietary habits, smoking behaviors, and heavy alcohol consumption. In Asia, males are more susceptible to developing GC than females. Variations in H. pylori strains and prevalence rates may contribute to the differences in incidence and mortality rates across Asian countries. Large-scale H. pylori eradication was one of the effective ways to reduce GC incidences. Treatment methods and clinical trials have evolved, but the 5-year survival rate of advanced GC is still low. Efforts should be put towards large-scale screening and early diagnosis, precision medicine, and deep mechanism studies on the interplay of GC cells and microenvironments for dealing with peritoneal metastasis and prolonging patients' survival. [ABSTRACT FROM AUTHOR]

Introduction: Over the past several decades, Europe and the United States have experienced a rapid increase in esophageal adenocarcinoma. Research and countermeasures against Barrett's esophagus, its precancerous lesion, are progressing. Because esophageal adenocarcinoma has an extremely poor prognosis when diagnosed in an advanced stage, recommendations for early cancer detection have been made based on the various proven etiological factors of Barrett's esophagus and the actual cancer risk of Barrett's esophagus. In recent years, there have been indications of an increase in esophageal adenocarcinoma in Japan, and a similar trend of cancer will occur shortly in other Asian countries. Consequently, Asian countries must implement similar countermeasures against Barrett's esophagus and esophageal adenocarcinoma, referencing the knowledge gained thus far in Europe and the United States., Areas Covered: This review summarizes the latest findings on the etiologic factors of Barrett's esophagus and discusses the differences between Westerners and Asians. The current status of Barrett's esophagus in Japan and other Asian countries is also summarized., Expert Opinion: The etiological factors and cancer incidence of Barrett's esophagus in Asia diverge somewhat from those observed in Europe and America. Therefore, it is imperative to implement measures that are tailored to the actual circumstances of Asian people.

Aim: To investigate the association between use of nonsteroidal anti-inflammatory drugs (NSAID) and Helicobacter pylori infection, interactive effect of H. pylori infection and NSAID use on the development of peptic ulcer disease (PUD), and the effect of H. pylori eradication therapy on PUD development. Material and Methods: We performed a systematic literature search in EMBASE and PubMed for relevant articles published in English between January 1989 and August 2010, with the following MeSH and/or key words: non-steroidal anti-inflammatory drugs, or NSAIDs, Helicobacter pylori, or H. pylori, peptic ulcer disease or PUD, and randomized-control study or clinical trial. The meta-analysis was conducted using the Review Manager 4.2.2. Results: In the analysis of five studies, the pooled prevalence of H. pylori infection was 74.5% and 71.1% in NSAID users and non-NSAID users, respectively, (OR = 0.65; 95% CI: 0.35-1.20, p = .170). In the analysis of nine studies, the pooled prevalence of PUD in NSAID users was 31.2% and 17.9% in the presence and absence of H. pylori infection, respectively, (OR = 3.08; 95% CI: 1.26-7.55, p = .010). Moreover, in the analysis of seven studies, PUD developed in 6.4% and 11.8% of NSAID users with and without eradication therapy, respectively (OR = 0.50; 95% CI: 0.36-0.74, p < .001). The preventive effect of the eradication therapy was further revealed in NSAID-naive users (OR = 0.26; 95% CI: 0.14-0.49, p < .0001) and in the Asian population (OR = 0.30; 95% CI: 0.16-0.56, p < .001). Conclusion: NSAID use is not associated with H. pylori infection in patients with PUD. PUD is more common in H. pylori positive than in negative NSAID users. Moreover, H. pylori eradication therapy reduces PUD incidence in NSAID users, especially in naive users and in the Asian population. [ABSTRACT FROM AUTHOR]

