Leukemia is a cancer of the bone marrow where blood cells are formed. It is characterized by an increased production of abnormal cells, which are actually immature cells (blasts) that do not develop to maturity. Over time, as the number of abnormal blood cells builds up in the blood, they crowd out healthy blood cells, making it difficult for blood to carry out its normal functions.
Scientists have yet to establish direct causes of leukemia, although certain risk factors increase a person’s chances of developing the disease, such as smoking, exposure to high amounts of radiation, old age, and genetic predispositions to cancer.