BAINBRIDGE ISLAND, Wash. (AP) _ Darrell and Nina Hallett love their dog Comet and have reached deeply into their wallets to prove it.

The couple spent $45,000 on a stem cell transplant for their golden retriever, who is recovering from lymphoma, a type of cancer that attacks the immune system.

Dr. Edmund Sullivan, a Bellingham veterinarian, performed the transplant last summer, using stem cells from another golden retriever.

Sue Hendrickson, a friend of the Halletts, owns Comet's mother and 11 other dogs. She spent months tracking down 40 of Comet's relatives to donate blood, eventually finding three perfect matches.

She flew to Florida to get Rico, the biggest of the three and the one who could yield the most stem cells, and delivered him to the Fred Hutchinson Cancer Research Center in Seattle, which donated advice and facilities for the transplant.

The cancer center has performed hundreds of bone-marrow or stem-cell transplants on dogs over the past four decades, as researchers perfected techniques used to treat cancer in humans.

Comet's transplant happened in June. After a long, steady recovery, he appears to be showing signs that he's been cured.