Global prevalence and diversity of the oncogenic cagA gene of Helicobacter pylori
- VernacularTitle:Дэлхийн хүн амын дундах Helicobacter pylori-ийн онкоген cagA-гийн тархалт ба олон янз байдлын судалгаа
- Author:
Saruuljavkhlan B
1
;
2
;
3
;
Namsrai R
3
;
Gantuya B
1
;
2
;
Oyuntsetseg Kh
1
;
Yoshio Yamaoka
3
Author Information
1. Endoscopy Unit, Mongolia-Japan Hospital, MNUMS
2. Department of Gastroenterology and Hepatology, School of Medicine, MNUMS
3. Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Japan
- Publication Type:Journal Article
- Keywords:
Oncoprotein;
virulence;
gastric cancer;
genetic admixture
- From:
Mongolian Journal of Health Sciences
2026;93(3):8-16
- CountryMongolia
- Language:Mongolian
-
Abstract:
Background:CagA (cytotoxin-associated gene A protein) is an oncoprotein produced by Helicobacter pylori, a bacterium implicated in gastric carcinogenesis. CagA has been identified in all H. pylori strains isolated from patients with gastric cancer. To date, comparative studies investigating the genetic diversity of the cagA gene at the international level remain limited, and its pathogenic mechanisms have not yet been fully elucidated.
Aim:To characterize the global and regional diversity of the cagA gene in H. pylori, and to evaluate the relationship of its prevalence and genotypic variants with gastric cancer.
Materials and Methods:This molecular epidemiological study analyzed 9,276 H. pylori genomes from human hosts across 93 countries that were publicly available in international databases as of November 2024, together with 300 newly generated whole-genome sequences of H. pylori isolates from the Mongolian population that had not previously been deposited in public databases. To determine the genetic diversity of this oncogene, comprehensive genome bioinformatics analyses were performed, including genomic, phylogenetic, genotypic, and in silico protein analyses.
Result:After quality control, 7,150 H. pylori genomes were included in the final analysis. Overall, 80.9% (n=5,783) of H. pylori strains were found to harbor the cagA gene, with the highest prevalence observed in Asia and the lowest in Europe. Maximum-likelihood phylogenetic analysis revealed substantial genotypic diversity of cagA and marked geographic variation in its distribution. Specifically, five distinct CagA protein types were identified, two of which represented previously undescribed novel types. The distribution of CagA types was found to correlate more strongly with the incidence of gastric cancer than the mere presence of cagA-positive H. pylori.
Conclusion:The majority of H. pylori strains in human populations worldwide harbor the CagA oncoprotein, with an overall prevalence of approximately 81%. Differences among CagA types may contribute to regional variation in gastric cancer risk. The diversification and evolutionary changes of the cagA gene may reflect recent processes of genetic admixture, which in turn shape its geographic and ethnic distribution as well as its pathogenic potential.
- Full text:202609270137389002601_8-16_Дэлхийн хүн амын дундах Helicobacter pylori-ийн онкоген cagA-гийн тархалт ба олон янз байдлын судалгаа.pdf
