[Emphasize the interpretation of atypical signals in the application of fluorescence in situ hybridization separation probes].

With the development of precision medicine and molecular pathology, fluorescence in situ hybridization (FISH) technology has been widely promoted and applied in department of pathology. In FISH detection, the most commonly used probes are HER2 amplification probes and a variety of separation probes. When detecting pathological specimens using separation probes, some specimens may show atypical signals other than the typical red-green separation signals. The observation, understanding and interpretation of atypical signals may affect the results of FISH, which are related to molecular subtyping and drug treatment of the patient. Eight types of atypical signals of separation probes in FISH detection based on reading experience were summarized and analyzed. At the same time, this article provides evidence and analysis on whether the gene has been rearrangedthrough verification experiments, image analysis and experimental analysis in literature, aiming to enhance the understanding of readers to atypical signals of FISH separation probes.