[Editorial] Cancer: mixed messages, common purpose (Lancet)

On Jan 2, a research paper published in Science by Cristian Tomasetti and Bert Vogelstein proclaimed that most individual cancers, 65%, could be attributed to `bad luck`--random events such as errors in DNA replication--rather than to environmental or inherited risk factors. This eyecatching message has drawn comment, partly because of the inbuilt uncertainty in the study`s methods and headline estimate (with its 95% confidence interval of 39-81) and partly because of the conclusion`s incompatibility with public health evidence and thinking.