⁃ DISEASE CHARACTERISTICS:

• Screening Cohort

‣ At high- or low-risk for lung cancer

⁃ Smoking history ≥ 20 pack years\*

• With or without workplace exposure to asbestos

• NOTE: \* Participants with \< 20 pack years of smoking are eligible if 50 years of age or older

• Rule-Out Lung cancer group

‣ Referred for evaluation of suspicious nodules with 1 of the following diagnoses:

• Lung cancer

∙ Nonmalignant nodules (control group)

⁃ PATIENT CHARACTERISTICS:

• Not pregnant

• No prior malignancy except nonmelanoma skin cancer

⁃ PRIOR CONCURRENT THERAPY:

• Not specified