Ancestral origin of Helicobacter pylori strains predicts risk of gastric cancer

Helicobacter pylori infects half the world and causes significant gastro-dudenal disease including gastric neoplasia. Generally, gastric cancer rates correlate with H pylori prevalence but in some areas there are regions where infection is nearly universal, but rates of gastric cancer are low. In Colombia, there is a 25-fold increase in gastric cancer rate in the Andean mountain (high risk) region compared to the coastal (low risk) region, despite similarly high (90%) prevalence of H pylori in the two locations. In this landmark study, de Sablet and colleagues investigated the ancestral origin of H pylori strains isolated from subjects in these high- and low-risk regions and determined whether this is a predictive determinant of precancerous lesions. Remarkably, they show that strains from the high-risk region were all of European phylogeographic origin, whereas those from the low risk region were of either European (34%) or African origin (66%). Furthermore, they show that European strain origin was strongly predictive of increased premalignant histological lesions and epithelial DNA damage, even in the low-risk region; African strain origin was associated with reduced severity of these parameters (see page …