University of Pennsylvania Cancer Center
Last Modified: May 18, 1998
Unlike vaccines that are used to prevent infectious disease, cancer vaccines attempt to stimulate the body's own immune system to recognize cancer cells as foreign and destroy them.
These researchers examined tyrosinase, a normal protein present in melanin (which gives moles their color), and in melanoma cells. Patients were treated with tyrosinase plus QS21, which helps to "energize" the immune system, stimulating the patients immune T-cells to recognize the tyrosinase. They hoped that these same T-cells would recognize the patients' melanoma cells (which also contain the tyrosinase) and destroy them.
In a Phase I trial of 9 patients with Stage III or Stage IV melanoma who also had a certain immune system characteristic (HLA-A2.1 positive), the researchers found that two patients demonstrated a clear and highly significant post-vaccination in crease in immune CD-20+ T-cell frequency against the tyrosinase peptide. No patients experienced any unexpected toxicity, and the trials are ongoing to further augment the immune response and determine the effects in fighting cancer.