Chronic myelogenous leukemia (CML) is one of a group of myeloproliferative disorders. These are disorders that affect the bone marrow, in which excess red blood cells, granulocytes, and/or platelets are produced. It is also referred to as chronic myeloid leukemia, chronic granulocytic leukemia, or chronic myelocytic leukemia.
CML accounts for about 15%–20% of all cases of adult leukemia (Faderl et al., 1999).
More than 95% of patients diagnosed with CML have the presence of a cytogenetic anomaly known as the Philadelphia chromosome (Ph1), a translocation of genes on chromosomes 9 and 22, which causes the Abelson (ABL) oncogene on chromosome 9 to transfer to a site on chromosome 22 known as the breakpoint cluster region (BCR). This ABL/BCR fusion causes the abnormal production of tyrosine kinase protein, which causes the abnormal myelopoiesis of CML (Deininger, Goldman, & Melo, 2000). Ph1-negative CML is more difficult to identify and generally has a poorer response to treatment and shorter overall survival than Ph1-positive CML (Onida et al., 2002).
New CML cases in 2011 in the United States are estimated to approach 5,150 for both males and females, with an estimated 270 deaths (American Cancer Society, 2011a).