title: Deletion 9p23 to 9p11.1 as sole additional abnormality in a Philadelphia positive chronic myeloid leukemia in blast crisis: a rare event.
abstract: BACKGROUND
  Chronic myeloid leukemia (CML) is a myeloproliferative disorder characterized by the presence of a derivative chromosome 22 [der(22)] commonly called Philadelphia chromosome (Ph). The Ph chromosome is a product of the reciprocal translocation t(9;22)(q34.1;q11.2). Additional genetic changes occur in less than 10 % of CML cases at the time of diagnosis and other genetic changes are seen in 60-80 % of the cases in advanced disease. Even though deletions in chromosome 9 are not rare findings in advanced phase-CML, del(9)(p23p11.1) as sole additional abnormality detected by fluorescence in situ hybridization (FISH) technique, to our knowledge has not been described in the literature.
  
  
  RESULTS
  A complete cytogenetic and molecular cytogenetic analysis, molecular biology method (reverse transcription polymerase chain reaction (RT-PCR)), and immunophenotype confirmed to be a CML case in blast crisis (BC). It revealed del(9)(p23p11.1) as sole abnormality detected by FISH technique besides Ph chromosome, which leads to monoallely of tumor suppressor gene CDKN2A (cyclin-dependent kinase inhibitor 2A) before Imatinib mesylate (IM) treatment.
  
  
  CONCLUSIONS
  The patient did not demonstrate a good response to IM treatment. The underlying mechanisms and prognostic implications of these cytogenetic abnormalities are discussed.
authors.affiliation: Department of Molecular Biology and Biotechnology, Human Genetics Division, Atomic Energy Commission, P.O. Box 6091, Damascus, Syria.
authors.forename: Abdulsamad
authors.initials: A
authors.lastname: Wafa
authors.affiliation: Department of Molecular Biology and Biotechnology, Human Genetics Division, Atomic Energy Commission, P.O. Box 6091, Damascus, Syria.
authors.forename: Manar
authors.initials: M
authors.lastname: Asa'ad
authors.affiliation: Department of Molecular Biology and Biotechnology, Mammalians Biology Division, Atomic Energy Commission, Damascus, Syria.
authors.forename: Adnan
authors.initials: A
authors.lastname: Ikhtiar
authors.affiliation: Institute of Human Genetics, Jena University Hospital, Jena, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Liehr
authors.affiliation: Department of Molecular Biology and Biotechnology, Human Genetics Division, Atomic Energy Commission, P.O. Box 6091, Damascus, Syria.
authors.forename: Walid
authors.initials: W
authors.lastname: Al-Achkar
keywords: CDKN2A gene; Chronic myeloid leukemia; Philadelphia chromosome; Prognostic factors; del(9)(p24p12)