Relationship of The Lung Microbiome With PD-L1 Expression And Immunotherapy Response in Lung Cancer

Background: Lung cancer is the primary cause of cancer-related deaths worldwide. The human lung serves as a niche to a unique and dynamic bacterial community that is related to the development of multiple diseases. Here, we investigated the differences in the lung microbiomes of patients with lung cancer. Methods: 16S rRNA sequencing was performed to evaluate the respiratory tract microbiome present in the bronchoalveolar lavage fluid. Patients were stratified based on programmed death-ligand 1 (PD-L1) expression levels and immunotherapy responses. Results: In total, 84 patients were prospectively analyzed, of which 59 showed low (<10%), and 25 showed high (>10%) PD-L1 expression levels. The alpha and beta diversities did not significantly differ between the two groups. Veillonella dispar was dominant in the high-PD-L1 group; the population of Neisseria was significantly higher in the low-PD-L1 group than in the high-PD-L1 group. In the immunotherapy responder group, V. dispar was dominant, while Haemophilus influenzae and Neisseria perflava were dominant in the non-responder group. Conclusion: The abundances of Neisseria and V. dispar differed significantly in relation to PD-L1 expression levels and immunotherapy responses. Thus, these two genera may be considered targets for lung cancer immunotherapy.