(eh-peh-DER-mul growth FACK-ter reh-SEP-ter) Protein on the surface of some cells to which epidermal growth factor binds, which causes the cells to divide. EGFR is found at abnormally high levels on the surface of many types of cancer cells. Also called ErbB1 or HER1.

See EGF-R.

Protein on the surface of some cells that allows them to bind and react to epidermal growth factor. Some cancer cells have mutations that cause too much of this protein to be produced and so are encouraged to grow by epidermal growth factor. For example, large amounts of the protein are often present in the cells of non-small cell lung cancers, sometimes in a mutated, over-active form.