In medicine, leukemia is a "progressive, malignant disease of the blood-forming organs, characterized by distorted proliferation and development of leukocytes and their precursors in the blood and bone marrow. Leukemias were originally termed acute or chronic based on life expectancy but now are classified according to cellular maturity. Acute leukemias consist of predominantly immature cells; chronic leukemias are composed of more mature cells."
- B-Cell chronic lymphocytic leukemia, also called chronic lymphocytic leukemia (CLL).
- B-Cell prolymphocytic leukemia