LAUSR

Abstract Subtraction hybridization identified genes displaying differential expression as metastatic human melanoma cells terminally differentiated and lost tumorigenic properties by treatment with recombinant fibroblast interferon and mezerein. This approach permitted cloning of multiple genes displaying enhanced expression when melanoma cells terminally differentiated, called melanoma differentiation associated (mda) genes. One mda gene, mda‐7, has risen to the top of the list based on its relevance to cancer and now inflammation and other pathological states, which based on presence of a secretory sequence, chromosomal location, and an IL‐10 signature motif has been named interleukin‐24 (MDA‐7/IL‐24). Discovered in the early 1990s, MDA‐7/IL‐24 has proven to be a potent, near ubiquitous cancer suppressor gene capable of inducing cancer cell death through apoptosis and toxic autophagy in cancer cells in vitro and in preclinical animal models in vivo. In addition, MDA‐7/IL‐24 embodied profound anticancer activity in a Phase I/II clinical trial following direct injection with an adenovirus (Ad.mda‐7; INGN‐241) in tumors in patients with advanced cancers. In multiple independent studies, MDA‐7/IL‐24 has been implicated in many pathological states involving inflammation and may play a role in inflammatory bowel disease, psoriasis, cardiovascular disease, rheumatoid arthritis, tuberculosis, and viral infection. This review provides an up‐to‐date review on the multifunctional gene mda‐7/IL‐24, which may hold potential for the therapy of not only cancer, but also other pathological states.