Abstract

Helicobacter pylori (H pylori) are important human pathogens, responsible for most peptic ulcer diseases, gastritis, gastric adenocarcinomas and gastric lymphoma. For many individuals the organism is of low virulence, causing only mild inflammation, and may be causal in the generation of dyspeptic symptoms. Howewer, H. pylori infection appears to be the dominant factor in peptic ulcer disease, and has been recognized as a major risk factor for cancer of the mid and distal stomach. Longstanding H. pylori-induced gastric inflammation often leads to atrophic gastritis, which is considered to be the first important step in the histogenesis of gastric cancer. Epidemiological observations were clear that the World Health Organization classed H. pylori, in 1994, as a type-I cancerigenous agent.