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Cancer-fighting genes in elephants could help tackle one of the biggest killers of people, according to research. Despite their large bodies and long lifespans, elephants are much less likely to die from cancer than humans, with death rates of less than 5 percent.

The paradox has puzzled scientists because more cells lead to greater replications (复制), which increases the possibility of the body failing to detect damaged DNA or a faulty cell that can result in tumors(肿瘤). Elephants live for almost as long as humans and weigh up to five tons.

However, a group of British and European scientists say they have taken a big step towards solving Peto’s paradox, named after the British epidemiologist Sir Richard Peto. Elephants, they say, carry a much larger more diverse group of tumor-fighting proteins.

The findings, published last week in the journal Molecular Biology and Evolution, raise hopes that the cancer fighting genes in elephants could be the key to tackling cancer, which kills about 167, 000 Britons yearly. Cells keep dividing throughout an organism’s life, each carrying the risk of producing a tumor. One of the body’s weapons is a gene called p53 known as the “guardian of the genome”, which hunts cells with faulty DNA. It encourages the cell to repair itself or self-destruct, keeping the cell from combining with others and producing tumors.

Humans have two versions of p53 but elephants have 40, said the researchers. Biochemical analysis and computer simulations also showed that an elephant’s p53 genes are structurally slightly different, providing a much larger anti-cancer toolkit. The researchers suspect that while faulty cells might be able to skirt two p53 versions, they cannot combine with other cells as easily in the face of dozens.

The findings will open the way for research on how p53 genes of elephants are activated and on medical treatment for humans.