The other day Katie, a golden retriever who lives on five acres in El Dorado County, took a leisurely walk out to the barn, sniffed around and had a nap. Not remarkable for a dog, except that nobody expected this one to be alive today.

Katie's story may involve 21st century advances in molecular biology and genomics, but the basic plot is an ancient one: Man takes care of dog; dog repays man many times over.

Katie was among 57 dogs, all with end-stage cancers, to receive an experimental drug through a clinical trial at the UC Davis Small Animal Hospital. The dogs, who had exhausted all conventional therapies, each gained extra time — more than two years so far in Katie's case. In return, the dogs gave medical science some of the first evidence that molecules known as multi-targeted kinase inhibitors, taken in tablet form, are safe and effective against a variety of naturally occurring cancers.

UC Davis Cancer Center is at the forefront of efforts to coordinate animal and human cancer research to improve cancer treatment for people as well as pets. The Cancer Center's Integrated Cancer Research Program, a collaboration of more than 200 investigators from more than a dozen scientific disciplines, includes 19 veterinary oncologists and basic scientists at the UC Davis School of Veterinary Medicine.

"Everyone wins in this collaboration," says Cheryl London, an assistant professor of surgical and radiological sciences in the School of Veterinary Medicine. A Harvard-trained veterinary oncologist, London heads the UC Davis Cancer Center's Cancer Biology in Animals Program together with Ron Wisdom, assistant professor of hematology/oncology.

"Our dog and cat patients win, because they get access to novel therapeutics that can potentially help slow down their cancer progression or even cure their cancers," London says. "And we win, because we learn more about the potential efficacy of these drugs for treating human cancers."

Clinical trials of new anti-cancer drugs can be conducted more quickly in dogs and cats, because the regulatory oversight that applies to human test subjects doesn't exist for animals. Trials in pets are also less expensive, because charges for everything from blood tests to CT scans are lower in veterinary medicine. A cancer clinical trial that might take five years and many millions of dollars in human volunteers can be completed in five months for $100,000 in animals.

Katie's remission after taking SU11654, an experimental oral anti-cancer agent, gave oncologists important information about a promising new agent long before it could have been obtained through human clinical trials.

One of London's newest clinical trials will test another investigational anti-cancer drug, 2-methoxyestradiol. The drug — 2-ME2 for short — is being studied in human clinical trials involving patients with prostate cancer, metastatic breast cancer and multiple myeloma, a malignancy of certain white blood cells.

London hopes the drug may also work against sarcoma, a soft-tissue cancer that is very common in cats and dogs. She has already shown that the drug kills sarcoma cells in the laboratory dish. Now she hopes to find that the drug does the same for sarcoma tumors in pets. She received funding for her study, however, from a foundation dedicated to finding cures for human cancers.

The V Foundation, a North Carolina-based organization established in memory of ESPN broadcaster Jim Valvano, recognized that an animal study might generate important answers for human sarcoma patients — and do so quickly.

While sarcomas are common in dogs and cats, they are relatively uncommon in humans, affecting about 8,100 children and adults in the United States each year. The larger pool of potential animal sarcoma patients makes a clinical trial easier to organize in cats and dogs than in people.

London expects to know sometime this year whether 2-ME2 is effective against canine and feline sarcomas. If it is, veterinary oncologists will have a new tool for fighting a common cancer in pets — and a path will be cleared for tests in humans with sarcomas.

Cancer wasn't Katie's first crisis. The golden retriever was picked up as a stray, with a litter of puppies, about six years ago. Mother and pups were taken to an animal shelter, the pups were adopted and Katie was sent to Homeward Bound, a golden retriever rescue organization based in Elverta. Two families, in quick succession, adopted Katie. But the dog tried to run away from both adoptive homes, winding up back at the rescue organization each time.

The third adoption took. Carla and Michael McCreary tracked Katie down and brought her back home whenever she ran away. At some point, the dog stopped trying to escape. At obedience school with Carla, Katie got off to a rough start but went on to earn effusive praise from the instructor at graduation. As a volunteer with the Sacramento SPCA's Love on Loan pet visitation program, Katie revealed a special empathy for the most withdrawn kids at the Children's Receiving Home, a Sacramento shelter for abused and abandoned children and adolescents. "Katie," Carla says, "gives back everything she is given."

Two years ago, Carla found a lump on the dog's chest. She and her husband went to extraordinary lengths for their adopted pooch: two surgeries, chemotherapy and, when those measures failed, participation in London's clinical trial. The trial required daily medication at home and monthly trips to UC Davis for blood work and X-rays. And London couldn't promise the effort would make any difference in Katie's illness.

Of the 57 dogs with advanced malignancy enrolled in the trial of SU11654, 16 experienced no progression of disease during the study and 11 had measurable reductions in tumor burden. Six dogs, including Katie and Basil (shown on this issue's cover), had a complete response. Their tumors disappeared.

Katie, now 8 or 9 years old, returns to see London every three months. The dog's chest X-rays remain clear and her blood work is perfect.