A fluorescence in situ hybridization study of complex t(9;22) in two chronic myelocytic leukemia cases with a masked Philadelphia chromosome.
The t(9;22)(q34;q11) is evident in more than 90% of patients with chronic myelocytic leukemia (CML) and gives rise to the Philadelphia chromosome (Ph). Approximately 5%-10% of CML patients show variant translocations involving other chromosomes in addition to chromosomes 9 and 22. In some variant translocations, additional material is transferred on der(22), resulting in a masked Ph chromosome. In this paper, we report two apparently Ph-negative (Ph-) CML cases showing a t(7;9;22)(q22;q34;q11) and a t(8;9;22)(q12;q34;q11), respectively. A detailed molecular cytogenetic characterization was performed by fluorescence in situ hybridization (FISH), which disclosed the presence of the 5'BCR/3'ABL fusion gene on the der(7) and der(8) chromosomes, respectively. Derivative (22) appeared as a masked Ph chromosome in both cases. FISH analysis with appropriate BAC/PAC clones allowed us to precisely characterize the complex chromosomal rearrangements that were not detected by conventional cytogenetic analysis.
Zagaria
Antonella
A
Department of Hematology, University of Bari, Piazza Giulio Cesare 11, 70124 Bari, Italy.
Anelli
Luisa
L
Albano
Francesco
F
Storlazzi
Clelia Tiziana
CT
Liso
Arcangelo
A
Roberti
Maria Grazia
MG
Buquicchio
Caterina
C
Liso
Vincenzo
V
Rocchi
Mariano
M
Specchia
Giorgina
G
D002892:Chromosomes, Human, Pair 22 / Q000235:genetics*; D002898:Chromosomes, Human, Pair 8 / Q000235:genetics; D002899:Chromosomes, Human, Pair 9 / Q000235:genetics*; D016044:Fusion Proteins, bcr-abl / Q000235:genetics / Q000378:metabolism; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics*; D054438:Leukemia, Myeloid, Chronic, Atypical, BCR-ABL Negative / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D014178:Translocation, Genetic
D016044:Fusion Proteins, bcr-abl