Biological therapy, or biotherapy, is the use of natural and manufactured substances derived from the body in order to fight cancer.

• Immunotherapy, the main focus of biological therapy, works to boost or restore the body's immune system so it can better recognize and fight disease, including melanoma. Established and experimental treatments for melanoma include interferons, interleukins, biochemotherapy, vaccine therapy, and antibody-based therapies. For details, see Immunotherapy.
• Gene therapy, the introduction of new genetic material to damaged genes or cancer cells. The goal of gene therapy is to replace damaged cells with healthy ones, or to make cancer cells more sensitive to the effects of the immune system, immunotherapy, and chemotherapy. For details, see Gene Therapy.
• Angiogenesis inhibitors prevent or alter the growth of new blood vessels that feed malignant tumors. For details, see Angiogenesis Inhibitors.