Gene amplification refers to an increase in the number of copies of a gene in a genome. Cancer cells, for example, sometimes produce multiple copies of a gene(s) in response to signals from other cells or the environment.
Gene amplification. One well-known example of gene amplification and cancer is amplification of the HER2 gene in a subset of breast cancers. HER2 gene amplification results in the production of excess HER2 protein on the surface of the cancer cell. About 20% of breast tumors have amplification of HER2 or have a overexpression of non-amplified HER2. These tumors are known as HER2-positive breast cancers, and they can often be effectively treated with drugs that specifically target and neutralize the excess HER2 protein produced by the patient's tumor. This is an example of personalized medicine in oncology.
Cancer Genetics and Comparative Genomics Branch