Chronic Myeloid Leukemia

Chronic myeloid leukemia (CML) is a type of blood cancer that develops when bone marrow cells acquire a specific genetic mutation, most commonly the Philadelphia chromosome (a fusion of chromosomes 9 and 22 creating the BCR-ABL gene), which causes uncontrolled production of abnormal white blood cells. CML typically progresses through three phases: a chronic phase (which may last for years with few or mild symptoms), an accelerated phase with worsening symptoms and harder-to-control blood counts, and a blast phase (also called blast crisis) that resembles acute leukemia. Early symptoms are often subtle or absent, but as the disease progresses, patients may experience fatigue, weakness, unintentional weight loss, night sweats, fever without infection, abdominal fullness or pain from an enlarged spleen, easy bruising or bleeding, and bone pain. Diagnosis requires blood tests showing persistently elevated white blood cell counts with immature cells present, bone marrow biopsy to assess cell types and maturation, and genetic testing (cytogenetics, FISH, or PCR) to confirm the presence of the Philadelphia chromosome or BCR-ABL fusion gene. Treatment has been revolutionized by targeted therapy drugs called tyrosine kinase inhibitors (TKIs) such as imatinib, dasatinib, and nilotinib, which specifically block the abnormal protein produced by the BCR-ABL gene and can control the disease in most patients for many years. With modern TKI therapy, many CML patients achieve normal or near-normal life expectancy, though treatment typically continues indefinitely, and regular monitoring through blood tests and molecular testing is essential to ensure the disease remains controlled and to detect any signs of resistance or progression.