What is leukemia? Leukemia is really a number of different disorders and they are all characterized by the accumulation of these cancer cells, these malignant white blood cells in the bone marrow and the blood. It's really a cancer of that particular organ, the bone marrow. Usually come through a tension because of symptoms related to problems with the bone marrow patients become anemic or they have bleeding because of pollard counters below or they develop infections because they don't have the normal white blood cells, so it really gets to the normal bone marrow function that's compromised in some of these diseases at least.

Steven Coutre is an associate professor of Medicine, and the division of Hematology.