Chimeric BCR/ ABL gene detected by fluorescence in situ hybridization in three new cases of Philadelphia chromosome-negative chronic myelocytic leukemia

• Published in: Cancer genetics and cytogenetics 2003-03, Vol.141 (2), p.114-119
• Main Authors: Costa, Dolors, Espinet, Blanca, Queralt, Rosa, Carrió, Ana, Solé, Francesc, Colomer, Dolors, Cervantes, Francisco, Hernández, José Angel, Besses, Carles, Campo, Elias
• Format: Article
• Language: English
• Subjects: Adult; Aged; Biological and medical sciences; Chromosomes, Human, Pair 9; Female; Fusion Proteins, bcr-abl - genetics; Genes, abl; Hematologic and hematopoietic diseases; Humans; In Situ Hybridization, Fluorescence; Leukemia, Myelogenous, Chronic, BCR-ABL Positive - genetics; Leukemia, Myeloid, Chronic, Atypical, BCR-ABL Negative - genetics; Leukemias. Malignant lymphomas. Malignant reticulosis. Myelofibrosis; Male; Medical sciences; Middle Aged
• ISSN: 0165-4608; 1873-4456
• DOI: 10.1016/S0165-4608(02)00662-3

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.