Chronic myelogenous leukemia (CML), also known as chronic granulocytic leukemia, is a type of cancer that affects the blood-forming cells in the bone marrow. It is a slowly progressing disease that involves the overproduction of white blood cells, specifically granulocytes, which are a type of white blood cell that helps fight infections.

CML is caused by a specific genetic abnormality called the Philadelphia chromosome, which results from a translocation between chromosomes 9 and 22. This translocation creates a new gene, BCR-ABL, which produces an abnormal enzyme called tyrosine kinase. This enzyme promotes the uncontrolled growth and division of bone marrow cells, leading to the excessive production of white blood cells.

Symptoms of CML may not be apparent in the early stages, but as the disease progresses, they may include:

1. Fatigue
2. Weakness
3. Weight loss
4. Night sweats
5. Abdominal discomfort due to an enlarged spleen
6. Frequent infections
7. Shortness of breath
8. Easy bleeding or bruising

Diagnosis of CML typically involves a combination of blood tests, bone marrow biopsy, and genetic testing to detect the Philadelphia chromosome or the BCR-ABL gene.

Treatment for CML has significantly improved over the years, with the introduction of targeted therapies called tyrosine kinase inhibitors (TKIs). These drugs, such as imatinib (Gleevec), dasatinib (Sprycel), and nilotinib (Tasigna), block the activity of the abnormal tyrosine kinase enzyme, slowing the progression of the disease and improving patient outcomes. In some cases, chemotherapy, radiation therapy, or bone marrow transplantation may also be considered, particularly for patients who do not respond to TKIs or for those in advanced stages of the disease.

Regular monitoring and follow-up care are essential for managing CML, as the disease can progress to a more aggressive form called accelerated phase or blast crisis, which requires more intensive treatment.