Genetic polymorphisms in the cag pathogenicity island ofHelicobacter pyloriand risk of stomach cancer and high‐grade premalignant gastric lesions (original) (raw)
Related papers
Scientific Reports, 2020
Helicobacter pylori (HP) colonizes the human stomach and induces acute gastritis, peptic ulcer disease, atrophic gastritis, and gastric adenocarcinoma. Increased virulence in HP isolates derives from harboring the cag (cytotoxin-associated genes) pathogenicity island (cagPAI). We analyzed the microvariants in cagPAI genes with the hypothesis that they may play an important role in determining HP virulence. We tested DNAs from cagA positive patients HP isolates; a total of 74 patients with chronic gastritis (CG, N = 37), intestinal metaplasia (IM, N = 21) or gastric cancer (GC, N = 16) from Mexico and Colombia. We selected 520 non-synonymous variants with at least 7.5% frequency in the original sequence outputs or with a minimum of 5 isolates with minor allele. After adjustment for multiple comparisons, no variants were statistically significantly associated with IM or GC. However, 19 non-synonymous showed conventional P-values < 0.05 comparing the frequency of the alleles between...
A GWAS on Helicobacter pylori strains points to genetic variants associated with gastric cancer risk
BMC biology, 2018
Helicobacter pylori are stomach-dwelling bacteria that are present in about 50% of the global population. Infection is asymptomatic in most cases, but it has been associated with gastritis, gastric ulcers and gastric cancer. Epidemiological evidence shows that progression to cancer depends upon the host and pathogen factors, but questions remain about why cancer phenotypes develop in a minority of infected people. Here, we use comparative genomics approaches to understand how genetic variation amongst bacterial strains influences disease progression. We performed a genome-wide association study (GWAS) on 173 H. pylori isolates from the European population (hpEurope) with known disease aetiology, including 49 from individuals with gastric cancer. We identified SNPs and genes that differed in frequency between isolates from patients with gastric cancer and those with gastritis. The gastric cancer phenotype was associated with the presence of babA and genes in the cag pathogenicity isl...
Diagnostic Microbiology and Infectious Disease, 2007
Helicobacter pylori is a bacterium associated with upper gastrointestinal diseases in humans. However, only a small proportion of infected people become sick. Although several studies have tried to establish an association between known virulence markers and clinical outcomes, in many cases the results have been conflicting. The aim of this study was to investigate the importance of virulence markers to predict clinical outcome in Brazil. Mixed infections by genetically unrelated strains detected by vacA genotyping were found in 18% of the patients. The cagA and cagE genes and the vacAs1 genotype were associated with the development of peptic ulcer disease (PUD). The cagAvacAs1m1 genotype was associated with PUD and duodenal ulcer (DU). Conversely, jhp947 was not associated with DU or PUD, indicating that this gene is not a universal virulence marker. These results also show that a high proportion of the patients were simultaneously infected by cag-positive and cag-negative H. pylori types. This finding suggests the existence of a dynamic equilibrium between the loss and gain of the cag pathogenicity island, probably depending on the physiologic conditions of the patient's stomach. To the best of our knowledge, this is the first study that has documented this finding in Brazil.
Infection, Genetics and Evolution, 2019
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Association between Helicobacter pylori hopQI genotypes and human gastric cancer risk
Cellular and molecular biology (Noisy-le-Grand, France), 2016
The Helicobacter pylori use a number of mechanisms to survive in the stomach lumen and can lead to gastritis and reduction in stomach acid secretion. It has been found that the risk of developing gastric carcinoma is associated to heterogeneity of H. pylori virulence factors such as HopQ. The HopQ is one of the outer membrane proteins involved in bacterial adherence to gastric mucosa and has been suggested to also main role in the virulence of H. pylori. The purpose of the current study was to investigate the association between different H. pylori virulence hopQI (types I) genotyping and patients with gastroduodenal disorders. For this purpose 58 stomach biopsies of the patients with gastric cancer and 100 saliva samples from healthy and H. pylori infected individuals were collected and studied. Then genomic DNA was purified and PCR was done for desired gene via specific primers. The H. pylori infections were diagnosed using PCR for GlmM gene. Then frequencies of hopQI+ and hopQI- ...
