Epidemiology of Helicobacter pylori and CagA-Positive Infections and Global Variations in Gastric Cancer

Abstract

Gastric cancer is a major health burden and is the fifth most common malignancy and the third most common cause of death from cancer worldwide. Development of gastric cancer involves several aspects, including host genetics, environmental factors, and Helicobacter pylori infection. There is increasing evidence from epidemiological studies of the association of H. pylori infection and specific virulence factors with gastric cancer. Studies in animal models indicate H. pylori is a primary factor in the development of gastric cancer. One major virulence factor in H. pylori is the cytotoxin-associated gene A (cagA), which encodes the CagA protein in the cag pathogenicity island (cag PAI). Meta-analysis of studies investigating CagA seropositivity irrespective of H. pylori status identified that CagA seropositivity increases the risk of gastric cancer (OR = 2.87, 95% CI: 1.95–4.22) relative to the risk of H. pylori infection alone (OR = 2.31, 95% CI: 1.58–3.39). Eradicating H. pylori is a strategy for reducing gastric cancer incidence. A meta-analysis of six randomised controlled trials (RCTs) suggests that searching for and eradicating H. pylori infection reduces the subsequent incidence of gastric cancer with a pooled relative risk of 0.66 (95% CI: 0.46–0.95). The introduction in regions of high gastric cancer incidence of population-based H. pylori screening and treatment programmes, with a scientifically valid assessment of programme processes, feasibility, effectiveness and possible adverse consequences, would impact the incidence of H. pylori-induced gastric cancer. Given the recent molecular understanding of the oncogenic role of CagA, targeting H. pylori screening and treatment programmes in populations with a high prevalence of H. pylori CagA-positive strains, particularly the more oncogenic East Asian H. pylori CagA strains, may be worth further investigation to optimise the benefits of such strategies.

<p>LINC01272 Promotes Migration and Invasion of Gastric Cancer Cells via EMT</p>

“…GC remains one of the most common malignancies worldwide, although there has been a decrease in both the incidence and mortality associated with GC in most developed countries in recent decades. 1,2 The prognosis of several patients diagnosed with GC is poor, especially that of patients with advanced GC. 22,23 Identification of specific early diagnostic markers is key to GC diagnosis.…”

“…1 More than 70% of new GC cases occur in developing countries, and the highest GC incidence and mortality have been reported in Eastern Asian countries, including China, Japan, and Korea. 2,3 Most patients with GC are already at an advanced stage when diagnosed and have a poor prognosis, although chemotherapy and surgery are the main treatment options for advanced GC. [4][5][6] One of the main reasons for the low survival rate of GC in 5 years is the lack of specific early diagnostic biomarkers.…”

The Plausibility of Helicobacter Pylori and CagA Strains Related Infertility Among Males in Alexandria, Egypt

“…The prevalence of infection remains >80% in developing countries, while it dramatically declined in the developed countries . (11,18) Infection is usually acquired during childhood and is related to socio-demographic factors such as low socio-economic status, poor hygiene, and dietary habits. (19) The most probable mode of transmission is person-to-person spread but oral-oral and fecal-oral transmissions have also been reported.…”

“…This protein is immunodominant and is recognized immunologically early following infection with H. pylori CagA-positive strains both by gastric mucosal IgA and serum IgG responses. (11) Infected idiopathic infertile males, especially those with serum antibodies to CagA, have reduced sperm motility and a greater number of necrotic and apoptotic sperms in their ejaculates. (9) Simultaneously, such cases have increased systemic level of interleukin-8 (IL-8), IL-1 b, IL-6 and tumour necrosis factor-alpha (TNF-α); that may cause sperm damage.…”

Assessment of a novel method to detect clarithromycin-resistant Helicobacter pylori using a stool antigen test reagent

“…Helicobacter pylori (H. pylori) infects the gastric mucosa, where it causes chronic inflammation, which, in turn, increases the risk of gastric cancer [1][2][3][4]. It is known that H. pylori eradication reduces the risk of gastric cancer [3,[5][6][7][8].…”