Clinically, BAL and sputum profiling demonstrates utility in COPD management: First, MUC5AC, CC16, and EV-related proteins serve as diagnostic/prognostic biomarkers; second, sputum microbiome and inflammatory markers (e.g., eosinophil levels) guide personalized therapies (e.g., targeted biologics); lastly, longitudinal monitoring enables precise assessment of disease progression and treatment response. This evidence concerns the gene MUC5AC and chronic obstructive pulmonary disease.