Causal relationship between oral/gut microbiota and lung cancer: a two-sample Mendelian randomization study

Several studies have already proven a significant correlation between the microbiota and lung cancer. In this study, we explore the potential relative oral and gut microbiota which influence the risk of lung cancer.

We utilized genome-wide association study (GWAS) data from oral microbiota (2984 healthy individuals) and gut microbiota (2002 healthy individuals) and lung cancer with a two-sample Mendelian randomization (MR) analysis method. In this analysis, oral microbiota and gut microbiota were conducted as exposure. Lung cancer data obtained from GWAS including a total of 212,453 individuals. Inverse-variance weighted (IVW) method was used as the primary method.

IVW analysis identified that genus Pauljensenia, Capnocytophaga and Aggregatibacter in oral microbiota are potentially protective against lung cancer. On the contrary, higher abundances of bacteria within the genus Granulicatella, Streptococcus, Saccharimonadaceae TM7x and Neisseria in oral microbiota were associated with increased lung cancer risk. Among gut bacteria, species Enterococcus faecalis were positively associated with an increased risk of lung cancer.

The findings of this study suggest a potential causal relationship between distinct oral and gut microbial communities and lung cancer risk, offering valuable insights into microbial candidates that may serve as targets for future diagnostic innovations.