How does the immune system fight cancer?

The Emporer of Cells – Cancer cells
Almost perfectly. We are generally oblivious to how well the immune system protects us from cancer. Lymphocytes recognise cells by the small fragments of protein displayed on their surface (“passport please”). Cancer cells are almost identical to normal human cells, but will display slightly different proteins on their surface from those on healthy cells. This is usually enough for the lymphocyte to recognise the affected cell and trigger the immune response which allows the immune system to destroy the evolving cancer cells. This is a highly efficient system, and the immune system finds and destroys almost all cancers as they develop. The effectiveness of the immune system in performing this surveillance and control of developing cancers is unfortunately well illustrated in people suffering immunodeficiency (see picture above).
