Most cancer cells do not develop as a consequence of mutation in normal genes. Rather, cancer more commonly develops from the activation of genes that are normally present in the body. As a result, the immune system does not necessarily recognize cancer cells as foreign invaders, as it recognizes viruses or bacteria, and so does not respond to cancer as it does to infectious diseases.

Despite the immune system's inability to recognize most cancer cells as foreign, researchers have discovered that cancer cells do express antigens on their surfaces that may be unique to individual tumors, shared by multiple tumor types, or may mark the tissue from which a tumor arises.

Cancer immunotherapists have attempted to use antigens in each of these categories to stimulate more effective immune response to tumors, including melanoma. Clinical trials are investigating each of these antigen categories to determine which are the most effective at activating an antitumor effect.

See Vaccine Therapy for more information on this experimental treatment.

See Clinical Trials to learn more about these types of investigations.