Light micrograph the liver showing leukemic cell metastases. Leukemia is a malignant disease in which bone marrow and other blood-forming organs overproduce certain types of white blood cells. Whereas normal white blood cells play a protective immune-response role, leukemic white blood cells are immature and abnormal. they suppress normal blood cell production resulting in anemia, poor blood clotting, and a weakened immune system. Treatment includes anticancer drugs and bone marrow transplants. Here the leukemia has spread, from its original location.