Proteomic Analysis of Plasma Exosomes Enables the Identification of Lung Cancer in Patients With Chronic Obstructive Pulmonary Disease.

Chronic obstructive pulmonary disease (COPD) is confirmed as an independent risk factor for the development of lung cancer. Although low-dose CT screening significantly reduces the mortality rate of lung cancer, the misdiagnosis and missed diagnosis rates remain high in the COPD population. Additionally, several COPD patients are unable to undergo invasive histological examinations. Therefore, there is an urgent need for minimally invasive biomarkers to screen or diagnose lung cancer in COPD patients. In this study, peripheral blood samples were collected from COPD patients with and without lung cancer. Plasma exosomes (EVs) were extracted for proteomic analysis. Sixteen differentially expressed proteins (DEPs) were preliminarily selected via label-free quantification (LFQ) proteomic technology and comprehensive bioinformatics analysis. Parallel reaction monitoring (PRM) targeted validation identified five candidate proteins associated with COPD with lung cancer. Compared to the COPD group, KRT1, KRT9, and KRT10 were significantly upregulated in the COPD with lung cancer group, while GPLD1 and TF were downregulated. The biomarkers identified in our study provide a foundation for non-invasive screening and diagnosis of lung cancer in COPD patients and exploration of the mechanisms shared between COPD and lung cancer.