In Asia, the prevalence of Helicobacter pylori ( H. pylori) infection varies markedly in different countries. Higher prevalence rates are found in developing Asian countries while lower rates have been reported in more industrialized and developed countries. Within a country, the seroprevalence rates may vary between distinct geographic regions. H. pylori infection is an important etiological factor for the occurrence of non-cardia gastric adenocarcinoma. The incidence rate of gastric adenocarcinoma in Asia tends to mirror the seroprevalence rate of H. pylori infection; however, there are populations with high seroprevalence rates of H. pylori infection that paradoxically have low incidence rates of gastric adenocarcinoma. These diverse clinical outcomes are related to bacterial virulence factors, concomitant environmental factors, host susceptibility and immune response. This review summarizes the current epidemiology of H. pylori infection in Asia and analyzes these data in the context of gastric cancer epidemiology. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Although well established in the West, stool antigen tests (SAT) are not widely used in Asia. Data on the accuracy of this test in Asia is sparse and, to date, there have been no studies looking at the more refined monoclonal SAT. The aim of this study is to validate the diagnostic accuracy of a stool antigen test, Hp STAR, for the detection of Helicobacter pylori. METHODS: Consecutive new patients with dyspepsia, referred to the endoscopy unit were recruited. At endoscopy, biopsies were taken for rapid urease tests and histology. Stool specimens were collected before any therapy was given and were tested for H. pylori using the monoclonal SAT HpSTAR test. Samples were collected from 90 patients. The stool antigen results were compared with the results of rapid urease tests and histopathology, which were used together as the gold standard test in the diagnosis of H. pylori. RESULTS: Of the 90 patients tested, 45 were H. pylori positive and 45 were H. pylori negative. There was one false positive and one false negative test. The sensitivity, specificity, positive predictive value and negative predictive value for the Hp STAR were identical: 97.8% with a 95% confidence interval of 88.2–99.9%. The diagnostic accuracy was 97.8% with a 95% confidence interval of 92.2–99.7%. CONCLUSION: The monoclonal stool antigen test, HpSTAR is a highly accurate test for the diagnosis of H. pylori. [ABSTRACT FROM AUTHOR]

The article presents a study on the prevalence of Helicobacter pylori infection in Asian countries. It was found out that Helicobacter pylori transmission induced various upper gastrointestinal diseases, yet the reasons for its different clinical outcomes remain unknown. Investigator developed an interest in host factors such as gastric acid secretion and immune responses.

ABSTRACT Background. It is known that the incidence and mortality rate of gastric cancer is high among Japanese and Chinese populations, but extremely low in Thai and Vietnamese populations. The aim of this study was to investigate the prevalence of Helicobacter pylori infection and the differences in the glandular atrophy and intestinal metaplasia scores in stomach specimens of Asian adult subjects of different races. Materials and Methods. Chinese, Thai, Vietnamese and Japanese patients were matched by age, gender and endoscopic diagnosis, in order to compare the differences in incidence of H. pylori -related peptic ulcer disease and the prevalence of H. pylori infection among four Asian populations (n = 700). Glandular atrophy scores and intestinal metaplasia scores were also compared among four Asian populations divided into H. pylori -positive cases (n = 120, 109, 145, 80, respectively) and H. pylori -negative cases (n = 55, 66, 30, 95, respectively). Results. Among peptic ulcers, gastric ulcer was more frequently seen in Japanese subjects than in the other Asian populations examined. On the other hand, duodenal ulcer was more frequently seen in other Asian populations than in Japanese subjects. The prevalence of H. pylori infection was similar in the Japanese (Tokyo) and Chinese (Beijing and Fuzhou) populations. It was higher in Thai (Chiang Mai) subjects compared with Japanese subjects. On the other hand, Vietnamese (Ho Chi Minh) subjects had significantly lower rates of H. pylori infection than Japanese subjects. The glandular atrophy and intestinal metaplasia scores in the stomach were significantly higher in the H. pylori -positive Japanese subjects than in H. pylori -positive subjects belonging to other Asian populations, except for the higher glandular atrophy scores in Chinese rather than Japanese subjects. On the other hand, there were no significant differences in the glandular atrophy and intestinal metaplasia scores in the angulus of the stomach... [ABSTRACT FROM AUTHOR]

