Makishima et al. identified two classes of mutated genes by sequencing MDS and secondary AML samples: type 1 enriched in secondary AML compared with high-risk MDS (FLT3, PTPN11, WT1, IDH1, NPM1, IDH2, and NRAS) and type 2 enriched in high-risk compared with low-risk MDS (TP53, GATA2, KRAS, RUNX1, STAG2, ASXL1, ZRSR2, and TET2) [102]. The gene discussed is TET2; the disease is acute myeloid leukemia.