Helicobacter pylori (H. pylori ) infection is highly prevalent in human, affecting nearly half of the world's population; however, infection remains asymptomatic in majority of population. During its co-existence with humans, H. pylori has evolved various strategies to maintain a mild gastritis and limit the immune response of host. On the other side, presence of H. pylori is also associated with increased risk for the development of various gastric pathologies including gastric cancer (GC). A complex combination of host genetics, environmental agents, and bacterial virulence factors are considered to determine the susceptibility as well as the severity of outcome in a subset of individuals. GC is one of the most common cancers and considered as the third most common cause of cancer related death worldwide. Many studies had proved H. pylori as an important risk factor in the development of non-cardia GC. Although both H. pylori infection and GC are showing decreasing trends in the developed world, they still remain a major threat to human population in the developing countries. The current review attempts to highlight recent progress in the field of research on H. pylori induced GC and aims to provide brief insight into H. pylori pathogenesis, the role of major virulence factors of H. pylori that modulates the host environment and transform the normal gastric epithelium to neoplastic one. This review also emphasizes on the mechanistic understanding of how colonization and various virulence attributes of H. pylori as well as the host innate and adaptive immune responses modulate the diverse signaling pathways that leads to different disease outcomes including GC. Core tip: Although the incidence and mortality of gastric cancer (GC) is declining in recent decades but it still remains a major threat in developing countries as compared to developed one. Among various etiological agents, Helicobacter pylori (H. pylori ) play a detrimental role in development of GC. Through this review we focus on the recent progress in the field of research on H. pylori induced GC and providing the brief insight into H. pylori pathogenesis, the role of major virulence factors of H. pylori that modulates the host environment Submit a
CagL is a pilus protein of Helicobacter pylori that interacts with host cellular a5b1 integrins through its arginine-glycine-aspartate (RGD) motif, guiding proper positioning of the T4SS and translocation of CagA. Deletion or sequence variations of cagL significantly diminished the ability of H. pylori to induce secretion of IL-8 by the host cell. Therefore, this study was undertaken to investigate the association of cagL and its amino acid sequence polymorphisms with gastric cancer (GC), peptic ulcer disease (PUD), and non-ulcer dyspepsia (NUD) as there are no such studies from India. In total, 200 adult patients (NUD 120, PUD 30, GC 50) who underwent an upper gastrointestinal endoscopy were enrolled. H. pylori infection was diagnosed by rapid urease test, culture, histopathology, and PCR. The collected isolates were screened for cagL genotype by PCR and assessed for amino acid sequence polymorphisms using sequence translation. The prevalence of H. pylori infection in study population was 52.5 %. Most of the isolates were cagL genopositive (86.6 %), and all had RGD motif in their amino acid sequences. D58 and K59 polymorphisms in cagLgenopositive strains were significantly higher in GC patients (P \ 0.05). Combined D58K59 polymorphism was associated with higher risk of GC (3.8-fold) when compared to NUD. In conclusion, H. pylori cagL amino acid polymorphisms such as D58K59 are correlated with a higher risk of GC in the Indian population. Further studies are required to know the exact role of particular cagL amino acid polymorphisms in the pathogenicity of H. pylori infection.
The high prevalence and species diversity of NTM suggests the need for immediate and accurate characterization of NTM for proper treatment and management of patients.
cagPAI integrity and its different genes are linked to different forms of gastric disease and so may have a role in pathogenesis, diagnosis and management.
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