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From "Myth Busters” in the January/February 2015 issue of Iowa Outdoors magazine:
Cold-blooded animals like snakes, fish and sharks do get cancer, likely from polluted waters and foreign substances. While many questions still surround this issue, scientists hope the unique ways these animals deal with cancer might give hope for cancer treatments and possible cures in humans.
We don’t know much about how often these animals develop cancer, as it’s difficult to sample a large population, but we do know they suffer from the disease. Still, it appears sharks have a remarkable defense against cancer that could prove useful in learning how to beat cancer in humans.
Scientists have studied how new blood vessels appear to feed cancerous tumors with oxygen and nutrients. Find a way to prevent those new vessels from developing, and you’ve found a way to stop the tumor from growing. Shark cartilage does just that—it has a compound that keeps new blood vessels from forming, which starves the tumor.
Following that thinking, people have sold shark cartilage supplements for years, touting them as a way to prevent or cure cancer. Studies have not shown that swallowing a pill of ground-up shark cartilage does anything to prevent cancer, and this increased demand for shark cartilage can have harmful effects on shark populations. Researchers do, however, continue to look to sharks for clues on how to treat human cancers, reinforcing the importance of keeping shark populations, as well as populations of other cold blooded animals, healthy to allow further research.
Researchers are also looking at the naked mole rat, an east African mammal whose body temperature matches ambient temperatures. It does not get cancer in later life. A sugar substance found in the rodent’s tissues, which may give it flexible skin, aids in tissue repair and may protect it from developing cancer.
So while cold-blooded animals may not be completely cancer immune, their powerful defenses may prove beneficial in treating people. Another lesson? That a fully functioning, healthy ecosystem resplendent with all its animal populations is valuable for humans, too.
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