Man's best friend might also be a doctor's newest weapon in detecting cancer. Dogs are known to have a keen sense of smell — sharp enough, according to a new study, to detect the presence of cancer on a person's breath. German researchers trained dogs over nine months to distinguish between breath samples from lung cancer patients and from healthy people; the animals were able to identify 71 out of 100 cancer samples accurately, and also picked out 93% of the cancer-free samples.
What were they sniffing out? The scientists think the dogs were picking up on very subtle changes in certain volatile organic compounds in the breath, which may change when cancer is present. It may be possible to analyze cancer patients' breath for whatever compounds the dogs were identifying, but it's not clear what that is. "It is unfortunate that dogs cannot communicate the biochemistry of the scent of cancer!" the study's author noted.