LeukemiaLeukemia is a disease that affects the blood-forming tissues, mainly the bone marrow. Leukemia also affects the lymph glands and spleen. Leukemia causes the body to produce extreme amounts of abnormal white blood cells. This causes infections because the abnormal cells cannot stop infections like normal cells can. Leukemia also causes anemia. Anemia is a disease in which the body produces fewer blood cells. This happens because leukemia cells crowd the system. Leukemia also causes excessive bleeding. This happens because the amount of platelets decreases and clotting does not occur. Researchers believe that a change in genetic structure causes leukemia. Changes in genetic structure could be caused by environmental problems. Some of these problems could be: birth defects, radiation, viruses and chemicals. Leukemia is not hereditary and is not contagious. There are two main types of leukemia, lymphocytic and granulocytic. In lymphocytic leukemia, the white blood cells, known as lymphocytes, produced in the lymph glands and bone marrow are abnormal or immature. In granulocytic leukemia this causes an increase in white blood cells known as granulocytes. Granulocytes are produced in the bone marrow and other tissues. Granulocytes affected by leukemia cannot fight infections. There are two ways leukemia can occur. One is acute and the other is chronic. Acute leukemia is found mostly in children. Proceeds ar...