What is chronic myeloid leukemia (CML)?

What is chronic myeloid leukemia (CML)?

• A. A mutation in myeloid stem cells leading to uncontrolled proliferation of cells, often associated with the Philadelphia chromosome.
• B. An acute lymphoblastic leukemia.
• C. Leukemia of lymphoid origin with no chromosomal abnormalities.
• D. A benign blood disorder.

Answer: (A)

Chronic myeloid leukemia is a clonal cancer of the myeloid lineage caused by a mutation in the hematopoietic stem cell that leads to uncontrolled proliferation of myeloid cells. The hallmark is the BCR-ABL fusion gene from the Philadelphia chromosome, which creates a constitutively active tyrosine kinase driving sustained growth and survival of granulocytic cells. This results in a high white blood cell count with maturing and mature granulocytes and often basophilia, typically in a chronic phase that can progress to accelerated or blast phases if untreated. Other descriptions don’t fit because this disease arises from myeloid cells, not lymphoid, so it isn’t an acute lymphoblastic leukemia. It is a malignant proliferative disorder, not a benign one, and the Philadelphia chromosome–driven BCR-ABL fusion is a defining feature, unlike leukemias described as lymphoid origin without chromosomal abnormalities.

Chronic myeloid leukemia is a clonal cancer of the myeloid lineage caused by a mutation in the hematopoietic stem cell that leads to uncontrolled proliferation of myeloid cells. The hallmark is the BCR-ABL fusion gene from the Philadelphia chromosome, which creates a constitutively active tyrosine kinase driving sustained growth and survival of granulocytic cells. This results in a high white blood cell count with maturing and mature granulocytes and often basophilia, typically in a chronic phase that can progress to accelerated or blast phases if untreated.

Other descriptions don’t fit because this disease arises from myeloid cells, not lymphoid, so it isn’t an acute lymphoblastic leukemia. It is a malignant proliferative disorder, not a benign one, and the Philadelphia chromosome–driven BCR-ABL fusion is a defining feature, unlike leukemias described as lymphoid origin without chromosomal abnormalities.