Applications of fluorescence in situ hybridization (FISH) in detecting genetic aberrations of medical significance

Fluorescence in situ hybridization (FISH) is a powerful technique used in the detection of chromosomal abnormalities. The high sensi- tivity and specificity of FISH and the speed with which the assays can be performed have made FISH a pivotal cytogenetic technique that has provided significant advances in both the research and diagnosis of haematological malignancies and solid tumours. From a medical perspective, FISH can be applied to detect genetic abnormalities such as characteristic gene fusions, aneuploidy, loss of a chromosomal region or a whole chromosome or to monitor the progression of an aberration serving as a technique that can help in both the diagnosis of a genetic disease or suggesting prognostic outcomes. FISH can also be applied to such research applications as gene mapping or the identification of novel oncogenes or genetic aberrations that contribute towards various cancers. FISH is based on DNA probes annealing to specific target sequence of sample DNA. Attached to the probes are fluorescent reporter molecules which under fluorescence microscopy confirm the presence or absence of a particular genetic aberration when viewed under fluorescence microscopy. The tech- nique has recently evolved to allow screening of the whole genome simultaneously through multicolour whole-chromosome probe techniques such as multiplex FISH or spectral karyotyping, or through an array-based method using comparative genomic hybridization. This simple, yet effective, technique has revolutionized cytogenetics and has become well established in its potential as a diagnostic and discovery tool in the fight against cancer.