Interestingly, 1 out of 6 aged Zrsr2m/mTet2−/− mice showed signs suggestive of progression to secondary AML, such as an increase of blasts in PB smears and myeloperoxidase (MPO) staining in spleen and liver sections (Supplementary Fig. 3e–g). This evidence concerns the gene MPO and acute myeloid leukemia.