Gene therapy has several applications in oncology, including the transduction into malignant tumor cells of genes encoding cytokines or coactivation factors to augment host antitumor responses and the transfer of tumor suppressor genes, particularly p53 (the most commonly mutated gene found in human cancers), to enhance the sensitivity of malignant cells to chemotherapeutic agents.

Use of viral vectors is associated with a risk of localized and systemic inflammation mediated by cytokines, which can be fatal.

Germ-line therapy inserts specific genes directly into the DNA of sperm, egg, or embryo, producing heritable alterations of the genome.

Progress has been made in treating several inherited disorders, including severe combined immunodeficiency, cystic fibrosis, and hemophilia