This does not mean, however, that stimulating the immune system will not treat cancers effectively. The limited success of single agents such as interferon, IL2 and vaccines suggests that immunological therapies will be useful for many cancers, particularly when given in combination with one another and with chemotherapy . Physicians are still learning how to use individual substances and combinations most effectively.
Precisely how the body rejects cancer is still not understood, and many substances, such as interferon, have a variety of actions in the body. Perhaps because of these factors, many agents with a proved capability of stimulating the immune system have failed to produce a long-lasting antitumor effect. Nevertheless, while avoiding unrestrained optimism and blind trust in the "miracle breakthroughs" that seem to occur every week, you should be aware that biological therapy is a new approach to controlling tumor growth that holds considerable promise.
