The results of a prospective study by researchers in the United States and China suggest that the type and abundance of bacteria found in the mouth may be linked to lung cancer risk in nonsmokers. The study, claimed to be the first of its kind, found that lower bacterial alpha diversity was associated with a greater risk of lung cancer among never-smokers. Taxa in the Bacteroidetes, Spirochaetes, and Firmicutes phyla of bacteria were also associated with altered risk.