Detection of chromosomal abnormalities using fluorescence in situ hybridization (FISH)

Background. A number of studies have demonstrated the use of molecular cytogenetic techniques for clinical diagnosis. We compared the results of FISH analysis and conventional cytogenetics on different tissue samples for detection of chromosomal aberrations and to assess the utility of FISH assay for clinical diagnosis. Methods. Karyotypic analysis was carried out on 50 samples-20 peripheral blood samples, 20 bone marrow samples and 10 prenatal (chorionic villi/amniotic fluid) samples. The same chromosome preparations were further subjected to FISH analysis using probes specific for chromosome X, Y, 21 or bcr-abl gene. Results. The results of FISH analysis were in conformity with the cytogenetic results in all the samples except one. FISH analysis could reveal hybridization signals even on poorly spread metaphase chromosomes and interphase nuclei, It was also possible to detect subtle chromosomal aberrations which were not detected using conventional chromosomal analysis. Conclusion. FISH is a powerful, sensitive molecular cytogenetic technique which can be used as an adjunct to conventional chromosomal analysis for prenatal diagnosis and the diagnosis and management of cancer patients. FISH analysis should be used as a supplement to conventional cytogenetics.