The survival from lung cancer has not changed over the past 15 years, despite the intensive application of combined modality therapy for advanced disease. Prevention and early diagnosis appear to be the most promising strategies for reduction of lung cancer mortality. A Keystone Colloquium was held April 1 to 7, 1991, on the Biology of and Novel Therapeutic Approaches for Epithelial Cancers of the Aerodigestive Tract, to discuss recent basic and clinical research in this area. This paper summarizes the presentations relevant to lung cancer, including genetic mechanisms, growth factors, neuropeptides, growth and differentiation, carcinogenesis, chemoprevention, multidrug resistance, and immunology.