Vaccines to fight cancer
A vaccine is a very common way of building up the immune system to fight infection. Using vaccines to fight breast cancer is relatively new, however, and still considered experimental. A vaccine for breast cancer may consist of an antigen cocktail of weakened or essentially dead elements of breast cancer cells that could stimulate an antibody response. The cancer vaccine might be prepared from your own deactivated cancer cells, or from extracts of breast cancer cells cultivated in a laboratory. Vaccines like this are only available in clinical trials. But as soon as these vaccines are proven effective and win FDA-approval, they will become available outside of clinical trials.
The vaccine is given by injection (usually under the skin). Once your immune system becomes aware of the antigens in the vaccine, it responds by making antibodies. Hopefully these antibodies will able to attack and destroy any remaining cancer cells. Later, if any new cancer cells appear, the circulating antibodies of the vaccine-educated immune system would destroy them also.
The challenges of cancer vaccines
Although vaccines have a strong track record in fighting many serious infections (such as polio, mumps, and measles), they are very much in the experimental stage for cancer. One problem is the way cancer progresses. It begins when one of your normal cells becomes abnormal and starts multiplying out of control, generation after generation. Each generation produces variations.
Eventually the cancer has countless faces, with a limitless variety of antigens that need to be targeted by antibodies. The cancer vaccine, however, results in a LIMITED number of antibodies against the specific cancer cell antigens that were in the ORIGINAL vaccine preparation. These antibodies may not be effective against the full range of newly developing cancer cells.
In addition, an effective vaccine must summon antibodies that target the bad cells and leave normal cells alone. The trick is to catch the cancer cells as soon as they form, and make the vaccine with cancer cell parts that are NOT shared by normal cells.
Researchers are investigating ways to identify cancer cells at this very early stage. This could be done perhaps with chemicals that would tag the problem cells, and then alter them enough so that the immune system perceives them as abnormal and attacks them.
Antibodies to fight cancer genes
Another approach is to produce antibodies against specific cancer genes called oncogenes. Normal oncogenes keep cell growth under control and suppress cancer by directing the production of a host of special proteins that conduct business as usual around the cell. Abnormal, malfunctioning oncogenes, however, such as a faulty HER2/neu gene, fail to regulate cancer cell growth, resulting in tumors. These abnormal cancer genes or their related proteins provide a very precise target for an antibody. If the abnormal gene is only found in your cancer cells, and not in your normal cells, the antibody can do a good job destroying cancer cells, leaving the rest of you alone.
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