Publication: Diagnostic role of conventional cytogenetics and fluorescence in situ hybridization (fish) in chronic myeloid leukemia patients
Date
2006
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Kathmandu University
Abstract
Introduction: The limitation of cytogenetic analysis is that the Ph chromosome cannot be detected in clumped
metaphase or in interphase cells. Fluorescence in situ hybridization (FISH) is a highly sensitive molecular genetic
technique, which enables to detect break point cluster region – Abelson (BCR-ABL) complex and minimal residual
disease in all Ph positive CML patients not only in metaphase but also in interphase cells.
Aims: To detect Ph chromosome in CML patients by the use of conventional cytogenetics and FISH.
Material and methods: The bone marrow samples were collected in heparinised syringe from 35 diagnosed CML
patients and transported to cytogenetic laboratory for chromosomal analysis. Conventional karyotype was prepared
by direct harvesting and short-term culture. The FISH analysis was carried out on interphase cells of two patients to
confirm the cytogenetic diagnosis.
Results: Out of 35 CML patients, 17 (49.9%) were 100% Philadelphia positive, 10(28.5%) were 50-70% Ph+
mosaics and 3(9%) were 100% Ph negative. In 5 patients (14.25%) cytogenetic analysis failed to confirm the
presence or absence of Ph chromosome. FISH was carried out in interphase cells from bone marrow preparations of
two patients. The signals for BCR-ABL fusion gene was absent in Ph- negative CML patients. In Ph positive
patients, the FISH analysis detected BCR-ABL fusion gene seen as a yellow signal on interphase cells.
Conclusion: Conventional cytogenetics is a useful method for detection of Ph chromosome in metaphase stage of
cell division. FISH can be used in interphase stage of cell division for the same purpose.
Key words: CML, FISH, Chromosomal analysis, Philadelphia chromosome