termsTerm
Overexpression
aka overexpressed, overexpresses, over-expression, over-expressed, overexpressing, over-expressing, abundant on
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.
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.
Category
Biology basics