TET2 deficiency alone (CebpaΔ/+Tet2Δ/Δ) did not give rise to AML and cells which retained expression of the p42 isoform from one allele (Cebpa+/p30) only sporadically underwent leukemic transformation, in line with unaltered Cebpa expression levels in these cells (Fig. 2f; Supplemental Fig. 2f; 1.03 ± 0.14 vs. 1.0 ± 0.04 (relative expression) in Cebpafl/p30 and Cebpafl/+ cells n = 2–3/group, respectively). This evidence concerns the gene TET2 and acute myeloid leukemia.