The many distinct types of mature blood cells, such as red blood cells for carrying oxygen, white blood cells for immune protection and platelets for wound clotting, arise from hematopoietic stem and progenitor cells in the bone marrow. Hematologic malignancies are cancers that begin in these cells, and are subdivided according to which type of blood cell is affected:
- Lymphoblastic or lymphocytic – a malignancy in the lymphoid lineage that includes white blood cells such as T lymphocytes and B lymphocytes. Examples include acute lymphoblastic leukemia, chronic lymphocytic leukemia, lymphomas and multiple myeloma.
- Myelogenous or myeloid – a malignancy in the myeloid lineage that includes precursor cells to red blood cells, platelets and white blood cells such as granulocytes. Examples include acute myelogenous leukemia, chronic myelogenous leukemia, myelodysplastic syndromes and the myeloproliferative neoplasms, such as essential thrombocythemia, polycythemia vera and myelofibrosis.