Nearly two-thirds of mutations in human cancers are attributable to random errors that occur naturally in healthy, dividing cells during DNA replication, researchers report in the 24 March issue of Science. Though mutations that cause human cancer have traditionally been thought to originate from heredity or environmental sources, these results — grounded in a novel mathematical model based on data from around the world — support a role for so-called "R" or random mutations in driving the disease.

Jason Silverstein, an anthropologist in training at Harvard, was looking for feedback on his research into the role of physicians as border police in French refugee asylum policy. Under the policy, medical evaluation is a key element of the asylum process—if refugees can prove they suffered trauma, they can stay. If not, they must leave.