Duplication of chromosome 9 carrying a BCR/ABL chimeric gene in Philadelphia chromosome negative chronic myeloid leukemia

Cancer Genet Cytogenet. 1996 Jul 15;89(2):166-9. doi: 10.1016/0165-4608(96)00039-8.


We investigated a patient with Philadelphia chromosome (Ph) negative but BCR positive chronic myeloid leukemia (CML) by fluorescence in situ hybridization (FISH). In the chronic phase one chromosome 9 contained a BCR/ABL fusion gene instead of chromosome 22. Although in blast crisis, both chromosomes 9 had BCR/ABL fusion genes. This could be caused by duplication of the rearranged chromosome 9, which may have a significance similar to a double Ph chromosome. This may suggest that the critical event in CML is the formation of a BCR/ABL chimeric gene regardless of its locus in the genome.

Publication types

  • Case Reports

MeSH terms

  • Chromosome Aberrations*
  • Chromosomes, Human, Pair 9*
  • Fusion Proteins, bcr-abl / genetics*
  • Humans
  • In Situ Hybridization, Fluorescence
  • Karyotyping
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive / genetics*
  • Leukemia, Myeloid, Chronic, Atypical, BCR-ABL Negative / genetics*
  • Male
  • Middle Aged


  • Fusion Proteins, bcr-abl