DETECTION OF BCR-ABL FUSION GENE IN CHRONIC MYELOID LEUKEMIA PATIENTS BY CONVENTIONAL CYTOGENETICS AND RT-PCR

摘要

Philadelphia chromosome (Ph) is a characteristic chromosomal marker that is associated with chronic myeloid leukaemia (CML).Conventional cytogenetics is considered as the diagnostic hallmark for identification of Ph positive metaphases in CML. Howeverthe limitation of cytogenetic analysis is that the Ph chromosome cannot be detected in cases with no divisions or in clumped metaphases. These patients warrant other molecular techniques to detect BCR-ABL fusion gene, and to decipher complex Ph rearrangements. Aim of the present study was to detect Ph chromosome in CML patients by the use of conventional cytogenetics and RT-PCR. The bone marrow samples were collected from 62 diagnosed CML patients and detection of Ph chromosome/BCR-ABL transcripts werecarried out by conventional cytogenetics and RT -PCR. Out of 62 CML patients, 43 patients were Ph positive with additional chromosomal abnormalities (trisomy 8 and double Ph) found in two among them. In 12 patients cytogenetic analysis failed to confirmthe presence or absence of Ph chromosome. The RT~PCR analysis was carried out in 55 patients, of which 44 patients demonstrated the presence of BCR-ABL transcript. Conventional cytogenetics is the useful method for detection of Ph chromosome in metaphase stage of cell division. Cytogenetic analysis also helps to identify any additional chromosome abnormalities. RT-PCR can be used in patients where cytogenetics fails or in doubtful cases, for confirmation.