For more than a decade researchers have been trying to supercharge human defense systems against cancer with the help of a vaccine. These injections are not designed to prevent cancer from starting. Instead they provide a patient's immune system with intel on what the enemy—cancer cells—looks like. Ordinarily, cancerous cells do not look different enough from normal cells to trigger an immune system response, but we have figured out ways to highlight and target some of the proteins that are unique to these malignancies.