See the sound clips, especially the one called “Try this at home?”.
“I think wounding alone is not going to do it. The compound alone is probably not going to do it. But together, I think it’s more likely to happen.”
This quote is more than a year old (which means it’s probably based on data from around 2 years ago), but it shows that you probably need both pieces for success: the wound (or some other kind of damage), as well as an appropriate cellular stimulus (in our case, a drug that effectively inhibits EGF).