Electron micrograph of H. pylori WIKIMEDIA, YTAKA TSUTSUMIHelicobacter pylori is a widespread bacterium that colonizes the gut mucosa in nearly half the human population, causing gastric inflammation and, in a small percentage of patients, stomach cancer—the second leading cause of cancer-related deaths worldwide. But the prevalence of H. pylori infections do not correlate with cancer incidence, suggesting other factors are at play. In a study published today (January 13) in PNAS, researchers provide evidence that those other factors include the ancestry of both the host and the pathogen: patients that are infected with H. pylori strains that have a distinct ancestry from their own are more likely to suffer severe disease.
“For the first time, [this study] suggests that we have to take the ancestry of both host and microbe into the equation,” said Emad El-Omar, a gastroenterologist and cancer biologist at the University of Aberdeen, who was not involved in the work. “We can’t just look at one or the other.”
The research is the latest study of two Colombian populations that have served as poster children for the study of gastric cancer. A coastal population of primarily African ancestry has a relatively low incidence of the disease as compared with a population of largely Amerindian descent in the Andes Mountains just 200 kilometers away. For years, pathologist and native Colombian Pelayo Correa, a pioneer of gastric cancer research, has puzzled over this discrepancy.
Curious ...
