Applications of Fluorescence In Situ Hybridization Technology in Malignancies

The molecular characterization of nonrandom recurrent cytogenetic abnormalities has identified numerous disease-related genes involved in hematologic and lymphoid malignancies. Cytogenetic analysis has become essential for disease diagnosis, classification, prognostic stratification, and treatment guidance. Fluorescence in situ hybridization (FISH) has greatly enhanced the field and enabled a more precise determination of the presence and frequency of genetic abnormalities. The advantages of FISH compared to standard cytogenetic analysis are that FISH can be used to identify genetic changes that are too small to be detected under a microscope, does not require cell culture, and can be applied directly on fresh or paraffin-embedded tissues for rapid evaluation of interphase nuclei. The application of FISH with a variety of chromosome-specific DNA probes helps to further define molecular subclasses and cytogenetic risk categories for patients with particular hematologic malignancies. FISH analysis is useful in identifying genetic abnormalities undetectable by conventional chromosomal analysis and monitoring residual disease during treatment and follow-up. Therefore, FISH has become an indispensable tool in the management of hematologic malignancies.