<prompt> All of the following statements about Philadelphia Chromosome in CML are true, except:Reciprocal translocation between long arm of chromosome 9 and long arm of chromosome 22The breakpoint cluster region BCR is located on the long arm of chromosome 22The ABL gene is located on chromosome 9The Philadelphia chromosome with the oncogenic BCR-ABL gene is found on chromosome 9  <response>: Answer is D The Philadelphia chromosome with the oncogenic BCR-ABL gene is found on chromosome 9 The Philadelphia chromosome with the oncogenic BCR-ABL gene fusion is the truncated chromosome 22 and not chromosome 9. The Philadelphia chromosome results from a reciprocal translocation between the ABL-1 oncogene on the long arm of chromosome 9 region q34 and the breakpoint cluster region BCR on the long arm of chromosome 22region q I I This reciprocal translocation, creates an elongated chromosome 9 der 9, and a truncated chromosome 22. The oncogenic BCR-ABL gene fusion is found on the shoer derivative 22 chromosome Philadelphia Chromosome. BCR-ABL encodes an oncogenic protein with tyrosine kinase activity Tyrosine Kinase Inhibitors are therefore used for treatment In agreement with the International System for Human Cytogenetic Nomenclature ISCN, this chromosomal translocation is designated as t9;22q34;q11. ABL stands for Abelson, the name of a leukemia virus which carries a similar protein. 