Here are some interesting facts about cytotoxin- associated gene A (CagA)- positive strains of H. pylori and its role in esophageal and gastric carcinoma.
- Chronic Helicobacter pylori infection results in lower gastric acid secretion by inducing atrophic gastritis, thus hinting to have an inverse association with EC.
- H. pylori infection reduces ghrelin synthesis due to loss of P/D1 cells in the fundus and body of stomach which decreases gastrointestinal motility and induces delay in gastric emptying, thus increasing the risk of GERD.
- Also the CagA positive strains induce fluctuations in the levels of somatostatin, gastrin, dopamine and other essential hormones, which might cause increased reflux symptoms and metaplastic changes in chronic cases.
- Upregulation of proinflammatory cytokines and impaired TNF-alpha levels might play a role in pathogenesis of esophageal and gastric carcinoma. Extragastric diseases such as Colorectal polyps, nonalcoholic fatty liver disease, dental caries, coronary heart disease, the parkinson's disease, and iron deficiency anemia are also associated with H pylori infection through multiple signaling pathways.
Inspite of much evidence, there have been arguments and debates on the underlying mechanisms in causing esophageal carcinoma. A meta- analytic study, on the other hand has recently concluded that CagA- positive strains of H. pylori have a protective role in EAC while there is no such clear association with ESCC.
- Jaskunwar Singh