Fluorescence in situ hybridization (FISH) is a molecular biology technique used to locate specific nucleic acid sequences in cells or tissues. By using fluorescently labeled nucleic acid probes, FISH allows researchers to directly visualize and localize DNA or RNA. This technology is widely used in chromosome analysis, gene mapping, karyotype analysis and other fields. FISH not only provides high spatial resolution but also allows for simultaneous detection of multiple targets, making it a powerful tool in biomedical research, clinical diagnostics, and cancer research.