Gene therapy for lung cancer.

Lung cancer is a leading cause of cancer death and standard chemotherapies are resulting in only marginal improvements in outcome. Experimental approaches involving gene therapy are attractive in this clinical setting. There are two basic types of genes utilized, either those intended to induce immunity or those that are directly tumoricidal. Immunity-inducing genes that have been used in model (and some human) systems include MHC molecules, costimulatory molecules, and cytokines such as IL-2, IL-4, IL-6, GM-CSF. These are intended to induce effective systemic immune responses against tumor antigens which would not otherwise develop. Direct toxic approaches include the reintroduction of tumor suppressor genes or enzymes which convert non-toxic drugs to toxic ones, such as herpes thymidine kinase. As a means for gene delivery, retroviruses are the most common vehicle, although Adenovirus vectors and direct DNA delivery have specific advantages.