A protein found on certain types of cells that binds to a substance called epidermal growth factor. The epidermal growth factor receptor protein is involved in cell signaling pathways that control cell division and survival. Sometimes, mutations (changes) in the EGFR gene cause epidermal growth factor receptor proteins to be made in higher than normal amounts on some types of cancer cells. This causes cancer cells to divide more rapidly. Drugs that block epidermal growth factor receptor proteins are being used in the treatment of some types of cancer. Epidermal growth factor receptors are a type of receptor tyrosine kinase. Also called EGFR, ErbB1, and HER1.