Chronic Myeloid Leukemia (CML)

Chronic myeloid leukemia (CML), also known as chronic myelogenous leukemia, is a fairly slow growing cancer that starts in the bone marrow. It"s a type of leukemia that affects the myeloid cells -- cells that form blood cells, such as red blood cells, platelets, and many types of white blood cells. In CML, leukemia cells tend to build up in the body over time. In many cases, people don't have any symptoms for at least a few years. CML can also change into a fastgrowing, acute leukemia that invades almost any organ in the body. Most cases of CML occur in adults, but it is also very rarely found in children. As a rule, their treatment is the same as for adults.


Leukemia is a type of cancer of the blood. There are different forms of leukemia depending on what type of blood cell is affected. "Chronic" describes a gradual or slow progression, and "myeloid" denotes the origin from myeloid cells, which are immature cells that normally become mature red blood cells, white blood cells, or platelets. In chronic myeloid leukemia, the bone marrow produces too many myeloid blood cells which are at various maturation stages including cells known as immature granulocytes, metamyelocyte, and myeloblasts. Platelets and basophils (different myeloid cells responsible, in part, for the allergic response) are also often overproduced at diagnosis. Excess production of myleloid blood cells in the bone marrow ultimately prevents the normal production of red blood cells, which are important in delivering oxygen to all cells in the body, and can also decrease production of platelets or thrombocytopenia. Platelets play a critical role to stop bleeding.

Different phases of CML


This specific genetic abnormality is an abnormal rearrangement of genetic material. Two chromosomes exchange a portion of their genes with genes on the other chromosome. This is known as a translocation. For CML, specifically, genes from chromosomes 9 are swapped with genes from chromosome 22. Translocation of the Abelson murine leukemia gene (ABL) on chromosomes 9 and the breakpoint cluster region (BCR) on chromosome 22 resulting in the Philadelphia chromosome (translocation of chormosomes 9 and 22, t(9;22)) can be detected in 95% of patients with CML either from cells circulating in the blood or in the bone marrow. The Philadelphia chromosome encodes a dysregulated tyrosine kinase (an enzyme in cells), which results in an abnormal behavior of the cells affected. This includes the formation of immortalized cells, increased cell turnover and proliferation, and abnormal cell maturation.

Risk Factors


Differential Diagnosis

Symptoms and clinical manifestations


Side effect

Bone Marrow Pathology