Displaying all 19 publications

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  1. Katz AR
    Am J Gastroenterol, 2007 Sep;102(9):2114-5.
    PMID: 17727450
    Matched MeSH terms: Stomach Neoplasms/microbiology
  2. Naing C, Aung HH, Aye SN, Poovorawan Y, Whittaker MA
    PLoS One, 2024;19(8):e0307172.
    PMID: 39173001 DOI: 10.1371/journal.pone.0307172
    BACKGROUND: Helicobacter pylori (H. pylori) is frequently associated with non-cardia type gastric cancer, and it is designated as a group I carcinogen. This study aimed to systematically review and meta-analyze the evidence on the prevalence of CagA status in people with gastric disorders in the Indo-Pacific region, and to examine the association of CagA positive in the risk of gastric disorders. This study focused on the Indo-Pacific region owing to the high disability adjusted life-years related to these disorders, the accessibility of efficient treatments for this common bacterial infection, and the varying standard of care for these disorders, particularly among the elderly population in the region.

    METHODS: Relevant studies were identified in the health-related electronic databases including PubMed, Ovid, Medline, Ovid Embase, Index Medicus, and Google Scholar that were published in English between 1 January 2000, and 18 November 2023. For pooled prevalence, meta-analysis of proportional studies was done, after Freeman-Tukey double arcsine transformation of data. A random-effect model was used to compute the pooled odds ratio (OR) and 95% confidence interval (CI) to investigate the relationship between CagA positivity and gastric disorders.

    RESULTS: Twenty-four studies from eight Indo-Pacific countries (Bhutan, India, Indonesia, Malaysia, Myanmar, Singapore, Thailand, Vietnam) were included. Overall pooled prevalence of CagA positivity in H. pylori-infected gastric disorders was 83% (95%CI = 73-91%). Following stratification, the pooled prevalence of CagA positivity was 78% (95%CI = 67-90%) in H. pylori-infected gastritis, 86% (95%CI = 73-96%) in peptic ulcer disease, and 83% (95%CI = 51-100%) in gastric cancer. Geographic locations encountered variations in CagA prevalence. There was a greater risk of developing gastric cancer in those with CagA positivity compared with gastritis (OR = 2.53,95%CI = 1.15-5.55).

    CONCLUSION: Findings suggest that the distribution of CagA in H. pylori-infected gastric disorders varies among different type of gastric disorders in the study countries, and CagA may play a role in the development of gastric cancer. It is important to provide a high standard of care for the management of gastric diseases, particularly in a region where the prevalence of these disorders is high. Better strategies for effective treatment for high-risk groups are required for health programs to revisit this often-neglected infectious disease.

