When you get a cut on your finger, the damaged skin cells secrete a protein called epidermal growth factor (EGF). Skin cells close to the cut have epidermal growth factor receptors (EGFR) in their membranes. 1. What part do you think EGF plays in the cell signaling pathway? Describe the process by which EGF leads to the cut being repaired.

2. Skin cancer results from a mutation in the production of EGFR, but not in the EDFR itself. Describe how a mutation that does not directly affect EGFR can still disrupt its production.

3. The use of antibody therapy in the treatment of cancer, in particular skin cancer, has shown great promise in recent years. The antibodies work in the extracellular part of EGFR. Explain how the antibody therapy affects the cell signaling pathway and why it is effective.