Of mice and men

EXPERIMENTS on mice are widely used to help determine which new cancer therapies stand a good chance of working in human patients. Such studies are not perfect and, all too often, what works in a rodent produces little or no benefit in people. This has led researchers to explore the ways in which mice and men are dissimilar, in order to pick apart why the responses are different. A new study now proposes that the temperature in which lab mice are kept is one thing that does matter.

Mice, if left to their own devices, will seek places with a temperature of around 30°C to minimise heat loss from their small bodies. But lab mice rarely enjoy such toasty climes. Researchers tend to keep them at 20-26°C so that their cages stay cleaner for longer (mice then drink and urinate less) and so that lab technicians do not have to endure sweltering conditions. It has not been seen as a problem because mice are perfectly capable of maintaining their body temperatures in cooler environments. However, Elizabeth Repasky, an immunologist at Roswell Park Cancer Institute in Buffalo, New York, wondered if there might be more to it than that and designed an experiment to find out.