Particles in Exhaled Air – a New Diagnostic Tool for Patients with Lung Adenocarcinoma

Introduction: Diagnosis of lung cancer in late stages contributes to low survival. Screening with computed tomography decreases mortality but is not widely implemented. There is an unmet need for new tools to aid diagnosing and predicting prognosis. A non-invasive, easily accessible device analyzing exhaled air is therefore highly relevant. Aims and objectives: We investigated if exhaled breath particles (EBP) and particle flow rate (PFR) collected using the particles in exhaled air (PExA) device could diagnose primary lung adenocarcinoma (LUAD) and predict successful removal of LUAD. Methods: 17 patients listed for resection of LUAD stages IA - IIIA and 18 control patients were enrolled. EBP was collected before, one-month after surgery and at one timepoint in the control group. Proteomic analysis was done using Olink9s proximity extension assay technology. Microarray data from healthy lung tissue biopsies and primary LUAD tumors deposited on the NCBI9s GEO DataSets website were used for validation. Results: Of 92 proteins analyzed 5 proteins were found to be significantly higher in the LUAD cohort. PLTP and MET were significantly higher in LUAD patients. To validate our EBP findings we searched for correlating gene expressions. Within the GEO DataSets database, phospholipid transfer protein (PLTP) and hepatocyte growth factor (MET) could be validated in a larger cohort. PFR was higher in the LUAD cohort. Conclusions: PFR and EBP have never been used on LUAD. In the present study PFR alone could distinguish between LUAD and control patients. The current data suggests that PLTP and MET may be used to diagnose LUAD and to evaluate successful surgical removal of LUAD.