    Matched MeSH terms: Stomach Neoplasms/microbiology
  3. Alfizah H, Noraziah MZ, Chao MY, Rahman MM, Ramelah M
    Clin Ter, 2013;164(4):301-5.
    PMID: 24045512 DOI: 10.7417/CT.2013.1577
    Helicobacter pylori strains secrete a vacuolating cytotoxin (VacA), plays an important role for the development of peptic ulcer disease and gastro-duodenal diseases. vacA gene is responsible to regulate the activity of the vacuolating cytotoxin. The objective of this study was molecular detection of vacA gene and observes the vacuolating activity on human gastric adenocarcinoma (AGS) cells.
    Matched MeSH terms: Stomach Neoplasms/microbiology*
  4. Goh KL
    Med J Malaysia, 2009 Sep;64(3):187-92.
    PMID: 20527265
    Observations of racial differences in the prevalence of Helicobacter pylori in Malaysia have been intriguing. The Indians and Chinese consistently have a higher prevalence compared to the Malays. The racial cohort theory has been proposed to explain these differences where transmission and perpetuation of infection takes place within a racial group rather than between races, races being separate owing to the low rate of interracial marriages. Studies have demonstrated distinctive bacterial strains between races. Phylogenetic studies have shown that H. pylori isolates amongst Chinese and Indians are distinctive while Malays have Indian and other strains suggesting a more recent acquisition of the bacterium from Indians. H. pylori is recognized as the major causative factor in peptic ulcer disease and gastric cancer. Despite the high prevalence of H. pylori, Indians have a relatively low prevalence of peptic ulcer disease and a low incidence of gastric cancer. This paradox with regards to gastric cancer has been termed the "Indian enigma". Bacterial strain differences between races may be putative but this observation may also indicate gastroprotective environmental factors or a lower genetic susceptibility to develop cancer in the Indians.
    Matched MeSH terms: Stomach Neoplasms/microbiology
  5. Misra V, Pandey R, Misra SP, Dwivedi M
    World J Gastroenterol, 2014 Feb 14;20(6):1503-9.
    PMID: 24587625 DOI: 10.3748/wjg.v20.i6.1503
    Helicobacter pylori (H. pylori) is a gram negative microaerophilic bacterium which resides in the mucous linings of the stomach. It has been implicated in the causation of various gastric disorders including gastric cancer. The geographical distribution and etiology of gastric cancer differ widely in different geographical regions and H. pylori, despite being labeled as a grade I carcinogen, has not been found to be associated with gastric cancer in many areas. Studies in Asian countries such as Thailand, India, Bangladesh, Pakistan, Iran, Saudi Arabian countries, Israel and Malaysia, have reported a high frequency of H. pylori infection co-existing with a low incidence of gastric cancer. In India, a difference in the prevalence of H. pylori infection and gastric cancer has been noted even in different regions of the country leading to a puzzle when attempting to find the causes of these variations. This puzzle of H. pylori distribution and gastric cancer epidemiology is known as the Indian enigma. In this review we have attempted to explain the Indian enigma using evidence from various Indian studies and from around the globe. This review covers aspects of epidemiology, the various biological strains present in different parts of the country and within individuals, the status of different H. pylori-related diseases and the molecular pathogenesis of the bacterium.
    Matched MeSH terms: Stomach Neoplasms/microbiology*
  6. Castaño-Rodríguez N, Goh KL, Fock KM, Mitchell HM, Kaakoush NO
    Sci Rep, 2017 11 21;7(1):15957.
    PMID: 29162924 DOI: 10.1038/s41598-017-16289-2
    The gastric microbiome has been proposed as an etiological factor in gastric carcinogenesis. We compared the gastric microbiota in subjects presenting with gastric cancer (GC, n = 12) and controls (functional dyspepsia (FD), n = 20) from a high GC risk population in Singapore and Malaysia. cDNA from 16S rRNA transcripts were amplified (515F-806R) and sequenced using Illumina MiSeq 2 × 250 bp chemistry. Increased richness and phylogenetic diversity but not Shannon's diversity was found in GC as compared to controls. nMDS clustered GC and FD subjects separately, with PERMANOVA confirming a significant difference between the groups. H. pylori serological status had a significant impact on gastric microbiome α-diversity and composition. Several bacterial taxa were enriched in GC, including Lactococcus, Veilonella, and Fusobacteriaceae (Fusobacterium and Leptotrichia). Prediction of bacterial metabolic contribution indicated that serological status had a significant impact on metabolic function, while carbohydrate digestion and pathways were enriched in GC. Our findings highlight three mechanisms of interest in GC, including enrichment of pro-inflammatory oral bacterial species, increased abundance of lactic acid producing bacteria, and enrichment of short chain fatty acid production pathways.
    Matched MeSH terms: Stomach Neoplasms/microbiology*
  7. Sukri A, Hanafiah A, Kosai NR, Taher MM, Mohamed Rose I
    Malays J Pathol, 2017 Dec;39(3):235-242.
    PMID: 29279585 MyJurnal
