摘自美国 National Cancer Institute (NCI) 网站的一段话：

Does H. pylori cause cancer or other diseases?

Yes. Although H. pylori infection does not itself cause illness, chronic infection causes long-lasting inflammation in the stomach (called non-atrophic gastritis) in most people. This inflammation can lead to several possible conditions, including atrophic gastritis (thinning of the stomach lining caused by long-term inflammation) and certain types of stomach (gastric) cancer, particularly gastric adenocarcinoma and gastric mucosa-associated lymphoid tissue (MALT) lymphoma, which is a rare type of non-Hodgkin lymphoma. 

Because of its role in causing stomach cancer, in 1994 H. pylori was classified as a human carcinogen, or cancer-causing agent, by the World Health Organization’s International Agency for Research on Cancer (5). In 2021, the National Toxicology Program’s 15th Report on Carcinogens added chronic infection with H. pylori to its list of substances that are known or reasonably anticipated to cause cancer in humans.