Identifying Biomarkers for Lung Cancer Using Tissue Samples From Patients With Lung Cancer and From Healthy Participants

DISEASE CHARACTERISTICS: * Meets 1 of the following criteria: * Known or previously diagnosed lung cancer * Suspected lung cancer, including the following: * Completely resected stage I lung cancer (with no evidence of metastatic disease) for which patient is at risk for developing secondary disease * Suspected of having lung cancer due to clinical symptoms, such as positive sputum cytology, hemoptysis, unresolved pneumonia, persistent cough, and positive x-ray * Healthy volunteer PATIENT CHARACTERISTICS: * WBC ≥ 2,000/mm³ but ≤ 20,000/mm³ * Platelet count ≥ 50,000/mm³ * Not pregnant * No uncontrolled hypertension (i.e., systolic blood pressure \> 200 mm Hg, diastolic blood pressure \> 120 mm Hg) * No unstable angina * No known bleeding disorder * No other contraindications for white light bronchoscopic examination * No other contraindications for fluorescence examination PRIOR CONCURRENT THERAPY: * More than 3 months since prior fluorescent photosensitizing agents (hematoporphyrin derivatives) * More than 3 months since prior and no concurrent chemopreventative drugs (e.g., tretinoin) * More than 6 months since prior ionizing radiation treatment to the chest * More than 6 months since prior systemic cytotoxic chemotherapy * No concurrent anticoagulant therapy