    The multiracial population in Malaysia has lived together for almost a century, however, the risk of gastric cancer among them varies. This study aimed to determine the distribution of different gastric adenocarcinoma subtypes and Helicobacter pylori infection status among gastric adenocarcinoma patients. Patients with gastric adenocarcinoma were enrolled from November 2013 to June 2015. Blood samples were collected for detection of H. pylori using ELISA method. Gastric adenocarcinoma cases were more prevalent in the Chinese (52.8%), followed by the Malays (41.7%) and least prevalent in the Indians (5.6%). Gastric adenocarcinoma located in the cardia was significantly more prevalent in the Malays (66.7%) compared to the Chinese (26.3%), whereas non-cardia cancer was diagnosed more in the Chinese (73.7%) compared to the Malays (33.3%) [P = 0.019; OR = 5.6, 95 CI: 1.27 to 24.64]. The Malays also had significantly higher prevalence of gastric tumour located at the cardia or fundus than other gastric sites compared to the Chinese (P = 0.002; OR: 11.2, 95% CI: 2.2 to 56.9). Among the cardia gastric cancer patients, 55.6% of the Malays showed intestinal histological subtype, whereas all the Chinese had the diffuse subtype. More than half of the patients (55.3%) with gastric adenocarcinoma were positive for H. pylori infection and among them, 66.7% were Chinese patients. The risk of gastric adenocarcinoma in our population is different among ethnicities. Further studies on host factors are needed as it might play an important role in gastric cancer susceptibility in our population.
    Matched MeSH terms: Stomach Neoplasms/microbiology
  8. Tokudome S, Ando R, Ghadimi R, Tanaka T, Hattori N, Yang Z, et al.
    Asian Pac J Cancer Prev, 2007 Mar;8(3):462-3.
    PMID: 18159988
    The great variability in gastric cancer rates across Asia, with very high incidences in Japan and Korea, and exceedingly low incidences in ethnic Malays, whether in Malaysia or Indonesia, appears largely due to variation in Helicobacter pylori infection rates. While between 2% and 10.6% of gastric cancers in a recent Japanese survey were considered to be negative for bacterial infection on the basis of seropositivity and H. pylori-dependent mucosal atrophy, it is notoriously difficult to preclude past infection. The situation is greatly complicated by reported differences in the etiology of gastric cardia and non-cardia cancers. In the Western world there do appear to be tumours arising close to the esophageal-gastric junction which are not related to H. pylori and associated inflammation, but in most Asian populations these appear to be very rare. Therefore preventive efforts, and particularly screening, should be focused on markers of bacterial infection, with avoidance of unnecessary exposure to X-ray radiation.
    Matched MeSH terms: Stomach Neoplasms/microbiology*
  9. Goh KL, Cheah PL, Md N, Quek KF, Parasakthi N
    Am J Gastroenterol, 2007 Jan;102(1):40-5.
    PMID: 17100981
    To determine the risk factors for gastric cancer (GCA), with particular emphasis on ethnicity in our multiracial population.
    Matched MeSH terms: Stomach Neoplasms/microbiology*
  10. Gunaletchumy SP, Teh X, Khosravi Y, Ramli NS, Chua EG, Kavitha T, et al.
    J Bacteriol, 2012 Oct;194(20):5695-6.
    PMID: 23012278
    Helicobacter pylori is the main bacterial causative agent of gastroduodenal disorders and a risk factor for gastric adenocarcinoma and mucosa-associated lymphoid tissue (MALT) lymphoma. The draft genomes of 10 closely related H. pylori isolates from the multiracial Malaysian population will provide an insight into the genetic diversity of isolates in Southeast Asia. These isolates were cultured from gastric biopsy samples from patients with functional dyspepsia and gastric cancer. The availability of this genomic information will provide an opportunity for examining the evolution and population structure of H. pylori isolates from Southeast Asia, where the East meets the West.
    Matched MeSH terms: Stomach Neoplasms/microbiology
  11. Gunaletchumy SP, Seevasant I, Tan MH, Croft LJ, Mitchell HM, Goh KL, et al.
    Sci Rep, 2014 Dec 11;4:7431.
    PMID: 25503415 DOI: 10.1038/srep07431
    Helicobacter pylori infection results in diverse clinical conditions ranging from chronic gastritis and ulceration to gastric adenocarcinoma. Among the multiethnic population of Malaysia, Indians consistently have a higher H. pylori prevalence as compared with Chinese and Malays. Despite the high prevalence of H. pylori, Indians have a relatively low incidence of peptic ulcer disease and gastric cancer. In contrast, gastric cancer and peptic ulcer disease incidence is high in Chinese. H. pylori strains from Chinese strains predominantly belong to the hspEAsia subpopulation while Indian/Malay strains mainly belong to the hspIndia subpopulation. By comparing the genome of 27 Asian strains from different subpopulations, we identified six genes associated with risk of H. pylori-induced peptic ulcer disease and gastric cancer. This study serves as an important foundation for future studies aiming to understand the role of bacterial factors in H. pylori-induced gastro-duodenal diseases.
    Matched MeSH terms: Stomach Neoplasms/microbiology*
  12. Osman HA, Hasan H, Suppian R, Bahar N, Hussin NS, Rahim AA, et al.
    Asian Pac J Cancer Prev, 2014;15(13):5245-7.
    PMID: 25040982
    BACKGROUND: Helicobacter pylori (H. pylori) is one of the most important causes of dyspepsia and gastric cancer and diagnosis can be made by invasive or non-invasive methods. The Atlas Helicobacter pylori antigen test is a new rapid non-invasive method which is simple to conduct. The aim of this study was to determine its sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy.

