Dog detects ovarian cancer tissue 100 percent of the time.

We always knew they were our best friends!

"Ohlin Frank, a chocolate lab whose focus has the intensity of Sherlock Holmes, is only on his fourth training session at Penn Vet Working Dog Center, but he has been able to detect ovarian cancer tissue 100 percent of the time.

He and his fellow trainee, McBaine Chamberlain, a spunky springer spaniel who is a bit more excitable, are part of an interdisciplinary research project at the University of Pennsylvania's to help scientists discover a chemical footprint that might lead to earlier diagnostic tests to save human lives.

They are among 15 carefully bred detection dogs learning to sniff out explosives, drugs and missing people. And now, they will use their keen sense of smell to identify the earliest odor of ovarian cancer, a silent killer that is often diagnosed too late.

Ovarian cancer will kill more than 14,000 women in the United States this year and 22,000 new cases will be diagnosed, according to the National Cancer Institute.

But doctors still don't have a good diagnostic tool for ovarian cancer, so they hope the dogs and their keen sense of smell can lead them toward one."

The rest of the story, plus photos: http://abcnews.go.com/Health/dogs-trained-sniff-ovarian-cancer-develop-diagnostic-tool/story?id=19907889&singlePage=true