termsTerm
Amplification
aka amplifications, amplified, gene amplification, copy number gain, copy-number gain, copy number, copy-number, extra copies
When a cell has many extra copies of a gene instead of the normal two, so it makes far too much of that protein. HER2-positive breast cancer is the classic example.
Amplification is a copy-number change: a segment of DNA containing the gene is duplicated, sometimes to 50 or more copies, either within the chromosome or on separate circles of DNA (ecDNA). More copies mean more RNA and more protein, so an amplified oncogene behaves as if permanently over-activated. It is detected by in situ hybridisation (FISH/ISH) or sequencing and is a drug target in its own right: HER2 amplification is what trastuzumab and T-DXd exploit, and MET amplification is a common way lung cancers escape EGFR inhibitors.
Category
Biology basics