    MATERIALS AND METHODS: This prospective study was conducted between July 2012 and December 2013. Stool samples of 59 dyspeptic patients who underwent upper endoscopy were evaluated for H. pylori stool antigen.

    RESULTS: From the 59 patients who participated in this study, there were 36 (61%) males and 23 (39%) females. H. pylori was diagnosed in 24 (40.7%) gastric biopsies, 22 (91.7 %) of these being positive for the Atlas H. pylori antigen test. The sensitivity, specificity, PPV, NPV and accuracy were 91.7%, 100%, 100%, 94.6% and 96.6% respectively.

    CONCLUSIONS: The Atlas H. pylori antigen test is a new non-invasive method which is simple to perform and avails reliable results in a few minutes. Thus it can be the best option for the diagnosis of H. pylori infection due to its high sensitivity and specificity.

    Matched MeSH terms: Stomach Neoplasms/microbiology
  13. Breurec S, Guillard B, Hem S, Brisse S, Dieye FB, Huerre M, et al.
    PLoS One, 2011;6(7):e22058.
    PMID: 21818291 DOI: 10.1371/journal.pone.0022058
    The human population history in Southeast Asia was shaped by numerous migrations and population expansions. Their reconstruction based on archaeological, linguistic or human genetic data is often hampered by the limited number of informative polymorphisms in classical human genetic markers, such as the hypervariable regions of the mitochondrial DNA. Here, we analyse housekeeping gene sequences of the human stomach bacterium Helicobacter pylori from various countries in Southeast Asia and we provide evidence that H. pylori accompanied at least three ancient human migrations into this area: i) a migration from India introducing hpEurope bacteria into Thailand, Cambodia and Malaysia; ii) a migration of the ancestors of Austro-Asiatic speaking people into Vietnam and Cambodia carrying hspEAsia bacteria; and iii) a migration of the ancestors of the Thai people from Southern China into Thailand carrying H. pylori of population hpAsia2. Moreover, the H. pylori sequences reflect iv) the migrations of Chinese to Thailand and Malaysia within the last 200 years spreading hspEasia strains, and v) migrations of Indians to Malaysia within the last 200 years distributing both hpAsia2 and hpEurope bacteria. The distribution of the bacterial populations seems to strongly influence the incidence of gastric cancer as countries with predominantly hspEAsia isolates exhibit a high incidence of gastric cancer while the incidence is low in countries with a high proportion of hpAsia2 or hpEurope strains. In the future, the host range expansion of hpEurope strains among Asian populations, combined with human motility, may have a significant impact on gastric cancer incidence in Asia.
    Matched MeSH terms: Stomach Neoplasms/microbiology
  14. Ansari S, Yamaoka Y
    Int J Mol Sci, 2020 Oct 08;21(19).
    PMID: 33050101 DOI: 10.3390/ijms21197430
    Helicobacter pylori causes persistent infection in the gastric epithelium of more than half of the world's population, leading to the development of severe complications such as peptic ulcer diseases, gastric cancer, and gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Several virulence factors, including cytotoxin-associated gene A (CagA), which is translocated into the gastric epithelium via the type 4 secretory system (T4SS), have been indicated to play a vital role in disease development. Although infection with strains harboring the East Asian type of CagA possessing the EPIYA-A, -B, and -D sequences has been found to potentiate cell proliferation and disease pathogenicity, the exact mechanism of CagA involvement in disease severity still remains to be elucidated. Therefore, we discuss the possible role of CagA in gastric pathogenicity.
    Matched MeSH terms: Stomach Neoplasms/microbiology*
  15. Pabalan N, Jarjanazi H, Ozcelik H
    J Gastrointest Cancer, 2014 Sep;45(3):334-41.
    PMID: 24756832 DOI: 10.1007/s12029-014-9610-2
    BACKGROUND: Reported associations of capsaicin with gastric cancer development have been conflicting. Here, we examine 10 published articles that explore these associations using 2,452 cases and 3,996 controls.

