Dogs detect cancer
A study has or is being done to test dogs for detecting cancer. Their detecting positive samples 88-99% of the time.
They had a dog test 4 cancer patients that were said to be in remission from all the Dr.'s tests. One of the patients has the dog mark on their sample 24 of 25 times but when the Dr.'s tested it showed nothing. A year and a half later this persons cancer showed up again.