Lung cancer remains the leading cause of cancer death in the Western world. In spite of major advances in understanding the staging and prognostic factors of lung cancer, advances in survival have been minimal over the past 20 years. For patients with non-small cell carcinoma, surgical resection offers the only chance of meaningful survival. In contrast, for patients with small cell carcinoma, the sensitivity of this tumor type to cytotoxic therapy, including chemotherapy and radiation therapy, offers the only chance of long-term survival. However, it is clear that many factors in addition to stage of disease and performance status of the patient are important in predicting the prognosis for lung cancer. These factors include the biologic properties inherent in the tumor cells themselves. In this review, I evaluate recent findings in studies of the biology of lung cancer cells and consider the potential application of these findings in the treatment of patients with this disease.