Richard Peto Cancer Cells Divide Essay

In 1977, Richard Peto hypothesized that humans, because of their larger size, should exhibit a far greater prevalence of cancer than mice do. However, that is not the case. The logic behind Peto’s argument is relatively simple: Cells divide, and as they do this, there is a chance that each cell will gain a mutation that increases its growth rate. Humans, as a more massive and longer living species than mice, naturally have more cells and thus undergo far more cell divisions throughout the entirety of their lives. Because of this, humans have a much greater chance of obtaining such a mutation and should therefore be more susceptible to cancer caused by genetic mutations. Despite this, however, both humans and mice display about the same prevalence of cancer throughout their lives. Because of this finding, or what is referred to as Peto’s Paradox, scientists postulated that larger animals who carry

Schiffman and Vincent J. Lynch have come to a very similar conclusion in regards to elephants’ exceptional ability to fight against cancerous cells through a series of very unique proteins. One of the proteins studied was the p53 gene, which is critical in preventing the spread of cancerous cells. This gene has three abilities: it can prompt cells to repair genes, stop cells from dividing, and trigger cell-mediated suicide. While humans only have one copy of the p53 gene, scientists were able to identify twenty p53 genes within an elephant’s genome. In tracing an elephant’s genealogical lineage, they discovered the smaller, first ancestors of elephants had only one p53 gene, but as they grew and steadily evolved, so did the number of p53 genes within their genome. When testing the effects of these extra copies under radiation, scientists discovered that despite what damage was inflicted onto their cells, they did not try to repair them. Instead, they caused them to commit suicide. This proved to be a very unique and effective