Gastric Cancer, 2010
A (cagA)-positive Helicobacter pylori, resulting in the accumulation of alterations in the TP53 tumor suppressor gene in gastric cells. We investigated the association of the AICDA 7888 C/T polymorphism with H. pylori infection and the risk of gastric cancer and atrophic gastritis in Japanese subjects. Methods. The study subjects were 583 histologically diagnosed gastric cancer patients (cases) and 1637 age-and sexfrequency-matched control outpatients, who visited Aichi Cancer Center Hospital from the years 2001 to 2005. In the controls, serum anti-H. pylori IgG antibody and pepsinogens were measured to evaluate H. pylori infection and atrophic gastritis, respectively. Odds ratios (ORs) and 95% confi dence intervals (CIs) were calculated by a logistic model.
2021
Background: Infection with Helicobacter pylori is recognized as the main risk factor for gastric cancer (GC); the clinical outcome of this infection is variable and partially depends on the virulence of the infective strain. This study characterizes H. pylori virulence genes in patients with diverse gastric lesions, from preneoplasia to GC, from a South American region with high GC mortality rates.Methods: We studied the virulence profiles of H. pylori strains to colonize the antrum of 318 patients with non-atrophic gastritis (NAG), 58 patients with preneoplastic lesions (PN), and 90 with GC from Ibagué, Colombia. The presence of 16S rDNA, the cagA and cagE genes, and the vacA s1, s2, m1, and m2 alleles were determined by PCR.Results: H. pylori infection was detected in 44% of all patients, 41.2% in NAG, 43.1% in PN and 54.4% of GC patients (p= 0.0813). cagA and cagE genes were significantly more frequent in and GC than in NAG (p= <.0001). The vacA s1m1 haplotype was significantl...
Helicobacter, 2008
Background-cagA-positive and vacA s1 and m1 genotypes of Helicobacter pylori are associated with an elevated risk of gastric cancer (GC). We determined these genotypes using paraffinembedded gastric biopsy specimens harvested from infected individuals and compared genotype distributions in two Colombian populations residing in geographic regions with a high and low incidence of GC. Methods-DNA from paraffin-embedded gastric biopsies from 107 adults was amplified using primers specific for cagA, for the cag 'empty site', for the s and m alleles of vacA, and for H. pylori 16S rRNA. Results-H. pylori infection was detected by molecular assays in 97 (90.7%) biopsies. Complete genotyping of cagA and vacA was achieved in 94 (96.9%) cases. The presence of cagA was detected in 78 of 97 cases (80.4%); when considered separately, cagA and vacA s regions were not significantly associated with a particular geographic area. The vacA m1 allele and s1m1 genotypes were more common in the area of high risk for GC (p = .037 and p = .044, respectively), while the vacA m2 allele and s2m2 genotypes were more prevalent in the low-risk area. The prevalence of the combination of cagA-positive, vacA s1m1 genotypes was 84.3% and 60.5% for high and low risk areas, respectively (p = .011). Conclusions-H. pylori cagA and vacA genotyping from paraffin-embedded gastric biopsies permitted reliable typability and discrimination. The more virulent cagA-positive s1m1 strains, as well as vacA m1 genotype, were more prevalent in high risk than in low risk areas, which may contribute to the difference in GC risk between those two regions.
Asian Pacific Journal of Cancer Prevention, 2015
Background: Gastric cancer (GC) is the third most common cancer regarding mortality in the world. The cag pathogenicity island (PAI) of Helicobacter pylori which contains genes associated with a more aggressive phenotype may involve in the pathogenesis of gastrointestinal disease. We here aimed to examine the associations of cagH, cagL, orf17, and cagG genotypes of H. pylori cag PAI with severe gastrointestinal disease. Materials and Methods: A total of 242 H. pylori strains were genotyped. Histopathological examination and classification of subjects were performed. Results: The frequencies of the cagH, cagL, cagG, and orf17 genotypes were 40/54 (74.1%), 53/54 (98.1%), 38/54 (70.4%), and 43/54 (79.6%), respectively, in patients with peptidic ulceration (PU),while in the control group, the frequencies were 87/147 (59.6%) for cagH, 121/146 (82.9%) for cagL, 109/146 (74.7%) for cagG, and 89/146 (61.0%) for orf17. The results of simple logistic regression analysis showed that the cagL and orf17 genotypes were significantly associated with an increased risk of PU not GC; the ORs (95% CI) were 10.950 (1.446-82.935), and 2.504 (1.193-5.253), respectively. No significant association was found between the cagH and cagG genotypes and the risk of both the PU and the GC in Iran (P>0.05). Finally, multiple logistic regression analysis showed that the cagL genotype was independently and significantly associated with the ageand sex-adjusted risk for PU; the OR (95% CI) was 9.557 (1.219-17.185). Conclusions: We conclude that the orf17 and especially cagL genotypes of H. pylori cag PAI could be factors for risk prediction of PU, but not GC in Iran.