Bull, the dog in my avatar, had mesothelioma...human asbestos cancer. Go figure? At the time he was one of a handfull, and none survived it. That's why we went hunting for the month after his surgery, until I could see he wasn't interested in it anymore, then we went home for a "soft landing".
Thankfully I'd had him collected, and I have one of those 'miricle' pups. The young Tank has a lot of his daddy and his grandpa in him, for which I'm thankful.
Chief, another of Bull's pups, is now almost 9. He shows some signs of aging...mainly getting stoved up after a lengthy hunt, and a greying muzzle. But so far he recovers well with a couple of Bufferin, and has unending desire. He's a far better pheasant hunter than his daddy was.
I'm certainly not looking for any cancer to invade either of these dogs lives, but time will tell. And if it did, I'd not consider it as being hereditary.