The goal of this project is to improve lung cancer screening in high-risk individuals by identifying biomarkers of preclinical disease and disease risk that are measured in minimally invasive and non-invasive biospecimens. Existing biomarkers for lung cancer diagnosis as well as new biomarkers discovered specifically in this clinical setting will be examined. Biomarkers that identify individuals at highest risk for being diagnosed with lung cancer prior to the appearance of concerning symptoms could increase the utility of lung cancer surveillance and the efficiency of lung cancer chemoprevention clinical trials. Achieving these goals would improve the detection and treatment of early stage and incipient lung cancer, while restricting the risk of these procedures to those individuals who currently exhibit the early molecular warning signs of impending disease.