The rising prevalence of antibiotic resistance and the long-term safety following eradication therapy are important issues in the management of Helicobacter pylori infection. The prevalence of clarithromycin, levofloxacin, and metronidazole resistance of H. pylori has increased to 21%, 27%, and 45%, respectively, in the Asia-Pacific region. Personalized treatment guided by susceptibility testing may provide a reliably excellent eradication rate in the first-line treatment but is costly and not widely available. Population-specific empirical therapy according to the local prevalence of antibiotic resistance may be an alternative strategy. Levofloxacin-based therapy and bismuth quadruple therapy are the recommended second-line rescue therapy. Susceptibility testing or genotypic resistance-guided therapy is the preferred treatment for refractory H. pylori infection, but empirical therapy may be an acceptable alternative. Eradication of H. pylori leads to short-term perturbation of gut microbiota. The diversity of gut microbiota can be restored months after eradication therapy, but the speed of recovery varies with regimens. The short-term increases of antibiotic resistance of Escherichia coli and Klebsiella pneumoniae may be restored to basal states months after H. pylori eradication. Future studies that apply in-depth sequencing, such as shotgun metagenomics sequencing, are needed to clarify whether the compositions of gut microbiota at the species level are fully restored., (© 2020 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.)

Helicobacter pylori (HP) genetics may determine its clinical outcomes. Despite high prevalence of HP infection in Latin America (LA), there have been no phylogenetic studies in the region. We aimed to understand the structure of HP populations in LA mestizo individuals, where gastric cancer incidence remains high. The genome of 107 HP strains from Mexico, Nicaragua and Colombia were analyzed with 59 publicly available worldwide genomes. To study bacterial relationship on whole genome level we propose a virtual hybridization technique using thousands of high-entropy 13 bp DNA probes to generate fingerprints. Phylogenetic virtual genome fingerprint (VGF) was compared with Multi Locus Sequence Analysis (MLST) and with phylogenetic analyses of cagPAI virulence island sequences. With MLST some Nicaraguan and Mexican strains clustered close to Africa isolates, whereas European isolates were spread without clustering and intermingled with LA isolates. VGF analysis resulted in increased resolution of populations, separating European from LA strains. Furthermore, clusters with exclusively Colombian, Mexican, or Nicaraguan strains were observed, where the Colombian cluster separated from Europe, Asia, and Africa, while Nicaraguan and Mexican clades grouped close to Africa. In addition, a mixed large LA cluster including Mexican, Colombian, Nicaraguan, Peruvian, and Salvadorian strains was observed; all LA clusters separated from the Amerind clade. With cagPAI sequence analyses LA clades clearly separated from Europe, Asia and Amerind, and Colombian strains formed a single cluster. A NeighborNet analyses suggested frequent and recent recombination events particularly among LA strains. Results suggests that in the new world, H. pylori has evolved to fit mestizo LA populations, already 500 years after the Spanish colonization. This co-adaption may account for regional variability in gastric cancer risk.

Analysis of natural selection events is an attractive strategy for identification of functional variants shaped by gene-environmental interactions and human adaptation. Here, we identified PTK6, a Src-related tyrosine kinase gene, underlying positive selection in East Asian populations. Interestingly, PTK6 variant showed significant correlation with gastric cancer incidences which was the highest in East Asian populations. The high prevalence of gastric cancer in East Asians was also believed to be strongly affected by Helicobacter pylori infection and dietary habit. Therefore, we speculated a competitive interaction of cancer-associated molecules for activation/reduction, where PTK6 likely plays a role through CagA-driven signaling pathway after H. pylori infection. This hypothesis was also supported by our gene expression analysis and the dating of the selective event which was estimated to be ~16,500 years ago, much later than H. pylori invasion in human 50,000 years ago. Establishment of cross talk between PTK6 and CagA by functional studies may further elucidate the underlying biology of H. pylori-mediated gastric cancer.