Acute myelocytic leukaemia. Light micrograph of cancerous white blood cells (purple) in human acute myelocytic leukaemia. This blood smear is from the bone marrow. The disease is shown by the abnormally large number of myelocyte white blood cells among the small red blood cells. Myelocytes normally develop into granulocytic white blood cells. The uncontrolled growth of abnormal white blood cells in leukaemia reduces normal blood cell production leading to anaemia, poor blood clotting and a weakened immune system. Fever, tiredness and weight loss are also common. Treatment includes anti-cancer drugs and bone marrow transplants. Magnification: x400 at 35mm size.