In the 1970s, epidemiologist Richard Peto noted a paradox that puzzled scientists for decades: there is no correlation between an animal’s size and its risk for developing cancer. Tumor growth relies on random mutations. Therefore, since larger animals have more cells (and therefore more cell divisions), one would think that larger animals would be more likely to develop cancer than smaller ones. Two separate papers published in early October offer some explanation.
A study performed independently by Joshua Schiffman and Vincent Lynch and published in Nature, concluded that elephants have twenty copies of the TP53 gene. This gene is responsible for killing a cell when a DNA defect is detected, acting as a “tumor suppressor.” In other mammals, including humans, only one copy of TP53 is present. Therefore, an elephant’s genetic makeup allows it to successfully kill defective cells at a much higher rate than that of other mammals. However, Lynch notes that there are other biological factors at work, such as environment and metabolism. Regardless, this discovery brings researchers one step closer to understanding and developing stronger, more-informed strategies against cancer.