In a report published online in advance in Science this week, investigators at the Wellcome Trust Sanger Institute and their colleagues show that "insertional mutagenesis by the PiggyBac transposon can be used for cancer gene discovery in mice." In their analysis of 63 hematopoietic tumors, the team found that PiggyBac "is capable of genome-wide mutagenesis." In their screen, the Sanger Institute-led team found several cancer genes that were not identified in screens using other retrotranposo