Microbiota characteristics in different lung tissue sites of female patients with invasive adenocarcinoma

BACKGROUND: This study aimed to analyze and compare the differences of microbiota in different parts of lung in women with invasive lung adenocarcinoma and further clarify the characteristics of microbiota changes in tumor microenvironment (TME). METHODS: The study patients were all female who underwent lung surgery in our hospital between October 2021 and October 2022. The feasibility of tissue sampling was evaluated by imaging before surgery. Cancerous tissue, paracancerous tissue and normal lung tissue samples were collected from female patients pathologically diagnosed with invasive adenocarcinoma. 16SrRNA sequencing technology was used to detect the diversity, composition distribution and functional characteristics of microbiota in tissue samples. RESULTS: There was no significant difference in alpha diversity among bacterial communities at different lung locations in patients with invasive adenocarcinoma (p > 0.05), although a decreasing trend was observed in the Chao1 and ACE indices. Beta diversity analysis revealed that the microbial communities in cancerous and adjacent non-cancerous tissues exhibited similar structures (UniFrac PCoA: p > 0.05), but differed in species abundance (Unweighted UniFrac PCoA: p < 0.05). The microbiota composition is similar across different sites of invasive adenocarcinoma, but differs in species abundance. Compared to normal lung tissue, both tumor and paracancerous tissues show reduced overall species abundance, though Acinetobacter and Comamonas are significantly enriched (p<0.05). Functional predictions further indicated a shift in the tumor microenvironment, with an increase in Gram-negative bacteria, a decrease in Gram-positive bacteria, and a reduction in most microbial metabolic pathways. CONCLUSIONS: In different locations in the lungs of patients with invasive adenocarcinoma, the compositional structure and functional characteristics of the microbiota of cancer and paracancerous tissues were similar and differed significantly from those of normal lung tissues. Species abundance was significantly lower in cancer and paracancerous tissues, with a dominance of Gram-negative bacteria and a reduced abundance of metabolic pathways in the microbiota.