Chimeric BCR/ABL gene detected by fluorescence in situ hybridization in three new cases of Philadelphia chromosome-negative chronic myelocytic leukemia.
Three new cases are reported of cytogenetically Philadelphia-negative (Ph-) chronic myelocytic leukemia (CML), with positive BCR/ABL gene rearrangement according to a reverse transcriptase polymerase chain reaction technique. Fluorescence in situ hybridization (FISH) studies using different probes showed three different situations involving chromosomes 9 and 22 for the masked BCR/ABL fusion gene. With the use of BCR/ABL-extra signal and CEP 9 probes (Vysis, Downers Grove, IL, USA), FISH studies detected the BCR/ABL fusion gene at the end of chromosome 9 in patient 1, a BCR/ABL fusion gene on both chromosomes 22 in patient 2 (who was in an accelerated phase of CML), and a BCR/ABL fusion signal on chromosome 22 in patient 3. Interestingly, FISH interphase signals showed the same pattern in patients 1 and 3, but the BCR/ABL fusion gene was located on different chromosomes. Careful interpretation of the results and a simultaneous study of nuclei and metaphases are therefore recommended in each case. In conclusion, in cases of Ph- CML, FISH studies are of paramount importance since they can detect chromosomal reorganization and its location, and can also provide quantitative follow-up of these patients.
Costa
Dolors
D
Unitat Hematopatologia, Hospital del Mar, Barcelona, Spain. dcosta@clinic.ub.es
Espinet
Blanca
B
Queralt
Rosa
R
Carrió
Ana
A
Solé
Francesc
F
Colomer
Dolors
D
Cervantes
Francisco
F
Hernández
José Angel
JA
Besses
Carles
C
Campo
Elias
E
D000328:Adult; D000368:Aged; D002899:Chromosomes, Human, Pair 9; D005260:Female; D016044:Fusion Proteins, bcr-abl / Q000235:genetics*; D016313:Genes, abl; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics*; D054438:Leukemia, Myeloid, Chronic, Atypical, BCR-ABL Negative / Q000235:genetics*; D008297:Male; D008875:Middle Aged
D016044:Fusion Proteins, bcr-abl