Researchers have determined the structure of a biochemical substance that leads to a large majority of breast cancer tumors.

They figured out what a key enzyme, known as Aromatase, that produces estrogen, looks like.

Knowing its molecular structure will allow researchers to create drugs targeting it and stopping it, ultimately preventing breast cancer.

You'll recall we told you earlier this month that UAMS hopes to start human clinical trials this spring on a new breast cancer vaccine.

It's designed to trick the body into doing something it wouldn't naturally do -- produce antibodies that fight breast cancer cells.