title: Masked inv dup(22)(q11.23), tetrasomy 8 and trisomy 19 in a blast crisis-chronic myeloid leukemia after interrupted Imatinib-treatment.
abstract: BACKGROUND
  The Philadelphia (Ph) chromosome, or derivative chromosome 22 [der(22)], is a product of the reciprocal translocation t(9;22). It is the hallmark of chronic myelogenous leukemia (CML). It results in juxtaposition of the 5' part of the BCR gene on chromosome 22 to the 3' part of the ABL1 gene on chromosome 9. During CML progression 60-80 % of the cases acquire additional genetic changes. Blast crisis (BC) is characterized by the rapid expansion of a population of differentiation arrested blast cells (myeloid or lymphoid cells population), often presenting with secondary chromosomal abnormalities. Here we report an unusual CML-BC case with acquired secondary chromosomal aberrations observed after the patient had to interrupt a successful Imatinib treatment for overall 16 months.
  
  
  METHODS
  A complete cytogenetic and molecular cytogenetic analysis were performed and application of molecular genetic methods such as reverse transcription polymerase chain reaction (RT-PCR) finally characterized a complex karyotype including an inv dup(22)(q11.23), tetrasomy 8 and trisomy 19.
  
  
  CONCLUSIONS
  Here we report the first case of a BC after successfully initiated and suddenly interrupted Imatinib treatment. Changes present after such an instant indicate for a rapid progression after Imatinib is no longer suppressing the disease.
authors.affiliation: Department of Molecular Biology and Biotechnology, Atomic Energy Commission, Human Genetics Division, P.O. Box 6091, Damascus, Syria.
authors.forename: Abdulsamad
authors.initials: A
authors.lastname: Wafa
authors.affiliation: Department of Molecular Biology and Biotechnology, Atomic Energy Commission, Human Genetics Division, P.O. Box 6091, Damascus, Syria.
authors.forename: Suher
authors.initials: S
authors.lastname: Almedani
authors.affiliation: Jena University Hospital, Institute of Human Genetics, Jena, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Liehr
authors.affiliation: Department of Molecular Biology and Biotechnology, Atomic Energy Commission, Human Genetics Division, P.O. Box 6091, Damascus, Syria.
authors.forename: Walid
authors.initials: W
authors.lastname: Al-Achkar
keywords: Chronic myeloid leukemia; Clonal evolution; Philadelphia chromosome; Prognostic factors; Tetrasomoy 8; inv dup(22)(q11.23)