Source:http://linkedlifedata.com/resource/umls/id/C1514559
NCI: In biology, to make too many copies of a protein or other substance. Overexpression of certain proteins or other substances may play a role in cancer development.,NCI: Synthesis of excess polypeptide within the cell. Overexpression is often due to the amplification or deregulation of the gene which encodes the gene product.