Taking preventive measures Recent technological advances have made it possible to detect, in healthy individuals, premalignant blood cells that are likely to progress to hematologic cancer. These advances in early detection have fueled interest in “cancer interception,” the idea that drugs designed to treat advanced cancer might also be useful for cancer prevention. Uckelmann et al. now provide support for this concept in a study of mice genetically predisposed to develop acute myeloid leukemia. Early administration of an epigenetic therapy that had previously been shown to have anticancer activity in advanced leukemia models was able to eliminate preleukemia cells and extend survival of the mice. Science , this issue p. 586