John Cena's WWE career has almost reached its climax, and it seems that there are a number of questions still surrounding the 17-time World Champion.One of the biggest mysteries seems to be the number 54 and the role it plays in his career. Back at The Royal Rumble, when he made his first stop on the road to his retirement, Cena's titantron used the number 54, and it has always been a number he has worn on jerseys in the ring.It has finally been revealed that John Cena uses this number because it was his jersey number for his short-lived career as a football player in college.Many fans are unaware that Cena had a short run as a college football player, but it seems that the 54 he uses so regularly is a symbol of his humble beginnings and a reminder of where he started.John Cena takes on Brock Lesnar at WWE Wrestlepalooza this weekendJohn Cena will face one of the biggest tests he has been put up against as part of his retirement tour this weekend when he takes on Brock Lesnar. The Beast Incarnate made his return at SummerSlam to prove that he still has some issues with Cena, and they could finally be resolved at Wrestlepalooza.Cena's tour wouldn't be complete without Lesnar since the two men have their own storied history. Lesnar has also been away from the ring for more than two years, which could make this Cena's best chance at beating him.It will be interesting to see who is next on his retirement tour after Brock Lesnar, since Cena only has three months until he retires from wrestling for good, and there are several stars who want to step up and face him one last time.