The reason why elephants rarely develop cancer has always been a mystery to scientists. Despite being the world’s largest mammal with lifespan up to 70 years, the disease which only increases with body size and life expectancy, the illness seems to be non-existent among elephants.
According to the scientists from the University at Buffalo, elephants seem to carry copies of tumour-suppressing genes which contribute towards cancer resistance. The researchers analyzed different species of elephants- Asian, African savanna and African forest elephants and their living and extinct relatives to find out that these tumour suppressing genes ‘facilitated the evolution of increased body size by compensating for decreasing intrinsic cancer risk.’
Scientists claim that studying more about these natural cancer resistance genes might help in developing better cancer treatments. Chances of getting cancer increase with longer life span hence, making it a common disease among the elderly. However, it has been rarely found in elephants.
In the journal named eLife, scientists wrote that this genetic advantage might have been introduced before or while, today’s elephants would have evolved their exceptionally large frames. One of the authors, Dr Vincent Lynch said that chances for cancer increases with a big body as there are more cells but the fact that this isn’t true across species-which has been a long standing paradox in evolutionary medicine and cancer biology- indicates evolution found a way to reduce cancer risk.
Earlier, scientists have studied tumour suppressing gene TP53 but this time, Lynch claims that scientists wanted to focus if elephants have more copies of these genes and find out if the trend was general, or the trend was specific to one gene. The scientists found that it was general and that elephants have multiple copies of these genes which all collectively contribute to cancer resistance.
It is also believed that these genes repair DNA and are involved in internal stress resistance and growth, ageing and death of cells.
Lynch explained that if one picks a weird mammal there-s a fair chance it belongs to one of these groups- the Afrotherians and Xenarthrans: armadillos, aardvarks, sloths, anteaters; to which they found that the organisms they studied belonging to these groups all have an extra copies of tumor-suppressing genes. He added that this might be the reason why in the last Ice Age there were giant sloths and ancient mega-armadillos and claims that multiple copies of these genes might help these animals get huge in size.
Another author Dr Juan Manuel Vasquez, University of California, Berkeley stated that they can learn something new about how evolution works and find better ways to improve cancer treatments by determining how these big, long lived species evolved better ways to suppress cancer.