Our genes are responsible for making proteins that control just about every function in our body, and they are usually very well regulated. There are times, however, when something causes our genes to function abnormally and make too many copies of a protein. This is known in biology as “overexpression,” and it can play a role in cancer development. When investigators observe that certain proteins are overexpressed in cancer research, meaning highly active, they know they will need to look more closely at the gene responsible and potentially pinpoint the problem.
For example, researchers have learned that the overexpression or amplification of the HER2 gene is responsible for the development and progression of some aggressive types of breast cancer. Based on this information, clinicians can test the tumor of a patient to see what genes are highly expressed, or activated, and then find the best course of treatment for that individual patient. The continued identification of more genes and proteins linked to cancer by overexpression will also reveal new targets for treatment.