Scientists studying cancer in sea lions

SAUSALITO, Calif. - If you want to study cancer, study it in a creature far more susceptible to it than humans. That turns out to be sea lions according to the Marine Mammal Center in the Marin Headlands.

Sea lions are contracting and dying from cancer, at alarming rates in their uro/genital tracts, most often among the females.

"We are concerned that it is such a high incidence. It's 19 or so percent in this particular population of California sea lions which is very unusual for any mammal," says Dr. Padraig Duignan, Chief Pathologist at the Marine Mammal Center.

"And it's just in California sea lions so far, because of a virus. But, usually, a virus alone doesn't do it.  So, usually when you see a severe disease outbreak like this, in wildlife, there's some big underlying problem," adds Dr. Cara Field, a rehabilitation veterinarian.

It is not domoic acid, which has caused sea lion brain damage and killed of last crab season. "There's a Sea Lion Cancer Consortium, so we've got collaborators and researchers all over the country actually working on different aspect of this," says Dr. Duignan

For those many that do succumb to the cancer, researchers can immediately take a look at everything inside the animal that cause the death and that information is shared with researchers worldwide, including those who are looking at fighting human cancers.

"This is a very good model of cancer.  It's in a free living species, there's no laboratory animal. In a sense it's mot like the human population because we're not lab rates.  We are exposed to pollutants, toxins and virus and all these other influences that these sea lions are," says Dr. Duignan.

Stanford researchers are using brain tissue from sea lions killed by domoic acid to find new treatments for human epilepsy.  

Post mortem necropsies allow researchers to compare the diseased cancer patients against non cancer patients for genetic, viral and environmental, differences. 

"Certainly understanding why they get it and what the contributing factors are and 'do these contributing factors represent a risk to us?' is critically important for us in understanding what other risks there may be for us as well as other animals," says Dr. Field.

One lucky pup, once starving and suffering pneumonia, was given his exit exam Monday,  prior to his disease free release back into the wild later this week.