French scientists have trained dogs to detect prostate cancer in the urine of patients. They trained the dogs to sniff the urine of patients with healthy prostates and known prostate cancer. Then they had the dogs do blind smelling tests of urine. The dogs apparently became pretty good at it. Out of 66 tests, the dogs were correct 63 times. As many urologists will tell you, the PSA test that is the standard for detecting prostate cancer is not as accurate as we are led to believe. The next step is to understand the chemical that the dog is smelling to automate the process. Otherwise every urologist's office will need to keep a dog on site to smell patients' urines.
As an aside, this story reminds me of the episode in The X-Files where Scully discovered she had brain cancer when a monster targeted her for his next meal. Again, life imitates art.