Our bodies are well adapted to protecting us against foreign microbes like bacteria and viruses. Our immune system is designed to recognize a foreign molecule, like a protein from a virus, and create antibodies against these proteins to attack and destroy the virus. However, in the case of cancer, the invading cells come from our own bodies. So our immune system doesn?t recognize the cells as different from healthy, normal cells and, therefore, does not attack the cells. But in the growing field of cancer immunotherapy scientists are trying to devise ways to ?trick? the immune system into recognizing the cancer cell as a foreign invader and trigger an immune response to attack and destroy these cells. If successful, our own bodies could produce molecular sentinels designed to seek and destroy cancer.
It is important to note that this field of cancer immunotherapy is still developing. We have had successes in cancer preventive vaccines, like the HPV vaccine, to help prevent cervical cancers. In this case the immune system is preconditioned to recognize a protein in HPV, a virus associated with 70% of cervical cancers. If the virus invades the body, the immune system is activated and attacks the virus. By preventing the infection, the vaccine protects against a biological risk factor for cervical cancers. But while this is popularly called a ?cancer vaccine? that title is somewhat a misnomer because the vaccine doesn?t attack cancer cells.
However, there are researchers looking into cancer treatment vaccines which would attack the cancer cells. These vaccines would condition the immune system to recognize a specific alteration on a cancer cell and trigger an attack response if that alteration is detected. In this case a vaccine might be given as a part of a treatment to attack any cells that may have remained after surgery, radiation, or chemotherapy.
Because cancer cells carry a host of mutations and alterations, scientists are examining a variety of agents including DNA, proteins, sugars, and even cancer cells themselves to see what works best to trigger an immune response. And many of the studies are showing promising results. In fact, the NCI has a number of studies and trials underway in this area. And while we are still learning more about this field, it has potential to be a new weapon in our arsenal to fight this disease.
For more information on cancer vaccines, please visit the NCI?s website.