The Presence of dupA in Helicobacter pylori Is Not Significantly Associated with Duodenal Ulceration in Belgium, South Africa, China, or North America

Abstract

A previous study suggested that Helicobacter pylori strains possessing dupA are positively associated with duodenal ulceration and negatively associated with gastric adenocarcinoma. We determined the prevalence of dupA in H. pylori strains recovered from 4 independent populations and found a significant association with gastric cancer but not with duodenal ulceration.Helicobacter pylori infects approximately one-half of the world's population and is a major cause of peptic ulceration and gastric adenocarcinoma. Among infected persons, who develops disease depends on the bacterial strain's virulence, the host's genetic susceptibility, and environmental factors. H. pylori virulence factors associated with the development of ulceration and gastric cancer include VacA, CagA, BabA, and OipA [1][2][3][4][5][6]. Recently the gene dupA was identified in H. pylori strains isolated from patients in Colombia, South Korea, and Japan; infection with dupA-positive strains was significantly associated with duodenal ulceration but negatively associated with gastric cancer [7]. The mechanism appeared to involve induction of IL-8 secretion in gastric epithelial cells followed by increasing gastric inflammation [7]. Thus, dupA appeared to act like other proinflammatory virulence factors, including the cag pathogenicity island and, more controversially, oipA [5,6,8,9].

Relationship between ureB Sequence Diversity, Urease Activity and Genotypic Variations of Different Helicobacter pylori Strains in Patients with Gastric Disorders

“…Our results showed a 2.4-fold increased risk of peptic ulcer (95% CI: 0.483-11.93), compared with gastritis in the infected patients who had dupA positive strains; however, this association was not statistically significant. There are other controversial results for the noted association between gastrointestinal disorders and dupA status (Lu et al, 2005;Arachchi et al, 2007;Argent et al, 2007;Nguyen et al, 2010). Although an increased risk of DU was detected in our study, the lack of significance difference in these patients could be explained by the probable lack in the function of DupA or its secretion in the responsible strains (Jung et al, 2012).…”

Why is the coexistence of gastric cancer and duodenal ulcer rare? Examination of factors related to both gastric cancer and duodenal ulcer

“…Meanwhile, Lu et al [25] and Argent et al [26] reported that the expression of the duodenal ulcer-promoting gene A (dupA) may be associated with an increased risk of duodenal ulcer and a reduced risk of gastric cancer, because the pathogenic mechanism of dupA appears to involve the induction of high interleukin (IL)-8 production in the antrum, leading to antrum-predominant gastritis, a well- recognized characteristic of duodenal ulcer. However, Hussein [1] reported that dupA promotes duodenal ulceration in some populations and gastric ulcer and gastric cancer in others, and Argent et al [26], Nguyen et al [27], and Arachchi et al [28] indicated that about 40% of H. pylori-infected patients with duodenal ulcer do not have the dupA gene, so that they required further investigation into the effects of the dupA gene.…”

“…However, Hussein [1] reported that dupA promotes duodenal ulceration in some populations and gastric ulcer and gastric cancer in others, and Argent et al [26], Nguyen et al [27], and Arachchi et al [28] indicated that about 40% of H. pylori-infected patients with duodenal ulcer do not have the dupA gene, so that they required further investigation into the effects of the dupA gene. However, recently, Jung et al [29] have reported that, although cagA status was associated with inflammation and atrophy both in the antrum and in the corpus, homB (one of the hom family of H. pylori outer-membrane proteins) status was associated with inflammation and atrophy only in the corpus, so that homB gene status may be used as a factor for discriminating between the risk of gastric cancer and that of duodenal ulcer.…”

Molecular Epidemiology of Helicobacter pylori in Brazilian Patients with Early Gastric Cancer and a Review to Understand the Prognosis of the Disease

“…The jhp0917 gene encodes a protein of 475 amino acids, but lacks a region homologous to the Cterminus of virB4, while jhp0918 gene encodes a product of 140 amino acids that is homologous to the missing virB4 region [51]. Since its discovery, dupA gene has been studied by various authors, and the results of their researches suggest that, in some places, dupA gene is not associated with an specific disease [52], or it is suggested that it can be associated with gastric cancer development [53][54][55], or it is directly associated with the development of duodenal ulcer disease [50,56]. Considering all these results, it is suggested that there must be diversity in gene content that can contribute to bacterial adaptation to genetically different ethnic groups that make up de human population [57].…”