In the latest episode of Genetics Unzipped, presenter Dr Kat Arney takes a trip to the zoo to find out how studying tumours across the animal kingdom, from naked mole rats to elephants, can reveal insights into cancer in our own species.
From hydra to humans
In 2014, geneticists at the University of Kiel in Germany published a paper describing tumours in two different species of tiny freshwater Hydra. Little more than a tube with tentacles, Hydra comprise three distinct groups of stem cells. One of these groups, known as interstitial stem cells, turned out to be the source of the cancers, which severely impacted growth and fertility.
But while Hydra may be the simplest organisms currently known to develop cancer, they are far from the only example outside our own species. Kat explores how cancer has been found on virtually every branch of the tree of multicellular life, from the simplest to the most complex.
One recently published list of animals known to be affected by cancer stretches over more than twenty pages, including a line-up of marine creatures that reads like the menu from the world’s weirdest sushi restaurant. Tumours turn up in frogs, toads and other amphibians, and have been spotted in a range of reptiles such as snakes, turtles, tortoises and lizards.
Cancers appear in many species of bird from parakeets to penguins, cockatoos to cassowaries, black-bellied whistling ducks and common-or-garden budgerigars. From aardwolf to zebra, our fellow mammals are also affected by all manner of cancers: whales, wallabies, baboons, badgers, bongos and everything in between.
“How can I get me some of that elephant blood?”
Kat also tells the story of how a family trip to the zoo led to University of Utah paediatrician Professor Josh Schiffman discovering the biological secret that explains why elephants hardly ever get cancer.
While Schiffman was working with families with Li-Fraumeni syndrome, who have an inherited fault in the TP53 gene resulting in a very high cancer risk, he started wondering what role p53 might be playing in species at the other end of the spectrum.
A few weeks later he’s visiting Utah’s Hogle zoo with his family, and they’re checking out the elephant show. During the course of the demonstration, the elephant keepers explain that once a week at the zoo they draw blood from the veins in the African elephants’ ears to make sure that their charges are healthy. When Schiffman hears that, he has just one question for the zookeepers: “How can I get me some of that elephant blood?”
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Genetics Unzipped is the podcast from the UK Genetics Society, presented by award-winning science communicator Dr Kat Arney and produced by First Create the Media. Follow Genetics Unzipped on Twitter @geneticsunzip, and the Genetics Society at @GenSocUK