What does the Gospel of Peter have to do with the Da Vinci Code?

I'm doing a project on the comparison of them both. i know that the GoP is not in the bible because a lot of the stories dont match up to the bible and i know enough about the da vinci but i cant really find what the GoP says specifically that relates to the Da Vinci Code. Does the GOP talk about mary and jesus' relationship like the DVC? someone help pleaseeeee.