FISH : application in the diagnosis of haematological malignancies

Abstract

The use of cytogenetics for the detection of chromosomal abnormalities in haematological disorders is of vital importance. Chromosomal findings such as translocations, deletions and inversions are important for the classification and diagnosis of such disorders. In the acute leukaemias, the karyotype may be an important and independent prognostic factor in predicting remission, length of remission, and risk of relapse. Many studies showed that cytogenetic analysis and the identification of chromosomal aberrations were directly related to the treatment strategies adopted for each patient. The role of cytogenetics in diagnosis and management of leukaemias depends largely on the availability of abnormal bone marrow cells for karyotyping and the quality of metaphase spreads. Metaphase spreads from leukaemic cells are usually of inferior quality and quantity as compared to normal cells, which makes the detection of certain aberrations a tedious and difficult job. With the use of molecular cytogenetic techniques such as fluorescence in situ hybridisation (FISH), identification of certain aberrations that would not be resolved by conventional cytogenetic techniques is now possible. Moreover, FISH has the advantage over cytogenetics to investigate the chromosomes and genes in interphase as well as in metaphase cells. This presentation will highlight the importance of FISH in the detection of certain chromosomal abnormalities, and how such results will help in the management of patients with haematological malignancies.