Acute Myeloid Leukemia (AML) refers to a type of cancer that affects the blood and bone marrow. It is characterized by the rapid production of abnormal cells known as myeloblasts, or leukemic blasts, within the bone marrow. These cells are a type of abnormal white blood cell that do not mature properly. AML is considered an “acute” leukemia because it can progress quickly, often within weeks or months, if left unaddressed.
Understanding AML Cells
AML cells originate from myeloid stem cells in the bone marrow. Normally, myeloid stem cells develop into various types of mature blood cells, including red blood cells, platelets, and other white blood cells. In AML, however, these stem cells undergo genetic changes that prevent them from maturing into functional cells.
Instead, these abnormal myeloid cells, or myeloblasts, multiply uncontrollably and do not die. This rapid proliferation leads to a buildup of immature cells in the bone marrow and blood. While they are a type of white blood cell, these myeloblasts are unable to perform the protective functions of healthy white blood cells, such as fighting infection. The World Health Organization (WHO) classifies AML into subtypes based on the cells’ characteristics, including genetic abnormalities.
Impact on Blood Production
The rapid accumulation of AML cells within the bone marrow disrupts its ability to produce healthy blood cells. The abnormal myeloblasts crowd out the space needed for the development of red blood cells, white blood cells, and platelets. This displacement leads to a deficiency in these healthy blood components, causing various health consequences.
A shortage of red blood cells results in anemia, causing tiredness, dizziness, pale skin, or shortness of breath. A lack of white blood cells compromises the body’s immune system, leading to increased susceptibility to infections and delayed healing. Furthermore, a low platelet count impairs the blood’s clotting ability, which can cause easy bruising, unexplained bleeding, such as nosebleeds or bleeding gums, and small red or purple spots on the skin called petechiae.
Identifying AML Cells
The presence of AML cells is identified through diagnostic procedures. An initial step often involves a complete blood count (CBC), which measures blood cell types. This test may reveal abnormal counts, such as an excess or decrease in white blood cells, and reduced red blood cell and platelet counts. A blood film, examined under a microscope, can show leukemic blast cells.
A definitive diagnosis of AML requires a bone marrow aspiration and biopsy. During these procedures, a sample of bone marrow liquid and tissue is collected, usually from the hip bone, for microscopic examination. Specialized tests, like flow cytometry and genetic testing, are performed on these samples to characterize the AML cells. Flow cytometry identifies specific markers on the cell surface, while genetic tests (including cytogenetics and molecular testing) look for chromosomal abnormalities and gene mutations unique to the leukemic cells.
Strategies Against AML Cells
Addressing AML cells involves a multi-faceted approach to eliminate abnormal cells and restore bone marrow function. The goal of treatment is to achieve remission, where AML cells are significantly reduced, allowing healthy blood cell production to resume. Treatment plans are individualized, considering the AML subtype and the patient’s overall health.
Chemotherapy uses powerful drugs to kill fast-growing cells, including AML cells. Targeted therapies use drugs that attack unique molecular features or pathways within AML cells, often with less harm to healthy cells. In some cases, a stem cell transplant (also known as a bone marrow transplant) may be considered. This procedure replaces diseased bone marrow with healthy stem cells (from a donor or the patient’s own previously collected cells) to re-establish normal blood cell production.