The lecture speaker mentioned that elephants seemed to have extra copies of the p53 gene.
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Scientists have solved the long-lasting mystery that why elephants and larger mammals are less prone to cancer compared to smaller mammals despite having 100 times more cells than humans.
Compared with just one copy in humans, elephants’ cells contain 20 copies of a major cancer-suppressing gene, two teams of scientists report. To see whether this could be the case, the researchers collected white blood cells from elephants and humans and exposed the cells to radiation that caused their DNA to break.
Two other nearly cancer-free animals are the naked mole rat and the bowhead whale, which appear to use different genetic mechanisms to prevent the disease.
New research is out this week from a study looking at why elephants rarely get cancer. After three years, Schiffman has been able to establish why elephants have less incidence of cancer.
The database had details on 644 elephant deaths, and the researchers calculated that just 3.11 per cent of those elephants had cancer when they died.
Researchers say the discovery has implications for treating cancer in humans. It has sparked multiple studies around treatments surrounding TP53, and has brought information to light on how these grand animals have such low risk for cancer. They also found 20 copies of TP53 in African elephants in which one was original and 19 were formed over time.
The vast majority, 38 of them, are so-called retrogenes, modified duplicates that have been churned out over evolutionary time.
Elephants have extra genes that stop tumors long before they form.
While this may sound like a bad thing, it isn’t. After that, researchers came to the conclusion that TP53 makes the ill cells destroy themselves so that they don’t evolve to risky mutations.
“It’s as if the elephants said, ‘It’s so important that we don’t get cancer, we’re going to kill this cell and start over fresh, ‘” said Joshua Schiffman, one of the study’s author and a pediatric oncologist at the University of Utah School of Medicine.
“Elephants may have a more robust mechanism for killing damaged cells that are at risk for becoming cancerous”, the study said.
“By all logical reasoning, elephants should be developing a tremendous amount of cancer, and in fact, should be extinct by now due to such a high risk for cancer”, Schiffman said.
“The important suggestion of this study is that additional copies of [TP53] are enough to prevent elephants from getting cancer”, said Graham, who was not involved in the JAMA study.
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Another thought is to insert more TP53 genes into precancerous cells. While studies in humans are at least several years away, “we certainly think we’ve found something very intriguing”, Schiffman said. “We want to learn how to take advantage of that”.
