What Causes Chronic Myeloid Leukemia? Understanding Triggers, Symptoms, and Early Detection
Chronic Myeloid Leukemia (CML) is a type of cancer that affects the blood and bone marrow, characterized by the overproduction of abnormal white blood cells. While the exact mechanisms behind CML are still being studied, researchers have identified several key contributing factors. Among the most widely accepted causes are exposure to high levels of ionizing radiation and prolonged contact with certain environmental toxins—such as chemicals found in hair dyes and industrial solvents.
Primary Risk Factors Linked to CML Development
One of the most well-documented risk factors for CML is ionizing radiation exposure. This includes survivors of atomic bomb blasts, individuals who have undergone extensive radiation therapy, or those working in environments with unshielded radiation sources. Studies show a clear correlation between radiation dosage and increased leukemia risk, particularly years after initial exposure.
In addition to radiation, occupational or long-term exposure to benzene and other chemical agents commonly found in hair dyes, paint thinners, and plastics manufacturing has been associated with a higher incidence of CML. These substances can damage DNA in hematopoietic stem cells, leading to uncontrolled cell growth—a hallmark of leukemia.
Genetic Mutation: The Philadelphia Chromosome
At the core of CML pathology is a specific genetic abnormality known as the Philadelphia chromosome. This results from a translocation between chromosomes 9 and 22, creating the BCR-ABL1 fusion gene. This mutated gene produces a hyperactive tyrosine kinase enzyme that drives the excessive proliferation of myeloid cells in the bone marrow. While this mutation is acquired (not inherited), its trigger remains unclear—though environmental exposures may play a role in initiating it.
Recognizing Early Signs and Symptoms
CML often progresses slowly, which is why it's sometimes discovered incidentally during routine health screenings. Common early symptoms include:
- Unexplained fatigue and weakness
- Mild fever without infection
- Night sweats
- Abdominal fullness or discomfort due to an enlarged spleen (splenomegaly)
- Unintentional weight loss
Some patients remain asymptomatic in the early chronic phase, making regular blood tests crucial for early detection.
When to Seek Medical Evaluation
If you experience persistent fatigue, unexplained weight loss, or notice abdominal swelling on the left side, it's important to consult a hematologist. Similarly, if a routine complete blood count (CBC) reveals elevated white blood cell counts—especially with immature granulocytes—it should prompt further investigation.
Diagnostic Process for CML
Early diagnosis significantly improves treatment outcomes. A comprehensive evaluation typically includes:
Blood tests: A CBC can reveal abnormally high white blood cell levels and the presence of blast cells.
Bone marrow biopsy: This confirms the diagnosis by analyzing cell morphology and detecting the percentage of affected cells.
Cytogenetic testing: Fluorescence in situ hybridization (FISH) or polymerase chain reaction (PCR) tests identify the Philadelphia chromosome or BCR-ABL1 gene, confirming CML.
With targeted therapies like tyrosine kinase inhibitors (TKIs), CML has transformed from a fatal disease into a manageable chronic condition for many patients—highlighting the importance of timely screening and intervention.