There are several types of leukemia. They are grouped by how quickly the leukemia progresses (either acute, which develops and worsens over weeks to months, or chronic, which progresses slowly over a period of years) and by the type of blood cell affected (either lymphoid cells or myeloid cells). To complicate matters, some of the leukemias are known by more than one name (see below). 

Lymphoid precursor cells (also called stem cells) give rise to these three types of lymphocytes:

• B-lymphocytes (B-cells)
• T-lymphocytes (T-cells)
• Natural killer lymphoytes (NK-cells)

Leukemias affecting lymphoid cells are:

For information about each type of leukemia, click its name in the left column.

ALL	acute lymphocytic leukemia
	acute lymphoblastic leukemia
CLL	chronic lymphocytic leukemia
	small lymphocytic lymphoma
HCL	hairy cell leukemia (a rare variant of CLL)
LGL	large granular lymphocytic leukemia (a rare leukemia of the T-lymphocytes)

Myeloid precursor cells (also called stem cells) give rise to these blood cells:

• Erythrocytes (red blood cells)
• Thrombocytes (platelets)
• Monocytes (which develop into Macrophages)
• Granulocytes (includes neutrophils, basophils and eosinophils)

Leukemias affecting myeloid cells are:

For information about each type of leukemia, click its name in the left column.

*AML									acute myeloid leukemia
									acute myelogenous leukemia
									acute myeloblastic leukemia
									acute granulocytic leukemia
									acute non-lymphocytic leukemia
*There are eight subtypes of AML including myeloblastic, promyelocytic (APL), myelomonocytic (AMML), monocytic, erythroleukemia and megakaryocytic.
CML									chronic myeloid leukemia
									chronic myelogenous leukemia
									chronic granulocytic leukemia
CMML									chronic myelomonocytic leukemia