Chronic myeloid leukemia (CML)
CML primarily affects adults and over half of CML cases are diagnosed at age 65 or older. Roughly 6,000 people are diagnosed with CML every year, accounting for 10 percent of new leukemias. Only rarely does it affect children.
With CML, leukemia cells can also be found in other parts of the body, including the spleen.
CML occurs when chromosomes 9 and 22 "swap information” during cell division. Part of chromosome 9 goes to 22 and part of 22 goes to 9. This translocation results in shortened version of chromosome 22, known as the Philadelphia chromosome. The DNA swap leads to the formation of a new gene (an oncogene) called BCR-ABL. This gene produces a protein that causes the bone marrow to create too many myeloid white blood cells.
As the disease progresses it can result in a decrease of oxygen-carrying red blood cells and cause the symptoms of anemia: pallor, tiredness or shortness of breath.
DNA changes related to CML occur during the person's lifetime and are not inherited.
Physicians classify CML into three phases (chronic, accelerated, and blastic), according to the percentage of immature cells, or blasts, in the bone marrow, and other characteristics. This classification helps doctors choose the best treatment at the time of diagnosis.