"The estrogen receptor is like a keyhole in a locked door, and estrogen is the key that opens that door and "turns on" growth-promoting effects in the cell. However, among dozens of keys, you might find some that fit into the keyhole but do not work to turn the lock and open the door."
Feel free to be the first
Please review the linked page for context.
If you can think of something better than this,
please add it to the database