临床上，弥漫性肺实质病变的影像学表现常见，可提示多种疾病，鉴别诊断困难。其中一些病变最终被诊断为肺癌。由于呼吸道微生物在肺癌发生发展中发挥着重要作用，我们通过回顾性分析158名患者的下呼吸道（LRT）微生物组，寻找可以预测肺癌风险的微生物标志物2021年3月-2023年3月在广州医科大学第一附属医院住院治疗的患有弥漫性肺实质病变的患者。最终诊断为肺癌 21 例，肺部感染 93 例，其他病症（恶性肿瘤和感染除外）44 例。分析患者的临床特征和支气管肺泡灌洗液（BALF）宏基因组二代测序结果。体重指数（BMI）和LRT微生物多样性（Shannon、Simpson、物种丰富度和Choa1指数）显着降低（P肺癌患者 LRT 中嗜酸乳杆菌相对丰度显着较高（P < 0.001）（分别 < 0.001）。 BALF 中嗜酸乳杆菌的相对丰度与 BMI 相结合是肺癌风险的良好预测指标（曲线下面积 = 0.985，准确度 = 98.46%，敏感性 = 95.24%，特异性 = 100.00%；P< 0.001）。研究表明，微生物群落组成比例失衡、微生物多样性减少以及LRT中特定微生物标志物的存在可预测具有弥漫性肺实质病变影像学表现的患者患肺癌的风险。版权所有©2024 Wang，Xiao，卢、吴、陈、张、卢。

In clinical practice, imaging manifestations of diffuse lung parenchymal lesions are common and indicative of various diseases, making differential diagnosis difficult. Some of these lesions are eventually diagnosed as lung cancer.Because respiratory microorganisms play an important role in lung cancer development, we searched for microbial markers that could predict the risk of lung cancer by retrospectively analyzing the lower respiratory tract (LRT) microbiome of 158 patients who were hospitalized in the First Affiliated Hospital of Guangzhou Medical University (March 2021-March 2023) with diffuse lung parenchymal lesions. The final diagnosis was lung cancer in 21 cases, lung infection in 93 cases, and other conditions (other than malignancy and infections) in 44 cases. The patient's clinical characteristics and the results of metagenomic next-generation sequencing of bronchoalveolar lavage fluid (BALF) were analyzed.Body mass index (BMI) and LRT microbial diversity (Shannon, Simpson, species richness, and Choa1 index) were significantly lower (P< 0.001, respectively) and Lactobacillus acidophilus relative abundance in the LRT was significantly higher (P< 0.001) in patients with lung cancer. The relative abundance of L. acidophilus in BALF combined with BMI was a good predictor of lung cancer risk (area under the curve = 0.985, accuracy = 98.46%, sensitivity = 95.24%, and specificity = 100.00%; P< 0.001).Our study showed that an imbalance in the component ratio of the microbial community, diminished microbial diversity, and the presence of specific microbial markers in the LRT predicted lung cancer risk in patients with imaging manifestations of diffuse lung parenchymal lesions.Copyright © 2024 Wang, Xiao, Lu, Wu, Chen, Zhang and Lu.