
Can't speak for all breeds, or individuals for that matter, but generally speaking with my Basset puppies they had pink testicles. I've just checked (LOL) my 4.4 year old boy here and his are now pink with black pigment (mottled - nice!) just as he has elsewhere on his body. I'd suggest B-e-c-k-y that if you are concerned about what's going on with your lad, you mentioned this to your vet next time you visit. Any abnormal skin texture, or of course, lumps and bumps must be checked.
We've had a couple with prostate flare-ups (quite possible the result of living around bitches coming in and out of season in our small show/breeding kennel) in later life. If this happened, I'd normally had them castrated to prevent this from keeping on happening. One I had chemically castrated to avoid surgery. And that appeared to work too. None of this involved cancer. The only cancers I had in my males, most of whom remained entire, was lymphoma in a 12 year old and oral cancer in one at around the same age.
I'd suggest that bone cancer tends to run in breeds (Rotties lots at the moment), castrated or not. As far as I'm aware, it's normally the bone growth that's affected if a dog/bitch is neutered too young.