So her actions aren't uncommon, I think the fact that she kept it secret for so long (not even telling her family) is part of the shock.
So, if you had a gene that indicated a chance of cancer, would you have surgery to prevent it? Personally, I'd use that information to keep an eye on it, and catch it early. It's nice that we have advanced to gain this knowledge, but it's not for certain, and maybe thinking that your genes will make you sick... would make you sick. Do you think state of mind has an impact on health?
"You should the forums"
Better words never said.