From: Buffalo Edu
Study suggests how elephants became big and cancer-resistant
All things being equal, large, long-lived animals should have the highest risk of cancer.
The calculation is simple: Tumors grow when genetic mutations cause individual cells to reproduce too quickly. A long life creates more opportunities for those cancerous mutations to arise. So, too, does a massive body: Big creatures — which have many more cells — should develop tumors more frequently.
Why, then, does cancer rarely afflict elephants, with their long lifespans and gargantuan bodies? They are some of the world’s largest land animals.
A new study delves into this sizeable mystery, showing that elephants possess extra copies of a wide variety of genes associated with tumor suppression.
But this phenomenon is not unique to elephants, scientists say. The research concluded that duplication of tumor suppressor genes is quite common among elephants’ living and extinct relatives, including in small ones like Cape golden moles (a burrowing animal) and elephant shrews (a long-nosed insectivore). The data suggest that tumor-suppression capabilities preceded or coincided with the evolution of exceptionally big bodies, facilitating this development.