Fluorescence in situ hybridization (FISH) is a significant molecular technique used to determine the status of a gene in human cells. Genes are the basic hereditary units comprised of deoxyribonucleic acid (DNA). DNA resides in the nucleus as chromosomes, with 46 chromosomes in the human cell.
FISH uses fluorescently labeled DNA probes to target a specific sequence of DNA that may represent a gene or a particular sequence of a gene. It helps detect genetic aberrations, such as amplification, translocation, or gene deletion. This technique is used for many purposes, including caring for cancer patients from initial diagnosis to evaluation of remission. The quantitative nature of this test makes it more objective. FISH testing may also be used to qualify patients for chemotherapy or to predict their prognosis.
Fresh preparations such as cytospins, touch preps, or formalin-fixed, paraffin-embedded (FFPE) tissues may be used.
