Leukaemia blood cells. Coloured scanning electron micrograph (SEM) of white blood cells on a filter from a patient suffering from myeloid leukaemia, a form of cancer. These are immature granulocyte cells. Myeloid leukaemia causes the production of excessive amounts of these cells in the myeloid tissue of the bone marrow, leading to reduced levels of other blood cells. A lack of red cells leads to anaemia, with bruising and bleeding due to a lack of platelets. Serious infections may also develop, because abnormal white cells do not attack foreign organisms. Treatment includes chemotherapy, transfusions and bone marrow transplants. Magnification: x4000 at 6x7cm size.