What is the "Philadelphia chromosome"?

What is the "Philadelphia chromosome"?

The Philadelphia chromosome is a genetic mutation identified in certain malignancies. Specifically, 95% of CMLs, or chronic myelogenous leukemia, as well as a certain percentage of acute lymphoid leukemias, have the presence of the Philadelphia chromosome. The Philadelphia chromosome is defined as having the presence of the translocation of chromosome 9 and 22. What does that mean? It means that a portion or a piece of the chromosome number 9 moves to the chromosome number 22. The Philadelphia chromosome, 9-22 translocation, and BCR-ABL are all synonymous with the genetic mutation responsible for the diagnosis of chronic myelogenous leukemia as well as a certain population of acute lymphoid leukemia.