Characteristics Of Airway Microbiome In Non-small Cell Lung Cancer Patients And Its Relationship To Tumor Clinical Features

Background:Lung cancer is one of the most common cancer worldwide and has high rates of morbidity.Previous studies have demonstrated that the airway microbiome in patients with lung cancer are different from healthy or benign control in both community diversity and relative abundance of specific genera.It is necessary to explore whether the airway microbiome is related to tumor clinical features,which affect the prognosis of patients.Objective:To characterize airway microbiome in non-small cell lung cancer patients and investigate the relationship between airway microbiome and tumor stage,metastasis status,EGFR gene mutation status of patients with non-small cell lung cancer.Methods:We collected sputum samples from 85 patients with non-small cell lung cancer and 5 patients with benign lung diseases.The next-generation sequencing technique based on 16S rRNA V3-V4 variable region was used to sequence.First of all,we divided the samples into the NSCLC group(NSCLC)and lung benign disease group(Benign).Then,according to tumor stage,lung cancer cases were divided into group F_S1(stageⅠ),F_S2(stageⅡ),F_S3(stageⅢ),F_M1(M1a of stage Ⅳ)and F_M2(M1b or M1c of stage Ⅳ).Next,we grouped the non-small cell lung cancer cases by metastatic status,including cases without lung metastasis or distant metastasis(Non_M)and cases with intrathoracic metastasis(Intra).Meanwhile,according to the status of regional lymph node metastasis,cases of group Non-M were divided into group with regional lymph node metastasis(LNM_Y)and group without regional lymph node metastasis(LNM_N).Finally,patients with lung adenocarcinoma were divided into group EGFR+with EGFR gene mutation and group EGFR-without EGFR gene mutation.The characteristics of airway microbiome were compared base on groups above using bioinformatics methods.Results:At the phylum level,Firmicutes(40%)had the highest relative abundance in the sputum samples from non-small cell lung cancer patients,while Streptococcus(21%)ranked the first at the genus level.The alpha-diversity was similar(Chao1 index P=0.0670 Simpson index P=0.7379,Shannon index P=0.8879),while the beta-diversity was significantly different(PERMANOVA,P=0.001)between NSCLC and Benign.Besides,the relative abundance of Pseudomonas was significantly higher in NSCLC.In addition,differences in the airway microbiome were also compared between patients with different tumor clinical features.The alpha-diversity or beta-diversity were uncorrelated with tumor stage,intrathoracic metastasis,lymph node metastasis or EGFR mutation status.LEfSe analysis of samples from different tumor stages showed that the relative abundance of Actinobacillus in F_S1,SR1 and Peptococcus and Leuconosto in F_S2,Escherichia in F_M1 significantly increased.Compared with Non_M,the relative abundance of Peptostreptococcus,Peptococcus and Escherichia in Intra were significantly higher,while the relative abundance of Streptococcus was significantly lower.Compared with LNM_N,the relative abundance of Parvimonas and Pseudomonas was significantly higher in LNM_Y.Finally,compared with EGFR-,the relative abundance of Prevotella,Porphyromonas,Dialister and Desulfovibrio was significantly higher in EGFR+.Conclusions:The community structure of airway microbiome in non-small cell lung cancer patients is significantly different from patients with benign lung disease,with enriched Pseudomonas in non-small cell lung cancer patients.The airway microbiome composition of patients with non-small cell lung cancer is related to their tumor clinical features,such as tumor stage and metastatic status,including intrathoracic metastasis and lymph node metastasis.Lung adenocarcinoma patients with EGFR gene mutation have different airway microbiome from patients without EGFR gene mutation.