Leukemias are classified according to whether they develop from lymphoid or myeloid stem cells, and whether the disease process is acute or chronic. Below are some of the major types of leukemia:
Lymphoid Leukemias:
Lymphoid leukemias are cancers of the blood and bone marrow that occur when the bone marrow makes too many lymphocytes (a type of white blood cell).
One of two major lymphoid leukemias, is the most common type of cancer in children, though it may also occur in adults. It is also referred to as acute lymphocytic or acute lymphoid leukemia.
Represents the other major form of lymphoid leukemia. CLL is the second most common type of leukemia in adults. It often occurs during or after middle age; it rarely occurs in children.
Is a rare type of lymphoid leukemia often classified as a subtype of CLL, and is usually slow-growing. However, there is a variant (called HCL-V) which behaves more aggressively.
Is a rare type of lymphoid leukemia in which T cells are the abnormal leukemic cells, rather than the B cells found in most lymphoid leukemias. ATLL is thought to be almost exclusively caused by infection with a retrovirus called human T cell lymphotropic virus (HTLV-1).
Myeloid Leukemias:
Myeloid leukemias are cancers of the blood and bone marrow that occur when the bone marrow overproduces immature myeloid cells.
Is one of two major types of myeloid leukemia. AML is also called acute myelogenous leukemia, acute myeloblastic leukemia, acute granulocytic leukemia or acute nonlymphocytic leukemia. It is the second most common type of leukemia in adults.
In CML, the other major form of myeloid leukemia, too many bone marrow stem cells develop into a type of white blood cell called granulocytes. Some of these bone marrow stem cells never become mature white blood cells. These immature cells are called blasts. Over time, the granulocytes and blasts crowd out the red blood cells and platelets in the bone marrow.
