Lung microbiota analysis in early-stage lung adenocarcinoma

Lung adenocarcinoma (LUAD) is a predominant subtype of lung cancer and is highly lethal. The lung tissue microbiota has been implicated in lung cancer biology but remains incompletely defined at early stages. We enrolled 40 patients with early-stage LUAD. After sequencing quality control, 34 early-stage LUAD tissues and 17 distal noncancerous lung (NC) tissues were retained, including 14 matched LUAD-NC pairs. Microbiota differences were profiled by 16S rRNA sequencing. Early-stage LUAD tissues contained more low-prevalence taxa, with higher richness metrics, but evenness-sensitive indices remained unchanged. β-Diversity analyses further supported that differences were driven primarily by the presence and absence of community membership rather than shifts in high-abundance taxa. Differential abundance analysis using MaAsLin2 identified a set of genera associated with early-stage LUAD, including <i>unclassified_f__Oscillospiraceae</i> and <i>norank_c__Eremiobacteria</i>, as well as several genera decreased in tumors. The microbial features identified through stability screening moderately distinguished early-stage LUAD from NC tissues in out-of-bag validation. Network analysis revealed denser and more clustered topology in early-stage LUAD along with a shift in central taxa compared with NC. Finally, inferences based on PICRUSt2 suggested redistribution of predicted functional potentials across modules linked to microbial cell-envelope programs, ecological interaction traits, and immunometabolic pathways. These findings collectively reveal microbiota alterations in lung tissues associated with early-stage LUAD and support the feasibility of early detection based on microbiota characteristics.<h4>Importance</h4>Microbial dysbiosis has been recognized as a critical factor in the development of lung cancer, but most current research has focused on the gut rather than the lung microbiota. Identifying the key microbes involved in the development of lung adenocarcinoma is therefore essential. In this study, we analyzed the composition and structure of the microbiota in early-stage lung adenocarcinoma tissues in comparison to noncancerous lung tissues. Our findings provide novel insights into the diagnostic potential of the lung microbiota in early-stage lung adenocarcinoma and enhance our understanding of its involvement in tumor progression and the discovery of potential therapeutic targets.