 Antibodies are proteins that are found in the blood. Antibodies normally protect us from foreign invaders, such as bacteria or viruses. They help destroy these foreign substances by binding to them and activating white blood cells or blood proteins, resulting in their destruction. Tumour cells also have antigens which can be targeted by antibodies. A receptor expressed in high amounts over-expressed on various cancer cells, called the epidermal growth factor EGFR has been identified, studied and targeted with a variety of antibodies. 