Metabolomic Characteristics of Patients With Non-Small Cell Lung Cancer in Plasma, Tissue and Exhaled Breath Condensate: A Case-Control Study

IntroductionLung cancer is a malignant tumor with high global incidence and mortality. Early screening and diagnosis can substantially extend patient survival, yet achieving this remains a challenging objective.MethodsWe collected tissue and plasma samples from patients with benign pulmonary nodules and non-small cell lung cancer (NSCLC). Exhaled breath condensate (EBC) samples were obtained from these patients using a breath condenser. Differential metabolites were identified in samples from 22 NSCLC patients and 20 benign controls by means of ultra-performance liquid chromatography-high resolution mass spectrometry-based untargeted metabolomics.ResultsSeveral differential metabolites overlapped between plasma and tissue samples. Further analysis indicated that the differential metabolites from all three sample types participated in central carbon metabolism in cancer, protein digestion and absorption, and aminoacyl-tRNA biosynthesis. ROC curve analysis of plasma and tissue metabolites showed that each of the top 10 upregulated and downregulated metabolites yielded AUC values greater than 0.8. In EBC, only 29 differential metabolites were detected. Among these, lysine, acetildenafil, and 1-(cyclohexylmethyl) proline may be involved in the progression of NSCLC.ConclusionThis study identified distinctive metabolic markers in plasma, tissue, and EBC from NSCLC patients. However, the purpose of this observational study was merely exploratory, rather than to use these differential metabolites as a diagnostic test for non-small cell lung cancer.