Consistent with the similar transduction efficiencies detected among groups before serial replating assay and transplantation, the immortalized cells and leukemias induced in all groups have similar viral copy numbers (Supplementary Figure S4), suggesting that insertional mutagenesis was unlikely responsible for the differences in colony-forming potential and leukemia latency and penetrance between Setbp1 mutants and wild-type groups. This evidence concerns the gene SETBP1 and leukemia.