If your beloved dog gets cancer, it could be a heartbreaking and scary event — but your dog's misfortune could help save a lot of people's lives down the road. A lot of the cutting edge of cancer research involves studying canine tumors and treating canine cancer aggressively — and humans could benefit quite a bit from the results.
Top image: Jim McCluskey/Flickr.
Last week, when we did our feature on the latest developments in cancer treatment research, the subject of learning from canine tumors came up, but we couldn't fit it into the completed article. Since then, we've seen more discussion of how studying dogs' tumors can help — ABC News did a feature about dog owners volunteering their pets for clinical trials for a more aggressive form of radiation therapy, with great results. And Texas A&M University announced some very encouraging results from a trial on using T-cell therapy on dogs that had already undergone chemotherapy.
While we were working on our cancer article, we spoke to Ralph deVere White, director of the U.C. Davis Cancer Center, who said that examining canine tumors can allow all sorts of advances. For one thing, dogs are genetically closer to humans than mice are, as the TAMU press release points out. But also, says White:
We're comparing what's happening in dogs to [human] patients. People didn't like working with dog tumors, because they said, 'Oh gosh, they're so unpredictiable. They have multiple abnormalities. You can't reproduce them." And so people wanted mice. But if you think about dogs, they live with us. They live in our environment... You can biopsy their tumors. You can image their tumors. You can do pharmacodynamics. You can treat them for cure. You can monitor their response. And then you can relate all of that back to what's happening in [human] patients.
[U.C. Davis has] one of the best veterinary schools [with] 8,000 visits a year. People bring in their dogs and cats to be cured. So we set up a big program, and we're trying to grow it, especially for lymphomas and sarcomas — you know, can we bring new advanced treatments to the dogs, in the hope that the dogs will inform us about patients?
A second program that White mentioned involves mice: recently, mice have been developed that don't have "natural killer cells" that have prevented researchers from implanting part of a human patient's tumor directly into the mouse. When you do this, about half the tumors continue growing. And when you look at the tumors under the microscope, they look very similar to what came out of the patient, and when you check them for the major molecular abnormalities, such as EGFR and RAS mutations, the mice "seem to very faithfully reproduce those."
You treat that mouse, and you wipe out those cells that are responsive to blocking the EGFR receptor — and then they come back. [The question is] can you look at the molecular events in the mouse when they come back and say, "Okay, if you have that mutation, it seems to [have a] bypass mechanism." Can you then develop a way to block that, and see if that works? Then what you would hope is that the next patient comes in, you take the tumor, and molecularly analyze their tumor and say, "Gosh, you're like Mouse 51. So this is the treatment. And when you relapse, we have the next treatment ready." And that's what we hope to do.