Cancer rates in humans is apparently proportional to height. (Don't have a reference for that.) But humans and mice get cancer at the same rate -- even though we are a lot bigger. And elephants get very few cancers despite the obvious size difference. Why? It seems that a gene helps. Humans have one copy of the p53 gene. Elephants have many. Experiments show that elephant cells bombarded with cancer causing chemicals or radiation commit suicide.
However, it's not a simple magic bullet. Experiments in which mice get extra amounts of p53 have shown that the molecule has a downside: It can accelerate aging. “It has to be kept under tight control,” Dr. Muller said.
But p53 is not the only weapon nature has developed to fight cancer. _ Naked mole rats, for example, live up to 30 years without ever getting cancer. One weapon they use is a protein that arrests the growth of fast-dividing cells. It senses when these cells bump into other cells and brings their division to a halt._
That is an entirely different solution from the one elephants appear to have evolved. And elephants are the only animals yet found that fight cancer with extra p53 genes. So Dr. Schiffman speculates that parrots, tortoises and whales may all have special longevity tactics of their own.
“The war on cancer was going on long before there were humans,” he said. “So let’s look at nature’s strategies.”