Friday, May 06, 2011

Cancer in whales, dinosaurs and birds

Whales have amazing defenses against cancer. It's one reason they're able to get so big...

... Caulin and Maley argue that when animals evolve to larger sizes, they must evolve a better way to fight against cancer. It’s possible that a blue whale simply has a souped-up version of our own defenses. We have proteins that monitor our cells for over-eager growth, for example; they can kill or zombify cells that on the road to cancer...

Caulin and Maley suggest that nature has carried out this experiment as well. We have one copy of a gatekeeper gene called TP53, for example. Elephants–which are at a greater risk for cancer–have a dozen copies of the same gene.

.... Scientists could look at closely related species that span a big range of sizes, searching for telling differences in their cancer defences. Whales and dolphins would be a good pick, since blue whales are 2,000 times bigger than the petite Commerson’s dolpin.

But such an undertaking would have to overcome a lot of inertia in the world of cancer research. Cancer biologists don’t look to big animals as models to study–which is one reason there’s not a single fully-sequenced genome of a whale or a dolphin for scientists to look at...

Maybe scientists don't need to look at whales. Dinosaurs were big for a long, long time. Sure, they're pretty small now, but maybe they kept some of the cancer defenses that let them grow big. We just need to study cancer in small but long-lived dinosaurs, like parrots. Maybe we'll find relics of the defenses T-Rex had, and find a way to use those ...

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