Philadelphia Chromosome
Present in 20-30% of adults with ALL
Present in 2-3% of children with ALL
Present in 2-3% of children with ALL
An abnormality in your DNA, a fault, a fluke, a mishap, something which can change the way your life works forever. The Philadelphia chromosome is a chromosomal flaw that causes chronic myeloid leukemia, which is another branch of leukemia. Described as an “abnormally short chromosome, number 22 is one of the two chromosomes involved in a translocation (an exchange of material) with chromosome 9." Translocation takes place in one bone marrow cell and with the process of clonal expansion, (the production of many cells from one mutant cell) forms the leukemia. Discovered in 1960, the Philadelphia chromosome is the first consistent abnormality in the chromosomes of patients with acute lymphoblastic leukemia or chronic myeloid leukemia(CML). The discovery of this chromosome led to the finding of CML and many other gene mutations, including BCR-ABL and ABL-BCR, which are two new gene fusions that occur after the initial mutation of the chromosome (“Philadelphia”). Through our understanding of the Philadelphia Chromosome and the newly found gene mutations, we have been able to create a new drug, Gleevac. We’ve put a priority on new genetic targets and made an extensive advance in our knowledge on cancer.