Despite recent advances in the treatment of lung cancer, long-term survival remains rare. As more information pertaining to the biology of lung cancer is understood, it is hoped that improvements in outcome can be realized with the use of molecularly based therapies. The identification of gene mutations in lung cancer has led to the development of inhibitory therapies, including antisense oligonucleotides and direct injection of tumor-suppressor genes, such as wild-type p53. Other therapeutic approaches are targeted at inhibiting angiogenesis by blocking endogenous growth factors with antibodies or administering natural antiangiogenic substances. Recognition of the dendritic cell as one of the primary cells responsible for antitumor immunity has encouraged studies of immunotherapy for patients with lung cancer. In addition, studies have shown that dendritic cell function is defective in tumor-bearing animals. Research continues to explore of the effect of tumor on immune cell function and ways to overcome such defects. Rationally derived therapies based on these biological findings may advance the treatment, as well as early detection and prevention, of lung cancer, thereby improving patient outcomes.