Is superiority of human brains to chimps' responsible for higher cancer rates?

Washington, June 11 (ANI): Scientists at the Ovarian Cancer Institute are studying whether the cognitive superiority of human's brains over chimps' is responsible for the higher rates of cancer among humans.

"I was always intrigued by the fact that chimpanzees appear to have lower rates of cancer than humans. So we went back and reanalysed some previously reported gene expression studies including data that were not used in the original analyses," said John McDonald, chair of Georgia Tech's School of Biology and chief research scientist at the Ovarian Cancer Institute.

Working with his graduate students Gaurav Arora and Nalini Polivarapu, McDonald compared chimp-human gene expression patterns in five tissues: brain, testes, liver, kidneys and heart.

The researchers observed distinct differences in the way apoptosis-a mechanism whereby bodies destroy cancer cells-operates.

McDonald says that that finding suggests that humans do not "self-destroy" cells as effectively as chimpanzees do.

"The results from our analysis suggest that humans aren't as efficient as chimpanzees in carrying out programmed cell death. We believe this difference may have evolved as a way to increase brain size and associated cognitive ability in humans, but the cost could be an increased propensity for cancer," he said.

McDonald admitted that just like all evolutionary hypotheses, this can't be proven absolutely.

He, however, insists that his lab has recently obtained additional direct experimental evidence consistent with the hypothesis that apoptotic function is more efficient in chimps than in humans.

The study has been published in the online edition of the journal Medical Hypothesis. (ANI)