Dogs are known for their keen sense of smell and some researchers are hoping to use their ability in developing a early detection diagnostic tool for ovarian cancer, researchers said Thursday.

Using blood and tissue samples donated by ovarian cancer patient, researchers from the University of Pennsylvania's Working Dog Center have begun training three detection dogs to sniff out the key compound that indicates the presence of ovarian cancer. A detection dog or sniffer dog is a dog that is trained to and works at using its senses (almost always the sense of smell) to detect substances such as explosives, illegal drugs, or blood. In this case, it will be to find the chemical marker linked to ovarian cancer.

The researchers are building upon previous findings that showed early stage ovarian cancer alters odorous compounds in the body. Another study in Britain in 2004 demonstrated that dogs could identify bladder cancer patients by smelling their urine.

The results have so far been positive with one Labrador in particular, Ohlin Frank, correctly detect ovarian cancer tissue 100 percent of the time. Within two years, Penn Vet founder and executive director Cynthia M. Otto belives the dogs can be trained to narrow down a specific odor so scientists can design an inexpensive and less-invasive blood test to catch ovarian cancer while it's still curable.

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. About 70 percent of cases are identified after the cancer has spread, said Dr. Janos Tanyi, a Penn oncologist whose patients are participating in the study. For those women, the five-year survival rate is less than 40 percent, he said.

The study is being funded by an $80,000 grant from the Madison, N.J.-based Kaleidoscope of Hope Foundation.