{"entity":{"id":"overexpression","kind":"term","name":"Overexpression","aka":["overexpressed","overexpresses","over-expression","over-expressed","overexpressing","over-expressing","abundant on","overexpress"],"tldr":"When a cell makes much more of a particular protein than normal cells do. Drugs that home in on that protein can then hit the tumour harder than healthy tissue.","summary":"Overexpression can result from gene amplification, from a mutation in the gene's control region, or from signalling that keeps the gene switched on. It is what makes many antibody and ADC targets useful: TROP2, HER2, Nectin-4 and B7-H3 are all present at low levels on some normal cells but at far higher levels on particular tumours, so a targeted drug concentrates where the target is densest. Overexpression is scored by immunohistochemistry (0, 1+, 2+, 3+), and the threshold that counts as 'positive' can change as drugs improve, as happened with HER2-low.","asOf":"2026-09-09","wikipedia":"https://en.wikipedia.org/wiki/Gene_expression","links":[{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/Gene_expression"}],"tags":[],"related":["gene-expression","amplification","ihc","her2-low","biomarker"],"cancers":[],"sections":[],"technologies":["adc"],"targets":["her2","trop2","nectin4","b7h3"],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"category":"Biology basics"},"route":"/terms/overexpression/","neighbours":{"term":[{"id":"amplification","kind":"term","name":"Amplification","route":"/terms/amplification/"},{"id":"biomarker","kind":"term","name":"Biomarker","route":"/terms/biomarker/"},{"id":"gene-expression","kind":"term","name":"Gene expression","route":"/terms/gene-expression/"},{"id":"her2-low","kind":"term","name":"HER2-low and HER2-ultralow","route":"/terms/her2-low/"},{"id":"ihc","kind":"term","name":"Immunohistochemistry (IHC)","route":"/terms/ihc/"}],"technology":[{"id":"adc","kind":"technology","name":"Antibody-drug conjugate (ADC)","route":"/technologies/adc/"}],"target":[{"id":"b7h3","kind":"target","name":"B7-H3","route":"/targets/b7h3/"},{"id":"her2","kind":"target","name":"HER2","route":"/targets/her2/"},{"id":"nectin4","kind":"target","name":"Nectin-4","route":"/targets/nectin4/"},{"id":"trop2","kind":"target","name":"TROP2","route":"/targets/trop2/"}]}}