    METHODS: We used multiple search strategies in MEDLINE through PubMed to seek for suitable articles that had case-control design with gastric cancer as outcome.

    RESULTS: The outcomes of our study shows protection (odds ratio [OR] 0.55, P = 0.003) and susceptibility (OR 1.94, P = 0.0004), both significant with low and medium-high intake of capsaicin, respectively, although under relatively heterogeneous conditions (P(heterogeneity) = <0.0001). Outlier analysis resulted in loss of overall heterogeneity (P = 0.14) without affecting the pooled ORs. Among the subgroups, low intake elicited protection in both Korean (OR 0.37) and Mexican (OR 0.63) populations while high intake rendered these subgroups susceptible (OR 2.96 and OR 1.57, respectively). These subgroup values were highly significant (P = 0.0001-0.01) obtained in heterogeneous conditions (P(heterogeneity) 

    Matched MeSH terms: Stomach Neoplasms/microbiology
  16. Liou JM, Malfertheiner P, Lee YC, Sheu BS, Sugano K, Cheng HC, et al.
    Gut, 2020 12;69(12):2093-2112.
    PMID: 33004546 DOI: 10.1136/gutjnl-2020-322368
    OBJECTIVE: A global consensus meeting was held to review current evidence and knowledge gaps and propose collaborative studies on population-wide screening and eradication of Helicobacter pylori for prevention of gastric cancer (GC).

    METHODS: 28 experts from 11 countries reviewed the evidence and modified the statements using the Delphi method, with consensus level predefined as ≥80% of agreement on each statement. The Grading of Recommendation Assessment, Development and Evaluation (GRADE) approach was followed.

    RESULTS: Consensus was reached in 26 statements. At an individual level, eradication of H. pylori reduces the risk of GC in asymptomatic subjects and is recommended unless there are competing considerations. In cohorts of vulnerable subjects (eg, first-degree relatives of patients with GC), a screen-and-treat strategy is also beneficial. H. pylori eradication in patients with early GC after curative endoscopic resection reduces the risk of metachronous cancer and calls for a re-examination on the hypothesis of 'the point of no return'. At the general population level, the strategy of screen-and-treat for H. pylori infection is most cost-effective in young adults in regions with a high incidence of GC and is recommended preferably before the development of atrophic gastritis and intestinal metaplasia. However, such a strategy may still be effective in people aged over 50, and may be integrated or included into national healthcare priorities, such as colorectal cancer screening programmes, to optimise the resources. Reliable locally effective regimens based on the principles of antibiotic stewardship are recommended. Subjects at higher risk of GC, such as those with advanced gastric atrophy or intestinal metaplasia, should receive surveillance endoscopy after eradication of H. pylori.

    CONCLUSION: Evidence supports the proposal that eradication therapy should be offered to all individuals infected with H. pylori. Vulnerable subjects should be tested, and treated if the test is positive. Mass screening and eradication of H. pylori should be considered in populations at higher risk of GC.

    Matched MeSH terms: Stomach Neoplasms/microbiology*
  17. Maran S, Lee YY, Xu S, Rajab NS, Hasan N, Syed Abdul Aziz SH, et al.
    World J Gastroenterol, 2013 Jun 21;19(23):3615-22.
    PMID: 23801863 DOI: 10.3748/wjg.v19.i23.3615
    To identify genes associated with gastric precancerous lesions in Helicobacter pylori (H. pylori)-susceptible ethnic Malays.
    Matched MeSH terms: Stomach Neoplasms/microbiology
  18. Castaño-Rodríguez N, Kaakoush NO, Pardo AL, Goh KL, Fock KM, Mitchell HM
    Hum Immunol, 2014 Aug;75(8):808-15.
    PMID: 24929142 DOI: 10.1016/j.humimm.2014.06.001
    Gastric cancer (GC) is a progressive process initiated by Helicobacter pylori-induced inflammation. Initial recognition of H. pylori involves Toll-like receptors (TLRs), central molecules in the host inflammatory response. Here, we investigated the association between novel polymorphisms in genes involved in the TLR signalling pathway, including TLR2, TLR4, LBP, MD-2, CD14 and TIRAP, and risk of H. pylori infection and related GC.
    Matched MeSH terms: Stomach Neoplasms/microbiology
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