Chronic lymphocytic leukaemia. Light micrograph of cancerous blood cells in chronic lymphocytic leukaemia (CLL). Lymphocyte white blood cells (purple) and normal red blood cells (pink) are seen. The white blood cell count in this sample is abnormally high. CLL causes proliferation of abnormal lymphocytes and impairs the production of normal cells. This leads to symptoms such as anaemia, fever and enlargement of the liver and spleen. There is no cure, but anti-cancer drugs and radiotherapy may slow its progress. It is not always fatal, but opportunistic infections may kill sufferers. Magnification: x200 at 35mm size.