{"entity":{"id":"fish","kind":"term","name":"FISH / ISH (in situ hybridisation)","aka":["FISH","ISH","in situ hybridisation","in situ hybridization","fluorescence in situ hybridization","fluorescence in situ hybridisation","break-apart FISH","EBER in situ hybridisation","EBER"],"tldr":"A test that uses glowing DNA probes on a tissue slide to count gene copies or spot rearranged genes inside individual cells, used to confirm HER2 amplification, MYCN in neuroblastoma, or ALK and MYC rearrangements.","summary":"Fluorescence in situ hybridisation (or chromogenic ISH) shows whether a gene is amplified (extra signals per nucleus, as in HER2 with ratio ≥2.0 or ≥6 copies), deleted (del(17p) in CLL, 1p/19q in oligodendroglioma) or broken and rejoined (break-apart probes for ALK, ROS1, MYC, BCL2, BCL6 in 'double-hit' lymphoma). It works on routine fixed tissue and resolves equivocal IHC 2+ HER2 results. Interphase FISH is standard in myeloma and leukaemia cytogenetics; EBER ISH detects Epstein-Barr virus in tumours. NGS increasingly replaces it for fusions.","asOf":"2026-09-09","wikipedia":"https://en.wikipedia.org/wiki/Fluorescence_in_situ_hybridization","links":[{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/Fluorescence_in_situ_hybridization"}],"tags":[],"related":["her2-positive","cytogenetics","gene-amplification","gene-fusion"],"cancers":[],"sections":["diagnostics"],"technologies":["histopathology-ihc","cgp"],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"category":"Biomarkers"},"route":"/terms/fish/","neighbours":{"term":[{"id":"1p19q-codeletion","kind":"term","name":"1p/19q codeletion","route":"/terms/1p19q-codeletion/"},{"id":"b-all-cytogenetic-risk","kind":"term","name":"B-ALL risk groups (NCI criteria, ETV6::RUNX1, hyperdiploidy, hypodiploidy, iAMP21, IKZF1, CNS status)","route":"/terms/b-all-cytogenetic-risk/"},{"id":"cdkn2a-homozygous-deletion","kind":"term","name":"CDKN2A/B homozygous deletion","route":"/terms/cdkn2a-homozygous-deletion/"},{"id":"cll-ipi","kind":"term","name":"CLL-IPI (chronic lymphocytic leukaemia prognostic index)","route":"/terms/cll-ipi/"},{"id":"cytogenetics","kind":"term","name":"Cytogenetics and karyotype","route":"/terms/cytogenetics/"},{"id":"del5q","kind":"term","name":"del(5q) (5q- syndrome and lenalidomide response)","route":"/terms/del5q/"},{"id":"ependymoma-molecular-groups","kind":"term","name":"Ependymoma molecular groups (PF-A, PF-B, ZFTA, YAP1, MYCN)","route":"/terms/ependymoma-molecular-groups/"},{"id":"ebv-term","kind":"term","name":"Epstein-Barr virus (EBV) in cancer","route":"/terms/ebv-term/"},{"id":"foxo1-fusion-status","kind":"term","name":"FOXO1 fusion status and IRS group (rhabdomyosarcoma)","route":"/terms/foxo1-fusion-status/"},{"id":"gene-amplification","kind":"term","name":"Gene amplification and copy-number change","route":"/terms/gene-amplification/"},{"id":"gene-fusion","kind":"term","name":"Gene fusion","route":"/terms/gene-fusion/"},{"id":"her2-testing-in-biliary-cancer","kind":"term","name":"HER2 testing in biliary tract cancer (IHC, ISH and NGS)","route":"/terms/her2-testing-in-biliary-cancer/"},{"id":"her2-testing-uk-breast","kind":"term","name":"HER2 testing in the UK: reflex ISH, the ratio against the copy number, and where the UK differs from ASCO/CAP","route":"/terms/her2-testing-uk-breast/"},{"id":"her2-positive","kind":"term","name":"HER2-positive (IHC 3+ or ISH-amplified)","route":"/terms/her2-positive/"},{"id":"ph-like-all","kind":"term","name":"Ph-like (BCR::ABL1-like) acute lymphoblastic leukaemia","route":"/terms/ph-like-all/"},{"id":"segmental-chromosomal-aberrations","kind":"term","name":"Segmental chromosomal aberrations and ploidy (neuroblastoma)","route":"/terms/segmental-chromosomal-aberrations/"},{"id":"ss18-ssx-fusion","kind":"term","name":"SS18::SSX fusion (synovial sarcoma)","route":"/terms/ss18-ssx-fusion/"},{"id":"cyclin-d1-t11-14","kind":"term","name":"t(11;14), cyclin D1 and SOX11","route":"/terms/cyclin-d1-t11-14/"},{"id":"uveal-melanoma-prognostic-markers","kind":"term","name":"Uveal melanoma prognostic markers (GNAQ/GNA11, monosomy 3, gene-expression class)","route":"/terms/uveal-melanoma-prognostic-markers/"}],"section":[{"id":"diagnostics","kind":"section","name":"Diagnostics & Biomarkers","route":"/fronts/diagnostics/"}],"technology":[{"id":"cgp","kind":"technology","name":"Comprehensive genomic profiling","route":"/technologies/cgp/"},{"id":"histopathology-ihc","kind":"technology","name":"Histopathology & immunohistochemistry","route":"/technologies/histopathology-ihc/"}],"cancer":[{"id":"breast-cancer","kind":"cancer","name":"Breast cancer (all types)","route":"/cancers/breast-cancer/"},{"id":"colorectal","kind":"cancer","name":"Colorectal cancer","route":"/cancers/colorectal/"},{"id":"gallbladder","kind":"cancer","name":"Gallbladder cancer","route":"/cancers/gallbladder/"},{"id":"lung-cancer","kind":"cancer","name":"Lung cancer (all types)","route":"/cancers/lung-cancer/"},{"id":"non-hodgkin-lymphoma","kind":"cancer","name":"Non-Hodgkin lymphoma (all types)","route":"/cancers/non-hodgkin-lymphoma/"},{"id":"nsclc","kind":"cancer","name":"Non-small-cell lung cancer","route":"/cancers/nsclc/"},{"id":"pancreatic","kind":"cancer","name":"Pancreatic ductal adenocarcinoma","route":"/cancers/pancreatic/"},{"id":"prostate","kind":"cancer","name":"Prostate cancer","route":"/cancers/prostate/"},{"id":"tnbc","kind":"cancer","name":"Triple-negative breast cancer (TNBC)","route":"/cancers/tnbc/"}],"paper":[{"id":"paper-kwak-crizotinib-alk-nsclc-nejm-2010","kind":"paper","name":"Anaplastic lymphoma kinase inhibition in non-small-cell lung 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