When you are vaccinated for smallpox, measles, or shingles your body is flooded with antigens that trigger your immune system to produce antibodies and/or to activate immune “killer cells” to fight the perceived disease threat.
When the injected antigens are a weaker version of molecules in or on a cancer cell, the body creates ‘killer T cells’ to attack the cancer cells with that molecule. The body can also create B-cells that produce antibodies to the molecule, and by extension, the cancer cell. The activated immune cells and/or antibodies are then able to attack cancer cells in the future that have the same molecule—this could create lifelong immunity to that specific type of cancer.
Vaccines must mimic parts of the cancer cells in the body in order to be effective. And the body must be healthy enough to produce an immune response.
In 2010 the U.S. FDA approved the first-ever tumor vaccine, called Provenge (also called Sipuleucel-T), to treat prostate cancer. Numerous vaccines are now being tested. There are many types of cancer and identifying the specific makeup of each individual’s cancer cells and creating or matching a vaccine specific to that type of cancer can be time consuming and expensive.