Cain went to Arizona State and Brock went here at the U. Both were All-American's in wrestling - Brock won a national title.
The bout being fought in California is much closer to being considered a "home" fight for Velasquez than it is for Lesnar who lives in Minnesota pretty much year round, I think.
I would be very surprised if Cain was able to upset Lesnar, despite his currently unblemished record. He could prove me wrong if he can out strike Lesnar and keep him standing as much as possible.