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World J Gastroenterol. Aug 28, 2020; 26(32): 4739-4752
Published online Aug 28, 2020. doi: 10.3748/wjg.v26.i32.4739
Novel virulence factor dupA of Helicobacter pylori as an important risk determinant for disease manifestation: An overview
Jawed Alam, Avijit Sarkar, Bipul Chandra Karmakar, Mou Ganguly, Sangita Paul, Asish K Mukhopadhyay
Jawed Alam, Division of Infectious Diseases, Institute of Life Science, Bhubaneswar 751023, India
Avijit Sarkar, Bipul Chandra Karmakar, Mou Ganguly, Sangita Paul, Asish K Mukhopadhyay, Division of Bacteriology, ICMR-National Institute of Cholera and Enteric Diseases, Kolkata 700010, India
Author contributions: Alam J and Mukhopadhyay AK was involved in the conceptualization; Alam J, Karmakar BC and Sarkar A were involved in the writing the original draft; Sarkar A and Paul S performed the methodology; Karmakar BC was involved in collecting research; Ganguly M took part in the visualization; Ganguly M and Paul S wrote and edited the review; Paul S performed the validation; Mukhopadhyay AK supervised, critically revised and edited the manuscript; All authors have read and approve the final manuscript.
Supported by Council of Scientific and Industrial Research, Government of India, No. 12458; Department of Science and Technology, India, No. IF140909; and the Council of Scientific and Industrial Research, India, No. 09/482(0065)/2017-EMR-1.
Conflict-of-interest statement: All authors declare no conflicts of interest.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Corresponding author: Asish K Mukhopadhyay, PhD, Senior Scientist, Division of Bacteriology, ICMR-National Institute of Cholera and Enteric Diseases, P 33, CIT Road, Scheme XM, Beliaghata, Kolkata 700010, India.
Received: February 20, 2020
Peer-review started: February 20, 2020
First decision: February 29, 2020
Revised: June 23, 2020
Accepted: August 3, 2020
Article in press: August 3, 2020
Published online: August 28, 2020

Helicobacter pylori (H. pylori) is a microaerophilic, Gram-negative, human gastric pathogen found usually in the mucous lining of stomach. It infects more than 50% of the world’s population and leads to gastroduodenal diseases. The outcome of disease depends on mainly three factors: Host genetics, environment and bacterial factors. Among these, bacterial virulence factors such as cagA, vacA are well known for their role in disease outcomes. However, based on the global epidemiological results, none of the bacterial virulence (gene) factors was found to be associated with particular diseases like duodenal ulcer (DU) in all populations. Hence, substantial importance has been provided for research in strain-specific genes outside the cag pathogenicity island, especially genes located within the plasticity regions. dupA found within the plasticity regions was first demonstrated in 2005 and was proposed for duodenal ulcer development and reduced risk of gastric cancer in certain geographical regions. Due to the discrepancies in report from different parts of the world in DU development related to H. pylori virulence factor, dupA became an interesting area of research in elucidating the role of this gene in the disease progression. In this review, we shed light on the detailed information available on the polymorphisms in dupA and their clinical relevance. We have critically appraised several pertinent studies on dupA and discussed their merits and shortcomings. This review also highlights dupA gene as an important biomarker for DU in certain populations.

Keywords: Helicobacter pylori, Plasticity region, Duodenal ulcer, Gastric cancer, dupA gene

Core tip: A novel virulence factor dupA located in the plasticity region of Helicobacter pylori genome was found to be associated with duodenal ulcer development in certain geographical regions. Well-known bacterial virulence factors in this pathogen like cagA, vacA are not found to be associated with duodenal ulcer in Asia. Studies focused on the epidemiology and clinical relevance of dupA around the world exhibit significant variations. Hence, we focused on the variations in dupA and the plausible role of such variation in disease etiology with the goal of bringing attention to this topic to the scientific community and eventually opening up avenues for further research.