In UPN8, SMARCC2, UBR4, and ZNF143 mutations as well as JAK2 and TP53 mutations were identified at the ET phase, while SMARCC2, UBR4, ZNF143, and TP53, but not JAK2, -mutated clones proliferated at transformation to AML. This evidence concerns the gene UBR4 and acute myeloid leukemia.