Chronic myelogenous leukemia (CML) is a type of cancer that affects the blood and bone marrow. It is also known by several other names, including chronic myeloid leukemia, chronic granulocytic leukemia, and chronic myelocytic leukemia. These synonyms are used interchangeably to describe the same disease.
CML is a form of leukemia that originates in the bone marrow, where blood cells are produced. It specifically affects the myeloid cells, which are responsible for producing red blood cells, white blood cells, and platelets. In CML, there is an abnormality in the genetic material of the bone marrow cells, leading to uncontrolled growth and accumulation of immature white blood cells called blast cells.
The hallmark of CML is the presence of a specific genetic abnormality known as the Philadelphia chromosome. This abnormality occurs when two chromosomes, 9 and 22, break and swap genetic material. The resulting Philadelphia chromosome produces a fusion gene called BCR-ABL1, which leads to the overproduction of an enzyme that promotes the growth of cancer cells.
CML typically progresses slowly, with three distinct phases: chronic phase, accelerated phase, and blast crisis. In the chronic phase, patients may not experience any symptoms or may have mild symptoms such as fatigue, weight loss, and enlarged spleen. If left untreated, CML can progress to the accelerated phase, characterized by an increase in the number of blast cells. Finally, the blast crisis phase is marked by a rapid proliferation of blast cells, resembling acute leukemia.
Treatment options for CML have significantly improved in recent years, thanks to targeted therapies that specifically inhibit the activity of the BCR-ABL1 fusion protein. These targeted drugs, known as tyrosine kinase inhibitors (TKIs), have revolutionized the management of CML and can effectively control the disease in most patients. In some cases, a bone marrow transplant may be considered as a curative option.
In summary, chronic myelogenous leukemia (CML) is a type of blood cancer that arises from abnormal myeloid cells in the bone marrow. It is also referred to as chronic myeloid leukemia, chronic granulocytic leukemia, or chronic myelocytic leukemia. The presence of the Philadelphia chromosome and the BCR-ABL1 fusion gene are characteristic of CML. Early diagnosis and targeted therapies have greatly improved the prognosis for patients with CML.