Heidi Ledford in Nature:
Standard temperatures for housing laboratory mice affect the experimental results that often form the foundation for cancer-drug development. International guidelines call for laboratory mice to be kept at room temperature. Yet the rodents find that range — 20–26 °C — uncomfortably chilly, says immunologist Elizabeth Repasky of the Roswell Park Cancer Institute in Buffalo, New York. Mice, she notes, lose body heat more rapidly than humans, and, when given a choice, prefer to reside at a balmy 30 °C. At stake might be more than just creature comforts. In a study published today by Proceedings of the National Academy of Sciences1, Repasky and her colleagues report that in mice housed at room temperature, tumour growth was faster than in those housed at 30 °C, and immune responses to cancer were suppressed.
For physiologist Ajay Chawla of the University of California, San Francisco, the results cause little surprise. Mice living at room temperature have to work overtime to maintain their body temperature, and have high heart and metabolic rates, he says. “This study addresses an important issue that I think most of us have ignored,” says Chawla. “I tell my colleagues, 'You’re modelling human disease and pathology in an organism that is like somebody who is on speed'.”