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Biological Therapies

    Everyone accepts that the body has an immune system which helps to defend it against disease. This system is generally seen at the level of specialised blood cells, called macrophages, which recognise an invading foreign threat to the system - i.e. a bacterium or virus. They engulf these antigens and break them down to smaller proteins. Macrophages also release substances called cytokines, which alert other cells, the lymphocytes, to respond. There are two types of lymphocyte: B-lymphocytes, which produce antibodies, and T lymphocytes, which have the task of recording and memorising the antigens for the future. They also attack foreign invaders directly. There are other cells such as the white blood cells, whose job is to eat up the foreign invaders and destroy them.
    The idea behind biological therapies is that these defences can be activated to target cancer cells - and if they can be activated, the cancer cell will be destroyed by the body's own immune system. Sometimes this happens spontaneously.
    In order to replicate this process, a large number of biological substances, extracted from tumour and immune cells, have been investigated: interleukins, interferon's, tumour necrosis factor, prostaglandin and others. All of these substances have been trailed on cancer patients. Some have very minor side effects; some cause flu-like symptoms and some, such as interleukin-2, and have severe and life-threatening effects.
    This is a relatively new form of treatment, still highly experimental in its strategies and substances used. There is no doubt that some previously terminal patients are alive today because of this form of treatment.