Leukaemia blood cell. Coloured scanning electron micrograph (SEM) of a mis-shapen blood cell from a patient who has chronic lymphocytic leukaemia. This form of cancer is most often found in the elderly, and involves an increase in circulating levels of lymphocytes (a type of white blood cell). This causes a reduction in the proportion of red blood cells, leading to anaemia, as well as other complications such as enlargement of the liver and spleen, or improperly formed blood cells. The extremely distorted shape of this blood cell means it will not be able to function properly.