Genetic analysis has come a long way; we now have an ever-expanding collection of analytical tools in the diagnostic laboratory. So why do we still need a technique that usually only looks at one or two loci? The simple answer is that results from fluorescence in-situ hybridization (FISH) can quickly confirm diagnoses, guide clinicians’ judgements regarding differential diagnoses, and correlate results with clinical risk—thus enabling an informed choice of treatment type and intensity.
FISH employs fluorescently-labeled DNA probes to bind complementary DNA sequences within an interphase cell, or onto metaphase chromosomes. These sequences can then be visualized using fluorescent microscopy. The number, location and relative positions of the probe signals indicate chromosomal changes in a particular cell (Figure 1).
Many clinical trials use cytogenetic and FISH data to stratify patients according to specific risk factors. FISH is often used as a stand-alone technique for investigating abnormalities and following-up such patients, which, alongside its relatively low expense, makes it a very convenient investigative tool.
In this article we will explore the utility of FISH in today’s clinical laboratory and the future of the technique in the evolution of molecular testing.
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Figure 1. The FISH process.
Figure 2. Interphase cell showing amplified HER2 signal pattern.
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Read more: FISHing in the Genomic Testing Age !
Source: MedicalLaboratoryObserver
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