Definition

A protein found on certain types of cells that binds to a substance called epidermal growth factor. The HER1 protein is involved in cell signaling pathways that control cell division and survival. Sometimes, mutations (changes) in the EGFR gene cause HER1 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 HER1 proteins are being used in the treatment of some types of cancer. HER1s are a type of receptor tyrosine kinase. Also called EGFR, epidermal growth factor receptor, and ErbB1.