Researchers find coevolution of Heliobacter pylori strains has affected gastric cancer risk
Posted onJanuary 15, 2014
Gastric adenocarcinoma, a form of stomach cancer, is the second most common cause of death from cancer, accounting for 10 percent of all cancer deaths. The bacterium Helicobacter pylori, found in the gastric mucosa of more than half the people in the world, causes gastric adenocarcinoma. However, less than one percent of those who harbor the bacterium develop this cancer. To understand why the risk is greater in some than in others, Barbara Schneider of Vanderbilt University Medical Center in Nashville and her colleagues studied two geographically close populations with a similar prevalence of H. pylori but very different rates of gastric adenocarcinoma. They found that when H. pylori strains have had a long time to coevolve along with their human hosts, there is a reduced risk of gastric adenocarcinoma. The research appears in the Proceedings of the National Academy of Sciences.
Schneider and her team knew that in Central and South America, people who live on the coast are more likely to develop gastric cancer and precancerous gastric stomach lesions than those who live in the mountains. They wanted to see if genetic differences between coastal and mountain people and between the H. pylori they carried accounted for the difference in risk.