Characteristics of pathogenic microbes in lung microenvironment of lung cancer patients without respiratory infection

The characteristics of pathogenic microbes are useful for understanding the microbe-driven tumorigenesis. There is a lack of studies on the lung microecology for lung cancer (LC) patients without any respiratory infection. In this work, we aimed to describe the profiles of pathogenic microbes in lung microenvironment of non-small cell lung cancer (NSCLC) patients using pathogen targeted sequencing and 16S rDNA sequencing.

A total of 22 NSCLC patients (13 adenocarcinomas and 9 squamous cell carcinomas) without any pulmonary infection were enrolled. Among them, we collected 15 pieces of tumor tissues, 5 pieces of peritumoral tissues, 6 blood serum samples, and 5 broncho-alveolar lavage fluid (BALF) samples. Pathogen targeted sequencingand16S rDNA sequencing was performed for microbial classification.

The pathogen targeted sequencing results showed that 33, 14, 11, and 27 pathogenic microorganisms were detected in tumor tissues, peritumoral tissues, blood samples, and BALF, respectively. No common microorganisms were shared by four sample types. However, some common elements were shared by three sets: Streptococcus cristatus, Enterococcus, Staphylococcus haemolyticus, Corynebacterium pseudodiphtheria, Acinetobacter jungii, Haemophilus haemolyticus and Haemophilus parainfluenzae. Based on the 16S rDNA sequencing of two BALF samples, there were 104 OTUs found in one BALF sample and 127 OTUs in the other BALF sample; among them, there were 82 common ones, such as OTU1, OTU10, OTU101, OTU105, OTU106, and so on. Based on the above microbial classification and abundance, there might be enriched function in COG terms like COG1132, COG0438 and COG0745, and KEGG terms like K06147, K02029, and K09687.

This study emphasizes the role of the microbiome in LC patients without respiratory infection. These potential biomarkers of LC based on the taxonomic composition of pathogenic microorganisms might have clinical application.