I am divorcing my wife because she admit to prostitude in the old country and that was one of the questions on her green card application which she lied to she has her green card since 2004 can her green card be revoked because she lied to that question on her immigration application?

It's too late.. besides, you can't prove it.

No, and to be honest that was back then, and I am shocked that what happened in someone's past before you meet, is or should be a issue.

I don't even think you should have divorced her and even now looking to harm her for something from the past.

Thank heavens there is little you can do. But I do hope she gets her share in the divorce.