Ep. 6 - Why don't elephants get cancer?

Elephants are massive animals and can get quite old. So why don't more of them get cancer? The answer lies in their genetics. Hear more about this from one of our biologists, Professor Sam Benchimol. Elephants are among the largest and longest living animals. Only 3% of them will get cancer, which is very low considering the amount of cells divided over the lifespan of an elephant. To put it into perspective, 50% of Canadians will develop cancer in their lifetime. So why are elephants less susceptible to cancer? Scientists believe it's because they have more copies of p53 a major cancer fighting gene. Twenty copies to be exact, while humans have just one. Cancer occurs when certain growth and division genes get damaged in a cell. Unless that DNA damage gets repaired, the cells start growing and dividing uncontrollably, becoming cancer. DNA damage is easily repaired with our most valuable player p53. p53 activates repair proteins and freezes the cell division cycle so that the cell has time to fix the damage before it divides. p53 can also force the cell to die if the damage can't be repaired. So when a tumour's p53 gene is compromised, that's bad news for us, we lost our cancer fighting MVP. But if an elephant's p53 gene is compromised, the other 19 step up to the plate. Elephants would actually need to have almost all of their p53 genes deactivated before a high risk cancer develops. And the chances of that happening are quite low.