A Wilms Tumor 1 (WT1) Mutation Causes Myelodysplastic Syndrome in a Knock-in Mouse Model, and a Mixed Myelodysplastic/Myeloproliferative Neoplam in Double Knock-in Mice with WT1 and FLT3/ITD Mutations

Background: WT1 is a zinc finger transcriptional regulator and acts as a tumor suppressor gene in various cell types. WT1 mutations are reported in approximately 10% of both adult and pediatric patients with acute myeloid leukemia (AML), and at a lower frequency in patients with myelodysplastic syndome (MDS). Reported mutations consist of insertions, deletions or point mutations, and are thought to alter WT1 DNA-binding ability and result in a loss of function. WT1 mutations are associated with FLT3/ITD mutations in AML, suggesting possible leukemogenic cooperativity, and yet WT1 mutations have been independently associated with treatment failure and a poor prognosis. Recently, a physical interaction demonstrated between WT1 and TET2 suggests a common functional pathway, and explains the mutual exclusivity of these mutations in AML. Despite these observations, the functional contribution of WT1 mutations in hematologic malignancies is not entirely understood. To our knowledge, we are the first to describe here a hematologic phenotype in a WT1 mutant mouse model and in a novel WT1 mutant x FLT3/ITD crossbred mouse model.