Philadelphia chromosome or Philadelphia translocation is a specific chromosomal abnormality that's associated with chronic myelogenous leukemia (CML). It is due to a reciprocal translocation designated as t(9;22)(q34;q11), which means an exchange of genetic material between region q34 of chromosome 9 and region q11 of chromosome 22. The presence of this translocation is a highly sensitive test for CML, since 95% of people with CML have this abnormality (The remainder have either a cryptic trans… (More on Bcr-abl)