Chronic myelocytic leukemia (CML) may affect people of any age and of either sex, but is uncommon in children younger than 10 years. The disease most commonly develops in adults between the ages of 40 and 60. The cause usually is a rearrangement of two particular chromosomes into what is called the Philadelphia chromosome. The Philadelphia chromosome produces an abnormal enzyme (tyrosine kinase), which is responsible for the abnormal growth pattern of the white blood cells.
In CML, most of the leukemia cells are produced in the bone marrow, but some are produced in the spleen and liver. In contrast to the acute leukemias, in which large numbers of immature white blood cells are present, the chronic stage of CML is characterized by marked increases in the numbers of normal-appearing white blood cells and sometimes platelets. During the course of the disease, more and more leukemia cells fill the bone marrow and others enter the bloodstream.
Eventually the leukemia cells undergo more changes, and the disease progresses to an accelerated phase and then inevitably to blast crisis. Massive enlargement of the spleen is common in blast crisis, as well as fever and weight loss. Symptoms and Diagnosis Early on, in its chronic stage, CML may produce no symptoms. However, some people become fatigued and weak, lose their appetite, lose weight, develop a fever or night sweats, and notice a sensation of being full—which is usually caused by an enlarged spleen. As the disease progresses to blast crisis, people become sicker because the number of red blood cells and platelets decreases, leading to paleness, bruising, and bleeding.
Source: Portal Content Team