I highly doubt it has any correlation to AAS or HcG. Dude is only 29....at that age I don't care if you're smoking 20 boxes a day of cigarettes, you should not get cancer that young. If you do, that means it's your genetics that you inherited from your relatives. If he was 49 on the other hand, you could try to say that it might be the gear. But at 29, no way. Most people in here are older than that.
Not trying to be an A-hole however, this sucks a lot for him. I really hope he kicks cancers ass