Yes, there have been some studies that show animals (particularly cats) can detect cancer in humans. The theory is there may be something they can smell, that we can't. I just read about this in the last couple of weeks, but for the life of me, I can't remember where I read it......so I can't share it.
Also, for the person whose Yorkie could detect low blood sugar in her mom who was a diabetic - I have known that to be absolutely true also.
There are cats who live in nursing homes who know when someone is going to die and they will get in the bed with the person and won't leave till the person is gone. This has been documented in more than one nursing home. Keep those darned cats out of MY bed!
Animals are amazing!!!!!